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 Ammonium persulfate
Empirical formula (NH4)2S2O8
Molecular weight 228.20
Definition Ammonium persulfate contains not less
than 95 per cent. (NH4)2S2O8
Description Ammonium persulfate occurs as colourless
crystals, white crystalline powder.
Caution Powerful oxidising substance.
Use As a strengthening agent for flour.
(See Potassium Persulfate)
Chemical name Potassium persulfate
Empirical formula K2S2O8
Molecular weight 270.32
Definition Potassium persulfate contains less than
95 per cent. of K2S2O8.
Description Potassium persulfate occurs as
colourless or white, odourless crystals.
Caution Powerful oxidizing substance.
Use As a strengthening agent for flour.
Persulfate is converted to bisulfate and sulfate in bread.
Sulfates are slowly absorbed; large amounts may cause purgation.
Sulfates are formed in the body physiologically and excreted in the
urine as conjugates.
The nutritional value of gluten has been studied by examination
of the amino acid pattern before and after treatment with ammonium
persulfate at levels of 100 and 2000 ppm. At the lower level of
treatment no significant change in amino acids, other than in
methionine, was found. The higher level of treatment resulted in 46
per cent. loss of tryptophan, 20 per cent. loss of methionine and
slight losses of cystine, arginine and lysine. It also reduced the
digestibility of the protein by 21 per cent.; no significant effect on
digestibility was seen at the lower level of treatment (Schörmüller et
al., 1953). In studies on bread baked from flour treated at 100 ppm,
reduction of methionine was not observed, even after one month's
storage (Jansen et al., 1955).
It has been claimed that flour treated with ammonium persulfate
is liable to cause dermatitis in bakers (Teleky & Zitzke, 1932). Skin
tests ware reported to show sensitivity to ammonium persulfate
(Badham, 1935). These results have not been subsequently confirmed
(Amos, 1951; Maltha, 1954).
No data are available.
Rat. Groups of rats fed diets containing a high proportion of
flour or bread made from flour treated with ammonium persulfate at
levels of 0.02 and 0.1 per cent. showed no ill effects over a
six-month period. Weight gain, reproductive performance and
microscopical appearance of main organs were studied. The study was
carried through two generations (Arnold & Goble, 1949; Arnold & Goble,
Dog. Twelve dogs were fed on diets containing a high flour
content for a period of 5.5-16 months. The flour was treated with 0,
0.12 or 0.8 per cent. ammonium persulfate. No differences between the
control and test animals were observed with regard to weight gain,
appearance, renal function, haematology, urinary constituents, and
gross or microscopic appearance of major organs (Arnold & Goble,
1950). In another experiment dogs were fed flour treated at 0.027,
0.121 and 0.808 per cent. for various periods up to 90 days without
obvious ill effects (Arnold, 1949; Bentley et al., 1948).
None appear to be available, using either ammonium persulfate or
ammonium sulfate on treated flour or bread baked from it.
While one would not ascribe any serious significance to a small
residue of sulfate, there is a serious lack of long-term studies on
persulfate-treated flour or bread baked from it. There is some
suggestion that flour treated with ammonium persulfate is liable to
cause skin sensitization. Such studies as have been done on possible
toxic substances produced by treatment were strongly orientated
towards the production of "running fits", which we now know could not
be a hazard in this case. Further work is needed on the nutritional
aspects, particularly the vitamin content of treated flour and bread.
In the absence of more adequate toxicological data, it is not
possible to estimate an acceptable treatment level of flour.
Nevertheless it is not considered necessary to discontinue the use of
persulfates at present.
Further studies required
Adequate long-term studies are needed on flour treated at several
dose levels with ammonium persulfate and bread baked from it.
Amos, A. J. (1951) Chem. and Ind., 45, 946
Arnold, A. (1949) Cereal Chem., 26, 46
Arnold, A. & Goble, F. C. (1949) Fed. Proc., 8, 377
Arnold, A. & Goble, F. C. (1950) Cereal Chem., 27, 375
Badham, C. (1930-35) Annual Report of the Public Health Department,
New South Wales, 71
Bentley, H. R., Booth, R. G., Green, E. E., Heathcote, J. G.,
Hutchinson, J. B. & Moran, T. (1948) Nature (Lond), 161, 126
Jansen, A. P., Van der Linden, A. C. & Wöstmann, B. S. T. (1955)
Z.Lebenm. Unters. Forschg., 100, 345
Maltha, P. (1954) Die Mühle, 91, 2
Schörmüller, J., Störig, I. & Leichter, L. (1953) Z. Lebenm. Unters.
Forschg., 96, 1
Teleky, L. & Zitzke, E. (1932) Archiv. Gewerbepath. und
Gewerbehygiene, 3, 68