Absence of adverse effects of sodium metabisulphite in manufactured biscuits: results of subacute (28-days) and subchronic (85-days) feeding studies in rats
D. Ribera et al., Absence of adverse effects of sodium metabisulphite in manufactured biscuits: results of subacute (28-days) and subchronic (85-days) feeding studies in rats, FOOD ADDIT, 18(2), 2001, pp. 103-114
Sulphites are extensively used in the food and drinks industry. Their toxic
ity has been previously evaluated by addition to the diet or drinking water
of laboratory animals. Because interactions between sulphites and food con
stituents occur, the present work was conducted to determine the subacute a
nd subchronic toxicity of sulphite-bound compounds in a finished product: m
anufactured biscuits. The studies were performed on Sprague Dawley rats for
28 and 85 days of dietary exposure. Diets were prepared from sulphited or
untreated (controls) biscuits with the addition of sugar, protein, vitamins
and minerals according to the nutritional requirements of the animals. Gro
ups of 10 male and 10 female rats were administered diets containing sulphi
ted biscuits at levels of 0, 10, 35 and 75%, corresponding to 10-15, 35-45,
150-170 and 310-340 mg SO2/kg diet. In both studies, no death or clinical
abnormalities were reported. Growth rate, food consumption and food convers
ion efficiency were not affected by treatment. No dose-related changes were
observed for haematology, clinical chemistry, ocular examination, renal-fu
nction, urinalysis, organ weights or gross and microscopic examinations. Th
e liver concentrations of vitamins A, B-1, C and E were not significantly c
hanged except for an increase in vitamin E in high-dose males after 28 days
' exposure. Based on these data, the no-observed-adverse-effect level (NOAE
L) of sulphites in baked biscuits was judged to be 310 mg SO2/kg diet or 25
mg/kg body weight/day.