INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
WORLD HEALTH ORGANIZATION
TOXICOLOGICAL EVALUATION OF SOME
FOOD COLOURS, ENZYMES, FLAVOUR
ENHANCERS, THICKENING AGENTS, AND
CERTAIN FOOD ADDITIVES
WHO FOOD ADDITIVES SERIES 6
The evaluations contained in this publication were prepared by the
Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
4-13 June 19741
World Health Organization Geneva 1975
1 Eighteenth Report of the Joint FAO/WHO Expert Committee on
Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 557.
FAO Nutrition Meetings Report Series, 1974, No. 54.
Injection of 1 mg/kg bw i.v. into adult rats as an aqueous
solution resulted in 96% excretion in the bile (Ryan & Wright, 1961).
It has been suggested that the biliary excretion rate is related to
the relative protein-binding properties of the dye in liver and blood
(Priestly & O'Reilly, 1966). It is possible that Yellow 2G is
metabolized in a similar manner to tartrazine which has a structure
related to Yellow 2G (Gaunt et al., 1970; Walker, 1970; Westöö, 1965).
Incubation of Yellow 2G with a buffered bacterial suspension from rat
intestine for four hours at 37° under oxygen-free nitrogen resulted in
38% azo-reduction of the colour (Roxon et al., 1967).
No information available.
Yellow 2G was fed to four groups of 15 male and 15 female rats at
dietary levels of 0, 100, 1000 or 10 000 ppm for 13 weeks. The
colourant was decolourized in the caecum yielding a colourless product
which turned red on exposure to the air. No adverse effects were seen
in the rate of body weight gain, or in the results of haematological
examinations, serum chemistry, renal cell excretion and concentration
tests. No gross or micropathological effects were detected which could
be attributed to the colourant. There were isolated changes of the
weights of kidney, small intestine, adrenal glands and testes in rats
receiving 1000 or 10 000 ppm Yellow 2G but these were not considered
to be related to treatment. The caeca were enlarged in rats fed a diet
containing 10 000 ppm (Gaunt et al., 1970).
Four groups of three pigs of each sex were given Yellow 2G in
doses of 0 (control), 5, 50 or 500 mg/kg/day for 15 weeks. The faeces
of the pigs at the two higher dose levels developed a reddish colour
on exposure to the air, probably due to oxidation of a metabolite of
the colouring. There was an initial diarrhoea lasting one or two days
in half the pigs at the highest dose level. No adverse effects were
seen in the rate of body weight gain, haematology, examination of
urine, organ weights or histopathological examination (Gaunt et al.,
Groups of 48 male and 48 female mice (TF1 strain) were given 0
(control), 30, 300 or 1500 ppm Yellow 2G in the diet for 80 weeks. No
adverse effects were seen on the growth, appearance, or the behaviour
of the animals during the study. Histopathological examination in
progress (Gaunt et al., 1974).
Groups of 48 male and 48 female rats (Wistar strain) were given
diets containing 0 (control), 100, 1000 or 10 000 ppm of Yellow 2G for
two years. No adverse effects were seen on the growth, appearance, or
the behaviour of the animals during the study. Histopathological
examination in progress (Gaunt et al., 1974).
The short-term studies in the rat and pig did not reveal any
serious adverse toxicity. Two long-term studies in the mouse and rat
have been done but the results have not yet been reported. Multi-
generation, embryotoxicity including teratology studies are not
available but have been reported in progress. The metabolism has not
been examined to a satisfactory extent.
Not possible on the data available.
BIBRA (1971) Private communication
Gaunt, I. F. et al. (1971) Fd. Cosmet. Toxicol., 9, 343
Gaunt, I. F. et al. (1974) Fd. Cosmet. Toxicol. (In press)
Priestly, B. G. & O'Reilly, W. J. (1966) J. Pharm. Pharmacol., 18, 41
Roxon, J. J., Ryan, A. J. & Wright, S. E. (1967) Fd. Cosmet. Toxicol.,
Ryan, A. J. & Wright, S. E. (1961) J. Pharm. Pharmacol., 13, 492
Westöö, G. (1965) Acta. Chem. Scand., 19, 1309
Walker, R. (1970) Fd. Cosmet. Toxicol., 8, 659