FAO Nutrition Meetings
    Report Series No. 40A,B,C
    WHO/Food Add./67.29


    The content of this document is the result of the deliberations of the
    Joint FAO/WHO Expert Committee on Food Additives which met at Rome,
    13-20 December, 19651 Geneva, 11-18 October, 19662


    1 Ninth Report of the Joint FAO/WHO Expert Committee on Food
    Additives, FAO Nutrition Meetings Report Series, 1966 No. 40; 
    Wld Hlth Org. techn. Rep. Ser., 1966, 339

    2 Tenth Report of the Joint FAO/WHO Expert Committee on Food
    Additives, FAO Nutrition Meetings Report Series, 1967, in press; 

    Food and Agriculture Organization of the United Nations
    World Health Organization


    Chemical name                Chlorine

    Empirical formula            Cl2

    Molecular weight             70.91

    Use                          For the treatment of flour.

         In the absence of adequate chemical data from the manufacturers,
    specifications for chlorine have not been prepared and will not be
    established until the biological studies requested have been made

    Biological Data

    Biochemical aspects

         Chlorine oxidizes the flour protein in a manner that is presumed
    to resemble the effect of other oxidizing agents. In addition to
    modifying the sulfur-containing amino acids, chlorine may also enter
    into combination with proteins and unsaturated fatty acids.

         Halogenated proteins appear to behave nutritionally similarly to
    normal proteins but halogenation of polyunsaturated fatty acids, on
    the other hand, may alter their biological activity. Thus, for
    example, halogenated linoleic acid my cease to be effective as an
    essential fatty acid.

         Over-treatment of flour with 1950 ppm of chlorine resulted in the
    reduction of the unsaturated fatty acids in the flour to 40 per cent.,
    as compared with the untreated flour.  Oleic acid was probably
    converted into dichlorostearic acid, and linoleic and linolenic acids
    into a range of chlorinated compounds (Coppock et al., 1960).
    Treatment with up to 120 ppm did not materially change the major fatty
    acids (Daniels, 1960).

         When soft-wheat flours ware treated with chlorine, the chlorine
    content of the lipids increased markedly, the water soluble components
    to a lesser extent and the gluten only slightly. The lipids and
    water-soluble compounds comprised only 5 per cent. of the flour, but
    contained more than 90 per cent. of the added chlorine. The
    chlorine-containing lipids showed a decreased iodine value (Gilles et
    al., 1964).

         The chlorine content of unbleached flour was found to be 43-54 mg
    Cl per 100 g of flour, and that of bleached flour, 131-189 mg Cl per
    100 g. This author found that nearly all the additional chlorine was
    in water-solubles and gluten. At least 50 per cent. of the Cl in the
    gluten fraction was in the lipid. In the untreated flour, 70 per cent.

    is prime starch and this contained  20-25 per cent. of the Cl;
    treatment with chlorine did not, however, significantly increase the
    Cl in the prime starch (Sollers, 1961).

         Rats fed 4.1 per cent. of lipids extracted from chlorine-treated
    flour showed a decrease of polyunsaturated fatty acids in the fat
    depots and a corresponding increase of palmitic, oleic and palmitoleic
    acids when compared with control animals receiving 4.1 per cent. of
    added untreated flour lipid. The chlorine content of the adipose
    tissue was, however, only slightly increased. Effects of this nature
    could not be demonstrated at lower levels of fat intake more
    comparable with the amounts that might be ingested from the use of
    treated flour (Daniels et al., 1963).

    Acute toxicity

         No data are available.

    Short-term studies

         Rat. Five-groups of 3 rats were each fed diets containing 0,
    0.82 and 4.1 per cent. of untreated flour lipids, and 0.82 and 4.1 per
    cent. of lipid from flour treated with chlorine at a level of 1950
    ppm. At the 4.1 per cent. level the groups receiving lipid from the
    treated flour had thinner and rougher fur, fertility was reduced and
    lactation was also less efficient. Similar depression of fertility and
    lactation was observed with the group receiving 0.82 per cent. of
    treated lipid. These effects were consistently observed through 4
    generations and were not relieved by 8 weeks feeding of 2 per cent.
    linoleic acid (Daniels et al., 1960).

         Dog Two groups of 4 and 6 dogs were fed diets containing flour
    treated with 356 ppm of chlorine for 21-38 days without causing
    running fits. Dogs which had developed running fits on agene-treated
    flour recovered on being switched to chlorine-treated material
    (Arnold, 1949; Radomski et al., 1948; Bentley et al., 1948; Newell et
    al., 1947).

    Long-term studies

         Rat. A multigeneration study was started in 1955 and continued
    to the sixth generation until 1963. The animals received
    drinking-water containing an excess of 100 ppm of chlorine. There was
    no adverse effect on growth, fertility or mean life-span. There was no
    indication of a carcinogenic effect of the chlorinated water
    (Druckrey, 1965).


         The evidence available indicates that the effects on lipids are
    not of any great significance. The small change in polyunsaturated
    fatty acids that occurs at the commercial levels of treatment suggests
    that this effect is not significant in relation to the human diet as a

    whole. It seems unlikely that the chlorinated lipids have any
    significant toxic properties. There is a need for studies on
    chlorine-treated flour.


         Formal evaluation is not possible on the limited evidence
    available. Although it does not seen likely that the ingestion of
    chlorine-treated flour amounting to only 1.5 per cent. of total flour
    intake will have any serious toxicological significance, it seems
    desirable nevertheless, that more adequate toxicological and
    nutritional studies should be carried out.

         It is not considered necessary to discontinue the use of chlorine
    at present.

    Further work required

         Adequate long-term studies are needed on flour treated with
    chlorine at several dose levels and bread baked from it.


    Anon (1960) Brit. med. J., i, 1466

    Arnold, A. (1949) Cereal Chem., 26, 46

    Bentley, H. R., Booth, R. G., Green, E. N., Heathcote, J. G.,
    Hutchinson, J. B.& Moran, T. (1948) Nature, 161, 126

    Coppock, J. B. M., Daniels, N. W. R. & Russell Eggitt, P. W. (1960)
    Chem. and Ind., 17

    Daniels, D. G. H. (1960) J. Sci. Food Agric., 11, 664

    Daniels, N. W. R., Frape, D. L., Russell Eggitt, P. W. & Coppock, J.
    B. M. (1963) J. Sci. Food Agric., 14, 883

    Druckrey, H. (1965) Unpublished report submitted to WHO

    Gilles, K. A., Kaelbe, E. F. L. Youngs, O. L. (1964) Cereal Chem,
    41, 412

    Newell, G. W., Erickson, R. C., Gilson, W. E., Gershoff, S. N. &
    Elvejhem, C. A. (1947) J. Amer. med. Assoc., 135, 760

    Radomski, J. L., Woodard, G. & Lehman, A. J. (1948) J. Nutr.,
    36. 15

    Sollars, W. F. (1961) Cereal Chem., 38, 487

    See Also:
       Toxicological Abbreviations
       Chlorine (ICSC)
       Chlorine (WHO Food Additives Series 20)
       CHLORINE (JECFA Evaluation)
       Chlorine (PIM 947)