FAO Nutrition Meetings
Report Series No. 40A,B,C
TOXICOLOGICAL EVALUATION OF SOME
ANTIMICROBIALS, ANTIOXIDANTS, EMULSIFIERS,
STABILIZERS, FLOUR-TREATMENT AGENTS, ACIDS AND BASES
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
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
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).
No data are available.
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
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
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
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
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,
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.,
Sollars, W. F. (1961) Cereal Chem., 38, 487