Toxicological evaluation of some food
    additives including anticaking agents,
    antimicrobials, antioxidants, emulsifiers
    and thickening agents


    The evaluations contained in this publication
    were prepared by the Joint FAO/WHO Expert
    Committee on Food Additives which met in Geneva,
    25 June - 4 July 19731

    World Health Organization


    1    Seventeenth Report of the Joint FAO/WHO Expert Committee on
    Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 539;
    FAO Nutrition Meetings Report Series, 1974, No. 53.



         These substances have been evaluated for acceptable daily intake
    by the Joint FAO/WHO Expert Committee on Food Additives (see Annex 1,
    Ref. No. 20 and 27) in 1969 and 1971.

         The previously published monographs have been revised and are
    reproduced in their entirety below.



         In vitro hydrolysis with lipase proceeded readily to form
    stearic and lactic acid (Hodge, 1961). Rats fed either salt of this
    acid excreted only traces of lactate in the faecal fat with good
    utilization of stearic acid and calcium (Hodge, 1961).

         Experiments comparing the metabolism of mixed stearic acid and
    14C-lactic acid with calcium 14C-stearoyl lactylate (lactic acid
    labelled) showed 58% excretion of the 14C of the physical mixture and
    60% of the 14C-moiety as 14CO2 within 24 hours. There was no
    difference in C14-distribution and excretion between the two groups.
    Thus lactate derived from calcium stearoyl lactylate is metabolized
    normally (Hodge, 1955).


    Acute toxicity

    Animal    Route     (mg/kg bw)          Reference

    Rat       oral      over 25 000         Schuler & Thornton, 1952

    Short-term studies


         Groups of five male rats received CaSL at levels of 0.5, 2.0 and
    12.5% in their diet for 43 days. No animal died but the weights of
    liver, heart, brain, stomach and testes were increased at the 12.5%
    level, relative liver weight was increased at the 2% level and growth
    was reduced at the 2 and 12.5% level (Hodge, 1953).

         In a paired feeding study, groups of 10 rats were given 0 or 5%
    CaSL for 27 days. The test groups showed slightly lower food
    efficiency. Liver weight of the test group was increased but the
    histology was normal except for a slight increase in glycogen. In
    another paired feeding study, groups of 10 male and 10 female rats
    received either 0.5% CaSL or 12.5% of a 41:59 mixture of calcium
    lactate and stearic acid. The test groups grew a little better but had
    raised liver weight. Histology of livers and kidneys was normal in all
    groups and X-rays of femurs were comparable (Hodge, 1953a).

         Groups of five male rats received either 41:59 mixtures of
    calcium lactate and stearic acid for 32 days or 41:59 mixtures of
    sodium lactate and stearic acid for 52 days at 0, 0.5, 2 and 10% of
    the diet. At the 10% level the sodium lactate group had a slightly
    reduced growth, but the organ weights of brain, stomach, spleen, lung
    and testes were raised. Histology was normal. Some organ weights were
    reduced at the 10% level in the calcium lactate group but histology
    was normal (Hodge, 1953).

         Groups of eight male and eight female rats received either 3.5%
    cellulose fibre or 3.5% stearoyl lactylate in their diet for 90 days.
    There was no difference between groups in growth rate, food
    consumption, faecal fat elimination, gross and histopathology (Schuler
    et al., 1952).

         Groups of 10 male and 10 female rats received NaSL at 0, 0.5, 5
    and 12.5% in their diet for 102 days. Growth was reduced at the
    highest level. No abnormalities compared with controls were seen as
    regards urinalysis, haematology, and faecal excretion. At the highest
    test level the weights of liver, brain, stomach and spleen were
    increased but gross and histopathology were normal (Hodge, 1953).

         In a similar experiment on groups of 10 male and 10 female rats,
    CaSL was fed in the diet at levels of 0.5, 5 and 12.5% for 98 days.
    Growth was slightly retarded at 5% and significantly reduced at 12.5%
    and the relative weights of liver, stomach, heart, spleen and brain
    were increased at 12.5%. No histological abnormalities were seen in
    kidneys, brain, lung, spleen and liver, but at the 12.5% level
    lipogranulomata were detected in the adipose tissue. No increase in
    stainable liver fat was seen. Urinalysis and blood morphology were
    normal. Radiological studies of femurs were normal and showed that the
    additional dietary calcium had no effect on body load (Hodge, 1953a).

         Groups of 12 rats were fed for four weeks diets containing 0 or
    5% CaSL or a mixture of calcium lactate, stearic acid and lactic acid.
    The animals on CaSL grew best with better food efficiency and better
    calcium deposition in the bones than in controls. The liver weights of
    the CaSL group were greater than those of controls or the group on the
    mixed compounds. No other pathological changes were seen (Wisconsin
    Alumni Research Foundation, 1955).

         Twenty male rats received 0 or 5% NaSL for 28 days and 30 male
    rats received 0 or 5% CaSL for 32 days. Relative liver weights were
    normal compared with controls in the CaSL group but raised slightly in
    the NaSL group. Groups of five rats were sacrificed at 32, 60, 90 and
    140 days. Liver weights were normal in the NaSL group after 90 days
    (Hodge, 1954).

         Further experiments were undertaken to elucidate the effect of
    different levels of calcium and sodium on relative liver weights as
    well as the effect of the fat level of the diet on relative liver
    weights. The relative liver weights became normal when rats returned
    to stock diets. When diets contained physical mixtures of stearic
    acid, lactic acid and calcium carbonate, they produced comparable
    liver weights (Hodge, 1954). Similar tests using 5% CaSL, 4.3%
    stearoyl lactylic acid or 3% stearic acid in 24 groups of five male
    rats each at varying levels of dietary fat showed slightly reduced
    body weight in the groups receiving CaSL or stearoyl lactylic acid.
    Mortality was not affected by treatment. The relative liver weights
    were comparable for all groups and liver histology revealed no
    abnormalities (Hodge, 1959). In a similar experiment four groups of 32
    male rats each were fed diets containing 0 or 5% CaSL, 3.11% calcium
    stearate or 3.2% sodium stearate. The group on CaSL grew better than
    all other groups. The relative liver weights of the controls were
    higher than all other groups (C. J. Patterson Co., 1956). The chemical
    composition of the liver was determined in groups of 10 male and 10
    female rats given 0 or 5% CaSL for one month. Only slight changes in
    glycogen, protein and lipid content were noted, lipid and protein
    being slightly increased compared with controls (Hodge, 1955a).

         Groups of 25 rats received diets containing 0, 0.1, 1.0, 2, 3, 4,
    5 and 7.5% of calcium stearoyl lactylate for one month. At the two
    highest levels there was growth retardation with relative liver weight
    increase. Groups of five male rats were given diets containing either
    15% lard or 10% lard plus 5% calcium stearoyl lactylate for 30 days.
    The test group grew at a lower rate but relative liver weights were
    less than in the controls. Groups of 10 rats received diets containing
    5% of calcium palmityl lactylate or calcium oleyl lactylate for 30
    days. All test groups grew slower and had markedly raised relative
    liver weights compared with 5% calcium stearoyl lactylate. Kidney
    weights were normal for all groups and histological examination of
    liver, kidneys and fatty tissues revealed no abnormalities in any of
    these groups (Hodge, 1956).

         The appearance of "lipogranulomata" and the increased relative
    liver weight are related to the excessive intake of abnormal
    proportions of long-chain fatty acids. The balance between saturated
    and unsaturated fats (S:U ratio) in the human diet is about 0.6 if
    the diet contains 30 to 40% fat. Rats fed diets containing 35 to
    50% saturated fatty acid products (palmitic acid, stearic acid
    ethylstearate, monoglycerides and acetylated monoglycerides of

    hydrogenated lard) develop localized fat necrosis with formation of
    "lipogranulomata". The condition is preventable by simultaneous
    feeding of corn oil and reversible by a return to normal diet (Cox
    & De Eds, 1958; Herting & Crain, 1958; Ambrose et al., 1958).

         Groups of five rats were maintained for periods up to six months
    on diets containing varying levels of calcium stearyl dilactylate
    (3 to 25%) and stearoyl lactylate acid (8 to 22%). The total fat
    content was 20%. The outcome depended on the S:U ratio. The added fats
    were chosen to give ratios from 0.6 to 4.4. Growth was depressed with
    increasing percentage of calcium stearoyl lactylate at 16% and higher
    levels and with 14% and above for the acid. Mortality was high at
    levels of 20% and above. Relative liver weights were normal at S:U
    ratios of 0.6 (17% fat plus 3% calcium stearoyl lactylate or 17% fat
    plus 2.6% stearoyl lactylate acid) but rose with higher ratios.
    Lipogranulomata appeared at ratio values beyond 1.4. The iodine
    number of depot fats reflected the variation in S:U ratio of the
    diet. Restoration to the basal ration containing 20% fat caused
    disappearance of lipogranulomata in four to six months. No
    histopathological abnormalities were seen (Hodge et al., 1964). In a
    repeat experiment with 40 male and 40 female rats fed 25% calcium
    stearoyl lactylate or 18% stearoyl lactylate acid in their diet, all
    animals developed severe lipogranulomata with high mortality. Recovery
    was rapid if animals were placed on basal diet containing 20% fat
    (half corn oil half lard). Growth rate recovered and any deaths
    occurring were unrelated to the diet (Hodge, 1960).


         One male and three female beagles were fed a diet containing 7.5%
    calcium stearoyl lactylate; another group of one male and three
    females served as controls. After two years, no noteworthy differences
    were observed between the two groups. Urinalysis and haematological
    findings remained normal. No gross or microscopic changes were found
    attributable to administration of calcium stearoyl lactylate. Liver
    weights were within normal range; nor did the livers differ in
    moisture, protein, lipids, ash or glycogen content. Other organ
    weights were also normal. No adverse effects were observed in one dog
    receiving sodium stearoyl lactylate in his diet for one month at a
    level of 7.5%, then increased to 12.5% for two weeks and to 15% for
    another month. No changes occurred in the blood; organ weights and the
    microscopic appearance of the tissues were normal (Hodge, 1955b).

    Long-term studies

         None available.


         Adequate biochemical studies have revealed no differences between
    the metabolisms of 14C-labelled lactic acid when present as stearoyl
    ester and when mixed with an equivalent amount of stearic acid. Since
    all the lactic acid derived from stearoyl lactylate enters the
    metabolic pool after complete hydrolysis of the ester, it is
    justifiable to consider conventional long-term studies as unnecessary.
    Extensive short-term studies in rats have given variable and
    inconsistent results as regards levels producing no-effect on growth
    or relative liver weight. The 2% level has been taken to be the
    no-effect level for the rat. The dog appears to be a less sensitive
    species. It would be desirable to confirm that man metabolizes
    stearoyl lactylate similarly to other species.


    Level causing no toxicological effect

         Rat: 20 000 ppm (2%) in the diet equivalent to 1000 mg/kg bw.

    Estimate of acceptable daily intake for man

         0-20 mg/kg bw.


         Desirable: Studies confirming that this compound is metabolized
    by man in the same way as by other species.


    Ambrose, A. M., Robbins, D. J. & Cox, A. J. (1958) Fed. Res., 23, 536

    Cox, A. J. & De Eds, F. (1958) Amer. J. Path., 34, 263

    Herting, D. C. & Crain, R. C. (1958) Proc. Soc. exp. Biol. (N.Y.), 98,

    Hodge, H. C. (1953) Unpublished reported dated 2 April 1953, submitted
         by C. J. Patterson Co.

    Hodge, H. C. (1953a) Unpublished reported dated 18 July 1953,
         submitted by C. J. Patterson Co.

    Hodge, H. C. (1954) Unpublished report submitted by C. J. Patterson

    Hodge, H. C. (1955) Unpublished report dated 30 June 1955 submitted by
         C. J. Patterson Co.

    Hodge, H. C. (1955a) Unpublished report dated 28 May 1955 submitted by
         C. J. Patterson Co.

    Hodge, H. C. (1955b) Unpublished report dated 17 June 1955 submitted
         by C. J. Patterson Co.

    Hodge, H. C. (1956) Unpublished report submitted by C. J. Patterson

    Hodge, H. C. (1959) Unpublished report submitted by C. J. Patterson

    Hodge, H. C. (1960) Unpublished report submitted by C. J. Patterson

    Hodge, H. C. (1961) Unpublished report submitted by C. J. Patterson

    Hodge, H. C., Maynard, E. A., Downs, W. L. & Panner, B. (1954)
         Toxicol. appl. Pharmacol., 6, 350

    C. J. Patterson Co. (1956) Unpublished report

    Schuler, M. N., Kodras, R., Allebach, H. K. B. & Gilliam, W. S. (1952)
         Unpublished report submitted by Midwest Research Institute

    Schuler, M. N. & Thornton, M. H. (1952) Unpublished report submitted
         by Midwest Research Institute

    Wisconsin Alumni Research Foundation (1955) Unpublished report
         submitted by J. C. Patterson Co.

    See Also:
       Toxicological Abbreviations
       Stearoyl lactylic acid, calcium and sodium salts (WHO Food Additives Series 1)