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                 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.

    Biological Data

    (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.

    Biological Data

    Biochemical aspects

         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).

    Special studies

         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).

    Acute toxicity

         No data are available.

    Short-term tests

         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).

    Long-term studies

         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

    See Also:
       Toxicological Abbreviations