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    INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY

    WORLD HEALTH ORGANIZATION





    SAFETY EVALUATION OF CERTAIN FOOD
    ADDITIVES AND CONTAMINANTS



    WHO FOOD ADDITIVES SERIES: 44





    Prepared by the Fifty-third meeting of the Joint FAO/WHO
    Expert Committee on Food Additives (JECFA)





    World Health Organization, Geneva, 2000
    IPCS - International Programme on Chemical Safety


    ZEARALENONE

    First draft prepared by G.S. Eriksen1, J. Pennington2 & J.
    Schlatter3 with contributions from J. Alexander4 & A. Thuvander5

    1 Swedish University of Agricultural Sciences, Uppsala, Sweden; 2
    National Institute of Health, Bethesda, United States; 3 Swiss
    Federal Office of Public Health, Zrich, Switzerland; 4 National
    Institute of Public Health, Oslo, Norway; and 5 National Food
    Administration, Uppsala, Sweden

    Explanation
    Biological data
         Biochemical aspects
              Absorption, distribution, and excretion
              Biotransformation
              Effects on enzymes and other biochemical parameters
         Toxicological studies
              Acute toxicity
              Short-term studies of toxicity
              Long-term studies of toxicity and carcinogenicity
              Genotoxicity
              Reproductive toxicity
              Developmental toxicity
              Special studies
                   Hormonal effects
                   Immune responses
                   Macromolecular binding
                   Genotoxicity of metabolites
         Observations in humans
    Occurrence and intake
         Incidence and concentration of contamination
         Variables that affect contamination
              Weather and climate
              Agricultural production methods
              Varieties and cultivars
              Storage conditions
              Gamma irradiation
              Grain preservatives and disinfectants
              Food processing, preparation, and cooking
              Residues in animal tissues
         Regulation, control, and monitoring
         Dietary intake
              Estimates for Canada, 1987
              Estimates for Canada, 1999
              Estimates for Denmark, Finland, Norway, and Sweden
              Estimates for the United States, 'eaters only'
              Estimates for the United States, all persons
              Limitations of estimates
              Models of dietary intake
    Comments
    Evaluation
    References

    1.  EXPLANATION

         Zearalenone is a non-steroidal estrogenic mycotoxin produced by
    several  Fusarium spp. It has been implicated in numerous
    mycotoxicoses in farm animals, especially in pigs. Zearalenone is
    heat-stable and is found worldwide in a number of cereal crops, such
    as maize, barley, oats, wheat, rice, and sorghum (Kuiper-Goodman et
    al., 1987; Tanaka et al., 1988a) and also in bread (Aziz et al.,
    1997). Zearalenone was shown to be produced on corn by  Fusarium
    isolates from Australia, Europe, and North America (Vesonder et al.,
    1991) and in New Zealand (diMenna et al., 1997), the Philippines,
    Thailand, and Indonesia (Yamashita et al., 1995). The occurrence of
    zearalenone in food and feed was also demonstrated in South America
    (Dalcero et al., 1997; Molto et al., 1997), Africa (Doko et al.,
    1996), China and the former USSR (Ueno et al., 1986).  Fusarium
    isolates from bananas can also produce zearalenone (Jimnez et al.,
    1997).

         Zearalenone has not been evaluated previously by the Committee,
    although a mammalian metabolite, alpha-zeralanol (zeranol), was
    considered by the Committee at its twenty-sixth, twenty-seventh, and
    thirty-second meetings (Annex 1, references  59,  62, and  80) for
    use as a veterinary drug. The Committee allocated an ADI of 0-5 g/kg
    bw at the last meeting.

         The chemical structures of zearalenone and some of its
    metabolites are shown in Figure 1.

         The concentrations in food and feed vary over a wide range,
    depending on climatic conditions. Zearalenone was found in 11-80% of
    samples of wheat and 7-68% samples of barley for feed use collected
    randomly in south-west Germany in 1987 and 1989-93, with mean yearly
    contents of 3-180 g/kg in wheat (highest value, 8000 g/kg) and 3-36
    g/kg in barley (highest value, 310 g/kg) (Mller et al., 1997a,b).
    Wheat for human consumption was collected from all regions of Bulgaria
    (140 samples) after harvest in 1995, a year characterized by heavy
    rainfall in spring and summer. The frequency of contamination with
    zearalenone was 69%, with an average concentration in positive samples
    of 17 g/kg and a maximum of 120 g/kg (Vrabcheva et al., 1996).
    Zearalenone was found in 30% of 2271 maize samples collected in Buenos
    Aires and Santa Fe provinces of Argentina in 1983-94, at an average
    concentration of 165 g/kg (yearly variation, 46-300 g/kg) and a
    maximum of 2000 g/kg (Resnik et al., 1996). The concentrations in rye
    and wheat produced by alternative or ecological methods were higher
    than those in crops grown conventionally. Zearalenone was found in 40
    out of 201 grain samples, with average concentrations of 24 g/kg in
    wheat and 51 g/kg in rye in alternatively produced crops and 6 g/kg
    in wheat and 4 g/kg in rye in conventionally produced samples. The
    highest concentration of zearalenone was 199 g/kg, found in
    alternatively grown rye (Marx et al., 1995).

         Zearalenone can be excreted into milk after lactating cows are
    fed it in high doses. The maximum concentrations in the milk of one
    cow given an oral dose of 6000 mg zearalenone (equivalent to 12 mg/kg
    bw), 6.1 g/L zearalenone, 4 g/L alpha-zearalenol, and 6.6 g/L
    beta-zearalenol were found. Neither zearalenone nor its metabolites
    were found in the milk (< 0.5 g/L) of three lactating cows fed 50 or
    165 mg zearalenone (equivalent to 0.1 and 0.33 mg/kg bw) for 21 days
    (Prelusky et al., 1990). Zearalenone may be transmitted from
    contaminated grains into beer at various stages of the brewing
    process. Although high incidences (up to 58%) and high concentrations
    of zearalenone have been found in beers brewed locally in Africa
    (Nigeria, < 2 mg/L; Swaziland, < 53 mg/L; Zambia, < 4.6
    mg/L), zearalenone and alpha-or beta-zearalenol have not been found in
    Canadian, European, or Korean beers with the exception of one French
    beer, which contained 100 g/L (Okoye, 1987; Scott, 1996; Shim et al.,
    1997).

         A detailed review of 339 publications on zearalenone, including
    physico-chemical data, isolation and purification, analytical methods,
    mycology, laboratory and natural production, occurrence and stability
    in foods and feeds, and toxicity is available (Kuiper-Goodman et al.,
    (1987). The present monograph therefore covers only literature
    published since 1986, with the inclusion of older publications when
    they were considered highly relevant for the evaluation or when no
    newer data were found.

    2.  BIOLOGICAL DATA

    2.1  Biochemical aspects

    2.1.1  Absorption, distribution, and excretion

         Most investigations of the distribution of zearalenone have
    focused on tissue residues and metabolism rather than on
    pharmacokinetics, and few data are available on kinetic parameters
    such as absorption and biological half-life.

         Both intestinal mucosa and gut microflora from pigs metabolize
    zearalenone to alpha-zearalenol and to the glucuronides of both
    compounds (Olsen et al., 1987; Kollarczik et al., 1994). Healthy human
    intestinal microflora cultured in a continous flow system were unable
    to degrade zearalenone (Akiyama et al., 1997).

         Zearalenone is rapidly absorbed after oral administration.
    Although the degree of absorption is difficult to measure owing to
    extensive biliary excretion, it appears to be extensively absorbed in
    rats, rabbits, and humans (reviewed by Kuiper-Goodman et al., 1987).
    The uptake in a pig after a single oral dose of 10 mg/kg bw was
    estimated to be 80-85% (Biehl et al., 1993).

         When zearalenone dissolved in an isotonic solution was perfused
    into the small intestine of rats, the concentration decreased rapidly,
    only 4.5% remaining in the small intestine 20 min after injection. The
    disappearance of zearalenone from the small intestine followed
    first-order kinetics, with an average absorption rate constant of 9.3
    per h (Ramos et al., 1996). Zearalenone and its metabolites were found
    in the plasma of a pig < 30 min after the beginning of feeding
    (Kuiper-Goodman et al., 1987; Olsen et al., 1991; Biehl et al., 1993).
    Studies with radiolabelled zearalenone in mice showed that it is
    distributed to estrogen target tissues such as the uterus,
    interstitial cells of the testes, and ovarian follicles. Some
    radiolabel was also found in adipose tissues, indicating that storage
    in fat may take place (Kuiper-Goodman et al., 1987).

         Zearalenone and its metabolites are excreted mainly in the bile
    in most animal species except rabbits, in which urine is the main
    route. Most of an administered dose is excreted within 72 h
    (Kuiper-Goodman et al., 1987). The biological half-life of total
    radiolabel in immature pigs given a single intravenous dose of 5 mg/kg
    bw or a single oral dose of 10 mg/kg bw of radiolabelled zearalenone
    was estimated to be 87 h. When the bile was removed through a cannula,
    the half-life was reduced to 3.3 h. The authors attributed this
    difference to enterohepatic cycling of zearalenone in intact pigs. In
    pigs from which bile had been removed, about 46% of the total
    radiolabel was recovered in the bile, which was a significantly higher
    percentage than that recovered in the faeces of intact pigs treated
    intravenously (6.6%) or orally (22%;  p < 0.05). The concentration
    of radiolabel in plasma declined in a multiphasic manner in intact
    animals. In pigs exposed intravenously or orally, an initial
    absorption and distribution phase was followed by a reduced plasma
    concentration, a second maximal concentration, and an extended
    elimination phase. No secondary peak or extended elimination phase was
    observed in animals from which bile had been removed. In the pigs
    dosed orally, 45% of the administered dose was recovered in the urine
    during the first 48 h, 22% was recovered in the faeces, and the total
    accumulated recovery in urine and faeces after 48 h was 67% (Biehl et
    al., 1993).

         No effect of dose was found on the routes of excretion of
    zearalenone in Sprague-Dawley rats after a single oral dose of 1 or
    100 mg/kg bw (Fitzpatrick et al., 1988).

         The concentrations of zearalenone, alpha-zearalenol, and
    beta-zearalenol in the urine of a male volunteer 6, 12, and 24 h after
    a single oral dose of 100 mg zearalenone were 3.7 and 3 g/ml and not
    detected after 6 h; 6.9, 6, and 2.7 g/ml after 12 h; and 2.7, 4 and 2
    g/ml after 24 h. As the total recovery of zearalenone in faeces was
    not reported, the study gives no information on the relative
    importance of different routes of excretion in humans (Mirocha et al.,
    1981).

    FIGURE 8;V44je194.BMP

         In a study with the closely related compound alpha-zearalanol,
    the peak fraction of the dose appearing in human plasma was several
    times higher than in female rats, rabbits, dogs, and monkeys.
    alpha-Zearalanol disappeared much more slowly from the blood of humans
    and rabbits, the two species that excreted the compound mainly in
    urine, than from that of the other species studied (Midgalof et al.,
    1983).

    2.1.2  Biotransformation

         The main metabolites of zearalenone are alpha-and beta-zearalenol
    and the glucuronide conjugates of both the parent compound and its
    metabolites. In rat liver homogenate, rat microsomes, and rat
    hepatocytes  in vitro and in rats  in vivo after oral exposure, most
    of an administered dose of zearalenone is found as free zearalenone or
    its glucoronide conjugate, and only small amounts of the zearalenols
    and their conjugates are formed. Rat whole blood and erythrocytes can
    metabolize zearalenone to alpha-zearalenol (Kuiper-Goodman et al.,
    1987).

         In gilts given zearalenone in feed, the concentrations of
    alpha-zearalenol in plasma exceeded those of zearalenone in some
    studies, while the concentra-tions of the parent compound exceeded
    those of alpha-zearalenol in others (Bauer et al., 1987;
    Kuiper-Goodman et al., 1987). In some studies, all of the zearalenone
    detected in pigs was in the form of conjugated metabolites, while free
    zearalenone was also found in others. A significant fraction of the
    zearealenone in the urine of rabbits and pigs is in the form of
    alpha-zearalenol or its glucuronide conjugate (Kuiper-Goodman et al.,
    1987; Biehl et al., 1993).

         In a comparative study of the metabolism of zearalenone,
    significant differences between species were found in the metabolic
    profile in urine and faeces. A higher proportion of the administered
    zearalenone was metabolized to alpha-zearalenol in pigs than in rats
    or cows. In both humans and pigs, zearalenone was found mainly as
    glucoronide conjugates of zearalenone and alpha-zearalenol in urine.
    All of the metabolites found in humans during the 24 h of sampling
    were glucuronides (Mirocha et al., 1981).

         The metabolic profile of zearalenone in Sprague-Dawley rats was
    similar after a single oral dose of 1 or 100 mg/kg bw (Fitzpatrick et
    al., 1988).

         Further reduction of the C11-C12 double-bond leading to alpha-and
    -zearalanol was demonstrated in sheep in vivo in a study in which gas
    chromatography with mass spectrometry was used to determine
    zearalenone and its metabolites. The authors suggested that the
    failure to detect zearalanols in other species may be due to the use
    of high-performance liquid chromatography with fluorescence detection
    in those studies, as that method is much less sensitivity for
    zearalanols than for the fluorescent zearalenols, reduction of the
    C11-C12 double-bond leading to loss of fluorescence (Miles et al.,
    1996).

         Formation of alpha-zearalanol in bile  in vivo has been
    demonstrated by gas chromatography with mass spectrometry in cattle
    given 10 mg of either zearalenone or alpha-zearalenol by gavage
    (Kennedy et al., 1998).

    2.1.3  Effects on enzymes and other biochemical parameters

         Groups of 10 female Wistar rats and 20 controls received a single
    intraperitoneal injection of zearalenone dissolved in sterile olive
    oil at 0, 1.5, 3, or 5 mg/kg bw. The haematological parameters studied
    48 h later that differed in treated and control groups were a lower
    number of platelets and higher haematocrit and mean corpuscular volume
    in treated animals; the leukocyte and haemoglobin counts were higher
    in the groups given the two higher doses than in controls. The other
    parameters studied--erythrocyte count, mean erythrocyte haemoglobin
    concentration and mean haemoglobin--were not affected. The
    concentration of creatinine in serum decreased, whereas the total and
    conjugated bilirubin concentrations and alanine aminotransferase,
    aspartate aminotransferase, and alkaline phosphatase activities were
    all increased over control values. The authors concluded that the
    observed changes indicated hepatic toxicity and and probably
    impairment of blood coagulation processes (Maaroufi et al., 1996).

    2.2  Toxicological studies

    2.2.1  Acute toxicity

         The results of studies of acute toxicity with zearalenone are
    summarized in Table 1. When young female pigs were given single doses
    of zearalenone orally in gelatine capsules at 0, 3.5, 7.5, or 11.5
    mg/kg bw, vulva vaginitis and enlarged reproductive tracts were
    observed in all animals one week after dosing (Farnworth & Trenholm,
    1981).

    2.2.2  Short-term studies of toxicity

         Mice

         Groups of 10 B6C3F1 mice of each sex were fed diets containing
    zearalenone at 0, 30, 100, 300, 1000, or 3000 mg/kg of diet,
    equivalent to 0, 4.5, 15, 45, 150, or 450 mg/kg bw per day, for 13
    weeks. Two of the female mice fed 3000 mg/kg of diet died. The weight
    gain of male mice receiving doses of > 300 mg/kg of diet was
    depressed by 14% or more. Atrophy of the seminal vesicles and testes
    and cytoplasmic vacuolization of the adrenals were found in males fed
    1000 or 3000 mg/kg of diet, and squamous metaplasia of the prostate
    was observed in males fed 3000 mg/kg. Endometrial hyperplasia of the
    uterus was seen in all groups of treated females, but the incidence
    was not dose-related. Osteoporosis was observed in animals of each sex
    fed doses of > 100 mg/kg of diet, and myelofibrosis of the bone
    marrow was seen in mice fed > 300 mg/kg of diet (National
    Toxicology Program, 1982).

         Diets containing zearalenone at 0 or 10 mg/kg (equivalent to 0 or
    1.5 mg/kg bw per day) were fed to weanling female B6C3F1 mice (26
    control and 8 exposed animals) for eight weeks, resulting in a total
    intake of 2.2 mg/animal in the treated group. No differences between
    treated animals and controls were seen in body-weight gain or feed
    intake. Gross and histopathological evaluation of the thymus, spleen,
    liver, kidney, uterus, small intestine, colon, heart, brain, lungs,
    and bone marrow showed no alterations due to zearalenone, and the
    organ weights of treated and control animals were similar.
    Haematological examination revealed a statistically significant
    increase (p < 0.01) in the number of erythrocytes in treated animals,
    while other parameters were unchanged (Forsell et al., 1986).

         In a study of the detoxification of zearalenone with
    cholestyramine, groups of 12 female ICR mice, 15 days old and caged
    four by four, were given diets containing zearalenone at 0 or 6 mg/kg,
    equivalent to 0 or 0.9 mg/kg bw per day. After five days, the relative
    weight of the uterus was higher in treated mice (p < 0.01) than in
    controls (Underhill et al., 1995).

         Rats

         Groups of 9 or 10 Fischer 344/N rats of each sex were fed diets
    containing 0, 30, 100, 300, 1000, or 3000 mg/kg zearalenone,
    equivalent to 0, 3, 10, 30, 100, or 300 mg/kg bw per day, for 13
    weeks. No treatment-related deaths occurred. Weight gain was depressed
    by more than 17% in rats of each sex receiving doses > 100 mg/kg in
    the feed. Atrophy of the seminal vesicles and fibromuscular
    hyperplasia of the prostate were observed in rats fed 1000 or 3000
    mg/kg zearalenone, and ductular hyperplasia of the mammary gland was
    observed in animals of each sex at the highest dose. Endometrial
    hyperplasia of the uterus was seen in rats fed > 100 mg/kg of diet.
    Hyperplasia of the pituitary was seen in both males and females at the
    two higher doses and in 1/10 females fed 100 mg/kg of diet.
    Osteoporosis was observed in males at the two highest doses and in all
    treated females (National Toxicology Program, 1982).

         Rabbits

         Groups of six four-month-old rabbits were given zearalenone in
    the diet at concentrations of 0, 0.5, or 1 mg/kg of feed, equivalent
    to 0, 0.15, or 0.03 mg/kg bw per day, and groups of six
    eight-month-old animals were given 0, 1, or 4 mg/kg of feed,
    equivalent to 0, 0.03, or 0.12 mg/kg bw per day, for 18 days. Some of
    the treated animals died during the study. Histopathological
    alterations due to zearalenone were observed in the liver, kidney,
    lungs, heart, adrenal glands, spleen, and uterus of the
    eight-month-old but not the four-month-old animals. The
    histopathological alterations were not described quantitatively, and
    the number of rabbits surviving to the end of the study was not
    reported. The four-month-old rabbits showed a treatment-related
    increase in body-weight gain, food and water consumption, haemoglobin
    percentage, packed cell volume, and serum concentrations of calcium,

    phosphorus, and vitamin C, but the eight-month-old animals showed
    treatment-related decreases in these parameters. No explanation was
    given for the differences in observed effects (Abdelhamid et al.,
    1992).

        Table 1. Results of studies of the acute toxicity of zearalenone
                                                                           

    Species      Sex     Route             LD50         Reference
                                           (mg/kg bw)
                                                                           

    Mouse        M/F     Oral              > 2 000      National Toxicology
                                                        Program (1982)
    Mouse        F       Oral              > 20 000     Hidy et al. (1977)
    Mouse        F       Intraperitoneal   > 500        Hidy et al. (1977)
    Rat          M/F     Oral              > 4 000      National Toxicology
                                                        Program (1982)
    Rat          M/F     Oral              > 10 000     Hidy et al. (1977)
    Rat          M       Intraperitoneal     5 500      Hidy et al. (1977)
    Guinea-pig   F       Oral              > 5 000      Hidy et al. (1977)
    Guinea-pig   F       Intraperitoneal     2 500      Hidy et al. (1977)
                                                                           

    M, male; F, female
    
         Pigs

         Two female pigs were fed diets containing zearalenone at 0.25
    mg/kg of diet, equivalent to 10 g/kg bw per day, for 11 days and then
    feed without zearalenone for 5 days, and two other female pigs were
    fed diets containing zearalenone at 0.05 mg/kg of diet, equivalent to
    2 g/kg bw per day, for 21 days; one pig was used as a control.
    Treatment with 10 g/kg bw per day resulted in redness and swelling of
    the vulva, swelling of the mammary glands, and numerous vesicular
    follicles and some cystic follicles on the ovaries. With the low dose,
    no external changes were seen at the end of the experimental period,
    but autopsy showed a greater number of vesicular follicles on the
    ovaries in treated than in control animals (Bauer et al., 1987). The
    Committee noted that the small number of animals used rendered this
    study unsuitable for evaluating the toxicity of zearalenone.

         Groups of 10 Yorkshire gilts of an average age of 70 days were
    given diets containing zearalenone at a concentration of 2 mg/kg of
    diet (equivalent to 0.08 mg/kg bw per day) for the first two weeks and
    then 1.5 mg/kg of diet (equivalent to 0.06 mg/kg bw per day) for the
    remainder of two identical studies for 0 (control), 45, or 90 days.

    The feed was naturally infected, and no information was provided on
    the presence of other mycotoxins. Vulvar swelling and reddening were
    seen within seven days of exposure, but no difference was seen between
    treated and control animals in body weight or depth of back fat
    (Rainey et al., 1990).

         Zearalenone mycotoxicosis in suckling piglets of each sex,
    characterized by oedematous swelling and reddening of the vulva and
    sometimes associated with reddening and/or necrosis of the tail, was
    described in a case report. No signs of hyperestrogenism were seen in
    sows given feed contaminated with zearalenone at 3-24 mg/kg,
    equivalent to 0.1-1 mg/kg bw per day. Clinical signs usually appeared
    in the prenatally exposed piglets two to three days after birth but
    were apparent at birth in a few animals. The authors noted the poor
    hygienic conditions of the breeding unit (Dacasto et al., 1995).

         Six-week-old female pigs given  Fusarium culmorum extracts
    containing 80 mg/kg of zearalenone (equivalent to 3.2 mg/kg bw per
    day) and 5 mg/kg of deoxynivalenol (experimental details not reported)
    showed pathological alterations in the reproductive tract (Palyusik et
    al., 1990), but the lack of details and multiple exposures made this
    study unsuitable for evaluating the toxicity of zearalenone.

         Ruminants

         Seventy-one dairy cows and 25 replacement heifers were
    accidentally given feed contaminated with 1.5 mg/kg of zearalenone and
    1 mg/kg of deoxy-nivalenol for approximately 90 days. The daily feed
    rations were 7-10 kg for the cows and 1-2 kg for the heifers. Episodes
    of estrus were seen in most of the animals, starting about one week
    after the onset of exposure. Mammary development occurred in the
    prepubertal heifers, which were subsequently culled from the herd
    because of sterility (Coppock et al., 1990). The Committee considered
    this study to be of little value as it was not controlled, the dose
    received per body weight is not clear, and there was exposure to
    multiple mycotoxins.

    2.2.3  Long-term studies of toxicity and carcinogenicity

         Mice

         Groups of 50 male and 50 female B6C3F1 mice, seven weeks old,
    were fed diets containing zearalenone (purity, > 99%) at a
    concentration of 0, 50, or 100 mg/kg of diet (maximum tolerated dose)
    for 103 weeks. The average daily feed consumption as a percentage of
    that of controls was 99% for males at the low dose, 97% for males at
    the high dose, and 97% for females at both doses. The daily intake of
    zearalenone was approximately 0, 8, and 17 mg/kg bw for males and 0,
    9, and 18 mg/kg bw for females. No significant difference in survival
    was seen between groups, and 64-88% of the mice survived to
    termination of the study. No dose-related changes in body-weight gain
    were seen. No treatment-related non-neoplastic lesions were found in
    male mice, but females had estrogen-related effects in several

    tissues, including fibrosis in the uterus and cystic ducts in mammary
    glands, and myelofibrosis in the bone marrow. Hepatocellular adenomas
    were found in 4/50 male controls, 3/50 at the low dose, and 7/49 at
    the high dose and in 0/50 female controls, 2/49 at the low dose, and
    7/49 at the high dose, the last of which was statistically
    significantly different ( p < 0.006) from the incidence in the
    control group. The incidence of hepatocellular adenomas in untreated,
    historical control female B6C3F1 mice was 14/498. Statistically
    significant trends in the incidence of pituitary adenomas were
    observed for both males (control, 0/40; low dose, 4/45; high dose
    6/44;  p < 0.022) and females (control, 3/46; low dose, 2/43; high
    dose, 13/42;  p < 0.001), and the increased incidence was
    statistically significant in males ( p < 0.032) and females
    ( p < 0.003) at the high dose. Pituitary carcinomas were found in
    one male at the low dose and in two females at the high dose, but the
    incidence of pituitary carcinomas was not statistically significantly
    different in treated and control animals. The incidence of pituitary
    adenomas and carcinomas in untreated historical controls at the
    institute that conducted the study was 21/428 in females and 0/399 in
    males (National Toxicology Program, 1982).

         Rats

         Groups of 90 FDRL Wistar rats of each sex and 140 rats of each
    sex in the control group were fed diets containing zearalenone at
    doses of 0, 0.1, 1, or 3 mg/kg bw per day from approximately 28 days
    of age for 104 weeks. In order to maintain the appropriate daily
    doses, the concentration of zearalenone in the diet was adjusted
    weekly according to the body weights and food consumption measured in
    the previous week. The rats were derived from F0 parents fed
    equivalent concentrations for five weeks before mating and throughout
    mating and gestation, but not during lactation. Zearalenone had no
    effect on reproductive parameters in the parent generation, but
    treated males of the F1 generation had a transient but significant
    decrease in body-weight gain when compared with controls, although
    this effect was not seen at the end of the study. No statistically
    significant differences were seen among groups with respect to
    haematological, clinical chemical, or urinary parameters measured in
    10 animals per group sampled at weeks 13, 26, 65, and 104 or in the
    remaining animals killed at weeks 108 (males) and 111 (females) after
    the initiation of treatment. At the end of the study, significantly
    increased liver weights were found in males and females exposed to 3
    mg/kg bw, and the uterine weights were increased in females at the two
    higher doses. Rats receiving the highest dose showed increased
    trabeculation of the femur, but no histopathological changes were seen
    and no treatment-related tumours were found (Becci et al., 1982a). The
    Committee noted that survival rates and tumour incidences were not
    reported.

         Groups of 50 male and 50 female Fischer 344 rats, five weeks old,
    were fed diets containing zearalenone (purity, > 99%) at 0, 25, or 50
    mg/kg of diet (maximum tolerated dose) for 103 weeks. The average

    daily feed consumption as a percentage of that of the controls was
    102% for males at the low dose, 91% for males at the high dose, 96%
    for females at the low dose, and 98% for females at the high dose. The
    intake was estimated to be 1 mg/kg bw per day at the low dose and
    about 2 mg/kg bw per day at the high dose. The mean body-weight gain
    of treated rats was lower than that of controls, and the decreases of
    19% in males and 11% in females at the high dose after 44 weeks of
    exposure were dose-related. No significant difference in survival was
    observed between groups, and 74-82% of the rats survived to
    termination of the study. The non-neoplastic lesions observed were
    inflammation of the prostate gland, testicular atrophy, cysts or
    cystic ducts in mammary glands of males, an increased incidence of
    hepatocellular cytoplasmic vacuolization in males, and an increased
    incidence of chronic progressive nephropathy in animals of each sex.
    Increased incidences of retinopathy and cataracts were observed in
    males at both doses and in females at the low dose. No
    treatment-related increase in tumour incidence was found. Male rats at
    the low dose showed a significant ( p < 0.05) increase in the
    incidence of pituitary adenomas but with no significant dose-related
    trend. The combined incidence of pituitary adenomas and carcinomas
    showed no indication of treatment-related change (National Toxicology
    Program, 1982).

         A working group convened by the International Agency for Research
    on Cancer (IARC) in 1993 concluded on the basis of the three studies
    described above that there was limited evidence for the
    carcinogenicity of zearalenone in experimental animals (IARC, 1993).

    2.2.4  Genotoxicity

         The results of studies of the genotoxicity of zearalenone are
    summarized in Table 2.

    2.2.5  Reproductive toxicity

         Mice

         Newborn female C57BL/Crgl mice were injected subcutaneously with
    1 g of zearalenone daily for five days. Eight months after treatment,
    25 of 34 treated mice and 3 of 33 control mice had no corpora lutea.
    Treated mice also had dense collagen deposition in the uterine stroma,
    56% of animals had no uterine glands, and 59% had squamous metaplasia
    (Williams, B.A. et al., 1989).

         Intraperitonal injection of 10-30 g zearalenone to groups of
    four to nine female ICR mice on days 1-3 or 1-5 after birth resulted
    in delayed vaginal opening, persistent estrus in 60-80% of animals,
    and sterility accompanied by thickening of the vaginal epithelium at
    eight weeks of age. Vaginal opening was accelerated in animals given a
    single dose of 30 g on day 10 but was not affected in mice given the

    same dose on day 1, 3, 5, or 8. The incidence of persistent estrus was
    significantly increased in eight-week-old mice treated with
    zearalenone on day 1, 3, or 5 but not in those treated on day 8 or 10
    (Ito & Ohtsubo, 1994).

         Rats

         FDRL Wistar rats were given zearalenone at daily doses of 0, 0.1,
    1, or 10 mg/kg bw in the diet. After four weeks of exposure, the F0
    generation was bred to produce the F1a generation, and at sexual
    maturity the F1a generation was bred to give the F2a generation.
    The F0 and F1a generations were given zearalenone throughout
    mating and gestation but not during lactation. Zearalenone reduced the
    number of liveborn F1 pups per litter only at the highest dose while
    the doses of 1 and 10 mg/kg bw per day reduced the number of liveborn
    F2 pups per litter. Fertility was significantly decreased at the
    highest dose in both the F1 and F2 generations. Feeding
    zearalenone had no effect on the rate of survival of liveborn pups to
    4 or 21 days of age (Becci et al., 1982b).

         Guinea-pigs

         In three experiments, groups of three or four pregnant
    Murphy-Hartley guinea-pigs received diets containing zearalenone at 0,
    7, 14, or 21 mg/kg bw per day on days 1-8 after mating (experiment 1),
    0, 20, or 30 mg/kg bw per day on days 1-3, 4-5, or 6-8 after mating
    (experiment 2), and 0, 60, or 90 mg/kg bw per day on days 4-5 after
    mating (experiment 3). Blood samples were analysed for progesterone on
    days 8, 15, and 21 in experiment 1 and on days 15 and 21 in the other
    two experiments. All animals were killed with carbon monoxide on day
    22 after mating and the numbers of corpora lutea and fetuses and fetal
    length were determined. Histopathological examinations were made of
    the ovary, both uterine horns, placenta, and fetuses from all pregnant
    females. Only one of four animals receiving 21 mg/kg bw on days 1-8
    after mating became pregnant 21 days after mating, while other animals
    treated on those days became pregnant. No effect was seen on any
    maternal parameters or on fetal development after exposure to 7 or 14
    mg/kg bw per day on day 1-8 after mating. Three of five guinea-pigs
    treated with zearalenone at 20 mg/kg bw per day and one of four given
    30 mg/kg bw per day on days 1-3 after mating were found to be pregnant
    on day 22. Female guinea pigs given 20 or 30 mg/kg bw per day on days
    4-5 or 6-8 after mating and females treated with 60 or 90 mg/kg bw on
    days 4-5 had normal pregnancies, and all of the observed differences
    in progesterone concentrations between groups could be related to the
    pregnancy of the animals (Long & Diekman, 1989).

         Hamsters

         Groups of six litters of neonatal golden Syrian hamsters received
    zearale-none by subcutaneous injection at 0 (vehicle only) or 1 mg/pup
    at two days of age, and one group was untreated. Vaginal opening was
    accelerated in treated females, but administration of zearalenone did
    not affect the age at first estrus or cycling in the females or the
    mounting behaviour of males at 60-64 days of age. At 150 days of age,
    the females were ovariectomized and a 25-mg pellet of testosterone was
    implanted under the skin. At day 195, 67% of the exposed female
    hamsters and only one of 30 control females mounted a sexually
    receptive female. The mounting behaviour of the males was not affected
    by zearalenone on days 225 and 280. The authors concluded that the
    behaviour of females treated with zearalenone was masculinized but not
    defeminized (Gray et al., 1985).

         Pigs

         Groups of 10 Yorkshire gilts of an average age of 70 days were
    given diets containing zearalenone at a concentration of 2 mg/kg of
    diet (equivalent to 0.08 mg/kg bw per day) for the first two weeks and
    then 1.5 mg/kg (equivalent to 0.06 mg/kg bw per day) for the remainder
    of two identical studies for 0 (control), 45, or 90 days. The feed was
    naturally infected, and no information was provided on the presence of
    other mycotoxins. Gilts treated with zearalenone reached puberty at a
    younger age than controls, but the conception rates, ovulation rates,
    and embryonic survival were not affected (Rainey et al., 1990).

         Groups of six to eight prepubertal gilts of an average age of 178
    days and weighing 94 kg were fed diets containing zearalenone at 0 or
    10 mg/kg of diet, equal to 0.26 mg/kg bw per day, for two weeks in
    three replicate experiments. Two weeks after withdrawal of the
    zearalenone-containing diet, the gilts were exposed to boars for 15
    min/day for three weeks. Blood samples were collected every 20 min for
    4 h one week after the start of exposure and one week after withdrawal
    of zearalenone. Blood samples were also taken twice a week and
    analysed for progesterone to establish the age at puberty: no
    difference was found between control and exposed animals. The mean
    serum concentration of luteinizing hormone was reduced during exposure
    to zearalenone, but no significant difference in serum concentrations
    remained one week after the end of the exposure period. Zearalenone
    did not change the frequency or amplitude of spikes of luteinizing



        Table 2. Results of assays for genotoxicity with zearalenone
                                                                                                                                     

    Test system              Test object                          Concentration      Results               Reference
                                                                                                                                     

    Reverse mutation         S. typhimurium TA1535,               100 g/platea      Negative              Kuczuk et al. (1978)
                             TA1537, TA1538

    Reverse mutation         S. typhimurium TA1535, TA1537,       400 g/platea      Negative              Wehner et al. (1978)
                             TA98, TA100

    Reverse mutation         S. typhimurium TA1538, TA98,         50 g/platea       Negativeb             Bartholomew & Ryan 
                             TA100                                                                         (1980)

    Reverse mutation         S. typhimurium TA98, TA100           Not reporteda      Negative              Stark (1980)

    Reverse mutation         S. typhimurium TA1535, TA1537,       50 g/platea       Negativeb             Ingerowski et al. 
                             TA1538, TA98, TA100                                                           (1981)

    Reverse mutation         S. typhimurium (strains not          1000 g/platea     Negative              Tennant et al. 
                             reported)                                                                     (1987)

    Reverse mutation         S. typhimurium TA1535, TA1537,       1000 g/platea     Negative              Mortelmans et al. 
                             TA98, TA100 (preincubation)                                                   (1986)

    Gene mutation            S. typhimurium TA1535/pSK100          29.5 g/L         Negative              Kasamaki & Urasawa 
                             umu mutation                                                                  (1993)

    SOS repair               E. coli C600                         478 mg/L           Positivec             Ghedira-Chekir et al. 
                                                                                                           (1998)

    SOS chromotest           E. coli PQ37                         30 mg/La           Negative              Krivobok et al. (1987)

    Unscheduled DNA          Rat hepatocytes                      32 mg/L            Negative              Williams, G.M. et al. 
    repair                                                                                                 (1989)

    Point mutations/         S. cerevisiae D3                     1000 g/platea     Negative              Kuczuk et al. (1978)
    mitotic recombination

    Table 2. (continued)
                                                                                                                                     

    Test system              Test object                          Concentration      Results               Reference
                                                                                                                                     

    Forward mutation         Mouse lymphoma L5178Y                60 mg/La           Negative              McGregor et al. (1988)
                             Tk+/- cells

    Forward mutation         Mouse lymphoma L5178Y Tk+/- cells    65 mg/L            Negative              Tennant et al. (1987)

    Chromosomal aberration   Chinese hamster ovary cells          15 mg/L            Positived,e           Galloway et al. (1987)
                                                                  50 mg/L            Negativef

    Sister chromatid         Chinese hamster ovary cells          12.5 mg/L          Positived,e           Galloway et al. (1987)
    exchange                                                      40 mg/L            Positivef

    Chromosomal aberration   Human fibroblasts (HAIN55            9.5 g/L           Weakly positive       Kasamaki & Urasawa 
                             and CPAE)                                                                     (1993)

    Chromosomal aberration   Chinese hamster ovary cells          15 mg/L            Positived, negativef  Tennant et al. (1987)

    Sister chromatid         Chinese hamster ovary cells          12.5 mg/L          Positived, negativef  Tennant et al. (1987)
    exchange

    Chromosomal aberration   Chinese hamster V79 cells            32 mg/L            Negativea             Thurst et al. (1983)

    Sister chromatid         Chinese hamster V79 cells            32 mg/L            Negativea             Thurst et al. (1983)
    exchange

    Cell cycle delay         Chinese hamster V79 cells            32 mg/L            Negativea             Thurst et al. (1983)

    Table 2. (continued)
                                                                                                                                     

    Test system              Test object                          Concentration      Results               Reference
                                                                                                                                     
    Sister chromatid         Human peripheral lymphocytes         3 mg/Lg            Weakly positivea      Kuiper-Goodman et al. 
    exchange                                                                                               (1987)

    Gene mutation            B. subtilis H17, M45 rec+/-          100 g/disc        Positiveh             Ueno & Kubota (1976)
                                                                  20 g/disc         Negative
                                                                                                                                     

    a  With and without metabolic activation
    b  Cytotoxic at next highest concentration
    c  1-h preincubation with 6 mmol/L vitamin E prevented the effect.
    d  Without metabolic activation
    e  Tetraploidy and delayed cell cycle
    f  With metabolic activation
    g  Complete inhibition of DNA synthesis at 30 mg/L
    h  M45rec-, 2-3 mm and H17rec+, 0-1 mm growth inhibition at pH 6, 7, or 8 
    

    hormone secretion during exposure, and did not affect the numbers of
    corpora lutea or live fetuses or the serum concentration of
    follicle-stimulating hormone. Fetal weights were statistically
    significant greater in gilts receiving zearalenone than in controls
    (180  8.4 g in treated and 150  10 g in control animals) (Green et
    al., 1990). The Committee noted a small difference in the age of
    fetuses at examination (65  2.6 days of gestation for exposed animals
    and 63  2.8 for controls) and that use of the usual conversion factor
    for estimating dose from feed concentrations results in substantially
    higher doses because of the assumption of a body weight of 60 kg. In
    most studies in which the body weights of pigs are given, they are
    approximately 100 kg. The dose used in this study would be 0.4 mg/kg
    bw per day if the Committee's conversion factor were used.

         Prepubertal gilts were fed a diet containing zearalenone at 0 or
    10 mg/kg of diet  ad libitum (equivalent to 0.4 mg/kg bw per day,
    delivered dose not recorded) for 30 days from day 145 to day 193 of
    age; they then received control diet and were exposed to a boar for 60
    days. Vulvar swelling and reddening were observed throughout exposure
    from day 3-5, but the symptoms disappeared slowly when zearalenone was
    withdrawn. Exposed gilts had their first estrus significantly later
    than controls, but there was no significant difference in the
    proportion of animals reaching estrus within 60 days after withdrawal
    of the zearalenone-containing feed. The length of the first estrus
    cycle was not affected. In a second trial, sows were fed zearalenone
    in the diet at 0 or 10 mg/kg of diet beginning 14 days before they
    weaned their offspring and were then fed control diet and checked
    daily for their first post-weaning estrus. The interval between
    weaning and estrus was extended in sows given zearalenone, but the
    incidence of pregnancy or farrowing and the numbers of liveborn and
    dead pups per litter were not affected. No sign of hyperestrogenism
    was observed in gilts or sows (Edwards et al., 1987b).

         In sexually mature gilts given 2 kg of feed containing
    zearalenone at 0, 1, 5, or 10 mg/kg of diet (equivalent to 0, 0.04,
    0.2, and 0.4 mg/kg bw per day) on days 5-20 of estrus, the
    inter-estrus interval increased significantly from 21  0.3 days in
    the control group to 29  2.9 and 33  3.3 days in gilts fed 5 and 10
    mg/kg zearalenone in the diet. The inter-estrus interval was not
    affected in gilts given 1 mg/kg in the diet. Increased plasma
    concentrations of progesterone and prolonged maintenance of corpora
    lutea were observed in the gilts with prolonged cycles. The corpora
    lutea regressed when zearalenone was withdrawn from the diet (Edwards
    et al., 1987a).

         The frequency of pregnancy after mating was reduced in a pig
    given zearalenone at a dose of 108 mg/animal, equal to 1.1 mg/kg bw,
    in the diet daily on days 7-10 after mating, but not in a pig given
    the same dose on days 2-6 or 11-15 after mating (Long & Diekman,
    1986).

         Groups of 16 pubertal gilts given zearalenone at 0, 3, 6, or 9
    mg/kg of diet (equivalent to 0.12, 0.24, and 0.36 mg/kg bw per day)
    from immediately after the first estrus throughout gestation showed an
    increased incidence of pseudo-pregnancy, a decrease in breeding, and a
    decrease in the number of liveborn per litter at the two higher doses.
    Feeding of diets containing zearalenone to a limited (unspecified)
    number of boars from 32 days to one year of age at 0, 3, 6, or 9 mg/kg
    of diet (equivalent to 0.06, 0.12, and 0.18 mg/kg bw per day) had no
    effect on growth rate, puberty, or libido, but there was an indication
    of reduced sperm concentration and a small reduction in testicular and
    epididymal weights (Young & King, 1984). The Committee noted the lack
    of details.

         Groups of 14-16 lactating Yorkshire  Landrace cross-bred gilts
    were fed diets containing purified zearalenone at 0, 5, or 10 mg/kg of
    diet (equivalent to 0, 0.2, or 0.4 mg/kg bw per day) in two trials
    from day 7 of lactation until 40 days after the last breeding or until
    40 days after weaning if no estrus was observed. The only difference
    between the two trials was that the sows in trial 1 were first parity
    and those in trial 2 were second parity. The sows were inseminated 8
    and 30 h after observed estrus. Treatment with zearalenone did not
    alter the proportion of sows returning to estrus, but the time from
    weaning to estrus was significantly increased in trial 2, with a
    similar trend at the highest dose in trial 1. The average number of
    fetuses per pregnant sow decreased with increasing concentration of
    zearalenone in trial 2 but not in trial 1. Embryonic mortality,
    measured as the ratio of fetusus to corpora lutea in pregnant sows,
    increased in trial 2 but not in trial 1. A trend to a lower incidence
    of pregnancy was found at the end of trial 1, and there was great
    variation in feed consumption among all groups in this trial, which
    was attributed by the authors to the presence of 1.3-1.7 mg/kg
    deoxynivalenol in the diet (Young et al., 1990). The Committee noted
    that no information about Fusarium toxins other than zearalenone was
    given for trial 2.

         Groups of six mature cross-bred sows were fed diets containing
    zearalenone at 0 or 2.1 mg/kg of diet, equivalent to 0.085 mg/kg bw
    per day, from day 30 after mating throughout lactation. The piglets
    were weaned and weighed at 21 days of age, and three male and three
    female piglets from each group were kept for subsequent breeding and
    maintained on control diet. Zearalenone had no effect on breeding
    performance in the F0 generation, and no statistically significant
    differences were observed between treated and control animals with
    regard to parental body weight, litter size, number of livebirths per
    litter, piglet sex ratio, birth weight, or weaning weight.
    Furthermore, no significant differences were found in the ovarian or
    uterine weights of sows in the F0 generation, although a trend to
    ovarian atrophy and uterine enlargement was found. Sows in the control

    group had numerous large follicles on the ovaries, while the ovaries
    of the sows fed zearalenone contained only small, degenerated
    follicles. No treatment-related histopathological alterations were
    observed in the uterus or cervix of the sows. Examination of three
    female piglets on day 21 resulted in similar findings: although they
    had a slight, non-significant increase in age at first estrus, no
    difference was found in the ovarian or uterine weights of surviving
    female piglets. Male piglets had a small, non-significant reduction in
    testicular weight at 21 days of age, but with no consistent
    histopathological changes in the reproductive organs. The male
    offspring of sows given zearalenone were significantly older at first
    mount, but no differences were found in testicular weight at first
    mount, terminal body weight, or the number of successful inseminations
    of untreated sows (Yang et al., 1995).

    2.2.6  Developmental toxicity

         No teratogenic effect was found in CBA/Ca mice given single doses
    of 5-20 mg/kg bw zearalenone by gavage on day 9 of gestation (Arora et
    al., 1981, 1983). Zearalenone given at daily doses of 1-10 mg/kg bw by
    gavage to female Wistar rats on days 6-15 of gestation caused minor
    skeletal deformations, considered by the authors to be due to delayed
    ossification (Ruddick et al., 1976).

         In a two-generation study, FDRL Wistar rats were given
    zearalenone in the diet at doses of 0, 0.1, 1, or 10 mg/kg bw per day
    over both generations. After four weeks of exposure, the F0
    generation was bred to produce the F1a generations, and rats of both
    generations were given zearalenone throughout mating and gestation but
    not during lactation. One week after weaning of the F1a generation,
    the F0 generation was rebred. On day 20 of gestation, the F0
    animals were killed, and the numbers of implants, resorptions, corpora
    lutea, and viable fetuses were determined; fetuses were also examined
    for gross abnormalities, weight, and sex. In females fed 10 mg/kg bw
    per day, statistically significant reductions in the mean numbers of
    viable offspring per litter, corpora lutea per dam, and implantations
    per dam were found, with an increase in the number of resorptions per
    dam on day 20 of gestation. At the highest dose, soft-tissue
    abnormalities related to delayed fetal development were reported. At 1
    mg/kg bw, minor skeletal abnormalities were observed which were
    related to decreased growth. No unequivocal teratogenic effect was
    found (Becci et al., 1982b).

         Disruption of the development of growing blastocysts was observed
     in vitro when zearalenone was added to a medium containing growing
    mouse blastocysts or ovine oocytes (Long & Turek, 1989; Wallace &
    Rajamahendran, 1993).

         Three of four pigs given zearalenone in the diet at a dose of 110
    mg/animal per day (equivalent to 1.1 mg/kg bw per day) on days 7-10
    after mating did not become pregnant and had regressing corpora lutea,
    while all animals dosed on days 2-6 or 11-15 became pregnant (Long &
    Diekman, 1986). In mated pigs fed zearalenone at 1 mg/kg bw per day on

    days 7-10 after mating, initial degeneration of blastocysts was
    observed on day 11 and further degeneration and death on day 13
    (Diekman & Long, 1989; Long et al., 1992). Changes in the intrauterine
    environment, such as changes in the concentrations of Ca2+ or amino
    acids, were observed in pigs exposed to zearalenone at 1 mg/kg bw per
    day on days 7-10 after mating (Long et al., 1988).

         In nine New Zealand white rabbits weighing 3-4 kg which were
    given zearalenone orally at a dose of 12 mg/kg bw per day for 10 days,
    the compound was detected in uterine tubal fluid from day 1.
    Zearalenone caused an increase in the amount of intrauterine fluid,
    reduced its pH, and changed the concentrations of various amino acids
    and trace minerals. After the rabbits had been mated with untreated
    males on the last day of exposure, no gross abnormalities were found
    in fetuses examined 28-30 days after mating (Osborn et al., 1988).

         In three experiments, groups of three or four pregnant
    Murphy-Hartley guinea-pigs were given zearalenone orally at a dose of
    0, 7, or 21 mg/kg bw per day on days 1-8 after mating (experiment 1),
    0, 20, or 30 mg/kg bw per day on days 1-3, 4-5, or 6-8 after mating
    (experiment 2), and 0, 60, or 90 mg/kg bw per day on days 4-5 after
    mating (experiment 3). The incidence of pregnancy was reduced at the
    highest dose in experiment 1 and in guinea-pigs treated on days 1-3
    after mating in experiment 2, but no teratogenic effect was found
    (Long & Diekman, 1989).

         Studies of the reproductive and developmental effects of
    zearalenone after oral treatment are summarized in Table 3.

    2.2.7  Special studies

    2.2.7.1  Hormonal effects

         Several estrogenic effects of zearalenone have been observed in
    short-term and long-term studies of toxicity and in studies of
    reproductive toxicity in a number of mammalian species (see above).

          Estrogen receptor subtypes and estrogen response elements:
    Recent studies have shown that two subtypes of estrogen receptor (ER)
    exist in rats, mice, and humans, ER-alpha and ER-beta, which differ in
    the C-terminal ligand binding domain and the N-terminal
     trans-activation domain (Kuiper et al., 1998). It has also been
    shown that there are other subtypes of ER, namely the main form
    ER-beta1 and a major variant called ER-beta2 (Lu et al., 1998;
    Petersen et al., 1998). Analysis of competition for ligand binding
    revealed that ER-beta2 has an eightfold lower affinity for
    17beta-estradiol than ER-beta1 (Hanstein et al., 1999). ER-alpha and
    ER-beta are differently distributed in the body and also in cells
    within tissues such as the prostate and central nervous system
    (Shughrue et al., 1996; Brandenberger et al., 1997; Kuiper et al.,
    1997; Shughrue et al., 1997; Hrabovszky et al., 1998; Prins et al.,
    1998). In some cells, the expression of ER-beta mRNA is regulated by
    17beta-estradiol (Vladusic et al., 1998).  In vitro the two receptors

    can form heterodimeric complexes. Thus, the estrogenic signal could
    bind to an ER-alpha homodimer, an ER-beta homodimer, or a heterodimer
    complex, depending on whether the cell expresses only one or both
    receptors (Pettersson et al., 1997). ER-beta2 may also form
    heterodimers (Hanstein et al., 1999). Furthermore, some variation in
    the estrogen response element has been found in different
    estrogen-responsive genes, and the receptor subtypes vary in
    activating ability (Pennie et al., 1998).

         Studies on the estrogenicity of zearalenone and its derivatives
    up to 1987 were reviewed by Kuiper-Goodman et al. (1987), but only a
    few recent studies discriminate between the receptor subtypes.

          Binding: The binding of zearalenone to ER in target tissues and
    cells was < 1-10% that of 17beta-estradiol, whereas alpha-zearalanol
    showed somewhat stronger binding and beta-zearalanol much less binding
    (Kuiper-Goodman et al., 1987). The relative binding affinities of
    zearalenone and its derivatives to the rat uterine cytoplasmic
    receptor were in the order alpha-zearalanol > alpha-zearalenol >
    beta-zearalanol > zearalenone > beta-zearalenol (Tashiro et al.,
    1980).

          Binding and activation of ER in cells: In an immortalized
    pituitary cell line, zearalenone bound to the ER with an affinity of
    0.01 relative to 17beta-estradiol and induced prolactin excretion
    (Stahl et al., 1998).

         In a comparison of the potency of zearalenone and
    17beta-estradiol in two cell lines, MCF-7 which responds to
    physiological concentrations of 17beta-estradiol with cell division
    and protein synthesis and Le42 which are transfected with an
    estrogen-responsive element coupled to a reporter gene, the relative
    response was 2.5-5% (Mayr et al., 1992).

         The binding and activation of ER-alpha and ER-beta by zearalenone
    have been examined in cells transfected with human recombinant ERa and
    ERb complementary DNA in the presence of an estrogen-dependent
    reporter plasmid. In this model, 17beta-estradiol bound with high
    affinity, with a  Kd of 0.05-0.1 nmol/L. Zearalenone stimulated the
    transcriptional activity of both receptors at concentrations of 1-10
    nmol/L. In these experiments, zearalenone was found to be a full
    antagonist for ER-alpha and a mixed agonist-antagonist for ER-beta
    (Kuiper et al., 1998).

          Activation in animals: Several studies have shown that
    zearalenone and its derivatives initiate translocation of the receptor
    complex to the nucleus, beta-zearalanol being more effective than
    zearalenone; the latter was associated with a longer duration of
    nuclear retention of the receptor complex than the former or of
    17beta-estradiol. The studies also clearly demonstrated transcription
    and synthesis of estrogen-induced protein in the uterus of rats after
    zearalenone treatment, with a potency relative to that of

    17 beta-estradiol of 0.07 for alpha-zearala-nol, 0.02 for
    beta-zearalanol, and 0.001 for zearalenone (Katzenellebogen et al.,
    1979). The relative potency of zearalenone with respect to 17
    beta-estradiol and diethylstilbestrol in the uterotropic assay after
    subcutaneous or oral administration was about 0.001, whereas the
    potency relative to that of 17 beta-estradiol in the vaginal
    cornification assay was 0.001 after subcutaneous injection and 0.01
    after topical administration. alpha-Zearalanol had about the same
    potency in this assay but is usually several times more active in the
    uterotropic assay (Kuiper-Goodman et al., 1987).

         Male 70-day-old rats treated orally with zearalenone at 20 mg/kg
    bw per day for five weeks had increased serum prolactin values, but
    other parameters such as body and testis weights, serum luteinizing
    hormone and follicle stimulating hormone concentrations and volume
    fractions of Sertoli cells, spermatogonia, early and late primary
    spermatocytes, and long and round spermatids were not affected (Milano
    et al., 1995).

         Neonatal Charles River CD rats received 100 and 1000 g of
    zearalenone by subcutaneous injection on days 1-10 of life, were
    castrated on day 21, and received gonadotropin-releasing hormone on
    day 42, when luteinizing hormone was determined. Males and females
    exposed to either dose of zearalenone had decreased pituitary
    responsiveness to gonadotropin-releasing hormone. The highest dose of
    zearalenone increased the volume of the sexually dimorphic nucleus of
    the preoptic area in females, whereas no changes were seen in males
    (Faber & Hughes, 1991).

         In ovariectomized Charles River CD rats, subcutaneous injection
    of zearalenone at 8 mg/kg bw or zearalenol at 0.8 or 8 mg/kg bw did
    not inhibit tonic luteinizing hormone secretion and did not provide
    estrogenic priming for progesterone-induced luteinizing hormone
    secretion, but it did block gonadotro-pin-releasing hormone-induced
    luteinizing hormone secretion (Hughes et al., 1991).

         Daily injection of pregnant mice with 20 ng of 17 beta-estradiol
    or 2 g of zearalenone (equivalent to 10 g/kg bw) on days 15-20 of
    gestation increased the density of terminal end buds in the mammary
    glands. Zearalenone also increased epithelial differentiation and
    density (Hilakivi-Clarke et al., 1998).

         Kuiper-Goodman et al. (1987) based a risk assessment on a study
    on a 'no hormonal effect level' (NHEL) for alpha-zearalanol in
    ovariectomized monkeys in which vaginal cornification was used as the
    end-point. In rhesus monkeys treated orally for 10 days, the NHEL was
    225 g/kg bw per day (Parekh & Coulston, 1983), whereas a NHEL of
    < 50 g/ kg bw per day was found in a 90-day study with cynomolgus
    monkeys (Griffin et al., 1984). Kuiper-Goodman et al. (1987) suggested
    that zearalenone is less estrogenic than alpha-zearalanol and that the
    NHEL for zearalenone is probably higher. In support of that
    suggestion, effects were seen in pregnant mice at a dose of 80 g/kg
    bw per day (Hilakivi-Clarke et al., 1998).


        Table 3. Reproductive and developmental effects observed after oral exposure of various species to zearalenone
                                                                                                                                               

    Species   Age         No.      Route       Dose                   Duration            NOEL       Effects                     Reference
    (strain)                                                                              (mg/kg 
                                               mg/kg       mg/kg                          bw per 
                                               bw daya     feed                           day)
                                                                                                                                               

    Mouse     Adult       9,       Gavage      20                     1 day (day          < 20       No malformation,            Arora et al. 
    (CBA/Ca)  (pregnant   10-20                                       8 or 9 of                      increased late              (1981, 1983)
              female)                                                 gestation)                     fetal deaths

    Rat       Adult (6-8  50       Diet        0.1, 1,                Two-generation      0.1        Number of F2a2                 Becci et al. 
    (Wistar)  weeks)                           10                     study                          liveborn pups/litter        (1982b)
                                                                                                     decreased, increased 
                                                                                                     resorptions; increased 
                                                                                                     absolute and relative 
                                                                                                     adrenal, thyroid, and 
                                                                                                     pituitary weights in 
                                                                                                     Fo; skeletal 
                                                                                                     abnormalities related 
                                                                                                     to decreased growth
                                                                                          1          Maternal toxicity, 
                                                                                                     decreased fertility, 
                                                                                                     number of F1a1 live-born 
                                                                                                     pups/litter decreased, 
                                                                                                     increased resorptions; 
                                                                                                     soft-tissue 
                                                                                                     abnormalities (lack of 
                                                                                                     eyelids) related to 
                                                                                                     delay in fetal
                                                                                                     development
                                                                                          10         Medullary trabeculation 
                                                                                                     increased

    Table 3. (continued)
                                                                                                                                               

    Species   Age         No.      Route       Dose                   Duration            NOEL       Effects                     Reference
    (strain)                                                                              (mg/kg 
                                               mg/kg       mg/kg                          bw per 
                                               bw daya     feed                           day)
                                                                                                                                               

    Rat       Adult       10       Gavage      1, 5,                  Days 6-15           < 1        Delayed                     Ruddick et al. 
    (Wistar)  (pregnant                        10                     of gestation        (0.3       ossification                (1976)
              female)                                                                     according
                                                                                          to 
                                                                                          un-
                                                                                          published
                                                                                          data)

    Rat       Adult       approx.  Diet        (approx.    17         56 days             < 0.85     Decreased                   Ruzsas et al.
              (male       10       (un-        0.85)                                                 fertility of                (1978, 1979) 
              and                  purified                                                          males and 
              female)              in maize)                                                         females, 
                                                                                                     disturbed and 
                                                                                                     spermatogenesis, 
                                                                                                     disturbed 
                                                                                                     cycling, 
                                                                                                     decreased
                                                                                                     fertility of 
                                                                                                     offspring

    Rat       Adult       5-7      Oral        20                     5 weeks             < 20       Increased serum             Milano et al.
    (Wistar)  (70-day-                                                                                prolactin concentration     (1995)
              old, male)                                                                  > 20       No effect on
                                                                                                     body or testis
                                                                                                     weight, serum LH
                                                                                                     or FSH, volume
                                                                                                     fraction of Sertoli
                                                                                                     cells, early and 
                                                                                                     late spermatocytes, 
                                                                                                     or long and round
                                                                                                     spermatids

    Table 3. (continued)
                                                                                                                                               

    Species   Age         No.      Route       Dose                   Duration            NOEL       Effects                     Reference
    (strain)                                                                              (mg/kg 
                                               mg/kg       mg/kg                          bw per 
                                               bw daya     feed                           day)
                                                                                                                                               

    Guinea-   Adult,      3-4      Diet        7, 14, 21              1-8 (days 1-8       < 7        Reduced incidence of        Long & 
    pig       female                                                  after mating)                  pregnancy (21 mg/kg bw),    Diekman 
                                                                                                     altered levels of           (1989) 
                                                                                                     progesterone, no effect
                                                                                                     on litter size,
                                                                                                     fetal size

    Chicken   Female      4        Diet        (approx.    10-800     56 days             > 59       No effect on egg            Allen (1980);  
              (210 days)                       0.7-59)                                               production or egg size      Allen et 
                                                                                                                                 al. (1981)

    Turkey    Female      10       Diet        (approx.    100        56 days             < 4        Decreased egg               Allen et 
              (225 days)                       4)                                                    production (20%)            al. (1983)

    Mink      Female      4        Diet                    10, 20     21 days                        Increased weight of         Cameron et 
                                                                                                     uterus, vulva size          al. (1989)

    Mink      Female      8        Diet                    10, 20     4 weeks                        Increased gestation         Cameron et 
                                                                      before breeding                period, increased           al. (1989)
                                                                      to 3 weeks                     mortality, reduced 
                                                                      after whelping                 litter size

    Mink      Female      12       Diet                    20         2 months before                Reduced whelping, no        Yamini et 
                                                                      mating to 3 weeks              effect on mating,           al. (1997)
                                                                      after whelping                 histopathological 
                                                                                                     changes in uterus and 
                                                                                                     ovarian follicles

    Table 3. (continued)
                                                                                                                                               

    Species   Age         No.      Route       Dose                   Duration            NOEL       Effects                     Reference
    (strain)                                                                              (mg/kg 
                                               mg/kg       mg/kg                          bw per 
                                               bw daya     feed                           day)
                                                                                                                                               

    Mink      Female      12       Diet                    15.7       74-124 days                    Reduced whelping,           Yang et 
                                                                      (mated day 48,                 increased gestation         al. (1995)
                                                                      49, 56)                        length, reduced no. 
                                                                                                     of live kits, ovarian 
                                                                                                     follicular atrophy, 
                                                                                                     endometrial hyperplasia, 
                                                                                                     endometrial glandular 
                                                                                                     and myometrial atrophy, 
                                                                                                     endometritis

    Pigb      Pregnant    7        Diet        (approx.    2.2        Day 2 to            < 0.09     Reduced relative            Shreeve et 
              sow                  (mouldy     0.09)                  farrowing                      pituitary, thyroid,         al. (1978)
                                   wheat)                                                            and kidney weights, 
                                                                                                     increased relative 
                                                                                                     spleen and spinal 
                                                                                                     cord weights in 
                                                                                                     piglets. No maternal 
                                                                                                     toxicity, no increased
                                                                                                     resorption, no bone 
                                                                                                     abnormalities, no
                                                                                                     lesions

    Table 3. (continued)
                                                                                                                                               

    Species   Age         No.      Route       Dose                   Duration            NOEL       Effects                     Reference
    (strain)                                                                              (mg/kg 
                                               mg/kg       mg/kg                          bw per 
                                               bw daya     feed                           day)
                                                                                                                                               

    Pigb      Sow         4        Diet        0.28, 1.5,  7, 38, 64  Days 3-34 of        < 0.28     Increased serum             Long et 
                                   (culture    2.6                    gestation                      progesterone                al. (1982)
                                   of F.                                                  0.28       Decreased serum
                                   deoxy-                                                            roseum with
                                   nivalenol)                                                        progesterone and
                                                                                                     serum estradiol,
                                                                                                     decreased no. of sows 
                                                                                                     with fetuses, decreased 
                                                                                                     average fetal weight
                                                                                          1.5        Signs of
                                                                                                     hyperestrogenism,
                                                                                          > 2.6      endometrial morphology
                                                                                                     No effect on number 
                                                                                                     of pigs with corpora 
                                                                                                     lutea

    Pig       Sow         3-4      Diet        (approx.    25, 50,    Various             < 1        Infertility,                Chang et al. 
                                               1, 2, 4)    100                                       pseudogestation,            (1979)
                                                                                                     nymphomania, constant       
                                                                                                     estrus, decreased 
                                                                                                     offspring weight, 
                                                                                                     juvenile 
                                                                                                     hyperestrogenism

    Pigc      Pubertal    16       Diet        (approx.    3, 6, 9    Throughout          0.12       Decreased breeding          Young & King 
              gilt                             0.12,                  gestation                      and live litters,           (1984)
                                               0.24,                                                 increased 
                                               0.36)                                                 pseudo-gestation,
                                                                                                     no swollen vulvas
                                                                                                     or abortions

    Table 3. (continued)
                                                                                                                                               

    Species   Age         No.      Route       Dose                   Duration            NOEL       Effects                     Reference
    (strain)                                                                              (mg/kg 
                                               mg/kg       mg/kg                          bw per 
                                               bw daya     feed                           day)
                                                                                                                                               

              Boar,       ?        Diet        (approx.    3, 6, 9    330 days            > 0.36     No effect on growth         Young & King
              30 days                          0.12,                                                 rate, libido, puberty,      (1984)
                                               0.24,                                                 or indications of 
                                               0.36)                                                 reduction in sperm 
                                                                                                     concentration, 
                                                                                                     testicular weight, 
                                                                                                     or epididymal weight

    Pig       Boar        4        Diet        (approx.               56 days             > 2        No effect on copulatory     Ruhr et al.
                                               0.02,                                                 behaviour or male           (1983)
                                               0.2, 2)                                               reproduction

    Pig       Young       3        Gelatin     5, 10,                 1 day               > 5        Swollen and inflamed        Farnworth &
              male and             capsules    15                                                    vulvas, decreased           Trenholm 
              female                                                                                 adrenal weights             (1983)

    Pig       Young       9        Diet        (1.2)       30         Various             < 1.2      Precocious                  Vanyi & Szeky 
              male                                                                                   spermatogenesis,            (1980)
                                                                                                     damage to germinal 
                                                                                                     epithelium,
                                                                                                     interstitial-cell
                                                                                                     hyperplasia

    Pig       Pre-        24       Diet        (approx.    10         14 days             < 0.26     Reversible reduction        Green et al.
              pubertal                         0.26)                  (exposure ended                in serum                    (1990)
              female                                                  14 days before                 concentration of LH
                                                                      breeding)
                                                                      14 days before                 No effect on age
                                                                      breeding                       at puberty, number of
                                                                                                     corpora lutea or live
                                                                                                     fetuses, fetus weight,
                                                                                                     or fetus length

    Table 3. (continued)
                                                                                                                                               

    Species   Age         No.      Route       Dose                   Duration            NOEL       Effects                     Reference
    (strain)                                                                              (mg/kg 
                                               mg/kg       mg/kg                          bw per 
                                               bw daya     feed                           day)
                                                                                                                                               

    Pigc      Gilt        10       Diet        (0.01,      0.36,      122-144             0.02       Swollen and inflamed        Friend et al. 
                                               0.02,       0.47,      days                           vulvas                      (1990)
                                               0.05)       1.28

    Pig       Gilt        4        Diet        0.09        2.12       Day 30 of           > 0.09     No statistical              Yang et al. 
                                                                      gestation                      difference in weight        (1995)
                                                                      through                        at birth or weaning 
                                                                      weaning                        or ovarian, uterine, 
                                                                                                     or testicular weight
                                                                                                     in offspring. Increased
                                                                                                     age of F boars at first
                                                                                                     mount but no effect on
                                                                                                     precopulatory or
                                                                                                     copulatory behaviour

    Pig       Gilt        4        Diet        (approx.    108 mg/    4-5 days (2-6,      < approx.  Reduced incidence of        Long & 
                                               1.1)        animal     7-10, 11-15         1.1        gestaion and regressed      Diekman (1986)
                                                                      days t after                   corpora lutea after 
                                                                      mating)                        exposure on days 7-10,
                                                                                                     decreased LH on day 15
                                                                                                     and in prolactin on days
                                                                                                     10 and 15 after mating

    Pig       Sow         4        Diet        1                      4 days (days        < 1        Reduced frequency of        Diekman & 
                                                                      7-10 after                     spikes in LH secretion,     Long (1989)
                                                                      mating)                        reduced mean serum LH 
                                                                                                     and FSH, death of 
                                                                                                     blastocysts on days
                                                                                                     10-14

    Table 3. (continued)
                                                                                                                                               

    Species   Age         No.      Route       Dose                   Duration            NOEL       Effects                     Reference
    (strain)                                                                              (mg/kg 
                                               mg/kg       mg/kg                          bw per 
                                               bw daya     feed                           day)
                                                                                                                                               

    Pig       Sow         15       Diet        1                      4 days              < 1        Signs of degeneration       Long et al. 
                                                                      (days 7-10                     of blastocysts at day 11,   (1992)
                                                                      after                          advanced degeneration of
                                                                      mating)                        blastocysts at day 13. No
                                                                                                     changes in endometrium

    Pig       Gilt        10-15    Diet        (approx.    1, 5,      15 days             0.04       Reversible increase in      Edwards et al. 
                                               0.04,       10         (days 5-20                     length of estrous cycle     (1987a)
                                               0.2,                   of estrous                     and prolonged luteal
                                               0.4)                   cycle)                         maintenance

    Pig       Gilt        13-15    Diet        (approx.    10         30 days             < 0.4      Increased age at            Edwards et al. 
              (pre-                            0.4 ?)                                                first estrus                (1987b)
              pubertal)

    Pig       Sow         15-17    Diet        (approx.    10         14 days             < 0.4      Extended weaning to         Edwards et al. 
                                               0.4 ?)                 (before                        estrus interval, no         (1987b)
                                                                      weaning)                       effect on fertility, no
                                                                                                     sign of hyperestrogenism

    Pigb      Gilt (pre-  10       Diet        0.06        2 for 2    45 or 90            0.06       Vulvar swelling, younger    Rainey et al. 
              pubertal)            (added to               weeks,     days                           age at puberty, reduced     (1990)
                                   naturally               1.5                                       response to estradiol.
                                   infected                there-                                     No effect on body weight, 
                                   feed)                   after                                     conception rate, 
                                                                                                     ovulation rate, number
                                                                                                     of fetuses, or embryo 
                                                                                                     survival

    Table 3. (continued)
                                                                                                                                               

    Species   Age         No.      Route       Dose                   Duration            NOEL       Effects                     Reference
    (strain)                                                                              (mg/kg 
                                               mg/kg       mg/kg                          bw per 
                                               bw daya     feed                           day)
                                                                                                                                               

    Pigc      Gilt        6        Diet        (approx.    2.2, 22    9 (day 1            < 0.09     Small decrease in number    Kordic et al. 
                                               0.09,                  after mating                   of corpora lutea, number    (1992)
                                               0.88)                  to farrowing,                  of live  embryos, small 
                                                                      3 gilts in                     increase in stillborn 
                                                                      each group                     piglets, increased weight 
                                                                      killed at day                  of uterus; only the latter 
                                                                      26-27)                         effect at low dose (no
                                                                                                     statistical analysis)

    Sheep     Ewe         33       Oral        (0.03,      1.5, 3,    10 days (from       0.03       Reduced relative            Smith et al. 
                                               0.06,       6, 12,     day 7 in estrus                ovulation rate              (1990)
                                               0.11,       or 24      before mating)                 (pretreatment vs 
                                               0.23,       mg/animal                                 post-treatment), 
                                               0.45)                                                 considered irrelevant 
                                                                                                     by Committee
                                                                                          0.06       Increased duration of
                                                                                                     estrus, increased
                                                                                                     uterine weight 
                                                                                          0.11       Increased liver weight, 
                                                                                                     increased ovarian weight
                                                                                          0.23       Reduced incidence 
                                                                                                     of ovulation, reduced
                                                                                                     fertilization
                                                                                          0.45       No effect on live weight, 
                                                                                                     number of ovulating ewes 
                                                                                                     yielding ova, number of 
                                                                                                     ewes with ova yielding 
                                                                                                     fertilized ova

    Table 3. (continued)
                                                                                                                                               

    Species   Age         No.      Route       Dose                   Duration            NOEL       Effects                     Reference
    (strain)                                                                              (mg/kg 
                                               mg/kg       mg/kg                          bw per 
                                               bw daya     feed                           day)
                                                                                                                                               

    Sheep     Ewe         50       Oral        (0.03,      1.5, 3,    10 days (from       0.45       No effect on number of      Smith et al.
                                               0.06,       6, 12,     day 5 after                    ovulations, ovulation       (1990)
                                               0.11,       or 24      mating)                        rate, conception rate, 
                                               0.23,       mg/animal                                 incidence of gestation, 
                                               0.45)                                                 number of lambs born, 
                                                                                                     embryo or ova wastage

    Sheep     Ram         6        Diet                    12                                        No effect on volume of      Milano et al. 
                                                                                                     ejaculate or semen          (1991)
                                                                                                     concentration, motility, 
                                                                                                     or abnormalities

    Cattle    Bull        2        Diet (not               20         72 days                        Degeneration of germinal    Vanyi et al.
                                   purified)                                                         epithelium, 75% incidence   (1980)
                                                                                                     of sperm degeneration
                                                                                                                                               

    Updated from Kuiper-Goodman et al. (1987); LH, luteinizing hormone; FSH, follicle-stimulating hormone
    a In parentheses, estimated by the Committee on the basis of 1 mg/kg feed equivalent to 0.04 mg/kg bw per day
    b The feed was naturally infected and no information was given on possible occurrence of other mycotoxins.
    c The Committee noted the lack of details on the protocol, poor reporting, or poor experimental design.
    

         In blood, zearalenone and zearalanol bind to human sex
    hormone-binding globulin to some extent (Martin et al., 1978).

    2.2.7.2  Immune responses

          In vivo: Nine female B6C3F1 mice weighing 15-18 g were fed a
    diet supplemented with zearalenone at 10 mg/kg of diet (equivalent to
    1.5 mg/kg bw per day) for two weeks. After intravenous infection with
     Listeria monocytogenes, the splenic bacterial count showed an
    increasing trend on days 1 and 4 when compared with that in 11 control
    animals. No adverse effects were seen after eight weeks of feeding.
    The exposure did not affect the splenic plaque-forming response to
    sheep red blood cells or the delayed hypersensitivity response to
    keyhole haemocyanin after two or eight weeks (Pestka et al., 1987).

         Female B6C3F1 mice received zearalenone subcutaneously at a
    dose of 45 mg/kg bw, and 27 mice were then infected with 5  104
     L. monocytogenes cells. No difference in survival rate was seen in
    comparison with a group of 82 controls. When bacteria in the spleen
    were counted after intravenous infection with 104 cells (number of
    animals tested not given), no treatment-related differences were
    reported (Pung et al., 1984).

         When eight weanling female B6C3F1 mice were fed a diet
    supplemented with zearalenone at 10 mg/kg of diet (equivalent to 1.5
    mg/kg bw per day) for six weeks, no differences from 26 control
    animals were seen in the serum concentrations of immunoglobulins G, M,
    or A. Dietary administration of zearalenone had no effect on the
    leukocyte count or on differential lymphocyte, polymorphonuclear
    neutrophil, monocyte, or eosinophil counts (Forsell et al., 1986).

          In vitro: Zearalenone at a concentration of 13 g/ml inhibited
    phytohaema-gglutinin-induced lymphocyte blastogenesis in human and PVG
    rat peripheral blood lymphocytes, as measured by the incorporation of
    [3H]thymidine into human lymphocytes, by 50%. To produce a similar
    reduction in rat cell cultures, a concentration of 2.5 g/ml was
    required (Atkinson & Miller, 1984).

         Incorporation of [3H]thymidine into the DNA of human peripheral
    blood lymphocytes stimulated by phytohaemagglutinin was completely
    inhibited by exposure of the cells to zearalenone at 30 g/ml.
    Exposure to 14 g/ml inhibited DNA synthesis in mitogen-stimulated
    lymphocytes by 50%. No alteration in toxicity was observed when rat
    liver cells were present in the lymphocyte cultures (Cooray, 1984).

         The concentrations of zearalenone and four metabolites required
    to reduce [3H]thymidine uptake in mitogen-stimulated human
    lymphocytes by 50% were 3.5 g/ml for zearalenone, 6.3 g/ml for
    alpha-zearalenol, 36 g/ml for beta-zearalenol, 3.8 g/ml for
    alpha-zearalanol, and 33 g/ml for beta-zearalanol. The results
    indicate that a keto group or an alpha-hydroxyl at position C-6
    contributes to the lymphotoxicity. The concentration of each analogue

    that caused a 50% reduction in [3H]thymidine uptake was similar for
    all mitogens tested (leukoagglutinin, concanavalin A, and pokeweed
    mitogen), suggesting that zearalenone and its metabolites can inhibit
    mitogen-induced proliferation by both B and T lymphocytes (Forsell &
    Pestka, 1985).

         In order to study the effect of zearalenone on interleukin (IL)
    production, T cells of the EL-4 murine thymoma cell line were
    stimulated with phorbol-2-myristate-13-acetate and exposed for five
    days to zearalenone or alpha-zearalenol at concentrations of 50, 500,
    1000, 5000, or 10 000 ng/ml. Control cells were exposed to the vehicle
    (ethanol) only. The production of IL-2 and IL-5 was significantly
    increased in the presence of zearalenone or alpha-zearalenol at 5000
    and 10 000 ng/ml. The two toxins did not affect cell proliferation or
    viability, as shown in the 3-(4,5-dimethylthiazol-2-yl)
    2,5-diphenyltetrazolium bromide cytotoxicity assay (Marin et al.,
    1996).

    2.2.5.3  Macromolecular binding

         Several DNA adducts were detected by 32P-postlabelling in
    female BALB/c mice treated intraperitoneally with a single dose of
    zearalenone at 2 mg/kg bw in olive oil. A total of 1340 adducts/109
    nucleotides were found in liver and 111 adducts/109 nucleotides in
    kidney. Co-administration of 4 mg/kg bw alpha-toco-pherol significantly
    decreased DNA adduct formation in liver and in kidney to 713 and 45
    adducts/109 nucleotides, respectively (Grosse et al., 1997).

         In weanling female Sprague-Dawley rats fed a diet containing
    zearalenone at 0.05 mg/kg (equivalent to 5 g/kg bw) for three weeks,
    no DNA adducts were found by 32P-postlabelling in liver, kidney, or
    uterus DNA (Li et al., 1992). The Committee noted the very low dose of
    zearalenol used.

         When six-week-old female BALB/c mice were treated
    intraperitoneally or orally with zearalenone, 12-15 DNA adducts were
    found by 32P-postlabelling in the kidney and liver, at levels of 114
     37 adducts/109 nucleotides in kidney and 1393  324 adducts/109
    nucleotides in liver after intraperitoneal treatment and 548  50
    adducts/109 nucleotides in liver, after oral treatment with a single
    dose of 2 mg/kg bw. Six DNA adducts were found in the ovary but only
    after repeated doses of 1 mg/kg bw on days 1, 5, 7, 9, and 10, with a
    total number of DNA adducts after 10 days of 17  5 adducts/109
    nucleotides. Some adducts were common to all organs, while others were
    specific to one organ. In contrast, no DNA adducts were detected in
    the organs of male and female Sprague-Dawley rats after
    intraperitoneal treatment (no details given). The authors concluded
    that these results confirm the genotoxicity of zearalenone and its
    ability to induce hepatocellular adenomas rather than tumours of the
    genital organs in mice (Pfohl-Leszkowicz et al., 1995). The Committee
    disagreed, since the 32P-postlabelling method does not measure
    direct covalent DNA binding, and other (indirect) mechanisms of action
    may be involved.

    2.2.7.4  Genotoxicity of metabolites

         The results of studies of the genotoxicity of metabolites of
    zearalenone are summarized in Table 4.

    2.3  Observations in humans

         Zearalenone was measured in endometrial tissue from 49 women and
    found at a concentration of 48  6.5 ng/ml in tissue from 27 women
    with endometrial adenocarcinoma, at 170  18 ng/ml in tissue from 11
    women with endometrial hyperplasia, and at a concentration below the
    limit of detection in tissue from 11 women with normal proliferative
    endometrium. None was detected in eight samples of hyperplastic and
    five samples of neoplastic endometrial tissue (Tomaszewski et al.,
    1998).

         Zearalenone or zearalanol was suspected to be the causative agent
    in an epidemic of premature thelarche in girls aged six months to
    eight years which occurred in Puerto Rico between 1978 and 1981 (Senz
    de Rodriguez, 1984; Senz de Rodriguez et al., 1985), as these
    compounds were detected in blood plasma. The authors reported that
    homogenates of locally produced meat gave strong responses in a
    cytosol receptor assay with rat uterus, indicating the presence of
    substances that bind to estrogen receptors, although the United States
    Food and Drug Administration later failed to detect any of the
    estrogen growth promoters used in food (Anon., 1986). The involvement
    of natural sources of estrogenic compounds, such as some plant
    metabolites and mycotoxins, has not been ruled out. A statistically
    significant correlation was found between the pubertal changes and
    consumption of meat products and soya-based formula, but the
    associations explained only 50% of the investigated cases, and the
    authors suggested that better diagnosis and reporting or some
    unsuspected factor accounted for the reported increase in precocious
    pubertal changes (Freni-Titulaer et al., 1986).

         An increased incidence of early thelarche was also reported from
    southeastern Hungary, and zearalenone was found at concentrations of
    19-100 g/ml in serum and in samples of foods that had been consumed
    by the patients (Szuetz et al., 1997); however, the report lacked
    detailed information.

    3.  OCCURRENCE AND INTAKE

         Few estimates of human exposure to zearalenone have been
    published. This section provides information on the concentrations in
    plant-based foods and animal tissues, estimates of human intake of
    zearalenone, and guidelines for modelling dietary exposure to this
    substance. Previous comprehensive reviews of publications on
    zearalenone include those of Sundlof & Strickland (1986),
    Kuiper-Goodman et al. (1987), and Krska (1999). Zearalenone is
    determined in foods by high-performance liquid chromatography,
    thin-layer chromatography, or gas chromatography with mass
    spectrometry.

         Sundlof & Strickland (1986) reviewed the literature on the
    presence of zearalenone and alpha-zearalanol in animal tissues to
    determine whether consumption of these products poses a threat to
    human health. They summarized studies on the concentrations of
    zearalenone in milk after exposure of cows to this compound, the
    concentrations of zearalenone in tissue from cattle implanted with
    alpha-zearalanol, and the concentrations of zearalenone in muscle and
    liver from chickens exposed to [14C]zearalenone. They concluded that
    milk is not a likely source of residues of zearalenone and that
    because chicken muscle contained few binding sites for this substance,
    the likelihood of human exposure to zearalenone residues due to
    consumption of chicken was minimal. Because eggs accumulate a
    zearalenone metabolite in yolks, the authors suggested that they might
    be a source of exposure.

         Kuiper-Goodman et al. (1987) reviewed the toxicology, chemistry,
    mycology, natural occurrence, and stability of zearalenone in plant
    and animal products and reported its occurrence in foods from 23
    countries, including Australia, China, Mexico, South Africa, and the
    United States and countries in northern Europe. The greatest
    contamination was found in corn and corn products. The dietary intake
    of young Canadian males was estimated on the basis of consumption of
    corn breakfast cereals and popcorn, and that of children aged 1-4
    years of age was estimated on the basis of consumption of corn
    breakfast cereals, popcorn, and milk.

         The most recent overview (Krska, 1999) covers the occurrence of
    zearalenone in foods, the dietary intake estimates of Kuiper-Goodman
    et al. (1987) in Canada, residues in animal products, the effects of
    contamination on trade, and efforts to control contamination. The
    highest prevalences of zearalenone are reported in Canada, central and
    northern Europe, and the United States, although its occurrence was
    also reported in foods in Egypt, Italy, New Zealand, South Africa, and
    South America. Zearalenone occurs in many agricultural products,
    including cereals, mixed feeds, rice, and corn silage. The reported
    prevalences and concentrations in cereals and mixed feed vary
    considerably. Zearalenone can occur concomitantly with the
    trichothecenes nivalenol and deoxynivalenol, since the three compounds
    are produced by the same  Fusarium spp.

         A considerable increase in the concentration of zearalenone was
    found after treatment of three cereal samples and one barley sample
    with -glucosidase, indicating the presence of glucosides (Gareis et
    al., 1990), and zearalenone sulfate was isolated from cultures of
     Fusarium spp. grown on rice (Plasencia & Mirocha, 1991). The
    significance of such conjugates of zearalenone in plants, which are
    not detected by routine analysis, is not known.

    3.1  Incidence and levels of contamination

         Table 5 gives published values for concentrations of zearalenone
    in grains, grain products, legumes, nuts and seeds, fruits and
    vegetables, spices and herbs, muscle and organ meats, milk, and
    miscellaneous products. Because the purpose of this section is to
    evaluate human dietary intake of zearalenone, Table 5 does not include
    concentrations in animal feed. The data in Table 5 have a number of
    limitations for estimating intake: Information on incidence is of
    little value when it is based on few samples and when the samples were
    not collected in a random fashion. If the samples were chosen
    specifically because the food was of inferior quality (i.e. mouldy,
    damaged, or off-colour), the incidence rates and concentrations of
    zearalenone are likely to be high, and if those concentrations are
    used to estimate dietary intake, it will be exaggerated. Another
    limitation is that the information on zearalenone is derived from
    studies in which different analytical methods were used
    (high-performance liquid chromatography, thin-layer chromatography, or
    gas chromatography with mass spectrometry), which have different
    limits of detection. The incidence of positive samples is related to
    the sensitivity of the method, since the more sensitive the method the
    lower the detection limit and the greater the probability of a
    positive reponse.

         The reported incidence rates and concentrations of zearalenone in
    grains and grain products vary according to type of grain and to
    climatic, harvest, and storage conditions. Corn and wheat appear to be
    the commodities of greatest concern with respect to zearalenone
    contamination; other cereal grains appear to be less contaminated and
    are less widely consumed. Of the 13 grains represented in Table 5, six
    (acha, amaranth, buckwheat, millet, semolina, and tritical) were
    mentioned in only one reference, whereas the data for oats, rice, rye,
    and sorghum come from 4-11 countries in 4-12 references, and barley
    (18 countries, 30 references), corn (26 countries, 43 references), and
    wheat (25 countries, 43 references) were the best covered. In general,
    the mean values for barley were quite low, those for wheat were
    generally low, and those for corn were variable.

         In most of the studies, it was not possible to determine if the
    grain crops were intended for human consumption or for animal feed.
    Thus, although the aim was to summarize information on human foods,
    some of the crops listed in Table 5 may not have been grown for that
    purpose. Since the authors of the papers did not distinguish between
    corn and maize, the two products are listed together under 'corn',
    although the term used in the references is given when it is of
    interest. The term 'sweet corn', yellow or white corn used as a
    vegetable in the USA, was used in one reference (Stoloff & Francis,
    1980). Another paper (Abbas et al., 1988) referred to 'dent' corn. The
    corn analysed in different countries may represent different
    cultivars, subspecies, or commercial classifications.


        Table 4. Results of assays for genotoxicity with metabolites of zearalenone
                                                                                                                           

    Metabolite            Test system         Test object              Concentration  Results         Reference
                                                                                                                           

    Zearalanola           Reverse mutation    S. typhimurium TA1538,   250 g/plateb  Negativec       Bartholomew & Ryan
                                              TA98, TA100                                             (1980)

    Zearalanone           Reverse mutation    S. typhimurium TA1535,   50 g/plateb   Negativec       Ingerowski et al.
                                              TA1537, TA1538, TA98,                                   (1981)
                                              TA100 

    Zearalanol            Reverse mutation    S. typhimurium TA1535,   250 g/plateb  Negativec       Ingerowski et al.,
                                              TA1537, TA1538, TA98,                                   (1981)
                                              TA100

    Zearalanol            SOS chromotest      E. coli PQ37             106 mg/Lb      Negative        Scheutwinkel et al.
                                                                                                      (1986)

    Zearalanol            Gene mutation       B. subtilis H17, M45     Not reported   Positived       Scheutwinkel et al. 
                                              rec+/-                                                  (1986)

    Zearalanol            Sister chromatid    Chinese hamster          32 mg/Lb       Negative        Scheutwinkel et al.
                          exchange            V79 cells                                               (1986)

    alpha- and            SOS chromotest      E. coli PQ37             60 mg/Lb       Negative        Krivobok et al. 
    beta-Zearalenol                                                                                   (1987) 
    (1:1)

    Zearalenol-alphae     Gene mutation       B. subtilis H17, M45     100 g/disc    Negative        Ueno & Kubota 
    Zearalenol-betae                          rec+/-                   100 g/disc    Positive        (1976)
                                                                                                                           

    a  Specified as 'low and high melting point zearalanol'
    b  With and without metabolic activation
    c  Cytotoxic at 500 g/plate
    d  M45rec- 3 mm, H17rec+ 0 mm growth inhibition
    e  According to Kuiper-Goodman et al. (1987), zearalenol-beta is alpha-zearalenol and zearalenol-alpha
       is beta-zearalenol

    Table 5. Concentrations of zearalenone in foods
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b
                                        D/T       %         Mean       Range
                                                                                                                 

    Grains
    Acha (by season)   Nigeria                                                      Gbodi et al. (1986a)
      Dry, cold                         4/9       44        248        200-309      
      Dry, hot                          3/7       43        348        241-600      
      Humid, hot                        1/8       13        18                      
    Amaranth           Argentina                                                    Bresler et al. (1998)
    (by water
    activity)
      0.902                                                 0                       
      0.925                                                 1500                    
      0.950                                                 11 100                  
    Barley             Sweden           23/329    7         18                      Eriksen & Alexander (1998)
                       and Norway
    Barley, six        Southwest                  7-68      3-36       max, 311     Mller et al. (1997b)
    years              Germany
    Barley             Canada           3/210     1         13         4-21         Scott (1997) 
    Barley and         Uruguay          116/137   85        <100                    Pineiro et al. (1996a)
    malt
    Barley and         Uruguay          12/137    9                    100-200      Pineiro et al. (1996a)
    malt
    Barley and         Uruguay          8/137     6         > 200                   Pineiro et al. (1996a)
    malt
    Barley             Republic         0/30      0         0                       Ryu et al. (1996) 
                       of Korea
    Barley             Manitoba,        5/7       71        166        24-45        Usleber et al. (1996)
                       Canada
    Barley             Japan            7/17      41        4158       105-15 300   Yoshizawa & Jin (1995)
    Barley             Russian          0/NA      0         0                       Zakharova et al. (1995)
                       Federation
    Barley             Papua            0/3       0         0                       Yuwai et al. (1994)
                       New Guinea

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Barley             Republic         20/39     51        287        40-1416      Kim et al. (1993)
                       of Korea
    Barley             Canada           41/180    26        Most                    Stratton et al. (1993) 
                                                            <  0.3 
    Barley             Japan            13/18     72        24         2-97         Tanaka et al. (1993)
    Barley
      Undergrade       Republic         10/37     27                                Park et al. (1992)
                       of Korea
      Husked           Republic                                        183-1416     Park et al. (1992)
                       of Korea
      Naked            Republic                                        40-1081      Park et al. (1992)
                       of Korea

    Barley             Finland          2/30      7         26         21-30        Hietaniemi & Kumpulainen 
      Importedc                         0/3       0         0                       (1991)
    Barley             New Zealand      15/85     18                   max, 170     Lauren et al. (1991)
    Barley             Germany          0/14      0         0                       Ranfft et al. (1990)
    Barley             Netherlands      6/6       100       7          4-9          Tanaka et al. (1990)
    Barley,            Netherlands      0/1       0         0                       Tanaka et al. (1990)
    pearled
    Barley             Bavaria,         24/46     52        24         max, 320     Gleissenthal et al. (1989)
                       Germany
    Barley             USA              1/1       100       < 19                    Bagneris et al. (1986)
    Barley             Japan                                                        Lee et al. (1986)
      Husked                            3/6       50                   1-2          
      Unhusked                          29/31     94        24         1-388        
    Barley malt        Japan            5/5       100       23         3-48         Lee at al. (1986)
    Barley             Taiwan,          2/4       50        19         16-22        Ueno et al. (1986)
                       China
    Barley             Republic                                                     Lee et al. (1985)
                       of Korea
      Polished                          0/6       0         0                       
      Unpolished                        21/28     75        110        0-1281       

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Barley malt        Republic         4/4       100       19         2-36         Lee et al. (1985)
                       of Korea
    Barley             Japan                                                        Tanaka et al. (1985)
      Flour                             6/6       100       2          1-4          
      Pearled                           1/1       100       4                       
      Polished                          1/3       33        6                       
      Barley           Czechoslovakia             58                   61-261       Bartos & Matyas (1981)
    Barley             Western Canada   0/NA      0         0                       Prior (1976)
    Barley,            Scotland                                                     Gross & Robb (1975)
    stored
     <10 weeks                          0/NA      0         0                       
     12-51 weeks                        NA                             2100-26,500  
    Buckwheat          Beijing, China   0/1       0         0                       Ueno et al. (1986)
    flour

    Corn               Indonesia        2/16      13        11, 12                  Ali et al. (1998)

    Cornd              United Kingdom                                               Scudamore et al. (1998)
      Baby                              4/4       100       55         40-80        
      Flaked                            3/3       100       93         80-110       
      Germ                              7/7       100       67         50-80        
      Germ/bran                         6/6       100       330        160-540      
      Gluten                            8/40      20        270        80-480       
      Meal                              3/3       100       1080       640-1500     
      Screen                            4/4       100       1450       1300-1800    
    Cornd              Botswana         1/20      5         40                      Siame et al. (1998)
    and meal
    Corn               Italy            14/15     93        46         4-150        Visconti & Pascale (1998)
    Corn               Egypt            15/50     30        22.3                    Abd Alla (1997)
    Corn,              Canada                                                       Scott (1997)
    by year 
      1978-81                           21/77     27        105        30-475       
      1986-93                           87/126    69        65         5-647        

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Cornd              Hungary                                                      Fazekas et al. (1996)
      At harvest                                  17        30         6-79 
      Mouldy, stored                              88        1260       10-11 800    
    Corn,              Wisconsin,       NA/98               904                     Park et al. (1996)
    mouldy             USA
      Cobs                              NA/98               21 000                  
      Kernels                           NA/98               500                     
    Corn               Uruguay          71/76     93        < 100                   Pineiro et al. (1996a)
    Corn               Uruguay          2/76      2                    100-200      Pineiro et al. (1996a)
    Corn               Uruguay          4/76      5         > 200                   Pineiro et al. (1996a)
    Cornd,             Argentina                                                    Resnik et al. (1996)
    by year 
      1983                              9/126     7         154        140-350      
      1984                              54/138    39        46         25-150       
      1985                              17/35     49        114        95-332       
      1988                              40/108    37        158        100-1200     
      1989                              16/162    10        301        200-2000     
      1990                              195/491   40        120        100-350      
      1991                              121/288   42        151        100-800      
      1992                              127/349   36        168        97-1108      
      1993                              8/294     3         152        97-820       
      1994                              89/280    32        293        210-1500     
    Cornd              Republic of      1/15      7         71                      Ryu et al. (1996)
                       Korea
    Cornd              South Africa     3/161     2         NA                      Dutton & Kinsey (1995) 
    Corn,              Egypt            13/22     59                   9800-38,400  El-Maghraby et al. (1995) 
      yellow,
      white, 
      popcorn 
    Cornd,             Brazil           0/36      0                    0            Hennigen & Dick (1995)
      stored

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Corn               Kansas,                                                      Hooshmand & Klopfenstein
      Three moisture   USA                                             4875-4930    (1995)
      levels           

      With 5                                                           4480-4700    
      or 7.5 kGy
      With 10                                                          3175-3921    
      or 20 kGy
    Corn               Philippines      2/50      4         282        59-505       Yamashita et al. (1995)
    Corn               Thailand         1/27      4         923                     Yamashita et al. (1995) 
    Corn               Indonesia        0/12      0         0                       Yamashita et al. (1995) 
    Corn               Taiwan           2/32      6         25                      Rheeder et al. (1994)
    from
    South Africa 
    Corn               Papua New        0/3       0         0                       Yuwai et al. (1994) 
                       Guinea
    Corn               Republic of      8/46      17        151        4-388        Kim et al. (1993)
                       Korea
    Corn               Central          7/40      18        NA         max, 3       L'vova et al. (1993)
                       Russian
                       Federation
    Cornd              Bavaria                              0                       Abramson et al. (1992)
    Cornd              New Zealand      69/91     76                   max, 500     Lauren et al. (1991)
    Cornd,             Bulgaria         0/264     0         0                       Petkova-Bocharova et al. (1991)
    home-stored
    Corn               Minnesota, USA   10/339    3         NA                      Russell et al. (1991)
    Cornd              South India      NA                  1454                    Sivaswamy et al. (1991)

    Corn               Linxian,         16/27     59        44         14-169       Luo et al. (1990)
                       China
    Corn               Shangqiu,        1/20      5         39                      Luo et al. (1990)
                       China

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Cornd              India            2/22      9         NA                      Pande et al. (1990)
    Cornd              Germany          6/7       86        12         5-35         Ranfft et al. (1990)
    Corn,              Netherlands      1/1       100       677                     Tanaka et al. (1990)
    yellow
    Cornd              New Zealand      15/20     75                   100-16 000   Hussein et al. (1989)
    Corn               Brazil           15/328    5                    653-9830     Sabino et al. (1989)
    Corn,              Minnesota,       17/19     89        2700       0-13 200     Abbas et al. (1988) 
    mouldy             USA
    Corn               Linxian,         5/5       100       NA                      Hsia et al. (1988)
                       China
    Corn               Canada           0/1       0         0                       Tanaka et al. (1988b)
    Corn               Indonesia        7/26      27        6          1-14         Widiastuti et al. (1988a)
      Composite                         11/52     21        7          1-14         
      Damaged                           0/52      0         0                       
      Good                              0/52      0         0                       
      Green-yellow                      NA/52               580                     
      fluorescence
      Mouldy                            0/52      0         0                       
      Purple                            NA/52               1840       50-13 500    
    Corn,              Minnesota        2/2       100       100, 5000               Abbas et al. (1986)
    refused            and Indiana,
                       USA
    Corn               USA                                                          Bagneris et al. (1986)
      Shelled                           13/31     42        117        21-480       
      Unshelled                         6/7       86        982        19-3656
    Cornd,             Nigeria                                         max, 17 500  Gbodi et al. (1986b)
    mouldy
    Corn               Illinois,        5/5       100       1376       114-3008     Bennett et al. (1985)
                       USA
    Corn and           Canada                                                       Williams (1985)
    products
      Domestic                          23/81     28                   13-475       
      Imported                          1/61      2         200                     

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Cornd              Czechoslovakia             7         105                     Bartos & Matyas (1981)
    Corn               Western Canada   2/19      11        NA                      Prior (1981)
    Corn               Argentina        16/55     29                   200-750      Lopez & Tapia (1980)
    Corn,              USA              0/263     0         0                       Stoloff & Francis (1980)
    sweet, 
    canned/frozen
    Corn               Ontario, Canada  266/2022  13        3850       <10-141 000  Funnell (1979)
    Corn               Transkei         2/4       50                   max, 1100    Marasas et al. (1979)
    Corn               Zambia                     NA                   max 1800     Senti (1979)
    Corn               Yugoslavia       3/100     3         5100       43-10 000    Balzer et al. (1977)
    Cornd              Zambia           NA/17               290        100-800      Lovelace & Nyathi (1977)
    for beer                            NA/13               680                     
    brewing

    Corn               Mexico           6/139     4         NA                      Shotwell et al. (1977)
    Corn               Western Canada   0/6       0         0                       Prior (1976)
    Corn                                NA/5                           431-7622     Shotwell et al. (1976)
    Corn               USA              19/315    6         117        38-204       Stoloff et al. (1976)
    Corn               USA              6/26      23                   200-500      Eppley et al. (1974)
    Corn, stored wet   France           NA                  2350                    Jemmali (1973)
    Cornd              New Zealand                                     2200-4800    Lauren & Ringrose (1997)
    germ, fibre,
    gluten
    Corn flour         United Kingdom   NA/4                           6.5-41       Patel et al. (1996)
    Corn flour         Papua New        0/1       0         0                       Yuwai et al. (1994)
                       Guinea
    Cornd malt         Zambia           NA/13               680        max, 4000    Lovelace & Nyathi (1977)
    Cornmeal/flour     Canada                                                       Scott (1997)
      1978-81                           0/28      0         0                       
      1986-93                           14/126    11        26         5-178
    Cornmeal           Michigan, USA    3/11      27        38         8-100        Abouzied et al. (1991)
    Cornmeal           Mexico           12/50     24        NA                      Argumedo et al. (1985)
    Cornmeal           USA              9/11      82                   10-70        Ware & Thorpe (1978)
    Popcorn            Michigan, USA    1/8       12        10         10-10        Abouzied et al. (1991)

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Popcorn,           Canada           1/1       100       25                      Scott (1997)
    popped
    Millet             Papua New        1/1       100       440                     Yuwai et al. (1994)
    meal               Guinea

    Oats               Sweden and       14/233    6         26                      Eriksen & Alexander (1998)
                       Norway
    Oats               Finland          3/21      14        63         30-86        Hietaniemi & Kumpulainen (1991)
    Oats               New Zealand      10/29     34                   max, 90      Lauren et al. (1991)
    Oats               Germany                                                      Mller et al. (1998)
    Oats               Germany          2/7       29        10         8-11         Ranfft et al. (1990)
    Oats               Netherlands      3/3       100       22         16-29        Tanaka et al. (1990)
    Oats,              Netherlands      0/1       0         0                       Tanaka et al. (1990)
    unhusked
    Oats               Bavaria,         2/7       29        3          max, 8       Gleissenthal et al. (1989)
                       Germany
    Oats               USA              1/1       100       18                      Bagneris et al. (1986)
    Oats               Tbilisi,         0/1       0         0                       Ueno et al. (1986)
                       Georgia
    Oats               Czechoslovakia                       0                       Bartos & Matyas (1981)
    Oats               Finland                              2 300 000               Kallela & Saastamoinen (1981a)
    Oats               Western Canada   0/NA      0         0                       Prior (1976)
    Rice               Egypt            4/45      9         15.5                    Abd Alla (1997)
    Rice               United Kingdom                                               Patel et al. (1996)
      Basmati                           NA/4                           5-16
      Chinese                           0/4       0         0
    Rice               Uruguay          39/42     93        < 100                   Pineiro et al. (1996a)
                                        0/42      0                    100-200
                                        3/42      7         > 200        
    Rice               Russian                                                      L'vova et al. (1993)
                       Federation
                          Central       1/24      4         NA
                          South         3/12      25        NA                      

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Rice               South India      0/NA      0         0                       Sivaswamy et al. (1991)
    Rice               India            0/30      0         0                       Pande et al. (1990)
    Rice               Russian          0/280     0         0                       L'vova et al. (1984)
                       Federation
    Rice,              Papua New        1/1       100       3060                    Yuwai et al. (1994)
    brown              Guinea

    Rice               Brazil                                                       Soares & 
      Parboiled                         NA                  0                       Rodriquez-Amaya (1989)
      Polished                          NA                  0                       
    Rye                Sweden and       0/31      0         0                       Eriksen & Alexander (1998)
                       Norway
    Rye                Germany                                                      Marx et al. (1995)
      Conventional
      production                        NA/100              4                       
      Alternative
      production                        NA/100              51         max, 199     
    Rye                Russian          0/NA                0                       Zakharova et al. (1995)
                       Federation
    Rye                Finland          0/31      0         0                       Hietaniemi & Kumpulainen
    Importedc                           0/10      0         0                       (1991)
    Rye                Germany          2/6       33        8          7-9          Ranfft et al. (1990)
    Rye                Netherlands      1/4       25        11                      Tanaka et al. (1990)
    Rye                Bavaria,         15/31     48        17         max, 100     Gleissenthal et al. (1989)
                       Germany
    Rye                Canada           0/1       0         0                       Tanaka et al. (1988b)
    Rye,               Republic of      3/5       60        2          3-4          Lee et al. (1985)
    polished           Korea

    Semolina           South India      0/NA      0         0                       Sivaswamy et al. (1991)
    Sorghum            Botswana         0/19      0         0                       Siame et al. (1998)
    and meal

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Sorghum            South Africa     0/7       0         NA                      Dutton & Kinsey (1995)
    Sorghum            USA              5/5       100       504        47-1280      Bagneris et al. (1986)
    Sorghum malt       Zambia           NA/8                < 100                   Lovelace & Nyathi (1977)
    Triticale          South Africa     1/2       50        NA                      Dutton & Kinsey (1995)
    Wheat              Sweden and       7/101     7         5                       Eriksen & Alexander (1998)
                       Norway
    Wheat              Egypt            5/40      13        8.8                     Abd Alla (1997)

    Wheat              Egypt            10/NA                          28-42        Aziz et al. (1997) 
    Wheat              Southwest                                                    Mller et al. (1997a)
                       Germany 
     1987                               67/84     80        178        1-8036       
     1989                               11/78     14        3          1-6          
     1990                               9/80      11        5          1-15         
     1991                               10/80     13        20         1-109        
     1992                               15/78     19        4          1-20         
     1993                               28/45     62        11         2-52         
    Wheat,             Ontario,         9/95      10        14         5-33         Scott (1997)
    soft               Canada

    Wheat,             Western Canada   1/88      1         4                       Scott (1997)
    hard
    Wheat              Switzerland      NA/92               > 60                    Bucheli et al. (1996)
    Wheat              Uruguay          101/106   95        < 100                   Pineiro et al. (1996a)
                                                  2/106     2                       100-200
                                                  3/106     3          >200         
    Wheat              Bulgaria                   69        17         max, 120     Vrabcheva et al. (1996) 
    Wheat              South Africa     0/5       10        NA                      Dutton & Kinsey (1995)
    Wheat              Sao Paulo,       3/NA                           40-210       Furlong et al. (1995a) 
                       Brazil
    Wheat,             Brazil           0/12      0         0                       Furlong et al. (1995b)
    stored

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Wheat,             Brazil
    stored,
      from
      Argentina                         0/4       0         0                       Furlong et al. (1995b)
    Wheat,             Brazil
    stored,
      from
      Uruguay                           0/4       0         0                       Furlong et al. (1995b)
    Wheat              Japan            4/17      24        677        53-1690      Yoshizawa & Jin (1995)
    Wheat              Russian          3/154     2         NA                      Zakharova et al. (1995)
                       Federation                           ('low')
    Wheat,             Papua New        1/1       100       1040                    Yuwai et al. (1994)
    ground             Guinea

    Wheat              Papua New        0/1       0         0                       Yuwai et al. (1994)
                       Guinea
    Wheat              Russian                                                      L'vova et al. (1993)
                       Federation                 
                         Central        1/31      3         NA                      
                         South          4/6       67        NA         max, 22      
    Wheat              Southwest                                                    Mller & Schwadorf (1993)
                       Germany
    Wheat              Canada                     30/201    15         Most, < 0.3  Stratton et al. (1993) 
    Wheat              Bavaria,                             0                       Abramson et al. (1992)
                       Germany
    Wheat              Finland          2/40      5         22         12-32        Hietaniemi & Kumpulainen
    Importedc                           0/10      0         0                       (1991)
    Wheat              New Zealand      48/151    32                   max, 460     Lauren et al. (1991)
    Wheat              South India      NA                  4744                    Sivaswamy et al. (1991)
    Wheat              Linxian,         6/15      40        <10                     Luo et al. (1990)
                       China
    Wheat              Shangqiu,        6/15      40        <10                     Luo et al. (1990)
                       China

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Wheat              India            0/30      0         0                       Pande et al. (1990)
    Wheat              Germany          7/21      33        27         4-64         Ranfft et al. (1990)
    Wheat              Netherlands      7/13      54        45         2-174        Tanaka et al. (1990)
    Wheat              Bavaria,         61/106    58        80         max, 1560    Gleissenthal et al. (1989)
                       Germany
    Wheat              Canada           9/10      90        9                       Tanaka et al. (1988b)
    Wheat              Japan            5/9       56        141        3-1254       Lee et al. (1986)
    Wheat              United Kingdom   4/31      13        1                       Tanaka et al. (1986)
    and barley
    Wheat              Scotland         10/10     100       9                       Tanaka et al. (1986)
    and barley
    Wheat              Beijing,         0/5       0         0                       Ueno et al. (1986)
                       China
    Wheat              Shanghai,        1/1       100       2                       Ueno et al. (1986)
                       China
    Wheat              Taiwan           9/22      41        16         4-32         Ueno et al. (1986)
    Wheat              Tbilisi,         0/2       0         0                       Ueno et al. (1986)
                       Georgia
    Wheat,             Republic         2/10      20        8, 40                   Lee et al. (1985)
    polished           of Korea
    Wheat,             Kansas and       3/33      9         35, 90, 115             Hagler et al. (1984)
    scabby             Nebraska, USA

    Wheat              Bavaria,         0/NA                0                       Abramson et al. (1982)
                       Germany
    Wheat              Czechoslovakia             46                   61-182       Bartos & Matyas (1981)
    Wheat              India            73/85     86                   max,         Neelakantan et al. (1979)
    and rice                                                           600 000
    Wheat              Virginia,        19/42     45                   360-11 050   Shotwell et al. (1977)
                       USA
    Wheat              Western Canada   0/NA      0         0                       Prior (1976)
    Wheat bran         Papua New        0/2       0         0                       Yuwai et al. (1994)
                       Guinea

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Wheat bran         Shanghai,        1/1       100       3                       Ueno et al. (1986)
                       China
    Wheat germ         Papua New        0/1       0         0                       Yuwai et al. (1994
                       Guinea
    Wheat flour        Papua New                                                    Yuwai et al. (1994
                       Guinea
      Fine-ground                       0/1       0         0                       
      Raw                               1/1       100       250                     
      Whole grain                       4/4       100       1893       1400-2570    
    Wheat flour        Michigan, USA    2/17      12        13         12-14        Abouzied et al. (1991)
    muffin mix
    Wheat flour        Egypt            4/NA                34                      Aziz et al. (1997)
    Wheat flour        Beijing,         0/3       0         0                       Ueno et al. (1986)
                       China
    Wheat flour        Shanghai,        0/1       0         0                       Ueno et al. (1986)
                       China
    Wheat flour        Japan            3/27      11        3          1-6          Tanaka et al. (1985)
    Bread              United Kingdom                                               Patel et al. (1996)
      Chapatti                          0/4       0         0
      Nan                               0/4       0         0                       
      Pitta                             0/4       0         0                       
    Bread, wheat       Egypt            4/NA                95                      Aziz et al. (1997)
    Bread,             Papua New        2/2       100       500        250-750      Yuwai et al. (1994)
    wheat crumbs       Guinea
    Breakfast          United Kingdom   8/56      14        < 51                    Norton et al. (1982)
    cereals
    Corn               Michigan, USA    7/8       88        12         5-20         Abouzied et al. (1991)
    cerealse
    Corn               Canada           0/60      0         0                       Scott (1997)
    cerealse
    Corn chips         Michigan, USA    0/6       0         0                       Abouzied et al. (1991)

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Grain
    products

    Corn flakes        Canada           1/1       100       10         13-20        Scott et al. (1978)
    Corn products      Brazil                               0                       Soares & Rodriquez-Amaya  (1989)
    Corn products,     USA              0/119     0         0                       Stoloff & Dalrymple (1977)
    dry-milled

    Crackers           Michigan, USA    3/18      17        12         10-16        Abouzied et al. (1991)
     and cookies,
    wheat and oat
    Mixed-grain        Michigan, USA    2/3       67        31         12-50        Abouzied et al. (1991)
    cerealse
    Noodles            United Kingdom                       Trace                   Patel et al. (1996)
    Oat cerealse       Michigan, USA    3/5       60        16         9-22         Abouzied et al. (1991)
    Poppadoms          United Kingdom   0/4       0         0                       Patel et al. (1996)
    Rice               Michigan, USA    1/4       25        12         12-12        Abouzied et al. (1991)
    cerealse
    Wheat              Michigan, USA    2/12      16        28         27-30        Abouzied et al. (1991)
    cerealse
    Wheat noodles      United Kingdom   0/4       0         0                       Patel et al. (1996)

    Legumes

    Beans, red         Papua New        0/1       0         0                       Yuwai et al. (1994)
                       Guinea
    Beans,             Bulgaria         0/260     0         0                       Petkova-Bocharova et al. (1991)
    home-stored
    Beans, dried       Brazil                               0                       Soares & Rodriguez-Amaya (1989)
    Beans              Yugoslavia       1/50      2         160                     Pepeljnjak (1984)
    Legumes            Western Canada   0/NA      0         0                       Prior (1981)
    Legumes            Western Canada   0/NA      0         0                       Prior (1976)
    Soya beans         Canada           6/97      6         24         5-39         Scott (1997)
    and productsf

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Soya beans         Uruguay          15/17     88        < 100                   Pineiro et al. (1996b)
                                                  0/17      0                       100-200
                                                  2/17      12         > 200
    Soya bean          South Africa     0/14      0         NA                      Dutton & Kinsey (1995)
    meal

    Soya beans         South Africa     13/417    3                                 Dutton & Kinsey (1995)
    Soya beans         Papua New        0/3       0         0                       Yuwai et al. (1994)
                       Guinea
    Soya beans         Egypt            0/100     0         0                       El-Kady & Youssef (1993)
    Soya beans         USA              0/180     0         0                       Shotwell et al. (1977)

    Nuts and 
    seeds

    Areca nuts         South India      0/NA      0         0                       Sivaswamy et al. (1991)
    Almonds            Egypt            0/NA      0         0                       Abdel-Gawad & Zohri  (1993)
    Almonds            Spain            0/34      0         0                       Jimenez et al. (1991)
    Cashews            Egypt            0/NA      0         0                       Abdel-Gawad & Zohri  (1993)
    Cashews            South India      0/NA      0         0                       Sivaswamy et al. (1991)
    Chestnuts          Egypt            0/NA      0         0                       Abdel-Gawad & Zohri  (1993)
    Coconut            South India      0/NA      0         0                       Sivaswamy et al. (1991)
    Cottonseeds        South Africa     0/3       0         NA                      Dutton & Kinsey (1995)
    Fennel             United Kingdom   NA/3                7                       Patel et al. (1996)
    seeds
    Hazelnuts          Egypt            0/NA      0         0                       Abdel-Gawad & Zohri  (1993)
    Hazelnuts          Egypt            0/20      0         0                       Abdel-Hafez & Saber (1993)
    Hazelnuts          Spain            0/29      0         0                       Jimenez et al. (1991)
    Oilseeds           Uruguay          58/64     90        <100                    Pineiro et al. (1996b)
                                        3/64      5                    100-200      
                                        3/64      5         > 200                   
    Peanut             Botswana         0/15      0         0                       Siame et al. (1998)
    butter

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Peanuts            South Africa     0/10      0         NA                      Dutton & Kinsey (1995)

    Peanuts            Spain            0/38      0         0                       Jimenez et al. (1991)
    Ground             South India      0/NA      0         0                       Sivaswamy et al. (1991)
    nuts

    Peanuts            Egypt            1/40      3         NA                      El-Maghraby & El-Maraghy (1987)
    Pistachios         Egypt            0/NA      0         0                       Abdel-Gawad & Zohri  (1993)
    Pistachios         Spain            0/32      0         0                       Jimenez et al. (1991)
    Sesame             United Kingdom   0/3       0         0                       Patel et al. (1996)
    seeds

    Sunflower          South Africa     0/1       0         NA                      Dutton & Kinsey (1995)
    seeds
    Sunflower          Spain            0/35      0         0                       Jimenez et al. (1991)
    seeds
    Sunflower          Russian          NA/58                                       L'vova et al. (1993)
    seeds              Federation
    Walnuts            Egypt            0/NA      0         0                       Abdel-Gawad & Zohri  (1993)
    Walnuts            Egypt            1/20      5         125                     Abdel-Hafez & Saber (1993)
    Walnuts            France           3/60      5                    50-450       Jemmali & Mazerand (1980)

    Fruits and
    vegetables

    Banana,            India            NA                  17 000                  Chakrabarti & Ghosal  (1986)
    infected
    Apricot,           Egypt            0/3       0         0                       Zohri & Abdel-Gawad  (1993)
    dried 
    Fig,               Egypt            0/4       0         0                       Zohri & Abdel-Gawad  (1993)
    dried 

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Job's              Japan            8/12      67        39         6-116        Tanaka et al. (1993)
    tears
    Job's              Japan            7/7       100       133        10-440       Tanaka et al. (1985)
    tears
    Mung               Papua New        0/1       0         0                       Yuwai et al. (1994)
    beans              Guinea

    Fruit,             Uruguay          148/154   96        < 100                   Pineiro et al. (1996b)
    dried                               3/154     2                    100-200      
                                        3/154     2         > 200                   
    Plum,              Egypt            0/3       0         0                       Zohri & Abdel-Gawad (1993)
    dried 
    Raisins            Egypt            0/3       0         0                       Zohri & Abdel-Gawad (1993)
    Tamarind           South India      0/NA      0         0                       Sivaswamy et al. (1991)
    Tomato             Egypt            4/15      27        80 000                  El-Morshedy & Aziz (1995
      Aldicarbg                         0/15      0         0                       
      Carbofurang                       1/15      7         10 000                  
      Fenamiphosg                       2/15      13        25 000                  
    Tomato             South India      0/NA      0         0                       Sivaswamy et al. (1991)
    Vegetables,        United Kingdom   NA/8                6                       Patel et al. (1996)
    tinnedh
    Vegetables,        Uruguay          98/99     99        < 100                   Pineiro et al. (1996b)
    dried                               0/99      0                    100-200      
                                        1/99      1         > 200                   

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Spices
    and herbs

    Asiseeds           South India      0/NA      0         0                       Sivaswamy et al. (1991)
    Chili              United Kingdom                                               Patel et al. (1996)
      Pickle                            0/4       0         0
      Powder                            NA/4                           4.5-15       
      Powder, hot                       NA/3                           1-11         
      Sauce                             NA/4                7                       
    Coriander          United Kingdom   NA/3                           4-7          Patel et al. (1996)
    seeds
    Coriander          South India      0/NA      0         0                       Sivaswamy et al. (1991)

    Curry              United Kingdom                                               Patel et al. (1996)
      Mix, dry                          NA/4                5.2                     
      Paste                             NA/4                           3-4          
      Powder                            0/3       0         0                       
    Curry              South India      0/NA      0         0                       Sivaswamy et al. (1991)
    leaves
    Five-spice         United Kingdom   NA/4                           3-5          Patel et al. (1996)
    powder
    Garlic             United Kingdom   0/4       0         0                       Patel et al. (1996)
    Garlic             United Kingdom   NA/4                4                       Patel et al. (1996)
    pickle
    Ginger             United Kingdom   0/4       0         0                       Patel et al. (1996)
    Ginger             South India      0/NA      0         0                       Sivaswamy et al. (1991)
    Mint               South India      0/NA      0         0                       Sivaswamy et al. (1991)
    leaves
    Mustard            India            NA                  36 000                  Chakrabarti & Ghosal (1987)
    seed
    Tandori            United Kingdom   0/3       0         0                       Patel et al. (1996)
    Spices,            Egypt            0/120     0         0                       El-Kady et al. (1995)
    24 kinds 

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Animal muscle and organs

    Meat               Uruguay          58/58     100       < 100                   Pineiro et al. (1996b)
    products
    Pig                                                                78-310i      James & Smith (1982)
    liver
    Chicken            Minnesota, USA                                  59-103j      Mirocha et al. (1982)
    muscle
    Chicken            Minnesota, USA                       681k                    Mirocha et al. (1982)
    liver
    Animal             Western Canada   0/24      0         0                       Prior (1981)
    tissue
    Liver              Western Canada   0/10      0         0                       Prior (1976)
    and kidney

    Milk

    Buttermilk         South India      0/NA      0         0                       Sivaswamy et al. (1991)
    Cows' milk         South India      NA                  25                      Sivaswamy et al. (1991)

    Cows' milk         Minnesota, USA                                               Mirocha et al. (1981)
      7 days after
      25 mg/kg diet                     1/1       100       210                     
      1 day after
      250 mg/kg diet                    1/1       100       45                      
      2 days after
      250 mg/kg diet                    1/1       100       62                      
    Sheep's            Minnesota, USA                       1-2                     Hagler et al. (1980)
    milkl

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Miscellaneous products

    Beer, Korean       Republic of      0/54      0         0                       Shim et al. (1997)
    and imported       Korea
    Beer               Canada           1/NA                                        Scott (1996) 
    Beer,              Canada           0/50      0         0                       Scott et al. (1993)
    Canadian
    and imported
    Beer               Lesotho          17/140    12                   300-2000     Martin & Keen (1978)
    Beer               Nigeria          4/4       100       153        49-264       Okoye (1987)
                                                            g/brew    g/brew
    Beer,              Zambia           NA/23               920        90-4600      Lovelace & Nyathi (1977) 
    opaque
    maize
    Cassava            Brazil                               0                       Soares & Rodriguez-Amaya (1989)
    flour
    Chili/almond       United Kingdom   NA/4                5                       Patel et al. (1996)
    oil
    Cocoa beans        Uruguay          69/69     100       < 100                   Pineiro et al. (1996b)
    Corn oil           New Zealand      1/1       100       4600                    Lauren & Ringrose (1997)
    Cottonseeds        Egypt                                0                       Mazen et al. (1990)
    Cottonseed         Egypt                                0                       Mazen et al. (1990)
    meal
    Cottonseed         Egypt                                0                       Mazen et al. (1990)
    cake
    Fermented          Swaziland        6/55      11                   8000-5300    Martin & Keen (1978)
    products
    Infant             Canada           9/60      15        4.2                     Roscoe (1998)
    foods
    Infant             Japan            0/27      0         0                       Isohata et al. (1986)
    foodsm

    Table 5. (continued)
                                                                                                                 

    Food               Geographical     Incidencea          Concentration           Reference
                       location                             (g/kg or g/L)b        
                                        D/T       %         Mean       Range
                                                                                                                 
    Infant             Canada           8/13      62                   < 3-4.5      Roscoe (1998)
    mixed
    cereals
    Infant             Canada           7/8       88                   < 3-6.9      Roscoe (1998)
    soya
    cereal
    Phanen             Botswana         0/20      0         0                       Siame et al. (1998)

    Ragi               South India      NA                  2056                    Sivaswamy et al. (1991)
    Sesame             United Kingdom   0/3       0         0                       Patel et al. (1996)
    oil
    Sugar                                                                           Bosch & Mirocha (1992)
    beets
      Mouldy field                      6/25      24                   12-391       
      Commercial
      stockpiles                        0/10      0         0                       
    Tea,               Croatia          0/7       0         0                       Halt (1998)
    herbal
    Toddy              South India      NA                  765                     Sivaswamy et al. (1991)
                                                                                                                 

    NA, not available

    a Incidence presented as number of times zearalenone was detected (D) in the total
      number of samples analysed (T). The percent incidence (D/T  100) was rounded to the
      nearest whole number, 0.5 being rounded upwards. 
    b Concentrations above the limit of detection are given as mean values and ranges.
      The concentrations of zearalenone in foods were reported in several units,
      including ng/g, ppb, g/g, mg/kg, ppm, g/L, and mol/kg. To allow comparisons
      of values from different references, most of the values are expressed in g/kg.
    c Barley imported from Canada and Sweden; rye imported from Germany, Hungary, the
      Russian Federation, Sweden, and the USA; wheat imported from Canada, Germany,
      Hungary, Saudi Arabia, and the USA

    Table 5. (continued)
                                                                                                                 


    d Referred to as maize in the cited reference.
    e Breakfast cereals
    f Soya products included soya flour, soya bean protein, tofu, and soya sauce.
    g Tomatoes grown on soil treated with these nematicides
    h Not further described
    i Zearalenone at 40 mg/kg feed for four weeks
    j Zearalenone at 100 mg/kg feed for eight days
    k Zearalenone at 10 mg/day (5 mg/kg bw)
    l Sheep received a dose of 1.8 g zearalenone.
    m Rice sticks, two samples; biscuits, eight samples; gruel, eight samples;
      rice cake, one sample; apple juice, two samples; vegetable soup, one sample;
      mixed fruit juice, two samples; tomato juice, one sample; peach juice,
      one sample; mandarin orange juice, one sample
    n Larval stage of the Emperor moth
    

         The concentrations of zearalenone in the grain products in Table
    5, which include breads, breakfast cereals, crackers, cookies, and
    noodles from six countries, were low or below the limit of detection.

         The concentrations in legumes, available from 12 references
    representing nine countries, and in nuts, from 12 references
    representing 11 countries, were mostly below the limit of detection.
    The values for fruits and vegetables, available from nine references
    representing seven countries, were mostly below the limit of detection
    or low, but a high concentration was found in infected bananas in
    India. The authors (Chakrabarti & Ghosal, 1986) reported that infected
    bananas are preferred by the population because of their sweet taste.
    The concentrations of zearalenone in a number of spices and herbs
    (four references from three countries) were usually at or below the
    limit of detection.

         In five references from three countries, the concentrations of
    naturally occurring zearalenone in animal tissues were below the limit
    of detection or low, although the values can be temporarily elevated
    when animals have been treated with zearalenone (James & Smith, 1982;
    Mirocha et al., 1982; Annex 1, reference  82; see below for more
    discussion.)

         The concentrations in milk are described in only three references
    from two countries. Zearalenone and its metabolites may occur in the
    milk of animals fed or dosed with the substance, but the normal
    concentrations are usually below the limit of detection or low (see
    below for more discussion).

         Miscellaneous products were reported in 16 references
    representing 15 countries, with values below the limit of detection.
    Of particular interest are the concentrations in beers made from
    contaminated grains in Africa (Martin & Keen, 1978; Okoye, 1987;
    Lovelace & Nyathi, 1977). Zearalenone and alpha-and beta-zearalanol
    have not been found in beers from Canada, Europe (except at 100 g/L
    in one French beer), or the Republic of Korea (Okoye, 1987; Scott,
    1996; Shim et al., 1997).

    3.2  Variables that affect contamination

         The concentrations of zearalenone may increase in moist grains
    during storage. The factors that favour its production in foods are
    generally the same as those that favour the development and growth of
     Fusarium mould in crops during growth, harvest, and storage. The
    variables that affect the incidence and concentration of zearalenone
    in foods are described below.

    3.2.1  Weather and climate

         The results of reports on the effects of rainfall, temperature,
    and humidity on the concentration of zearalenone in foods are
    inconsistent, probably because the combination of these variables is
    difficult to control for. In general, zearalenone production by
     Fusarium spp. is greater in mouldy samples and is favoured by wet
    climates (high rainfall) and especially by wet, cool weather. Cliver
    (1990) reported that the production of zearalenone on corn and other
    cereals is favoured by temperatures near freezing for an extended time
    and by cycles of temperature from low to moderate.

         The effects of moisture content, relative humidity, temperature,
    and rainfall on mycotoxin production were determined in 130 samples of
    post-harvest and stored corn in Sao Paulo, Brazil, throughout one year
    (Pozzi et al., 1995).  Fusarium spp. were the main contaminants, and
    a significant positive correlation was found for the presence of
     Fusarium with the moisture content of grains and a significant
    negative correlation with minimum and medium temperatures, rainfall,
    and relative humidity.

         The occurrence of mycotoxins (including zearalenone) in wheat,
    rye, rice, corn, and sunflower seeds collected from commercial batches
    in four grain-producing areas of the Russian Federation was greater in
    the humid, southern regions and in Kazakhstan and Uzbekistan (L'vova
    et al., 1993).

         The 1990 barley crop in the southern part of the Republic of
    Korea was reported to have been heavily contaminated with  Fusarium
    mycotoxins because of the high rainfall and humidity during that year
    (Park et al., 1992).

         A combined effect of water activity and temperature on
    zearalenone synthesis in corn has been reported. A constant
    temperature of 25 C was most favourable, but both  F. graminearum
    growth and zearalenone production at this temperature were inhibited
    at a water activity of 0.90. With short incubation times, toxin
    accumulation was greater at a water activity of 0.97 than at 0.95, but
    this relationship was inverted with longer incubation (Montani et al.,
    1988).

         When  Fusarium isolates from wheat were tested for their ability
    to produce trichothecenes and zearalenone, 12 of 13 isolates of
     F. culmorum produced zearalenone, with particularly high yields in
    cultures of seven pathogenic isolates. A higher temperature (20 C)
    during the first week of incubation increased the yield (Chelkowski et
    al., 1984).

    3.2.2  Agricultural production methods

         In 1993, 1.7% of the cereal deliveries in 24 cereal-collecting
    centres in Switzerland were affected by  Fusarium, but only 0.2% were
    affected in 1994. The concentrations of mycotoxins were not affected
    by whether the cereals were grown conventionally or without
    fungicides, insecticides, and bioregulators (Bucheli et al., 1996).

         The organophosphate nematicide fenamiphos and the carbamate
    nematicides carbofuran and aldicarb reduced the occurrence of
     Fusarium spp. on the roots and fruits of tomato plants, and
    zearalenone production at harvest was inhibited or reduced in
    comparison with controls (El-Morshedy & Aziz, 1995).

         In 100 samples of German rye and 101 samples of wheat grown
    conventionally or ecologically, zearalenone was found in 40 samples,
    with average concentrations of 6 g/kg in conventionally grown wheat,
    24 g/kg in alternatively grown wheat, 4 g/kg in conventionally grown
    rye, and 51 g/kg in alternatively grown rye. The highest
    concentration of zearalenone was 199 g/kg in alternatively grown rye
    (Marx et al., 1995).

    3.2.3  Varieties and cultivars

         When grains from 14 inbred and 4 single-cross hybrids of corn
    were inoculated with three isolates of  Gibberella zeae, the hybrids
    appeared to have less resistance to toxin formation than the inbred
    varieteies. Analysis of variance indicated a highly significant
    variation between corn varieties and fungal isolates (Shannon et al.,
    1980).

         The zearalenone content of corn subspecies may vary, but no
    information was available in the literature about the zearalenone
    content of different types of corn or its products. Corn, also called
    maize and Indian corn, belongs to the family Gramineae (grass) and is
    of the genus and species  Zea mays. The corn grain consists of an
    outer hull, the soft endosperm being used for corn flour, the hard
    endosperm to make corn meal and corn grits, and the soft oily germ for
    corn oil. A number of subspecies or commercial classifications of corn
    are based on kernel texture (Yamaguchi, 1983): Dent corn (indentata)
    has a depression in the crown of the kernel caused by unequal drying
    of the hard and soft starch making up the kernel. The grains have a
    corneous endosperm with soft white starch. Flint corn ( indurata) is
    the field corn characterized by a starchy endosperm. The kernels are
    large and broad with rounded tops. When they are harvested at the
    immature stage, they are called roasting ears and are used as a
    vegetable. Flint corn contains little soft starch. Flour or soft corn
    ( amylacea) kernels have a soft or floury rather than a vitreous
    endosperm. This corn is composed largely of soft starch and has soft,
    mealy, easily ground kernels. Sweet corn ( sacchorata) has grains
    with a sweetish endosperm at the immature stage. Starch accumulation
    occurs with maturity, but less sugar is converted to starch than in

    the other corn types. There are a number of sweet corn varieties, with
    yellow, white, or black kernels. Popcorn ( everta) is an extreme type
    of flint corn with small, hard kernels, and a large portion of the
    endosperm is horny. The ears and kernels are small. When the kernels
    are heated, the moisture turns to steam and causes an explosion,
    bursting the seed coat and exposing the white fluffy endosperm. It is
    devoid of soft starch.

    3.2.4  Storage conditions

         Zearalenone can grow on corn not only in the field but also
    during storage, especially when the corn has too much moisture when
    harvested and is not dried properly before storage (Cliver, 1990). In
    Hungary, 88% of mouldy stored corn samples contained zearalenone; the
    incidence of contamination and the mycotoxin concentrations were
    markedly lower in samples that were not mouldy. During harvest, only
    17% of samples contained zearalenone (Fazekas et al., 1996).

         Zearalenone production was inhibited almost completely in
    high-moisture corn grains kept under atmospheres enriched with 20-60%
    carbon dioxide with 20 or 5% oxygen. Less carbon dioxide was needed to
    inhibit fungal development and toxin formation in the presence of less
    oxygen (Paster et al., 1991).

         Zearalenone was not detected in amaranth grains at 25 C with a
    water activity of 0.902, and maximum accumulation occurred at a water
    activity of 0.92 at 35 days and 0.95 at 29 days (Bresler et al.,
    (1998).

         The disappearance of zearalenone from contaminated corn was
    dependent on the concentration of water, temperature, and the length
    of exposure. A degradation rate of 84% was seen with 10% water at 80
    C for 16 h and 75% degradation under the same conditions for 8 h;
    only 3% degradation was seen with 3% water at 50 C for 2 h (Abd Alla,
    1997).

         In a study of the production of zearalenone in corn by seven
    isolates of  Fusarium under different conditions of water activity,
    temperature, and incubation time, two isolates of  F. graminearum were
    the most active. The culture conditions that resulted in the highest
    yields were a water activity of 0.97, two weeks' incubation at 28 C,
    and 40 days' incubation at 12 C. These conditions were also optimal
    for two isolates of  F. oxysporum, but for the remaining isolates the
    maximum concentrations of zearalenone were obtained at room
    temperature and 30 days' incubation. At 37 C, zearalenone was not
    detected under any of the conditions assayed (Jimenez et al., 1996).

         Six of 25 mouldy sugar beet rot samples collected in the field
    contained zearalenone at concentrations of 12-390 g/kg, whereas 10
    samples from commercial stockpiles showed no activity (Bosch &
    Mirocha, 1992).

         Stored rice was comparatively resistant to contamination with
    mycotoxins, none being found in 208 samples; however, zearalenone was
    detected in some samples subjected to experimental self-heating
    (L'vova et al., 1984).

         The only mycotoxin found in wheat maintained at 15 and 22 C for
    10 weeks was ochratoxin A (Abramson et al., 1982).

         Zearalenone was found in both cobs and grain of freshly harvested
    corn with 26-35% humidity. Maximum amounts were found in cobs when the
    temperature reached 30-45 C due to self-heating, and the highest
    concentra-tion of zearalenone was found on days 8-12 after the onset
    of self-heating (L'vova et al., 1981).

    3.2.5  Gamma irradiation

         Gamma-irradiation greatly reduced the natural occurrence of
     Fusarium mycotoxins in wheat, flour, and bread, the zearalenone
    concentrations being reduced from 28-42 g/kg to 20 g/kg in wheat and
    from 95 to 45 g/kg in flour after exposure to 4 kGy. A sharp drop in
     Fusarium toxin concentrations occurred at 5 kGy, and all were
    eliminated at 6 or 8 kGy (Aziz et al., 1997).

         Significant reductions in the zearalenone concentration of corn
    were found after gamma irradiation at 10 or 20 kGy, with no
    significant interaction between radiation dose and grain moisture
    level (Hooshmand & Klopfenstein, 1995).

         At 9 kGy, neither mycotoxin growth nor toxin production could be
    detected in corn or rice inoculated with  F. graminearum or
     F. tricinctum (Halasz et al., 1989).

    3.2.6  Grain preservatives and disinfectants

         Strains of  F. semitectum that produced zearalenone were found
    in amaranth grains both before and after surface disinfection (Bresler
    et al., 1995).

         In a study of the effects of the grain preservatives Luprosil
    (propionic acid) and Gasol (organic acids with other compounds) on the
    growth of mycelium and the zearalenone content of stored oats infected
    by  Fusarium, both preservatives completely prevented the growth of a
    visible mycelium. Luprosil had no influence on the toxin content of
    the oats, but Gasol decreased the percentage of the total toxin by 60%
    in three days, 85% in 14 days, and 90% in 28 days (Kallela &
    Saastamoinen, 1981a). Luprosil and Gasol completely prevented visible
    mycelium growth of  F. graminearum on contaminated oats, wheat, and
    barley, and Gasol, but not Luprosil, reduced the amount of zearalenone
    in the crops (Kallela & Saastamoinen, 1981b). The degree to which
    zearalenone in milled grains was destroyed by Gasol depended on the
    dose applied. A dose twice that recommended destroyed all the toxin in

    the grains, whereas one-eighth of the recommended dose prevented the
    growth of the fungus but only slightly reduced the amount of toxin at
    onset. Later, the growth of the fungus was more vigorous and
    significantly more toxin was present in the treated grain than in the
    grain that had not been treated with Gasol (Kallela & Saastamoinen,
    1982).

         No aflatoxin or zearalenone was reported in grains that had been
    treated with dichlorvos at 20 mg/kg, whereas untreated samples
    contained zearalenone at an average concentration of 150 000 g/kg
    (Rao & Harein, 1973).

    3.2.7  Food processing, preparation, and cooking

         Like most mycotoxins, zearalenone is heat-stable, and
    decomposition during cooking or processing is therefore unlikely
    (Fink-Gremmels, 1989). No change was observed when pure zearalenone
    was heated for 4 h at 120 C, and when it was present in ground corn
    no decomposition was seen after 44 h at 150 C (Gilbert, 1989). Wet
    milling of contaminated corn concentrated zearalenone in the gluten
    fraction by two-to sevenfold; some remained in the soluble fraction
    but almost none in the starch fraction (Bennett et al., 1978a,b).
    After corn grown in New Zealand had been passed through a commercial
    wet-milling plant, only 600 g/kg was present in concentrated steep
    liquor whereas 2200-4800 g/kg were present in the germ, fibre, and
    gluten fractions (Lauren & Ringrose, 1997).

         Dry-milling of corn resulted in recovery of 10-20% zearalenone in
    grits (Bennett et al., 1976). Processing of rice grain resulted in a
    substantial reduction in the concentration of zearalenone, by 88% in
    rice groats and 37% in cooked rice (L'vova et al., 1984). About 60% of
    zearalenone survives bread baking, 40-50% survives noodle manufacture,
    and 80% remains after biscuit manufac-ture (Gilbert, 1989).

         Zearalenone has been reported in beers from Lesotho, Swaziland,
    and Zambia (Lovelace & Nyathi, 1977; Martin & Keen, 1978; Okoye,
    1987). The mean concentration of zearalenone that passed from mouldy
    guinea-corn into native Nigerian beer ( burukutu) was about 51% of
    that in the starting mixture, suggesting moderate stability during
    fermentation. About 12% of the zearalenone was discarded in the solid
    residue (Okoye, 1987).

    3.2.8  Residues in animal tissues

         The amount of detectable zearalenone in animal tissues depends on
    the contamination of feed, treatment of animals with zearalenone or
    alpha-zearalanol, duration of exposure to the toxin, the persistence 
    of zearalenone in the animal, and species variation in response to the
    mycotoxin. Few attempts have been made to detect zearalenone in animal
    products or to determine residue rates (Kuiper-Goodman et al., 1987;
    Gilbert, 1989).

    3.2.8.1  Muscle and organ meats

         Plasma clearance of implanted alpha-zearalanol in cattle was
    rapid and the drug did not accumulate appreciably in any edible
    tissue. After 65 days, no residues could be detected (Sharp & Dyer,
    1972).

         The concentration of zearalenone in liver from a pig given feed
    containing zearalenone at 40 mg/kg for four weeks was 78-128 g/kg
    (James & Smith, 1982). Zearalenone was found in 23 samples of piglet
    liver and 16 pig milk samples from animals with mycotoxicosis or fed
    mouldy feed (Sandor, 1984).

         Chickens fed feed containing 100 mg/kg zearalenone for eight days
    had concentrations of 59-103 g/kg in muscle and up to 681 g/kg in
    liver (Mirocha et al., 1982). Substantial residues of zearalenone and
    its metabolites were found in the livers of chickens during the first
    24 h after exposure to [14C]zearalenone, but the amount of
    radiolabel declined rapidly thereafter. The lowest concentrations were
    found in skeletal muscle (Dailey et al., 1980).

         The maximum residue limits recommended by the Committee at its
    thirty-second meeting for use of zeranol (alpha-zearalanol) as a
    veterinary drug were 10 g/kg in bovine liver and 2 g/kg in bovine
    muscle (Annex 1, reference 80). When recommending maximum residue
    limits for veterinary drugs, the Committee uses food factors of 100
    g/day for liver and 300 g/day for muscle in calculating a theoretical
    maximum daily intake to ensure that, when used according to good
    practice in the use of veterinary drugs, the intake would not exceed
    the ADI. On the basis of the recommended maximum residue limits and
    these food factors, the theoretical maximum daily intake of
    alpha-zearalanol is 1.6 g/day.

    3.2.8.2  Eggs

         Eggs accumulated metabolites of zearalenone in the yolks, even
    after 94% of the dose had been eliminated in excreta (Dailey et al.,
    (1980). In an experiment to determine the effects of corn and grain
    sorghum on the performance of laying hens, egg production decreased
    significantly and lesions were more severe in hens fed grain sorghum
    than in those fed corn. Analysis of the grains revealed the presence
    of low concentrations of zearalenone and other mycotoxins in the
    sorghum (Branton et al., 1989).

    3.2.8.3  Milk

         Experimental studies have shown some transmission of zearalenone
    and alpha-and beta-zearalanol into the milk of sheep (Hagler et al.,
    1980), cows (Mirocha et al., 1981), and pigs (Pullar & Lerew, 1937;
    Miller et al., 1973; Kurtz & Mirocha, 1978; Palyusik et al., 1980;
    Vanyi et al., 1983) given high concentrations of zearalenone. Once
    administration was stopped, the concentrations in milk dropped

    sharply, although the compound was still detectable after five days in
    sheep milk (Hagler et al., 1980) and pig milk (Palyusik et al., 1980).
    Dairy cattle fed a diet containing 25 mg/kg of zearalenone for seven
    days excreted only 1.3 mg/kg of zearalenone and its metabolites in
    milk, indicating that milk is not a likely source of zearalenone
    residues (Mirocha et al., 1981, 1982).

         The milk of one cow given 6000 mg zearalenone (equivalent to 12
    mg/kg bw) contained maximum concentrations of 6.1 g/L zearalenone, 4
    g/L alpha-zearalenol, and 6.6 g/L beta-zearalenol. Neither
    zearalenone nor its metabolites was found in the milk (< 0.5 g/L) of
    three lactating cows fed 50 or 165 mg zearalenone (equivalent to 100
    or 330 g/kg bw per day) for 21 days (Prelusky et al., 1990).

         No residue of zearalenone was found in animal products after
    administration of lower dietary concentrations (Shreeve et al., 1979;
    Young et al., 1982). None was detected in several normal pig milk
    samples (Palyusik et al., (1980), and zearalenone has not been
    detected in normal retail milk samples, although only limited
    surveillance has been undertaken (Gilbert, 1989). Only minimal
    transmission of zearalenone to bovine milk has been demonstrated under
    realistic concentrations of exposure (Krska, 1999).

    3.3  Regulation, control, and monitoring

         Owing to the huge amounts of corn that are found in world trade,
    contamination by zearalenone is of economic relevance, and reliable
    means of control are needed. As the risk of contamination is a
    criterion of quality in trade, especially for corn and corn products,
    many cereal companies include analysis for zearalenone in their
    internal quality control of corn production. Livestock producers and
    food and feed processors are concerned by the presence of zearalenone
    in corn because their competitiveness and profitability depend on
    control of mycotoxins in animal diets. Because mould-damaged corn is
    often used in animal feed, the risk for zearalenone intoxication is
    highest for farm animals. Six countries--Austria, Brazil, France,
    Romania, the Russian Federation, and Uruguay--have set maximum
    tolerated concentrations of zearalenone at 30-1000 g/kg in some or
    all foods, and three countries--Cyprus, Hungary, and The Netherlands--
    have set maximum tolerated concentrations for all mycotoxins at 0-0.5
    g/kg in some foods. Questions have been raised, however, about the
    rationale used by governments to regulate zearalenone and about the
    implementation of guidelines in different countries (Krska, 1999). The
    only country that has provided a rationale for setting limits for
    mycotoxins (other than aflatoxins) in human foods and animal feeds is
    Canada, where risk assessments have been performed for
    deoxynivalenol, zearalenone, and ochratoxin A (Van Egmond, 1993).

         A pilot study for monitoring mycotoxin contamination of foods and
    feeds was implemented in Uruguay with technical assistance from FAO to
    determine the potential hazard of food and feed contaminants (Pineiro
    et al., 1996b). The principal commodities were wheat, barley, rice,
    corn, soya, dairy products, feeds, dried fruits, dried legumes, oil

    seeds, cocoa beans, and organ meats, and zearalenone was included
    among the mycotoxins analysed. The results for 1993-95 showed that
    feed had the highest concentrations of mycotoxins, but the regulatory
    limits for toxins were exceeded by less than 3% in wheat, 9% in
    barley, and 7% in rice samples.

    3.4  Dietary intake

         Only three reports are available of human dietary intake of
    zearalenone: two from Canada (Kuiper-Goodman et al., 1987; Canada,
    1999) and one from the Nordic countries (Eriksen & Alexander, 1998).
    Estimates are provided here for the US population and for the five
    regional diets established by the WHO Global Environment Monitoring
    System-Food Contamination Monitoring and Assessment Programme
    (GEMS/Food). Guidelines are given for a model of exposure to
    zearalenone.

    3.4.1  Estimates for Canada, 1987

         Kuiper-Goodman et al. (1987) estimated the intake of zearalenone
    by Canadians on the basis of the assumption that the mean
    concentration of zearalenone in corn used for corn-based breakfast
    cereals was 39.3 g/kg. The estimated daily intake of zearalenone from
    the consumption of corn cereals containing 33 g/kg, popcorn
    containing 18.6 g/kg, and beefsteak by the highest consumption group,
    12-19-year-old males, is shown in Table 6. The estimated average daily
    exposure to zearalenone from corn cereals for the whole group and for
    eaters and 90th percentile consumers was 0.12, 1.2, and 2.5 g/person,
    respectively, and the intake from popcorn was estimated to be 0.06,
    0.52, and 1.3 g/person, respectively. The total from all three
    sources for the whole group was 0.19 g/day or 0.003 g/kg bw per day.

         Kuiper-Goodman et al. (1987) also calculated the intake of
    zearalenone for 1-4-year-old children (Table 7). On the basis of body
    weight, the children's greatest exposure to zearalenone was from corn
    cereals. Exposure to zearalenone in other foods such as wheat, flour,
    or milk could increase the estimates, and exposure to estrogens from
    other sources would add to the estrogenic burden. The authors
    recommended that exposure to other sources of related estrogens (such
    as alpha-zearalanol in milk) be estimated.

        Table 6. Zearalenone intake of Canadian males aged 12-19 years, 1987
                                                                                     
    Food                        Zearalenone     Food         Zearalenone intake
                                concentration   intake                               
                                (g/kg)         (g/day)      g/day   g/kg bw per day
                                                                                     

    Corn cereals                33
      All persons                               3.6          0.12     0.002
      Eaters only                               37           1.2      0.020
      90th percentile eaters                    76           2.5      0.042
    Popcorn                     19
      All persons                               3            0.06     0.001
      Eaters only                               28           0.52     0.009
      90th percentile eaters                    72           1.3      0.022
    Beefsteak                   1.0
      All persons                               13           0.01     0.000
      Eaters only                               150          0.15     0.003
      90th percentile eaters                    340          0.34     0.006

    Total                                                    0.19     0.003
                                                                                     

    Adapted from Kuiper-Goodman et al. (1987); body weight, 60 kg

    The consumption figures for cereals and beefsteak were obtained from the
    Nutrition Canada Survey conducted by Health and Welfare Canada, and those
    for popcorn were obtained from a food consumption survey of the
    US Department of Agriculture.
    
    3.4.2  Estimates for Canada, 1999

         The estimated intake of zearalenone by 60-kg Canadian adults
    (Table 8) is based on the concentrations of zearalenone in 10 products
    and the estimated consumption of six of those foods. The estimated
    mean intake of zearalenone was < 0.98 g/day or < 0.016 g/kg bw per
    day. The contributions of the foods to the daily intake of zearalenone
    were 30% from hard wheat, 30% from amber durum wheat, 20% from corn,
    15% from rice, 4% from barley, 4% from soft wheat, 3% from cornmeal
    products, and none from oats, soya beans, or tinned beans.

         The estimated intake of zearalenone by infants (Table 9) is based
    on the concentrations of zearalenone in infant cereal, infant formula,
    and creamed corn and the consumption of these products by infants aged
    6-9 months. The daily estimated mean intake was < 0.52 g or < 0.06
    g/kg bw. The intake comprises 60% from infant formula, 23% from
    infant cereals, and 17% from creamed corn.

    3.4.3  Estimates for Denmark, Finland, Norway, and Sweden

         Eriksen & Alexander (1998) calculated the average daily intake of
    zearalenone on the basis of the intake of wheat, rye, barley, and oats
    derived from food balance sheets. The intakes were 0.48 g/day (0.01
    g/kg bw per day) in Denmark; 1.2 g/day (0.02 g/kg bw per day) in
    Sweden; 1.3 g/day (0.02 g/kg bw per day) in Finland; and 1.5 g/day
    (0.02 g/kg bw per day) in Norway. Because the information on food
    intake on balance sheets reflects the national concentration
     per capita, results based on this information are probably
    over-estimates. When food consumption data derived from individual
    quantitative questionnaires were used to calculate the daily intake of
    zearalenone from the same commodities in Denmark and Norway, the
    average daily intakes were 1.2 g/day (0.02 g/kg bw per day) in
    Denmark and 1.1 g/day (0.02 g/kg bw per day) in Norway. It is
    curious that the average daily intake for Denmark was higher when
    individual intake data were used than when the data from balance
    sheets were used.

        Table 7. Zearalenone intake of Canadian children aged 1-4 years, 1987
                                                                                       

    Food                         Zearalenone     Food         Zearalenone intake
                                 concentration   intake                                
                                 (g/kg)         (g/day)      g/day    g/kg bw per day
                                                                                       

    Corn cereals                 33
      All children                               2.2          0.07      0.005
      Eaters only                                21           0.69      0.050
      90th percentile eaters                     76           2.5       0.042
    Popcorn                      19
      All children                               1.1          0.02      0.001
      Eaters only                                11           0.21      0.015
      90th percentile eaters                     18           0.33      0.023
    Beefsteak                    1.0
      All children                               3.4          0.00      0.000
      Eaters only                                46           0.05      0.003
      90th percentile eaters                     110          0.11      0.008
    Milk                         1.0
      All children                               380          0.38      0.027
      Eaters only                                670          0.67      0.047
      90th percentile eaters                     950          0.95      0.066

    Total intake of all                                       0.47      0.033
    children
    Total intake of eaters                                    1.6       0.12
    only
                                                                                       

    Adapted from Kuiper-Goodman et al. (1987); body weight, 14 kg.
    Consumption figures for cereals and beefsteak were obtained
    from the Nutrition Canada Survey conducted by Health and
    Welfare Canada, and those for popcorn were obtained from
    a food consumption survey of the US Department of Agriculture.
    
        Table 8. Zearalenone intake of 60-kg Canadian adults, 1999
                                                                                              
    Food                          Zearalenone    Food            Zearalenone intake 
                                  concentration  intake          
                                  (g/kg)        (g/day)         g/day      g/kg bw per day
                                                                                              

    Barley                        < 8.3          4.7             < 0.039     < 0.001
    Beans, tinned                 < 10           NR
    Cornmeal or flour productsa   < 13           2.0             < 0.025       0.000
    Corn, kernel or cob           < 41           4.8             < 0.2       < 0.003
    Oats                          < 5.0          NR
    Rice                          < 7.4          20              < 0.15      < 0.003
    Soya beans                    < 10           NR
    Wheat, amber durum            < 3.7          64              < 0.24      < 0.004
    Wheat, hard                   < 5.6          53              < 0.3       < 0.005
    Wheat, soft                   < 7.4          5.3             < 0.039     < 0.001

    Table 8. Zearalenone intake of 60-kg Canadian adults, 1999
                                                                                              
    Food                          Zearalenone    Food            Zearalenone intake 
                                  concentration  intake          
                                  (g/kg)        (g/day)         g/day      g/kg bw per day
                                                                                              
    Total                                                        < 0.98      < 0.016
                                                                                              

    Adapted from Canada (1999); NR, not reported; assumed to be insignificant
    a Includes tortillas, natchos, and other corn snacks and products
    
    3.4.4  Estimates for the USA (eaters only)

         Estimates for the intake of zearalenone in US diets are based on
    food intake data from the US Department of Agriculture Continuing
    Survey of Food Intakes by Individuals for 1989-91 (Krebs-Smith et al.,
    1997). The survey derived information on dietary intake information
    from a one-day recall and from a two-day food record for 11 488
    individuals. Table 10 gives the daily intake of foods likely to
    contain zearalenone for individuals who reported eating the food on
    one or more days, as mean intakes for eaters who were 2 years of age
    and older and for men aged 20-39 years and the 90th percentile intakes
    of men aged 20-39.

         In the absence of more reliable data, the concentrations of
    zearalenone in foods in the 1999 Canadian estimates were also used for
    the USA, with the addition of a value of 10 g/kg for popcorn since no
    value for this commodity was included in the Canadian estimates. The
    concentration of zearalenone in durum wheat was used for pasta, the
    value for soft wheat was used for cakes, doughnuts, or sweet rolls,
    and the value for hard wheat was used for the other grain products.
    Because wheat is the primary ingredient in biscuits, yeast bread,
    pasta, and rolls, the value for wheat was used directly. Since the
    other grain products contain ingredients other than wheat, such as
    sugar, shortening, eggs, milk, fruit, cheese, and meat, the
    consumption figures were reduced by one-half in order to avoid
    overestimating the zearalenone intake from these products.

         For several of the grain products (cooked cereal, ready-to-eat
    cereals, and tortillas), the type of grain was not specified. Cooked
    cereals in the USA include wheat and rice, oatmeal being counted
    separately; ready-to-eat cereals are made of wheat, corn, oats, and
    rice; and tortillas are made of either flour or corn. The
    concentrations of zearalenone in hard wheat were used for these
    products as it was suspected that most are wheat-based.

    3.4.5  Estimates for the USA, all persons

         Table 11 shows the average daily intakes of foods in the USA by
    all persons aged 2 years or older and for men aged 20-39 years, on the
    basis of the food composition values used for eaters only. The
    zearalenone intakes of all persons are additive, whereas those for
    eaters only are not since they would not be expected to consume all
    the foods listed on a given day.

        Table 9. Zearalenone intake of 8.7-kg Canadian infants, 6-9 months of age, 1999
                                                                                       

    Food                         Zearalenone     Food       Zearalenone intake
                                 concentration   intake                                
                                 (g/kg)         (g/day)    g/day      g/kg bw per day
                                                                                       

    Infant cereal                < 3.4           35         < 0.12      < 0.014
    Infant formula               < 3.0           100        < 0.31      < 0.036
    Creamed corn (vegetable)     < 3.0           30         < 0.089     < 0.010

    Total                                                   < 0.52      < 0.060
                                                                                       

    Adapted from Canada (1999)
    
    3.4.6  Limitations of estimates

         The estimates of dietary intake of zearalenone given by
    Kuiper-Goodman et al. (1987) were based on only three foods for men
    and four for young children and did not include values for cornmeal or
    cornflour products, corn kernels, rice, or wheat products. The
    estimates are therefore probably low, as indicated by comparing these
    results with those in the more recent Canadian study (Table 12), which
    include seven foods in adult diets and three in infant diets. Although
    the figures from the 1999 Canadian study were used for the US
    estimates, these are higher than the ones for Canada, perhaps because
    more food products were included and as a result of the overestimates
    of zearalenone in finished grain products, especially those of wheat.
    The zearalenone concentration in wheat was assigned to the full weight
    of some wheat products and half the weight of products with other
    ingredients, which may have been too generous an assumption, but the
    fraction of wheat in all finished wheat products is difficult to
    estimate.

         Accurate estimates of dietary intake of zearalenone are hampered
    by the following limitations:

    *    Lack of reliable data on the zearalenone content of foods as
         consumed, as the values for zearalenone given in the literature
         (Table 5) are usually for raw commodities. It is difficult to
         predict the percent of zearalenone that will remain in a finished
         product and to estimate the contribution of a cereal grain to a
         finished grain product, as finished products have added
         ingredients like water and sugar that add to their weight and
         dilute the zearalenone.

    *    Lack of plans for random sampling of commodities to be analysed
         for zearalenone and inadequate numbers of samples. If the foods
         to be analysed are selected because they are mouldy, damaged, or
         off-color or because of a particularly wet or cool harvest
         season, the incidence and concentration of zearalenone in the
         foods will be higher than under normal circumstances.

    *    In many studies, it is not clear if the values given are for the
         raw or prepared food or for the entire grain or only the edible
         portion, and it is often impossible to determine the subspecies
         or cultivar of rice, wheat, rye, barley, or corn or the extent of
         processing or milling.

    *    No guideline or standard protocol is available for using the
         percent incidence and the mean concentration of positive samples
         in estimating the potential intake of zearalenone from a food. If
         the incidence of contamination is high, the mean concentration of
         positive samples may be used in making estimates, but if the
         incidence is low or if only a few samples were analysed, use of

         the mean of positive samples may overestimate the intake of
         zearalenone. Furthermore, the percent incidence of contamination
         with zearalenone is related to the sensitivity of the analytical
         method used.

    *    Lack of information on the effects of processing and cooking on
         the zearalenone content. Although the heat stability and water
         insolubility of zearalenone are indicated in several references,
         the effects on the concentration of zearalenone of fractionating
         grains and using only portions for food are not clear. Data from
         various references (Table 5) generally show lower concentrations
         of zearalenone in grain products and in milled and polished
         grains than in the raw commodities.

         Table 13 shows that corn, corn products, and wheat products are
    important sources of zearalenone in Canada and the USA. Although the
    concentrations are probably higher in corn and corn products, wheat
    products are consumed in larger amounts in both countries and thus
    contribute more zearalenone to the daily intake. In the Nordic
    countries, the main sources of zearalenone were wheat, rye, and oats.
    Kuiper-Goodman et al. (1987) did not consider the contributions of
    wheat products and rice to zearalenone intake in their estimates of
    dietary intake.

         Table 14 shows the dietary intake of zearalenone in the five WHO
    GEMS/Food regional diets, Middle Eastern, Far Eastern, African, Latin
    American, and European, the last covering the diets in Australia,
    Europe, and the USA. Only the grain and legume groups were considered
    in assessing the dietary intake of zearalenone because it does not
    occur to any large extent in the other food groups. As the zearalenone
    concentrations for the foods were the same as those used for the
    Canadian dietary assessment presented in Table 8 and the US dietary
    assessment presented in Tables 10 and 11, the variables in the
    regional diets were different intake levels of grains and legumes.
    Table 14 shows that the daily intake of zearalenone is < 3.5 g in
    the Middle East, < 3.3 g in the Far East, < 2.5 g in Africa,
    < 2.2 g in Latin America, and 1.5 g in Europe. The European intake
    (< 1.4 g/day) is comparable to that estimated for the USA (< 1.7
    g/day) in Table 12. The higher intakes in the other regions are
    probably due to higher intakes of grains and legumes, as shown in
    Table 14. The intakes, expressed per kilogram of body weight, are
    < 0.059 g for the Middle East, < 0.056 g for the Far East,
    < 0.041 g for Africa, < 0.036 g for Latin America, and < 0.025 g
    for Europe. The European intake is comparable to that of Canada
    (< 0.016 g/kg per day), the Nordic countries (0.02 g/kg per day),
    and the USA (< 0.030 g/kg per day).

         Table 15 shows the contributions of the grain and legume
    commodities to the total intake of zearalenone in the regional diets.
    The main sources were maize or corn (31%) and wheat (52%) in the
    Middle Eastern diet; rice (62%) in the Far Eastern diet; maize or corn


        Table 10. Estimates of zearalenone intake of 70-kg men in the USA, eaters only
                                                                                          

    Food                       Zearalenone         Food         Zearalenone intake
      Age (years)              concentration       intake                                 
                               (g/kg)             (g/day)      g/day     g/kg bw per day
                                                                                          

    Corn                       < 41                
        All > 2                                    86           < 3.5
        Men 20-39                                  110          < 4.5      < 0.064
        Men 20-39, 90th                            230          < 9.3      < 0.13
        percentile

    Corn chips                 < 13
        All > 2                                    42           < 0.53
        Men 20-39                                  54           < 0.69     < 0.010
        Men 20-39, 90th                            100          < 1.3      < 0.019
        percentile
    Popcorn                    approx. 10                       
        All > 2                                    37             0.37
        Men 20-39                                  49             0.49       0.007
        Men 20-39, 90th                            86             0.86       0.012
        percentile
    Oatmeal                    < 5
        All > 2                                    250          < 1.2
        Men 20-39                                  320          < 1.6      < 0.023
        Men 20-39, 90th                            490          < 2.4      < 0.035
        percentile

    Table 10. (continued)
                                                                                          

    Food                       Zearalenone         Food         Zearalenone intake
      Age (years)              concentration       intake                                 
                               (g/kg)             (g/day)      g/day     g/kg bw per day
                                                                                          
    Rice                       < 7.4
        All > 2                                    170          < 1.2
        Men 20-39                                  220          < 1.6      < 0.023
        Men 20-39, 90th                            410          < 3.0      < 0.043
        percentile

    Wheat productsa

    Biscuits                   < 5.6
        All > 2                                    58           < 0.32
        Men 20-39                                  76           < 0.43     < 0.006
        Men 20-39, 90th                            120          < 0.69     < 0.010
        percentile

    Bread, yeast               < 5.6 
        All > 2                                    72           < 0.40
        Men 20-39                                  92           < 0.52     < 0.007
        Men 20-39, 90th                            180          < 0.98     < 0.014
        percentile
    Wheat productsb 
    Pasta                      < 3.7
        All > 2                                    120          < 0.46
        Men 20-39                                  180          < 0.65     < 0.009
        Men 20-39, 90th                            370          < 1.4      < 0.019
        percentile
    Wheat productsc 
    Cake                       < 7.4
        All > 2                                    45d          < 0.33
        Men 20-39                                  52d          < 0.38     < 0.005
        Men 20-39, 90th                            95d          < 0.70     < 0.010
        percentile

    Table 10. (continued)
                                                                                          

    Food                       Zearalenone         Food         Zearalenone intake
      Age (years)              concentration       intake                                 
                               (g/kg)             (g/day)      g/day     g/kg bw per day
                                                                                          
    Doughnuts and              < 7.4
    sweet rolls                
        All > 2                                    41d          < 0.30
        Men 20-39                                  50d          < 0.37     < 0.005
        Men 20-39, 90th                            85d          < 0.63     < 0.009
        percentile

    Wheat productse
        Cookies                < 5.6
        All > 2                                    21d          < 0.12
        Men 20-39                                  30d          < 0.17     < 0.002
        Men 20-39, 90th                            66d          < 0.37     < 0.005
        percentile
    Crackers                   < 5.6
        All > 2                                    12d          < 0.07
        Men 20-39                                  14d          < 0.08     < 0.001
        Men 20-39, 90th                            24d          < 0.13     < 0.002
        percentile

    Pancakes and waffles       < 5.6
        All > 2                                    50d          < 0.28
        Men 20-39                                  75d          < 0.42     < 0.006
        Men 20-39, 90th                            120d         < 0.67     < 0.010
        percentile
    Pie < 5.6
        All > 2                                    80d          < 0.45
        Men 20-39                                  87d          < 0.49     < 0.007
        Men 20-39, 90th                            140d         < 0.80     < 0.011
        percentile

    Table 10. (continued)
                                                                                          

    Food                       Zearalenone         Food         Zearalenone intake
      Age (years)              concentration       intake                                 
                               (g/kg)             (g/day)      g/day     g/kg bw per day
                                                                                          
    Pizza                      < 5.6
        All > 2                                    100d         < 0.57
        Men 20-39                                  160d         < 0.87     < 0.012
        Men 20-39, 90th                            280d         < 1.6      < 0.022
        percentile

    Quickbreads and muffins    < 5.6
        All > 2                                    43d          < 0.24
        Men 20-39                                  54d          < 0.30     < 0.004
        Men 20-39, 90th                            110d         < 0.62     < 0.009
        percentile

    Mixed grainsa
    Cereal, cooked             < 5.6 
        All > 2                                    250          < 1.4
        Men 20-39                                  340          < 1.9      < 0.027
        Men 20-39, 90th                            500          < 2.8      < 0.040
        percentile
    Cereals,                   < 5.6              
    ready-to-eat               All > 2                            50       < 0.28
        Men 20-39                                  73           < 0.41     < 0.006
        Men 20-39, 90th                            110          < 0.63     < 0.009
        percentile

    Tortillas                  < 5.6 
    (wheat and corn)
        All > 2                                    60           < 0.34
        Men 20-39                                  87           < 0.49     < 0.007
        Men 20-39, 90th                            190          < 1.0      < 0.015
        percentile
                                                                                          


    a Zearalenone value for hard wheat used
    b Zearalenone value for durum wheat used
    c Zearalenone value for soft wheat used with one-half of the consumption value
    d One-half of the consumption figure reported by the US Department of Agriculture
    e Zearalenone value for hard wheat used with one-half of the consumption value

    Table 11. Estimates of zearalenone intake in the USA, all persons
                                                                                         

    Food                   Zearalenone         Food         Zearalenone intake
      Age (years)          concentration       intake                                    
                           (g/kg)             (g/day)      g/day        g/kg bw per day
                                                                                         

    Corn, vegetable        < 41
       All > 2                                 12           < 0.49
       Men 20-39                               13           < 0.53        <  0.008
    Corn chips             < 13
       All > 2                                 2            < 0.025
       Men 20-39                               4            < 0.050       < 0.001
    Popcorn                approx. 10
       All > 2                                 2             0.020
       Men 20-39                               2             0.020         0.000
    Oatmeal                < 5
       All > 2                                 12           < 0.060
       Men 20-39                               8            < 0.040       < 0.001
    Rice                   < 7.4
       All > 2                                 25           < 0.18
       Men 20-39                               38           < 0.28        < 0.004
    Wheat productsa
    Biscuits               < 5.6
       All > 2                                 3            < 0.017
       Men 20-39                               4            < 0.022        0.000
    Bread, yeast           < 5.6
       All > 2                                 59           < 0.33
       Men 20-39                               76           < 0.43        < 0.006
    Rolls                  < 5.6
       All > 2                                 15           < 0.084
       Men 20-39                               23           < 0.13        < 0.002
    Wheat productsb 
    Pasta                  < 3.7
       All > 2                                 31           < 0.12
       Men 20-39                               44           < 0.16        < 0.002
    Wheat productsc 

    Table 11. (continued)
                                                                                         

    Food                   Zearalenone         Food         Zearalenone intake
      Age (years)          concentration       intake                                    
                           (g/kg)             (g/day)      g/day        g/kg bw per day
                                                                                         

    Cake                   < 7.4
       All > 2                                 4d           < 0.03
       Men 20-39                               4d           < 0.03         0.000
    Doughnuts and sweet    < 7.4
    rolls
       All > 2                                 3d           < 0.022
       Men 20-39                               3d           < 0.022        0.000
     Wheat productse
    Cookies                < 5.6
       All > 2                                 4d           < 0.022
       Men 20-39                               4d           < 0.022        0.000
    Crackers               < 5.6
       All > 2                                 1d           < 0.006
       Men 20-39                               1d           < 0.006        0.000
    Pancakes and waffles   < 5.6
       All > 2                                 3d           < 0.017
       Men 20-39                               3d           < 0.017        0.000
    Pie                    < 5.6
       All > 2                                 4d           < 0.022
       Men 20-39                               3d           < 0.017        0.000
    Pizza                  < 5.6
       All > 2                                 10d          < 0.056
       Men 20-39                               18d          < 0.10        < 0.001
    Quickbreads and        < 5.6
    muffins
       All > 2                                 3d           < 0.017
       Men 20-39                               2d           < 0.011        0.000

    Table 11. (continued)
                                                                                         

    Food                   Zearalenone         Food         Zearalenone intake
      Age (years)          concentration       intake                                    
                           (g/kg)             (g/day)      g/day        g/kg bw per day
                                                                                         

    Mixed grainsa
    Cereal, cooked         < 5.6 
       All > 2                                 20           < 0.11
       Men 20-39                               14           < 0.078       < 0.001
    Cereals, ready-to-eat  < 5.6               
       All > 2                                 14           < 0.078       
       Men 20-39                               14           < 0.078       < 0.001
    Tortillas (wheat       < 5.6 
    and corn)
       All > 2                                 5            < 0.028
       Men 20-39                               9            < 0.050       < 0.001

    Total
       All > 2                                              < 1.7         
       Men 20-39                                            < 2.1         < 0.030
                                                                                         

    a  Zearalenone value for hard wheat used
    b  Zearalenone value for durum wheat used
    c  Zearalenone value for soft wheat used with one-half of the consumption value
    d  One-half of the consumption figure reported by the US Department of Agriculture
    e  Zearalenone value for hard wheat used with one-half of the consumption value

    Table 12. Summary of estimates of dietary intake of zearalenone
                                                                                                       

    Country                       Body        Zearalenone                         Reference
                                  weight                                      
                                  (kg)        g/day         g/kg bw per day
                                                                                                       

    Canada                                                                        Kuiper-Goodman 
         12-19-year-old males     60             0.19          0.003              et al. (1987) 
         1-4-year-old children    14             0.47          0.033
    Canada                                                                        Canada (1999)
         Adults                   60          < 0.98         < 0.016
         6-9-month-old infants    8.7         < 0.52         < 0.060
    Nordic countriesa                                                             Eriksen & Alexander 
         Denmark                  48             0.48          0.01               (1998)
         Finland                  66             1.3           0.02
         Norway                   73             1.5           0.02
         Sweden                   60             1.2           0.02
    Nordic countriesb                                                             Eriksen & Alexander 
         Denmark                  60             1.2           0.02               (1998)
         Norway                   60             1.1           0.02
    USA                                                                           This monograph
         All aged > 2 years                   < 1.7
         20-39-year-old men       70          < 2.1          < 0.030
                                                                                                       

    a Data from balance sheets
    b Data on individual intake
    

    (55%) and rice (31%) in the African diet; maize or corn (27%), rice
    (30%), and wheat (30%) in the Latin American diet; and wheat (67%) in
    the European diet.

    3.4.7  Models of dietary intake

         In order to improve calculations of dietary intake of
    zearalenone, more reliable data are needed on the incidence and
    concentration of the toxin in foods, especially in grain products as
    consumed and in foods that have high concentrations and are commonly
    consumed by some populations, such as corn-based beer in Africa and
    infected bananas in India. Differences in the zearalenone content of
    foods in western and developing countries must also be determined. The
    following conclusions can be drawn with regard to dietary exposure to
    zearalenone.

    *    The concentrations of zearalenone in animal products (meat, fish,
         poultry, milk, and eggs) are probably not significant.

    *    There appears to be only minimal transmission of zearalenone into
         the milk of dairy cows exposed to zearalenone.

    *    The concentrations of zearalenone in fruits, vegetables, and nuts
         are not significant, with the exception of infected bananas
         consumed in India.

    *    Humans do not usually eat mouldy foods except in conditions of
         poverty or famine.

    *    Unless legumes are consumed in large amounts or are known to be
         contaminated, they probably will not affect estimates
         significantly.

    *    Grains and grain products are probably the main sources of
         dietary zearalenone intake.

    *    Because the intake of grains and grain-based products may be
         higher in developing countries, intake of zearalenone may be
         higher than in developed countries. The grains that should be
         included in an intake assessment are those consumed in fair to
         large amounts by the population, but grains that are known or
         suspected to be contaminated should also be included even if they
         are consumed in small amounts. The data in Table 5 indicate that
         the zearalenone concentrations in barley, oats, rice, and rye are
         low, and they could be omitted from intake calculations unless
         they are consumed in large amounts or are contaminated.


        Table 14. Dietary intake of zearalenone in regional diets
                                                                                                                                                   
    Food item   Zearalenone        Middle                 Far Eastern               African              Latin American          European
                concentration      Eastern
                (g/kg)
                               Food     Zearalenone    Food      Zearalenone    Food     Zearalenone   Food     Zearalenone  Food     Zearalenone
                               (g/day)  (g/day)       (g/day)   (g/day)       (g/day)  (g/day)      (g/day)  (g/day)     (g/day)  (g/day)
                                                                                                                                                   

    Grains

    Barley     < 8.3           1.0      < 0.008        3.5       < 0.029        1.8      < 0.015       6.5      < 0.054      20       < 0.16
    Buckwheat  approx. 0       0.0      approx.        1.0       approx.        0.0      approx.       0.0      approx.      0.0      approx.
                                        0.000                    0.000                   0.000                  0.000                 0.000

    Maize      < 41            16       < 0.67         0.0       0.000          0.0      0.000         1.5      < 0.061      0.0      0.000
    Maize      < 13            32       < 0.40         31        < 0.40         110      < 1.3         40       < 0.51       8.8      < 0.11
    flour
    Sweet      approx. 0       0.0      approx.        0.0       approx.        7.7      approx.       0.0      approx.      14       approx.
    corn                                0.000                    0.000                   0.000                  0.000                 0.000
    Popcorn    approx. 10      0.2      < 0.002        0.2       < 0.002        0.2      < 0.002       0.2      < 0.002      0.2      < 0.002
    Millet     approx. 0       2.5      approx.        9.3       approx.        52       approx.       0.0      approx.      0.0      approx.
    flour                               0.000                    0.000                   0.000                  0.000                 0.000
    Oats       < 5.0           0.0      0.000          0.0       0.000          0.2      < 0.001       0.8      < 0.004      2.0      < 0.010
    Rice       < 7.4           49       < 0.36         280       < 2.1          100      < 0.76        86       < 0.64       12       < 0.087
    Rye        approx. 0       0.0      approx.        1.0       approx.        0.0      approx.       0.0      approx.      1.5      approx.
                                        0.000                    0.000                   0.000                  0.000                 0.000
    Sorghum    approx. 0       2.0      approx.        9.7       approx.        27       approx.       0.0      approx.      0.0      approx. 
    flour                               0.000                    0.000                   0.000                  0.000                 0.000
    Triticale  approx. 0       0.0      approx.        1.0       approx.        0.0      approx.       0.0      approx.      0.0      approx. 
    flour                               0.000                    0.000                   0.000                  0.000                 0.000
    Wheat,     < 5.6           0.3      < 0.002        0.0       0.000          0.0      0.000         0.0      0.000        0.0      0.000
    bulgur 
    Wheat,     < 3.7           1.0      < 0.004        0.3       < 0.001        0.0      0.000         2.8      < 0.010      1.3      < 0.005
    pasta
    Wheat      < 7.4           3.0      < 0.022        0.5       < 0.004        0.0      0.000         2.0      < 0.015      1.0      < 0.007
    pastry
    Wheat      approx. 0       0.1      approx.        0.1       approx.        0.0      approx.       0.0      approx.      0.0      approx. 
    germ                                0.000                    0.000                   0.000                  0.000                 0.000
    White      < 5.6           220      < 1.2          76        < 0.43         19       < 0.11        37       < 0.21       120      < 0.66
    bread

    Table 14. (continued)

    Food item      Zearalenone     Middle                   Far Eastern              African                 Latin American       European
                   concentration   Eastern
                   (g/kg)
                                  Food      Zearalenone    Food      Zearalenone    Food     Zearalenone   Food     Zearalenone  Food     Zearalenone
                                  (g/day)   (g/day)       (g/day)   (g/day)       (g/day)  (g/day)      (g/day)  (g/day)     (g/day)  (g/day)
                                                                                                                                                   
    Wholemeal      < 5.6          110       < 0.60         38        < 0.21         9.4      < 0.053       75       < 0.42       59       <0.33
    bread

    Total,                        430       < 3.3          450       < 3.1          330      < 2.3         250      < 1.9        240      < 1.4
    grains

    Legumes
    Soya           < 10           4.5       < 0.046        2.0       < 0.020        0.5      < 0.005       0.0      0.000        0.0      0.000
    beans
    Other          < 10           20        < 0.20         18        < 0.18         17       < 0.17        23       < 0.23       12       <0.12
    legumesa

    Total,                                  < 0.25                   < 0.20                  < 0.18                 < 0.23                < 0.12
    legumes

    Overall                                 < 3.5                    < 3.3                   < 2.5                  < 2.2                 < 1.5
    total
    Total                                   < 0.059                   < 0.056                  < 0.041                < 0.036               < 0.025  
    in g/kg
    bw per 
    dayb
                                                                                                                                                   

    Concentration assumed to be zero (approx. 0) or below detection limit in the other food groups
    a The zearalenone value for tinned beans was used for other legumes
    b Based on 60 kg
    


    *    Focus should therefore be directed to zearalenone in corn
         kernels, cornmeal and cornflour products, popcorn, rice, and
         wheat flour products. If possible, wheat flour products should be
         separated from those of durum wheat (pasta), soft wheat (cakes
         and pastries), and hard wheat (bread, crackers, cookies) because
         different wheat flours have different concentrations of
         zearalenone.

    *    It is important to determine whether other foods consumed by a
         population might contain zearalenone. Examples include infected
         bananas, beer brewed from contaminated grain, and tissues from
         alpha-zearalanol-injected animals.

    *    The intake of zearalenone by infants might be greater if they
         consume grain-or legume-based formula instead of human milk or a
         milk-based formula.

         The following equation could be used to estimate the intake of
    zearalenone by a population: the average daily intake of zearalenone
    (ZEA) is equal to the sum of the average daily gram intake (I) of
    seven foods (corn, cornmeal/cornflour products, popcorn, rice, pasta,
    cake/pastry, and bread/crackers/other hard-wheat flour products) by a
    defined age/sex group of a population multiplied by the average
    zearalenone concentration (g/kg; C) of each food:

         ZEA = (I)(C) corn + (I)(C) cornmeal/flour products + (I)(C)
         popcorn + (I)(C) rice + (I)(C) pasta + (I)(C) cake/pastry +
         (I)(C) bread/crackers/other hard-wheat flour products

        Table 15. Contributions of various commodities to total zearalenone intake
    in the five regional diets (% of intake)
                                                                              

    Commodity       Middle      Far          African     Latin       European
                    Eastern     Eastern                  American
                                                                              

    Barley            0         1              1         3            11
    Maize or corn     31        12             55        27           8
    Oats              0         0              0         0            1
    Rice              10        62             31        30           8
    Wheat             52        19             6         30           67
    Legumes           7         6              7         11           8

    Total             100       100            100       101          103
                                                                              
    
    4.  COMMENTS

         The average dietary intakes of zearalenone from cereals and
    legumes in the GEMS/Food regional diets were estimated to be 1.5
    g/day in the European diet and 3.5 g/day in the Middle Eastern diet.
    If a mean body mass of 60 kg is assumed, these intakes correspond to
    0.03 and 0.06 g/kg bw per day, respectively. The average dietary
    intakes of zearalenone estimated on the basis of individual dietary
    records are < 0.98 g/day (0.02 g/kg bw per day) for Canada, 1.2
    g/day (0.02 g/kg bw per day) for Denmark, 1.1 g/day (0.02 g/kg bw
    per day) for Norway, and < 2.1 g/day (0.03 g/kg bw per day) for the
    United States.

         The theoretical maximum daily intake of alpha-zearalanol when
    used as a veterinary drug was calculated to be 1.6 g/day (0.02 g/kg
    bw per day) on the basis of the recommended maximum residue limits of
    10 g/kg in cattle liver and 2 g/kg in cattle muscle (Annex 1,
    reference  80).

         Studies of the pharmacokinetics and metabolism of zearalenone
    indicate that it is extensively metabolized by intestinal tissue in
    pigs, and possibly in humans, during its absorption, with the
    formation of alpha-and beta-zearalenol and alpha-and beta-zearalanol,
    which are subsequently conjugated with glucuronic acid. The existence
    of this pathway limits the value of studies conducted by parenteral
    administration for assessing the risk associated with dietary intake.
    Biliary excretion with enterohepatic circulation occurs in rats and
    mice, while urinary excretion predominates in rabbits. Urinary
    excretion is also the main route of elimination in pigs, in spite of
    the demonstrated enterohepatic circulation of zearalenone, owing to a
    high degree of reabsorption in the gut. The very limited data in
    humans (one individual) suggest that urinary excretion is also
    significant. Differences between species in the metabolism of
    zearalenone were found: a higher proportion of an administered dose of
    zearalenone was metabolized to alpha-zearalenol in pigs than in rats
    or cattle. In humans as in pigs, zearalenone was found mainly in urine
    as glucuronide conjugates of the parent compound and alpha-zearalenol.

         Zearalenone has little toxicity after administration of single
    oral or intraperitoneal doses. In studies of oral administration for
    up to 90 days, the effects appeared to be dependent on the estrogenic
    activity of zearalenone and/or its metabolites. Pigs and sheep were
    more sensitive than rodents; in controlled studies with well-defined
    exposure to multiple doses, the NOEL in pigs was 40 g/kg bw per day
    on the basis of estrogenic effects in responsive tissues and
    reproductive performance, compared with a NOEL of 3 mg/kg bw per day
    in rats.

         Zearalenone has been tested for genotoxicity in a variety of test
    systems covering several end-points, including point mutations,
    unscheduled DNA synthesis, and chromosomal aberrations. The results
    were negative, except for the induction of chromosomal aberrations
    after exposure of mammalian cells  in vitro to very high
    concentrations. Evidence from a 32P-postlabelling assay that
    zearalenone modifies DNA was reported, but the Committee concluded
    that the results do not unequivocally demonstrate covalent binding of
    zearalenone and/or its metabolites to DNA and most likely reflect
    oxidative damage to DNA, since the DNA damage was greatly reduced by
    co-administration of the antioxidant alpha-tocopherol.

         Hepatocellular adenomas and pituitary tumours were observed in
    studies of long-term toxicity and carcinogenicity in mice, but only at
    doses greatly in excess of the concentrations that have hormonal
    effects, i.e. at 8-9 mg/kg bw per day or more. The Committee concluded
    that these tumours were a consequence of the estrogenic effects of
    zearalenone. A similar conclusion was drawn by the Committee at its
    thirty-second meeting with regard to a-zearalanol. In rats, there was
    no treatment-related increase in the incidence of tumours at doses of
    1-3 mg/kg bw per day.

    5.  EVALUATION

         The Committee concluded that the safety of zearalenone could be
    evaluated on the basis of the dose that had no hormonal effect in
    pigs, the most sensitive species. Using a safety factor of about 100,
    the Committee established a provisional maximum tolerable daily intake
    (PMTDI) for zearalenone of 0.5 g/kg bw. This decision was based on
    the NOEL of 40 g/kg bw per day in the 15-day study in pigs. The
    Committee also took into account the lowest-observed-effect level of
    200 g/kg bw per day in this study and the previously established ADI
    of 0-0.5 g/kg bw for the metabolite alpha-zearalanol, evaluated as a
    veterinary drug. The Committee recommended that the total intake of
    zearalenone and its metabolites (including alpha-zearalanol) should
    not exceed this value.

    6.  REFERENCES

    Abbas, H.K., Mirocha, C.J. & Tuite, J. (1986) Natural occurrence of
    deoxynivalenol, 15-acetyl-deoxynivalenol, and zearalenone in refusal
    factor corn stored since 1972.  Appl. Environ. Microbiol., 51, 
    841-843.

    Abbas, H.K., Mirocha, C.J., Meronuck, R.A., Pokorny, J.D., Gould, S.L.
    & Kommedahl, T. (1988) Mycotoxins and  Fusarium spp. associated with
    infected ears of corn in Minnesota.  Appl. Environ. Microbiol., 54,
    1930-1933.

    Abd Alla, E.S. (1997) Zearalenone: Incidence, toxigenic fungi and
    chemical decontami-nation in Egyptian cereals.  Nahrung, 41, 362-365.

    Abdel-Gawad, K.M. & Zohri, A.A. (1993) Fungal flora and mycotoxins of
    six kinds of nut seeds for human consumption in Saudi Arabia.
     Mycopathologia, 124, 55-64.

    Abdel-Hafez, A.I. & Saber, S.M. (1993) Mycoflora and mycotoxin of
    hazelnut ( Corylus avellana L.) and walnut ( Juglans regia L.) seeds
    in Eygpt.  Zentralbl. Mikrobiol., 148, 137-147.

    Abdelhamid, A.M., Kelada, I.P., Ali, M.M. & El-Ayouty, S.A. (1992)
    Influence of zearalenone on some metabolic, physiological and
    pathological aspects of female rabbits at two different ages.  Arch.
     Anim. Nutr., 42, 63-70.

    Abouzied, M.M., Azcona, J.I., Braselton, W.E. & Pestka, J.J. (1991)
    Immunochemical assessment of mycotoxins in 1989 grain foods: Evidence
    for deoxynivalenol (vomitoxin) contamination.  Appl. Environ.
     Microbiol., 57, 672-677.

    Abramson, D., Sinha, R.N. & Mills, J.T. (1982) Mycotoxin formation in
    moist wheat under controlled temperatures.  Mycopathologia, 20,
    87-92.

    Abramson, D., Richter, W., Rintelen, J., Sinha, R.N. & Schuster, M.
    (1992) Ochratoxin A production in Bavarian cereal grains stored at 15
    and 19% moisture content.  Arch. Environ. Contam. Toxicol., 23,
    259-265.

    Akiyama, H., Toyoda, M., Kato, M., Igimi, S. & Kumagai, S. (1997) The
    degradation of several mycotoxins by human intestinal microflora
    cultured by continous flow culture system.  Mycotoxins, 44, 21-27.

    Ali, N., Sardjono, Yamashita, A. & Yoshizawa, T. (1998) Natural
    co-occurrence of aflatoxins and  Fusarium mycotoxins (fumonisins,
    deoxynivalenol, nivalenol, and zearalenone) in corn from Indonesia.
     Food. Addit. Contam., 15, 377-384.

    Allen, N.K. (1980) Effect of zearalenone on reproduction in chickens.
     Poultry Sci., 59, 1577.

    Allen, N.K., Mirocha, C.J., Aakus-Allen, S., Bitgood, J.J., Weaver, G.
    & Bates, F. (1981) Effect of dietary zearalenone on reproduction of
    chickens.  Poultry Sci., 62, 1165-1174.

    Allen, N.K., Peguri, A., Mirocha, C.J. & Newman, J.A. (1983) Effects
    of  Fusarium cultures, T-2 toxin and zearalenone on reproduction of
    turkey females.  Poultry Sci., 62, 282-289.

    Anon. (1986) Precocious development in Puerto Rican children.
     Lancet, i, 721-722.

    Argumedo, L.M., Torreblanca, A., Rosiles, R. & Lopez, M.Y. (1985)
    Determination of aflatoxins and detection of zearalenone in samples of
    corn from nixtamal mills in Mexico City.  Tecnol. Aliment. (Mexico
     City), 20, 15-16, 18-19.

    Arora, R.G., Frolen, H. & Nilsson, A. (1981) Interference of
    mycotoxins with prenatal development of the mouse. I. Influence of
    aflatoxin B1, ochratoxin A and zearalenone.  Acta Vet. Scand., 22,
    524-534.

    Arora, R.G., Frolen, H. & Fellner-Feldegg, H. (1983) Inhibition of
    ochratoxin and teratogenesis by zearalenone and diethylstilboestrol.
     Food Chem. Toxicol., 21, 779-783.

    Atkinson, H.A.C. & Miller, K. (1984) Inhibitory effect of
    deoxynivalenol, 3-acetyldeoxynivalenol and zearalenone on induction
    of rat and human lymphocyte proliferation.  Toxicol. Lett., 23,
    215-221.

    Aziz, N.H., Attia, E.S. & Farag, S.A. (1997) Effect of
    gamma-irradiation on the natural occurrence of  Fusarium mycotoxins
    in wheat, flour and bread.  Nahrung, 41, 34-37.

    Bagneris, R.W., Gaul, J.A. & Ware, G.M. (1986) Liquid chromatographic
    determination of zearalenone and zearalenol in animal feeds and
    grains, using fluorescence detection.  J. Assoc. Off. Anal. Chem.,
    69, 894-898.

    Balzer, I., Bogdanic, C. & Muzic, S. (1977) Natural contamination of
    corn ( Zea mays) with mycotoxins in Yugoslavia.  Ann. Nutr. Aliment.,
    31, 425-430.

    Bartholomew, R.M. & Ryan, D.S. (1980) Lack of mutagenicity of some
    phytoestrogens in the  Salmonella /mammalian microsome assay.
     Mutat. Res., 78, 317-321.

    Bartos, J. & Matyas, Z. (1981) The occurrence of zearalenone in
    domestic grains.  Vet. Med. (Praha), 26, 505-512.

    Bauer, J., Heinritzi, K., Gareis, M. & Gedek, B. (1987) Vernderungen
    am Genitaltrakt des weiblichen Schweines nach Verftterung
    praxisrelevanter Zearalenonmengen.  Tierrztl. Prax., 15, 33-36.

    Becci, P.J., Voss, K.A., Hess, F.G., Gallo, M.A., Parent, R.A.,
    Stevens, K.R. & Taylor, J.M. (1982a) Long-term carcinogenicity and
    toxicity study of zearalenone in the rat.  J. Appl. Toxicol., 2,
    247-254.

    Becci, P.J., Johnson, W.D., Hess, F.G., Gallo, M.A. & Parent, R.A.
    (1982b) Combined two-generation reproduction-teratogenesis study of
    zearalenone in the rat.  J. Appl. Toxicol., 2, 201-206

    Bennett, G.A., Peplinski, A.J., Breeke, O.L. & Jackson, L.K. (1976)
    Zearalenone: Distribution in dry-milled fractions of contaminated
    corn.  Cereal Chem., 53, 299-307.

    Bennett, G.A., Vandegraft, E.E., Shotwell, O.L., Watson, S.A. & Bocan,
    B.J. (1978a) Zearalenone: Distribution in wet milling fractions from
    contaminated corn.  Cereal Chem., 55, 455-461.

    Bennett, G.A. & Anderson, R.A. (1978b) Distribution of aflatoxin
    and/or zearalenone in wet-milled corn products: A review.  J. Agric.
     Food. Chem., 26, 1055-1060.

    Bennett, G.A., Shotwell, O.L. & Kwolek, W.F. (1985) Liquid
    chromatographic determination of alpha-zearalenol and zearalenone in
    corn: Collaborative study.  J. Assoc. Off. Anal. Chem., 68, 958-961.

    Biehl, M.L., Prelusky, D.B., Koritz, G.D., Hartin, K.E., Buck, W.B. &
    Trenholm, H.L. (1993) Biliary excretion and enterohepatic cycling of
    zearalenone in immature pigs.  Toxicol. Appl. Pharmacol., 121,
    152-159.

    Bosch, U. & Mirocha, C.J. (1992) Toxin production by  Fusarium
    species from sugar beets and natural occurrence of zearalenone in
    beets and beet fibers.  Appl. Environ. Microbiol., 58, 3233-3239.

    Brandenberger, A.W., Tee, M.K., Lee, J.Y., Chao, V. & Jaffe, R.B.
    (1997) Tissue distribution of estrogen receptors alpha (ER-alpha) and
    beta (ER-beta) mRNA in the midgestational human fetus.  J. Clin.
     Endocrinol. Metab., 82, 3509-3512.

    Branton, S.L., Deaton, J.W., Hagler W.M., Jr, Maslin, W.R. & Hardin,
    J.M. (1989) Decreased egg production in commercial laying hens fed
    zearalenone-and deoxynivalenol-contaminated grain sorghum.  Avian
     Dis., 33, 804-808.

    Bresler, G., Brizzio, S.B. & Vaamonde, G. (1995) Mycotoxin-producing
    potential of fungi isolated from amaranth seeds in Argentina. 
     Int.J.  Food Microbiol., 25, 101-108.

    Bresler, G., Vaamonde, G., Degrossi, C. & Pinto, V.F. (1998) Amaranth
    grain as substrate for aflatoxin and zearalenone production at
    different water activity levels.  Int. J. Food Microbiol., 42, 57-61.

    Bucheli, B., Diserens, P., Rychener, M., Tieche, J.D. & Trenkner, N.
    (1996) Investigations on the infestation by  Fusarium and on
    contamination of mycotoxins of Swiss bread-making cereals of the
    1992-1994 harvests.  Mitt. Geb. Lebensm. Hyg., 87, 84-102.

    Cameron, J.K., Bursian, S.J. & Aulerich, R.J. (1989) The effect of
    zearalenone on reproductive parameters of female mink.  Toxicologist,
    9, 216

    Canada (1999) Unpublished data provided to WHO.

    Chakrabarti, D.K. & Ghosal, S. (1986) Occurrence of free and
    conjugated 12,13-epoxytrichothecenes and zearalenone in banana fruits
    infected with  Fusarium moniliforme. Appl. Environ. Microbiol., 51,
    217-219.

    Chakrabarti, D.K. & Ghosal, S. (1987) Mycotoxins produced by
     Fusarium  oxysporum in the seeds of  Brassica campestris during
    storage.  Mycopathologia, 97, 69-75.

    Chang, W.M., Kuttz, J.H. & Mirocha, C.J. (1979) Effects of the
    mycotoxin zearalenone on swine reproduction.  Am. J. Vet. Res., 40,
    1260-1267.

    Chelkowski, J., Visconti, A. & Manka, M. (1984) Production of
    trichothecenes and zearalenone by  Fusarium species isolated from
    wheat.  Nahrung, 28, 493-496.

    Cliver, D.O., ed. (1990)  Foodborne Diseases, New York: Academic
    Press.

    Cooray, R. (1984) Effects of some mycotoxins on mitogen-induced
    blastogenesis and SCE-frequency in human lymphocytes.  Food Chem.
     Toxicol., 22, 529-534.

    Coppock, R.W., Mostrom, M.S., Sparling, C.G., Jacobsen, B. & Ross,
    S.C. (1990) Apparent zearalenone intoxication in a dairy herd from
    feeding spoiled acid-treated corn.  Vet. Hum. Toxicol., 32, 246-248.

    Dacasto, M., Rolando, P., Nachtman, C., Ceppa, L. & Nebbia, C. (1995)
    Zearalenone mycotoxicosis in piglets suckling sows fed contaminated
    grain.  Vet. Hum. Toxicol., 37, 359-361.

    Dailey, R.E., Reese, R.E. & Brouwer, A. (1980) Metabolism of [14C]
    zearalenone in laying hens.  J. Agric. Food Chem., 28, 286-291.

    Dalcero, A., Magnoli, C., Chiacchiera, S., Palacios, G. & Reynoso, M.
    (1997) Mycoflora and incidence of aflatoxin B1, zearalenone and
    deoxynivalenol in poultry feeds in Argentina.  Mycopathologia, 137,
    179-184.

    Diekman, M.A. & Long, G.G. (1989) Blastocyst development on days 10 or
    14 after consumption of zearalenone by sows on days 7-10 after
    breeding.  Am. J. Vet. Res., 50, 1224-1227.

    Doko, M.B., Canet, C., Brown, N., Sydenham, E.W., Mpuchane, S. &
    Siame, B.A. (1996) Natural co-occurrence of fumonisins and zearalenone
    in cereals and cereal-based foods from eastern and southern Africa.
     J.  Agric. Food Chem., 44, 3240-3243.

    Dutton, M.F. & Kinsey, A. (1995) Ocurrence of mycotoxins in cereals
    and animal feedstuffs in Natal, South Africa 1994.  Mycopathologia,
    131, 31-36.

    Edwards, S., Cantley, T.C., Rottinghaus, G.E., Osweiler, G.D. & Day,
    B.N. (1987a) The effects of zearalenone on reproduction in swine. I.
    The relationship between ingested zearalenone dose and anestrus in
    non-pregnant, sexually mature gilts.  Theriogenology, 28, 43-49.

    Edwards, S., Cantley, T.C., Rottinghaus, G.E., Osweiler, G.D. & Day,
    B.N. (1987b) The effects of zearalenone on reproduction in swine. II.
    The effect on puberty attainment and postweaning rebreeding
    performance.  Theriogenology, 28, 51-58.

    El-Kady, I.A. & Youssef, M.S. (1993) Survey of mycoflora and
    mycotoxins in Egyptian soybean seeds.  J. Basic Microbiol,. 33,
    371-378.

    El-Kady, I.A., El-Maraghy, S.S.M. & Mostafa, E.M. (1995) Natural
    occurrence of mycotoxins in different spices in Egypt.  Folia
     Microbiol. (Praha), 40, 297-300.

    El-Maghraby, O.M. & El-Maraghy, S.S. (1987) Mycoflora and mycotoxins
    of peanut ( Arachis hypogaea L.) seeds in Egypt. 1. Sugar fungi and
    natural occurrence of mycotoxins.  Mycopathologia, 98, 165-170.

    El-Maghraby, O.M., El-Kady, I.A. & Soliman, S. (1995) Mycoflora and
     Fusarium toxins of three types of corn grains in Egypt with special
    reference to production of trichothecene-toxins.  Microbiol. Res.,
    150, 225-232.

    El-Morshedy, M.M. & Aziz, N.H. (1995) Effects of fenamiphos,
    carbofuran, and aldicarb on zearalenone production by toxigenic
     Fusarium spp. contaminating roots and fruits of tomato.  Bull.
     Environ. Contam. Toxicol., 54, 514-518.

    Eppley, R.M., Stoloff, L., Trucksess, M.W. & Chung, C.W. (1974) Survey
    of corn for  Fusarium toxins.  J. Assoc. Off. Anal. Chem., 57,
    632-635.

    Eriksen, G.S. & Alexander, J. (1998) Fusarium  Toxins in Cereals--A
     Risk Assessment (TemaNord, 502), Stockholm, Nordic Council of
    Ministers, pp. 22-27.

    Faber, K.A. & Hughes, C.L., Jr (1991) The effect of neonatal exposure
    to diethylstilbestrol, genistein, and zearalenone on pituitary
    responsiveness and sexually dimorphic nucleus volume in the castrated
    adult rat.  Biol. Reprod., 45, 649-653.

    Farnworth, E.R. & Trenholm, H.L. (1981) The effect of acute
    administration of the mycotoxin zearalenone to female pigs.
     J. Environ. Sci. Health B, 16, 239-252.

    Farnworth, E.R. & Trenholm, H.L. (1983) The metabolism of the
    mycotoxin zearalenone and its effects on the reproductive tracts of
    young male and female pigs.  Can. J. Anim. Sci., 63, 967-975.

    Fazekas, B., Kis, M. & Hajdu, E.T. (1996) Data on the contamination of
    maize with fumonisin B1 and other fusariotoxins in Hungary.  Acta
     Vet. Hung., 44, 25-37.

    Fink-Gremmels, J. (1989) The significance of mycotoxin assimilation
    for meat animals.  Dtsch. Tierarztl. Wochenschr., 96, 360-363.

    Fitzpatrick, D.W., Arbuckle, L.D. & Hassen, A.M. (1988) Zearalenone
    metabolism and excretion in the rat: Effect of different doses.
     J. Environ. Sci. Health B, 23, 343-354.

    Forsell, J.H. & Pestka, J.J. (1985) Relation of 8-ketotrichothecene
    and zearalenone analog structure to inhibition of mitogen-induced
    human lymphocyte blastogenesis.  Appl. Environ. Microbiol., 50,
    1304-1307.

    Forsell, J.H., Witt, M.F., Tai, J.-H., Jensen, R. & Pestka, J.J.
    (1986) Effects of 8-week exposure of the B6C3F1-mouse to dietary
    deoxynivalenol (vomitoxin) and zearale-none.  Food Chem. Toxicol.,
    24, 213-219.

    Freni-Titulaer, L.W. Cordero, J.F., Haddock, L., Lebron, G., Martinez,
    R. & Mills, J.L. (1986) Premature thelarche in Puerto Rico. A search
    for environmental factors.  Am. J. Dis. Child., 140, 1263-1267.

    Friend, D.W., Trenholm, H.L., Thompson, B.K., Hartin, K.E., Fiser,
    P.S., Asem E.K. & Tsang, B.K. (1990) The reproductive efficiency of
    gilts fed very low levels of zearalenone.  Can. J. Anim. Sci., 70,
    635-645.

    Funnell, H.S. (1979) Mycotoxins in animal feedstuffs in Ontario, 1972
    to 1977.  Can. J. Comp. Med., 43, 243-246.

    Furlong, E.B., Soares, L.M., Lasca, C.C. & Kohara, E.Y. (1995a)
    Mycotoxins and fungi in wheat harvested during 1990 in test plots in
    the state of Sao Paulo, Brazil.  Mycopathologia, 131, 185-190.

    Furlong, E.B., Soares, L.M., Lasca, C.C. & Kohara, E.Y. (1995b)
    Mycotoxins and fungi in wheat stored in elevators in the state of Rio
    Grande do Sul, Brazil.  Food Addit. Contam., 12, 683-688.

    Galloway, S.M., Armstrong, M.J., Reuben, C., Colman, S., Brown, B.,
    Cannon, C., Bloom, A.D., Nakamura, F., Ahmed, M., Duk, S., Rimpo, J.,
    Margolin, B.H., Resnik, M.A., Anderson, B. & Zeiger, E. (1987)
    Chromosome aberrations and sister chromatid exchanges in Chinese
    hamster ovary cells: Evaluations of 108 chemicals.  Environ. Mol.
     Mutag., 10, 1-175.

    Gareis, M., Bauer, J., Thiem, J., Plank, G., Grabley, S. & Gedek, B.
    (1990) Cleavage of zearalenone-glycoside, a 'masked' mycotoxin, during
    digestion in swine.  J. Vet. Med. B, 37, 236-240.

    Gbodi, T.A., Nwude, N., Aliu, Y.O. & Ikediobi, C.O. (1986a) The
    mycoflora and some mycotoxins found in acha ( Digitaria exilis Stapf.)
    in Plateau State, Nigeria.  Food Chem. Toxicol., 24, 339-342.

    Gbodi, T.A., Nwude, N., Aliu, Y.O. & Ikediobi, C.O. (1986b) The
    mycoflora and some mycotoxins found in maize (Zea mays) in the Plateau
    State of Nigeria.  Vet. Hum. Toxicol., 28, 1-5.

    Ghedira-Chekir, L., Maaroufi, K., Zakhama, A., Ellouz, F., Dhouib, S.,
    Creppy, E.E. & Bacha, H. (1998) Induction of a SOS repair system in
    lysogenic bacteria by zearalenone and its prevention by vitamin E.
     Chem.-Biol. Interact., 113, 15-25.

    Gilbert, J. (1989) Current views on the occurrence and significance of
     Fusarium toxins.  Soc. Appl. Bacteriol. Symp. Ser., 18, 89S-98S.

    Gleissenthal, J.L., Dietrich, R., Martlbauer, E., Schuster, M., Suss,
    A. & Terplan, G. (1989) A survey on the occurrence of Fusarium
    mycotoxins in Bavarian cereals from the 1987 harvest. Z.  Lebensm.
     Unters. Forsch., 188, 521-526.

    Gray, L.E., Jr, Ferrel, J.M., & Ostby, J.S. (1985) Alteration of
    behavioral sex differentiation by exposure to estrogenic compounds
    during a critical neonatal period: Effects of zearalenone,
    methoxychlor, and estradiol in hamsters.  Toxicol. Appl. Pharmacol.,
    80, 127-136.

    Green, M.L., Diekman, M.A., Malayer, J.R., Scheidt, A.B. & Long, G.G.
    (1990) Effect of prepubertal consumption of zearalenone on puberty and
    subsequent reproduction of gilts.  J. Anim. Sci., 68, 171-178.

    Griffin, T.B., Singh, A.R. & Coulston, F. (1984) No hormonal effect in
    non-human primates of oral zeranol. Report to the International
    Minerals and Chemical Company, Terre Haute, Indiana [cited in
    Kuiper-Goodman et al. (1987)].

    Gross, V.J. & Robb, J. (1975) Zearalenone production in barley.
     Ann. Appl. Biol., 80, 211-216.

    Grosse, Y., Chekir-Ghedira, L., Huc, A., Obrecht-Pflumio, S.,
    Dirheimer, G., Bacha, H. & Pfohl-Leszkowicz, A. (1997) Retinol,
    ascorbic acid and a-tocopherol prevent DNA adduct formation in mice
    treated with the mycotoxins ochratoxin A and zearalenone.
     Cancer Lett., 114, 225-229.

    Hagler, M., Danko, G., Horvath, L., Palyusik, M. & Mirocha, C.J.
    (1980) Transmission of zearalenone and its metabolite into ruminant
    milk.  Acta Vet. Acad. Sci. Hung., 28, 209-216.

    Hagler, W.M., Jr, Tyczkowska, K. & Hamilton, P.B. (1984) Simultaneous
    occurrence of deoxynivalenol, zearalenone, and aflatoxin in 1982
    scabby wheat from the midwestern United States.  Appl. Environ.
     Microbiol., 47, 151-154.

    Halasz, A., Badaway, A., Sawinsky, J., Kozma-Kovacs, E. & Beczner, J.
    (1989) Effect of gamma-irradiation on F-2 and T-2 toxin production in
    corn and rice.  Folia Microbiol. (Praha), 34, 228-232.

    Halt, M. (1998) Moulds and mycotoxins in herb tea and medicinal
    plants.  Eur. J. Epidemiol., 14, 269-274.

    Hanstein, B., Liu, H., Yancisin, M.C. & Brown, M. (1999) Functional
    analysis of a novel estrogen receptor-beta isoform.  Mol.
     Endocrinol., 13, 129-137.

    Hennigen, M.R. & Dick, T. (1995) Incidence and abundance of mycotoxins
    in maize in Rio Grande do Sul, Brazil.  Food Addit. Contam., 12,
    677-681.

    Hidy, P.H., Baldwin, R.S., Greasham, R.L., Keith, C.L. & McMullan,
    J.R. (1977) Zearalenone and some derivatives: Production and
    biological activities.  Adv. Appl. Microbiol., 22, 55-82.

    Hietaniemi, V. & Kumpulainen, J. (1991) Contents of  Fusarium toxins
    in Finnish and imported grains and feeds.  Food Addit. Contam., 8,
    171-181.

    Hilakivi-Clarke, L., Cho, E. & Clarke, R. (1998) Maternal genistein
    exposure mimics the effects of estrogen on mammary gland development
    in female mouse offspring.  Oncol. Rep., 5, 609-616.

    Hooshmand, H. & Klopfenstein, C.F. (1995) Effects of gamma irradiation
    on mycotoxin disappearance and amino acid contents of corn, wheat, and
    soybeans with different moisture contents.  Plant Foods Hum. Nutr.,
    47, 227-238.

    Hrabovszky, E., Kallo, I., Hajszan, T., Shughrue, P.J., Merchenthaler,
    I. & Liposits, Z. (1998) Expression of estrogen receptor-beta
    messenger ribonucleic acid in oxytocin and vasopressin neurons of the
    rat supraoptic and paraventricular nuclei.  Endocrinology, 139,
    2600-2604.

    Hsia, C.C., Wu, J.L., Lu, X.Q. & Li, Y.S. (1988) Natural occurrence
    and clastogenic effects of nivalenol, deoxynivalenol,
    3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol, and zearalenone in
    corn from a high-risk area of esophageal cancer.  Cancer Detect.
     Prev., 13, 79-86.

    Hughes, C.L., Jr, Chakinala, M.M., Reece, S.G., Miller, R.N.,
    Schomberg, D.W., Jr & Basham, K.B. (1991) Acute and subacute effects
    of naturally occurring estrogens on luteinizing hormone secretion in
    the ovariectomized rat: Part 2.  Reprod. Toxicol., 5, 133-137.

    Hussein, H.M., Franich, R.A., Baxter, M. & Andrew, I.G. (1989)
    Naturally occurring Fusarium toxins in New Zealand maize.  Food
     Addit. Contam., 6, 49-57.

    IARC (1993)  IARC Monographs on the Evaluation of the Carcinogenic
     Risk of Chemicals to Humans, Vol. 56,  Some Naturally Occurring
     Substances:  Heterocyclic Aromatic Amines and Mycotoxins, Lyon, pp.
    397-444.

    Ingerowski, G.H., Scheutwinkel, M. & Stan, H.J. (1981) Mutagenicity
    studies on veterinary anabolic drugs with the  Salmonella/microsome
    test.  Mutat. Res., 91, 93-98.

    Isohata, E., Toyoda, M. & Saito, Y. (1986) Studies on the chemical
    analysis of mycotoxin (XIV). Analytical results on zearalenone in baby
    foods.  Eisei Shikenjo Hokoku, 104, 142-144.

    Ito, Y. & Ohtsubo, K. (1994) Effects of neonatal administration of
    zearalenone on the reproductive physiology of female mice.  J. Vet.
     Med. Sci., 56, 1155-1159.

    James, L.J. & Smith, T.K. (1982) Effect of dietary alfalfa on
    zearalenone toxicity and metabolism in rats and swine.  J. Anim.
     Sci., 55, 110-118.

    Jemmali, M. (1973) Presence of an estrogenic factor of fungal origin:
    Zearalenone or F2, as a natural contaminant in corn.  Ann. Microbiol.
     (Paris), 124, 109-114.

    Jemmali, M. & Mazerand, C. (1980) The presence of zearalenone or F2 in
    commercial walnuts.  Ann. Microbiol. (Paris), 131B, 319-321.

    Jimenez, M., Mateo, R., Querol, A., Huerta, T. & Hernandez, E. (1991)
    Mycotoxins and mycotoxigenic moulds in nuts and sunflower seeds for
    human consumption.  Mycopathologia, 115, 121-127.

    Jimenez, M., Manez, M. & Hernandez, E. (1996) Influence of water
    activity and temperature on the production of zearalenone in corn by
    three  Fusarium species.  Int. J. Food Microbiol., 29, 417-421.

    Jimnez, M., Huerta, T. & Mateo, R. (1997) Mycotoxin production by
    Fusarium species isolated from bananas.  Appl. Environ. Microbiol.,
    63, 364-369.

    Kallela, K. & Saastamoinen, I. (1981a) The effect of grain
    preservatives on the growth of the fungus  Fusarium graminearum and
    on the quantity of zearalenone.  Acta Vet. Scand., 22, 417-427.

    Kallela, K. & Saastamoinen, I. (1981b) Decomposition of the  Fusarium
     graminearum toxin zearalenone in storage conditions.  Nord. Vet.
     Med., 33, 454-460.

    Kallela, K. & Saastamoinen, I. (1982) The effects of 'Gasol' grain
    preservative dosages on the growth of  Fusarium graminearum and the
    quantity of the toxin zearalenone.  Nord. Vet. Med., 34, 124-129.

    Kasamaki, A. & Urasawa, S. (1993) The effect of food chemicals on cell
    aging of human diploid cells in  in vitro culture.  J. Toxicol.
     Sci., 18, 143-153.

    Katzenellebogen, B.S., Katzenellenbogen, J.A. & Mordecai, D. (1974)
    Zearalenones: Characterization of the estrogenic potencies and
    receptor interactions of a series of fungal beta-resorcyclic acid
    lactones.  Endocrinology, 105, 33-40.

    Kennedy, D.G., Hewitt, S.A., McEvoy, J.D.G., Currie, J.W., Cannavan,
    A., Blanchflower, J. & Elliot, C.T (1998) Zeranol is formed from
     Fusarium spp. toxins in cattle  in vivo.  Food Addit. Contam., 15,
    393-400.

    Kim, J.C., Kang, H.J., Lee, D.H., Lee, Y.W. & Yoshizawa, T. (1993)
    Natural occurrence of  Fusarium mycotoxins (trichothecenes and
    zearalenone) in barley and corn in Korea.  Appl. Environ. Microbiol.,
    59, 3789-3802.

    Kollarczik, B., Gareis, M. & Hanelt, M. (1994)  In vitro
    transformation of the  Fusarium mycotoxins deoxynivalenol and
    zearalenone by the normal gut microflora of pigs.  Nat. Toxins, 2,
    105-110.

    Kordic, B., Pribicevic, S., Muntanola-Cvetkovic, M., Nikolic, P. &
    Nikolic, B. (1992) Experimental study of the effects of known
    quantities of zearalenone on swine reproduction.  J. Environ. Pathol.
     Toxicol. Oncol., 11, 53-55.

    Krebs-Smith, S.M., Guenther, P.M., Cook, A., Thompson, F.E.,
    Cucinelli, J. & Udler, J. (1997)  Foods Commonly Eaten in the United
     States. Quantities Consumed Per Eating Occasion and in a Day, 
    1989-91 (NFS Report No. 91-3), Washington DC: US Department of 
    Agriculture Agricultural Research Service.

    Krivobok, S., Oliver, P., Marzin, D.R., Seigle-Murandi, F. & Steimann,
    R. (1987) Study of the genotoxic potential of 17 mycotoxins with the
    SOS chromotest.  Mutagenesis, 2, 433-439.

    Krska, R. (1999)  Mycotoxins of Growing Interest. Zearalenone
    (MYC-CONF/99/5d), Third Joint FAO/WHO/UNEP International Conference on
    Mycotoxins, Tunis, 3-6 March.

    Kuczuk, M.H., Benson, P.M., Heath, H. & Hayes, A.W. (1978) Evaluation
    of the mutagenic potential of mycotoxins using  Salmonella
     typhimurium and  Saccharomyces cerevisiae.  Mutat. Res., 53, 11-20.

    Kuiper, G.G., Carlsson, B., Grandien, K., Enmark, E., Haggblad, J.,
    Nilsson, S. & Gustafsson, J.A. (1997) Comparison of the ligand binding
    specificity and transcript tissue distribution of estrogen receptors
    alpha and beta.  Endocrinology, 138, 863-870.

    Kuiper, G.G., Lemmen, J.G., Carlsson, B., Corton, J.C., Safe, S.H.,
    van der Saag, P.T., van der Burg, B. & Gustafsson, J.A. (1998)
    Interaction of estrogenic chemicals and phytoestrogens with estrogen
    receptor beta.  Endrocrinology, 139, 4252-4263.

    Kuiper-Goodman, T., Scott, P.M. & Watanabe, H. (1987) Risk assessment
    of the mycotoxin zearalenone.  Regul. Toxicol. Pharmacol., 7,
    253-306.

    Kurtz, H.J. & Mirocha, C.J. (1978) Zearalenone (F-2) induced
    estrogenic syndrome in swine. In: Syllie, T.D. & Morehouse, L.G., eds,
     Mycotoxic Fungi, Mycotoxins, Mycotoxicosis. An Encyclopedic
     Handbook, New York: Marcel Dekker, Vol. 2, pp. 260-265.

    Lauren, D.R. & Ringrose, M.A. (1997) Determination of the fate of
    three  Fusarium mycotoxins through wet-milling of maize using an
    improved HPLC analytical technique.  Food Addit. Contam., 14, 
    435-443.

    Lauren, D.R., Agnew, M.P., Smith, W.A. & Sayer, S.T. (1991) A survey
    of the natural occurrence of  Fusarium mycotoxins in cereals grown in
    New Zealand in 1986-1989.  Food Addit. Contam., 8, 599-605.

    Lee, U.S., Jang, H.S., Tanaka, T., Hasegawa, A., Oh, Y.J. & Ueno, Y.
    (1985) The coexistence of the  Fusarium mycotoxins nivalenol,
    deoxynivalenol, and zearalenone in Korean cereals harvested in 1983.
     Food Addit. Contam., 2, 185-192.

    Lee, U.S., Jang, H.S., Tanaka,T., Hasegawa, A., Oh, Y.J., Cho, C.M.,
    Sugiura, Y. & Ueno, Y. (1986) Further survey on the  Fusarium
    mycotoxins in Korean cereals.  Food Addit. Contam., 3, 253-261.

    Li, D., Chen, S. & Randerath, K. (1992) Natural dietary ingredients
    (oats and alfalfa) induce covalent DNA modifications (I-compounds) in
    rat liver and kidney.  Nutr. Cancer, 17, 205-216.

    Long, G.G. & Diekman, M.A. (1986) Characterization of effects of
    zearalenone in swine during early pregnancy.  Am. J. Vet. Res., 47,
    184-187.

    Long, G.G. & Diekman, M.A. (1989) Effect of zearalenone on early
    pregnancy in guinea pigs.  Am. J. Vet. Res., 50, 1220-1223.

    Long, G.G. & Turek, J.J. (1989). Effect of zearalenone on the growth
    of mouse embryos from blastocysts to the egg cylinder stage 
     invitro.  Am. J. Vet. Res., 50, 296-300.

    Long, G.G., Diekman, M.A., Tuite, J.F., Shannon, G.M. & Vesonder, R.F.
    (1982) Effect of Fusarium roseum corn culture containing zearalenone
    on early pregnancy in swine.  Am. J. Vet. Res., 43, 1599-1603.

    Long, G.G., Diekman, M.A. & Scheidt, A.B. (1988) Effect of zearalenone
    on days 7 to 10 postmating on intrauterine environment in sows and
    migration of embryos in sows.  J. Anim. Sci., 66, 452-458.

    Long, G.G., Turek, J., Diekman, M.A. & Scheidt, A.B. (1992) Effect of
    zearalenone on days 7 to 10 post-mating blastocyst development and
    endometrial morphology in sows.  Vet. Pathol., 29, 60-67.

    Lopez, T.A. & Tapia, M.O. (1980) Identification of the mycotoxin
    zearalenone in Argentina.  Rev. Argent. Microbiol., 12, 29-33.

    Lovelace, C.E. & Nyathi, C.B. (1977) Estimation of the fungal toxins,
    zearalenone and aflatoxin, contaminating opaque maize beer in Zambia.
     J. Sci. Food Agric., 28, 288-292.

    Lu, B., Leygue, E., Dotzlaw, H., Murphy, L.J., Murphy, L.C. & Watson,
    P.H. (1998) Estrogen receptor-beta mRNA variants in human and murine
    tissue.  Mol. Cell Endocrinol., 138, 199-203.

    Luo, Y., Yoshizawa, T. & Katayama, T. (1990) Comparative study on the
    natural occurrence of  Fusarium mycotoxins (trichothecenes and
    zearalenone) in corn and wheat from high-and low-risk areas for human
    esophageal cancer in China.  Appl. Environ. Microbiol., 56, 
    3723-3726.

    L'vova, L.S., Bystriakova, Z.K. & Shatilova, T.I. (1981) Mycotoxin
    formation during the storage of unprocessed freshly harvested corn.
     Prikl. Biokhim. Mikrobiol., 17, 766-772.

    L'vova, L.S., Bystriakova, Z.K., Merkulov, E.M., Shatilova, T.I. &
    Kizlenko, O.I. (1984) Possible contamination of rice grains by
    mycotoxins in a temperate climate.  Vop. Pitan., 1, 64-68.

    L'vova, L.S., Orlova, N.I.U., Bystriakova, Z.K., Omel'chenko, M.D. &
    Remele, V.V. (1993) Propagation of toxigenic fungi and mycotoxins in
    various grains.  Prikl. Biokhim. Mikrobiol., 29, 70-79.

    Maaroufi, K., Chekir, L., Creppy, E.E., Ellouz, F. & Bacha, H. (1996)
    Zearalenone induces modifications of haemotological and biochemical
    parameters in rats.  Toxicon, 34, 535-540.

    Marasas, W.F., van Rensburg, S.J. & Mirocha, C.J. (1979) Incidence of
     Fusarium species and the mycotoxins, deoxynivalenol and zearalenone,
    in corn produced in esophageal cancer areas in Transkei.  J. Agric.
     Food Chem., 27, 1108-1112.

    Marin, L., Murtha, J., Dong, W. & Pestka, J.J. (1996) Effects of
    mycotoxins on cytokine production and proliferation in EL-4 thymoma
    cells.  J. Toxicol. Environ. Health, 48, 379-396.

    Martin, P.M.D. & Keen, P. (1978) The occurrence of zearalenone in raw
    and fermented products from Swaziland and Lesotho.  Sabrouaudia, 16,
    15-22.

    Martin, P.M., Horwitz, K.B., Ryan, D.S. & McGuire, WL. (1978)
    Phytoestrogen interaction with estrogen receptors in human breast
    cancer cells.  Endocinology, 103, 1860-1867.

    Marx, H., Gedek, B. & Kollarczik, B. (1995) Comparative investigations
    of mycotoxological status of alternatively and conventionally grown
    crops.  Z. Lebensm. Unters. Forsch., 201, 83-86.

    Mayr, U., Butsch, A. & Schneider, S. (1992) Validation of two  in
     vitro test systems for estrogenic activities with zearalenone,
    phytoestrogens and cereal extracts.  Toxicology, 74, 135-149.

    Mazen, M.B., El-Kady, I.A. & Saber, S.M. (1990) Survey of the
    mycoflora and mycotoxins of cottonseeds and cottonseed products in
    Egypt.  Mycopathologia, 110, 133-138.

    McGregor, D.B., Brown, A., Cattanach, P., Edwards, I., McBride, D.,
    Riach, C. & Caspary, W. (1988) Responses of the L5178Y TK+/TK-
    mouse lymphoma cell forward mutation assay. III. 72 coded chemicals.
     Environ. Mol. Mutag., 12, 85-154.

    diMenna, M.E., Lauren, D.R. & Hardacre, A. (1997) Fusaria and Fusarium
    toxins in New Zealand maize plants.  Mycopathologia, 139, 165-173.

    Midgalof, B.H., Dugger, H.A., Heider, J.G., Coombs, R.A. & Terry, M.K.
    (1983) Biotransformation of zeranol: Disposition and metabolism in the
    female rat, rabbit, dog, monkey and man.  Xenobiotica, 13, 209-221.

    Milano, G.D., Odriozola, E. & Lopez, T.A. (1991) Lack of effect of a
    diet containing zearalenone on spermatogenesis in rams.  Vet. Rec.,
    129, 33-35.

    Milano, G.D., Bec-Villalobos, D. & Ofelia Tapia, M. (1995) Effects of
    long-term zearalenone administration on spermatogenesis and serum
    luteinizing hormone, follicle stimulating hormone, and prolactin
    values in male rats.  Am. J. Vet. Res., 56, 954-957.

    Miles, C.O., Erasmuson, A.F., Wilkins, A.L., Towers, N.R., Smith,
    B.L., Garthwaite, I., Scahill, B.G. & Hansen, R.P. (1996) Ovine
    metabolism of zearalenone to alpha-zearalanol (zeranol).  J. Agric.
     Food Chem., 44, 3244-3250.

    Miller, J.K., Hacking, A., Harrison, J. & Gross, V.J. (1973)
    Stillbirths, neonatal mortality and small litters in pigs associated
    with the ingestion of  Fusarium toxin by pregnant sows.  Vet. Rec.,
    93, 555-559.

    Mirocha, C.J., Pathre, S.V. & Robison, T.S. (1981) Comparative
    metabolism of zearalenone and transmission into bovine milk.  Food
     Cosmet. Toxicol., 19, 25-30.

    Mirocha, C., Robison, T.S., Pawlosky, R.J. & Allen, N.K. (1982)
    Distribution and residue determination of [3H] zearalenone in
    broilers.  Toxicol. Appl. Pharmacol., 66, 77-87.

    Molto, G.A., Gonzalez, H.H., Resnik, S.L. & Pereyra-Gonzalez, A.
    (1997) Production of trichothecenes and zearalenone by isolates of
    Fusarium spp. from Argentinian maize.  Food Addit. Contam., 14,
    263-268.

    Montani, M.L., Vaamonde, G., Resnik, S.L. & Buera, P. (1988) Influence
    of water activity and temperature on the accumulation of zearalenone
    in corn.  Int. J. Food Microbiol., 6, 1-8.

    Mortelmans, K., Haworth, S., Lawlor, T., Speck, W., Tainer, B. &
    Zeiger, E. (1986)  Salmonella mutagenicity tests. 2. Results from the
    testing of 270 chemicals.  Environ. Mutag., 8, 1-119.

    Mller, H.M. & Schwadorf, K. (1993) A survey of the natural occurrence
    of  Fusarium toxins in wheat grown in a southwestern area of Germany.
     Mycopathologia, 121, 115-121.

    Mller, H.M., Reimann, J., Schumacher, U. & Schwadorf, K. (1997a)
    Natural occurrence of  Fusarium toxins in barley harvested during
    five years in an area of southwest Germany.  Mycopathologia, 137,
    185-192.

    Mller, H.M., Reimann, J., Schumacher, U. & Schwadorf, K. (1997b)
     Fusarium toxins in wheat harvested during six years in an area of
    southwest Germany.  Nat. Toxins, 5, 24-30.

    Mller, H.M., Reimann, J., Schumacher, U. & Schwadorf, K. (1998)
    Natural occurrence of  Fusarium toxins in oats harvested during five
    years in an area of southwest Germany.  Food Addit. Contam., 15,
    801-806.

    National Toxicology Program (1982)  NTP Carcinogenesis Bioassay of
     Zearalenone in F 344/N Rats and F6C3F1 Mice (Technical Report Series
    No. 235), Research Triangle Park, North Carolina, Department of Health
    and Human Services.

    Neelakantan, S., Balasubramanian, T., Balasaraswathi, R., Jasmine,
    G.I. & Swaminathan, R. (1979) Occurrence of zearalenone in food grains
    stacked and stored in open air.  Indian J. Biochem. Biophys., 16,
    Suppl. 58.

    Norton, D.M., Toule, G.M., Cooper, S.J., Partington, S.R. & Chapman,
    W.B. (1982) In: Pepin, G.A., Patterson, D.S.P. & Gray, D.E., eds,
     Proceedings, Fourth Meeting on Mycotoxins in Animal Disease,
    Northumberland, Ministry of Agriculture, Fisheries and Food, pp.
    77-81.

    Okoye, Z.S. (1987) Stability of zearalenone in naturally contaminated
    corn during Nigerian traditional brewing.  Food Addit. Contam., 4,
    57-59.

    Olsen, M., Pettersson, H., Sandholm, K., Visconti, A. & Kiessling,
    K.H. (1987) Metabolism of zearalenone by sow intestinal mucosa
     in vitro. Food Chem. Toxicol., 25, 681-683.

    Olsen, M., Malmlof, K., Pettersson, H. & Grajewski, J. (1991)
    Influence of dietary fibre on plasma and urinary levels of zearalenone
    and metabolites in swine.  Mycotoxin Res., 7, 8-11.

    Osborn, R.G., Osweiler, G.D. & Foley, C.W. (1988) Effects of
    zearalenone on various components of rabbit uterine tubal fluid.
     Am. J. Vet. Res., 49, 1382-1386.

    Palyusik, M., Harrach, B., Mirocha, C.J. & Pathre, S.V. (1980)
    Transmission of zearalenone and zearalenol into porcine milk.  Acta
     Vet. Acad. Sci. Hung., 28, 217-222.

    Palyusik, M., Harrach, B., Horvath, G. & Mirocha, C.J. (1990)
    Experimental fusariotoxicosis of swine produced by zearalenone and T-2
    toxins.  J. Environ. Pathol. Toxicol. Oncol., 10, 52-55.

    Pande, N., Saxena, J. & Pandey, H. (1990) Natural occurrence of
    mycotoxins in some cereals.  Mycoses, 33, 126-128.

    Parekh, C.K. & Coulston, F. (1983) Determination of the hormonal
    no-effect level of zeranol in non-human primates. In: Meissonier, E. &
    Mitchell-Vigneron, J., eds,  Anabolics in Animal Production (OIE
    Symposium February 15-17), Paris, p. 353 [cited in Kuiper-Goodman et
    al. (1987)].

    Park, K.J., Park, A.R. & Lee, Y.W. (1992) Natural occurrence of
     Fusarium mycotoxins of the 1990 barley crop in Korea.  Food Addit.
     Contam., 9, 639-645.

    Park, J.J., Smalley, E.B. & Chu, F.S. (1996) Natural occurrence of
     Fusarium mycotoxins in field samples from the 1992 Wisconsin corn
    crop.  Appl. Environ. Microbiol., 62, 1642-1648.

    Paster, N., Blumenthal-Yonassi, J., Barkai-Golan, R. & Menasherov, M.
    (1991) Production of zearalenone  in vitro and in corn grains stored
    under modified atmospheres.  Int. J. Food Microbiol., 12, 157-165.

    Patel, S., Hazel, C.M., Winterton, A.G. & Mortby, E. (1996) Survey of
    ethnic foods for mycotoxins.  Food Addit. Contam., 13, 833-841.

    Pennie, W.D., Aldrige, T.C. & Brooks, A.N. (1998) Differrential
    activation by xenooestro-gens of ER alpha and ER beta when linked to
    different response elements.  J. Endocrinol., 158, R11-R4.

    Pepeljnjak, S. (1984) Mycotoxic contamination of haricot beans in
    nephropathic areas in Yugoslavia.  Microbiol. Aliments Nutr., 2,
    331-336.

    Pestka, J.J., Tai., J.-H., Witt, M.F., Dixon, D.E. & Forsell, J.H.
    (1987) Suppression of immune response in the B6C3F1 mouse after
    dietary exposure to the  Fusarium mycotoxins deoxynivalenol
    (vomitoxin) and zearalenone.  Food Chem. Toxicol., 25, 297-304.

    Petersen, D.N., Tkalcevic, G.T., Koza-Taylor, P.H., Turi, T.G. &
    Brown, T.A. (1998) Identification of estrogen receptor beta2, a
    functional variant of estrogen receptor beta expressed in normal rat
    tissues.  Endocrinology, 139, 1082-1092.

    Petkova-Bocharova, T., Castegnaro, M., Michelon, J. & Maru, V. (1991)
    Ochratoxin A and other mycotoxins in cereals from an area of Balkan
    endemic nephropathy and urinary tract tumours in Bulgaria. In:
    Castegnaro, M., Plestina, R., Dirheimer, G. & Chernozemsky, I.N., eds,
     Mycotoxins, Endemic Nephropathy and Urinary Tract Tumours (IARC
    Scientific Publications No. 115), Lyon, IARCPress, pp. 83-87.

    Pettersson, K., Grandien, K., Kuiper, G.G. & Gustafsson, J.A. (1997)
    Mouse estrogen receptor beta forms estrogen response element-binding
    heterodimers with estrogen receptor alpha.  Mol. Endocrinol., 11,
    1486-1496.

    Pfohl-Leszkowicz, A., Chekir-Ghedira, L. & Bacha, H. (1995)
    Genotoxicity of zearalenone, an estrogenic mycotoxin: DNA adduct
    formation in female mouse tissues.  Carcinogenesis, 16, 2315-2320.

    Pineiro, M.S., Scott, P.M. & Kanhere, S.R. (1996a) Mycotoxin producing
    potential of  Fusarium graminearum isolates from Uruguayan barley.
     Mycopathologia, 132, 167-172.

    Pineiro, M., Dawson, R. & Costarrica, M.L. (1996b) Monitoring program
    for mycotoxin contamination in Uruguayan food and feeds.  Nat.
     Toxins, 4, 242-245.

    Plasencia, J. & Mirocha, C.J. (1991) Isolation and characterization of
    zearalenone sulfate produced by  Fusarium spp.  Appl. Environ.
     Microbiol., 57, 146-150.

    Pozzi, C.R., Correa, B., Gambale, W., Paula, C.R., Chacon-Reche, N.O.
    & Meirelles, M.C. (1995) Postharvest and stored corn in Brazil:
    Mycoflora interaction, abiotic factors and mycotoxin occurrence.
     Food  Addit. Contam., 12, 313-319.

    Prelusky, D.B., Scott, P.M., Trenholm, H. & Lawrence, G.A. (1990)
    Minimal transmission of zearalenone to milk of dairy cows. 
     J. Environ.  Sci. Health B, 25, 87-103.

    Prins, G.S., Marmer, M., Woodham, C., Chang, W., Kuiper, G.,
    Gustafsson, J.A. & Birch, L. (1998) Estrogen receptor-beta messenger
    ribonucleic acid ontogeny in the prostate of normal and neonatally
    estrogenized rats.  Endocrinology, 139, 874-883.

    Prior, M.G. (1976) Mycotoxin determinations on animal feedstuffs and
    tissues in Western Canada.  Can. J. Comp. Med., 40, 75-79.

    Prior, M.G. (1981) Mycotoxins in animal feedstuffs and tissues in
    Western Canada 1975 to 1979.  Can. J. Comp. Med., 45, 116-119.

    Pullar, E.M. & Lerew, W.M. (1937) Vulvovaginitis of swine. 
     Aust. Vet.  J., 13, 28-31.

    Pung, O.J., Luster, M.I., Hayes, H.T. & Rader, J. (1984) Influence of
    steroidal and nonsteroidal sex hormones on host resistance in mice:
    Increased susceptibility to  Listeria monocytogenes after exposure to
    estrogenic compounds.  Infect. Immun., 46, 301-307.

    Rainey, M.R., Tubbs, R.C., Bennet, L.W. & Cox, N.M. (1990) Prepubertal
    exposure to dietary zearalenone alters hypothalamo-hypophyseal
    function but does not impair postpubertal reproductive functions in
    gilts.  J. Anim. Sci., 68, 2015-2022.

    Ramos, A.J., Hernandez, E., Pla-Delfina, J.M. & Merino, M. (1996)
    Intestinal absorption of zearalenone and  in vitro study of
    non-nutrive sorbent materials.  Int. J. Pharm., 128, 129-137.

    Ranfft, K., Gerstl, R. & Mayer, G. (1990) Determination and occurrence
    of zearalenone in cereals and mixed feeds.  Z. Lebensm. Unters.
     Forsch., 191, 449-453.

    Rao, H.R. & Harein, P.K. (1973) Inhibition of aflatoxin and
    zearalenone biosynthesis with dichlorvos.  Bull. Environ. Contam.
     Toxicol., 10, 112-115.

    Resnik, S., Neira, S., Pacin, A., Martinez, E., Apro, N. & Latreite,
    S. (1996) A survey of the natural occurrence of aflatoxins and
    zearalenone in Argentine field maize: 1983-1994.  Food Addit.
     Contam., 13, 115-120.

    Rheeder, J.P., Sydenham, E.W., Marasas, W.F., Thiel, P.G., Shephard,
    G.S., Schlechter, M., Stockenstrom, S, Cronje, D.E. & Viljoen, J.H.
    (1994) Ear-rot fungi and mycotoxins in South African corn of the 1989
    crop exported to Taiwan.  Mycopathologia, 127, 35-41.

    Roscoe, V.A. (1998)  Determination of Zearalenone in Infant Foods
     Using Immunoaffinity Columns and High Performance Liquid
     Chromatography (WPG-LB-25), Ottawa, Health Protection Branch Central
    Region.

    Ruddick, J.A., Scott, P.M. & Harwig, J. (1976) Teratological
    evaluation of zearalenone administered orally to the rat.  Bull.
     Environ. Contam. Toxicol., 15, 678-681.

    Ruhr, L.P., Osweiler, G.D., & Foley, C.W. (1983) Effect of the
    estrogenic mycotoxin zearalenone on reproductive potential in the
    boar.  Am. J. Vet. Res., 44, 483-485.

    Russell, L., Cox, D.F., Larsen, G., Bodwell, K. & Nelson, C.E. (1991)
    Incidence of molds and mycotoxins in commercial animal feed mills in
    seven midwestern states, 1988-1989.  J. Anim. Sci., 69, 5-12.

    Ruzsas, C., Biro-Gosztony, M. & Wller, L. (1978) Effect of pre- and
    perinatal administration of the fungus F2-toxin on the reproduction of
    the albino rat.  Dev. Endocrinol., 3, 57-60.

    Ruzsas, C., Biro-Gosztony, M., Wller, L & Mess, B. (1979). Effect of
    the fungal toxin (zearalenone) on the reproductive system and
    fertility of male and female rats.  Acta Biol. Acad. Sci Hung., 32,
    335-345.

    Ryu, J.C., Yang, J.S., Song, Y.S., Kwon, O.S., Park, J. & Chang, I.M.
    (1996) Survey of natural occurrence of trichothecene mycotoxins and
    zearalenone in Korean cereals harvested in 1992 using gas
    chromatography/mass spectrometry.  Food Addit. Contam., 13, 333-341.

    Sabino, M., Prado, G., Inomata, E.I., de O Pedroso, M. & Garcia, R.V.
    (1989) Natural occurrence of aflatoxins and zearalenone in maize in
    Brazil. Part II.  Food Addit. Contam., 6, 327-331.

    Senz de Rodriguez, C.A. (1984) Environmental hormone contamination in
    Puerto Rico.  New Engl. J. Med., 310, 1741-1742.

    Senz de Rodriguez, C.A., Bongiovanni, A.M. & Conde de Borrego, L.
    (1985) An epidemic of precocious development in Puerto Rican children.
     J. Pediatr., 107, 393-396.

    Sandor, G. (1984) Occurrence of mycotoxins in feed, animal organs, and
    secretions.  Acta Vet. Hung., 32, 7-69.

    Scheutwinkel, M., van der Hude, W. & Basler, A. (1986) Studies on the
    genotoxicity of the anabolic drugs trenbolone and zeranol.  Arch.
     Toxicol., 59, 4-6.

    Scott, P.M. (1996) Mycotoxins transmitted into beer from contaminated
    grains during brewing.  J. Assoc. Off. Anal. Chem. Int., 79, 875-882.

    Scott, P.M. (1997) Multi-year monitoring of Canadian grains and
    grain-based foods for trichothecenes and zearalenone.  Food Addit.
     Contam., 14, 333-339.

    Scott, P.M., Panalaks, T., Kanhere, S. & Miles, W.F. (1978)
    Determination of zearalenone in corn flakes and other corn-based foods
    by thin layer chromatography, high pressure liquid chromatography, and
    gas-liquid chromatography/high resolution mass spectrometry.  J.
    Assoc.  Off. Anal. Chem., 61, 593-600.

    Scott, P.M., Kanhere, S.R. & Weber, D. (1993) Analysis of Canadian and
    imported beers for  Fusarium mycotoxins by gas chromatography-mass
     spectrometry. Food Addit. Contam., 10, 381-389.

    Scudamore, K.A., Nawaz, S. & Hetmanski, M.T. (1998) Mycotoxins in
    ingredients of animal feeding stuffs: II. Determination of mycotoxins
    in maize and maize products.  Food Addit. Contam., 15, 30-55.

    Senti, F.R. (1979) Global perspective on mycotoxins. In:  Perspective
     on Mycotoxins, Rome: FAO, pp. 15-120.

    Shannon, G.M., Shotwell, O.L., Lyons, A.J., White, D.G. &
    Arcia-Aguirre, G. (1980) Laboratory screening for zearalenone
    formation in corn hybrids and inbreds.  J. Assoc. Off. Anal. Chem.,
    63, 1275-1277.

    Sharp, G.D. & Dyer, I.A. (1972) Zearalanol metabolism in steers.
     J. Anim. Sci., 34, 176-179.

    Shim, W.B., Kim, J.C., Seo, J.A. & Lee, Y.W. (1997) Natural occurrence
    of trichothecenes and zearalenone in Korean and imported beers.  Food
     Addit. Contam., 14, 1-5.

    Shotwell, O.L., Goulden, M.L. & Bennett, G.A. (1976) Determination of
    zearalenone in corn: Collaborative study.  J. Assoc. Off. Anal.
    Chem., 59, 666-670.

    Shotwell, O.L., Goulden, M.L., Bennett, G.A., Plattner, R.D. &
    Hesseltine, C.W. (1977) Survey of 1975 wheat and soybeans for
    aflatoxin, zearalenone, and ochratoxin.  J. Assoc. Off. Anal. Chem.,
    60, 778-783.

    Shreeve, B.J., Patterson, D.S.P., Roberts, B.A. & Wrathall, A.E.
    (1978) Effect of moldy feed containing zearalenone on pregnant sows.
     Br. Vet. J., 134, 421-427.

    Shreeve, B.J., Patterson, D.S. & Roberts, B.A. (1979) The 'carry-over'
    of aflatoxin, ochratoxin, and zearalenone from naturally contaminated
    feed to tissues, urine, and milk of dairy cows.  Food Cosmet.
     Toxicol., 17, 151-152.

    Shughrue, P.J., Komm, B. & Merchenthaler, I. (1996) The distribution
    of estrogen receptor-beta mRNA in the rat hypothalamus.  Steroids,
    61, 678-681.

    Shughrue, P.J., Lane, M.V. & Merchenthaler, I. (1997) Comparative
    distribution of estrogen receptor-alpha and -beta mRNA in the rat
    central nervous system.  J. Comp. Neurol., 388, 507-525.

    Siame, B.A., Mpuchane, S.G., Gashe, B.A., Allotey, J. & Teffera, G.
    (1998) Occurrence of aflatoxins, fumonisin B1, and zearalenone in
    foods and feeds in Botswana.  J. Food Prot., 61, 1670-1673.

    Sivaswamy, S.N., Balachandran, B. & Balanehru, S. (1991) South Indian
    foods: Contaminants and their effects.  Bull. Environ. Contam.
     Toxicol., 47, 251-260.

    Smith, J.F., di Menna, M.E. & McGowan, L.T. (1990) Reproductive
    performance of Coopworth ewes following oral doses of zearalenone
    before and after mating.  J. Reprod. Fertil., 89, 99-106.

    Soares, L.M. & Rodriguez-Amaya, D.B. (1989) Survey of aflatoxins,
    ochratoxin A, zearalenone, and sterigmatocystin in some Brazilian
    foods by using multi-toxin thin-layer chromatographic method.
     J. Assoc. Off. Anal. Chem., 72, 22-26.

    Stahl, S., Chun, T.Y. & Gray, W.G. (1998) Phytoestrogens act as
    estrogen agonists in an estrogen-responsive pituitary cell line.
     Toxicol. Appl. Pharmacol., 152, 41-48.

    Stark, A. (1980) Mutagenicity and carcinogenicity of mycotoxins: DNA
    binding as a possible mode of action.  Annu. Rev. Microbiol., 34,
    235-262.

    Stoloff, L. & Dalrymple, B. (1977) Aflatoxin and zearalenone
    occurrence in dry-milled corn products.  J. Assoc. Off. Anal. Chem.,
    60, 579-582.

    Stoloff, L. & Francis, O.J., Jr (1980) Survey for aflatoxins and
    zearalenone in canned and frozen sweet corn.  J. Assoc. Off. Anal.
     Chem., 63, 180-181.

    Stoloff, L., Henry, S. & Francis, O.J., Jr (1976) Survey for
    aflatoxins and zearalenone in 1973 crop corn stored on farms and in
    country elevators.  J. Assoc. Off. Anal. Chem., 59, 118-121.

    Stratton, G.W., Robinson, A.R., Smith, H.C., Kittilsen, L. & Barbour,
    M. (1993) Levels of five mycotoxins in grains harvested in Atlantic
    Canada as measured by high performance liquid chromatography.  Arch.
     Environ. Contam. Toxicol., 24, 399-409.

    Sundlof, S.F. & Strickland, C. (1986) Zearalenone and zeranol:
    Potential residue problems in livestock.  Vet. Hum. Toxicol., 28,
    242-250.

    Szuetz, P., Mesterhazy, A., Falkay, G.Y. & Bartok, T. (1997) Early
    telearche symptoms in children and their relations to zearalenon
    contamination in foodstuffs.  Cereals Res. Commun., 25, 429-436.

    Tanaka, T., Hasegawa, A., Matsuki, Y. & Ueno, Y. (1985) A survey of
    the occurrence of nivalenol, deoxynivalenol, and zearalenone in
    foodstuffs and health foods in Japan.  Food Addit. Contam., 2, 
    259-265.

    Tanaka, T., Hasegawa, A., Matsuki, Y., Lee, U.S. & Ueno, Y. (1986) A
    limited survey of  Fusarium mycotoxins nivalenol, deoxynivalenol, and
    zearalenone in 1984 UK harvested wheat and barley.  Food Addit.
     Contam., 3, 247-252.

    Tanaka, T., Hasegawa, A., Yamamoto, S., Lee, U.S., Sugiura, Y. & Ueno,
    Y. (1988a) Worldwide contamination of cereals by the  Fusarium
    mycotoxins, nivalenol, deoxynivalenol, and zearalenone. 1. Survey of
    19 countries.  J. Agric. Food Chem., 36, 979-983.

    Tanaka, T., Hasegawa, A., Yamamoto, S., Sugiura, Y. & Ueno, Y. (1988b)
    A case report on a minor contamination of nivalenol in cereals
    harvested in Canada.  Mycopathologia, 101, 157-160.

    Tanaka, T., Yamamoto, S., Hasegawa, A., Aoki, N., Besling, J.R.,
    Sugiura, Y. & Ueno, Y. (1990) A survey of the natural occurrence of
     Fusarium mycotoxins, deoxynivalenol, nivalenol, and zearalenone in
    cereals harvested in the Netherlands.  Mycopathologia, 110, 19-22.

    Tanaka, T., Teshima, R., Ikebuchi, H., Sawada, J., Terao, T. &
    Ichinoe, M. (1993) Sensitive determination of zearalenone and
    alpha-zearalenol in barley and Job's-tears by liquid chromatography
    with fluorescence detection.  J. Assoc. Off. Anal. Chem. Int., 76,
    1006-1009.

    Tashiro, F., Kawabata, Y., Naoi, M. & Ueno, Y. (1980)
    Zearalenone-estrogen receptor interaction and RNA synthesis in rat
    uterus. In: Preuser, H.J., ed.,  Medical Mycology, Stuttgart:
    Fischer, Suppl. 8, pp. 311-320.

    Tennant, R.W., Margolin, B.H., Shelby, M.D., Zeiger, E., Haseman,
    J.K., Spalding, J., Caspary, W., Resnik, M.A., Stasiewicz, S.,
    Anderson, B. & Minor, R. (1987) Prediction of chemical carcinogenicity
    in rodents from  in vitro genetic toxicity assays.  Science, 236,
    933-941.

    Thurst, R., Kneist, S. & Huhne, V. (1983) Genotoxicity of  Fusarium
    mycotoxins (nivalenol, fusarenon-X, T-2 toxin, and zearalenone) in
    Chinese hamster V79-E cells  in vitro. Arch. Geschwulstforsch., 53,
    9-15.

    Tomaszewski, J., Miturski, R., Semczuk, A., Kotarski, J. & Jakowicki,
    J. (1998) Tissue zearalenone concentration in normal, hyperplastic and
    neoplastic human endometrium.  Ginekol. Pol., 69, 363-366.

    Ueno, Y. & Kubota, K. (1976) DNA-attacking ability of carcinogenic
    mycotoxins in recombination-deficient mutant cells of  Bacillus
     subtilis. Cancer Res., 36, 445-451.

    Ueno, Y., Lee, U.S., Tanaka, T., Hasegawa, A. & Matsuki, Y. (1986)
    Examination of Chinese and USSR cereals for the  Fusarium mycotoxins,
    nivalenol, deoxynivalenol and zearalenone. Toxicon, 24, 618-621.

    Underhill, K.L., Rotter, B.A., Thompson, B.K., Prelusky, D.B. &
    Trenholm, H.L. (1995) Effectiveness of cholestyramine in the
    detoxification of zearalenone as determined in mice.  Bull. Environ.
     Contam. Toxicol., 54, 128-134.

    Usleber, E., Abramson, D., Gessler, R., Smith, D.M., Clear, R.M. &
    Martlbauer, E. (1996) Natural contamination of Manitoba barley by
    3,15-diacetyldeoxynivalenol and its detection by immunochromatography.
     Appl. Environ. Microbiol., 62, 3858-3860.

    Van Egmond, H.P. (1993) Rationale for regulatory programmes for
    mycotoxins in human foods and animal feeds.  Food Addit. Contam., 10,
    29-36.

    Vanyi, A. & Szeky, A. (1980) Fusariotoxicosis. 6. The effect of F-2
    toxin (zearalenone) on the spermatogenesis of male swine.  Magy
     Allattorv. Lapja, 35, 242-246.

    Vanyi, A., Timar, I. & Szeky, A. (1980) Fusariotoxicosis. 9. The
    effect of F-2 toxin (zearalenone) on the spermatogenesis of rams and
    bulls.  Magy. Allattorv. Lapja, 35, 777-780.

    Vanyi, A., Bata, A. & Sandor, G.S. (1983) Metabolism of zearalenone in
    pregnant sows. In:  Proceedings, International Symposium on
     Mycotoxins, September 6-8, 1981, Cairo, Egypt, pp. 311-315.

    Vesonder, R.F., Golinski, P., Plattner, R. & Zietkiewicz, D.L. (1991)
    Mycotoxin formation by different geographic isolates of  Fusarium
     crookwellense.  Mycopathologia, 113, 11-14.

    Visconti, A. & Pascale, M. (1998) Determination of zearalenone in corn
    by means of immunoaffinity clean-up and high-performance liquid
    chromatography with fluores-cence detection.  J. Chromatogr. A, 815,
    133-140.

    Vladusic, E.A., Hornby, A.E., Guerra-Vladusic, F.K. & Lupu, R. (1998)
    Expression of estrogen receptor beta messenger RNA variant in breast
    cancer.  Cancer Res., 58, 210-214.

    Vrabcheva, T., Gessler, R., Usleber, E. & Mrtlbauer, E. (1996) First
    survey on the natural occurrence of  Fusarium mycotoxins in Bulgarian
    wheat.  Mycopathologia, 136, 47-52.

    Wallace, C. & Rajamahendran, R. (1993) Effect of zearalenone on
    in-vitro early development of mouse embryos and on the maturation of
    bovine oocytes.  J. Anim. Sci., 71 (Suppl. 1), 223.

    Ware, G.M. & Thorpe, C.W. (1978) Determination of zearalenone in corn
    by high pressure liquid chromatography and fluorescence detection.
     J. Assoc. Off. Anal. Chem., 61, 1058-1062.

    Wehner, F.C., Marasas, W.F.O. & Thiel, P.G. (1978) Lack of
    mutagenicity to  Salmonella typhimurium of some  Fusarium
    mycotoxins.  Appl. Environ. Microbiol., 35, 659-662.

    Widiastuti, R., Maryam, R., Blaney, B.J., Salfina & Stoltz, D.R.
    (1988a) Corn as a source of mycotoxins in Indonesian poultry feeds and
    the effectiveness of visual examination methods for detecting
    contamination.  Mycopathologia, 102, 45-49.

    Widiastuti, R., Maryam, R., Blaney, B.J., Salfina & Stoltz, D.R.
    (1988b) Cyclopiazonic acid in combination with aflatoxins,
    zearalenone, and ochratoxin A in Indonesian corn.  Mycopathologia,
    104, 153-156.

    Williams, B.C. (1985) Mycotoxins in foods and foodstuffs. In: Scott,
    P.M., Trenholm, H.L. & Sutton, M.D., eds,  Mycotoxins: A Canadian
     Perspective, Ottawa: National Research Council Canada, pp. 49-53.

    Williams, B.A., Mills, K.T., Burrough, C.D. & Bern, H.A. (1989)
    Reproductive alterations in female C57BL/Crgl mice exposed neonatally
    to zearalenone, an estrogenic mycotoxin.  Cancer Lett., 46, 225-230.

    Williams, G.M., Mori, H. & McQueen, C.A. (1989) Structure-activity
    relationships in the rat hepatocyte DNA-repair test for 300 chemicals.
     Mutat. Res., 221, 263-286.

    Yamaguchi, M. (1983)  World Vegetables. Principles, Production and
     Nutritive Values, Westport, Connecticut: AVI Publishing Co. Inc.

    Yamashita, A., Yoshizawa, T., Aiura, Y., Sanchez, P.C., Dizon, E.I.,
    Arim, R.H. & Sardjono (1995)  Fusarium mycotoxins (fumonisins,
    nivalenol, and zearalenone) and aflatoxins in corn from Southeast
    Asia.  Biosci. Biotechnol. Biochem., 59, 1804-1807.

    Yamini, B., Bursian, S.J. & Aulerich, R.J. (1997) Pathological effects
    of dietary zearalenone and/or tamoxifen on female mink reproductive
    organs.  Vet. Hum. Toxicol., 39, 74-78.

    Yang, H.H., Aulerich, R.J., Helferich, W., Yamini, B., Chou, K.C.,
    Miller, E.R. & Bursian, S.J. (1995) Effects of zearalenone and/or
    tamoxifen on swine and mink reproduction.  J. Appl. Toxicol., 15,
    223-232.

    Yoshizawa, T. & Jin, Y.Z. (1995) Natural occurrence of acetylated
    derivatives of deoxynivalenol and nivalenol in wheat and barley in
    Japan.  Food Addit. Contam., 12, 689-694.

    Young, L.G. & King, G.J. (1984) Zearalenone and swine reproduction.
     J. Am. Vet. Med. Assoc., 185, 334-335.

    Young, L.G., King, G.J., McGirr, L. & Sutton, J.C. (1982) Moldy corn
    in diets of gestating and lactating swine.  J. Anim. Sci., 54, 
    976-982.

    Young, L.G., He, P. & King, G.J. (1990) Effects of feeding zearalenone
    to sows on rebreeding and pregnancy.  J. Anim. Sci., 1, 15-20.

    Yuwai, K.E., Rao, K.S., Singh, K., Tanaka, T. & Ueno, Y. (1994)
    Occurrence of nivalenol, deoxynivalenol, and zearalenone in imported
    cereals in Papua, New Guinea.  Nat. Toxins, 2, 19-21.

    Zakharova, L.P., Obol'skii, O.L., L'vova, L.S., Bystriakova, Z.K.,
    Kravchenko, L.V. & Tutel'ian, V.A. (1995)  Fusarium toxins in the
    cereal crop in Russia.  Vopr. Pitan., 2, 26-29.

    Zohri, A.A. & Abdel-Gawad, K.M. (1993) Survey of mycoflora and
    mycotoxins of some dried fruits in Egypt.  J. Basic Microbiol., 33,
    279-288.
    


    See Also:
       Toxicological Abbreviations
       ZEARALENONE (JECFA Evaluation)