Current study investigated the effects of potassium metabisulfite (E224), a common food preservative, in male rats following 28 days of oral exposure at doses: 0.7, 7.0, and 70 mg/kg b.w. Following autopsies, blood and tissues samples (liver, kidney, brain, and testes) were taken. Data were compared statistically at p < .05. Potassium metabisulfite caused significant dose-dependent reduction in most hematological parameters except the white blood cells and platelets that showed elevation. Biochemically, dose-dependent significant increase occurred in the oxidative stress biomarkers, the reactive oxygen species, and thiobarbituric acid reactive substances, while a concomitant significant decrease was noticeable in the antioxidant enzymes, superoxide dismutase, peroxidase, catalase, and non-enzymatic reduced glutathione and as well as total protein content in liver, kidneys, brain, and testes of treated animals. Mild to relatively severe histological alterations were noticeable in all tissues. The study for the first time shows that potassium metabisulfite is toxic even in very small quantity.

Novelty impact statement

Potassium metabisulphite designated as E224 is a food preservative used in many food items, but its effects on physiological health are lacking. Rats exposed to its oral doses for 28 continuous days demonstrated that it is toxic even at the lowest recommended concentration of 0.7 mg/kg body weight. It produces excessive free radicals and has every potential to damage the cells biochemically and structurally when used in slightly greater amounts.