Prevalence of hydrogen peroxide contamination in sterilized milk samples distributed in Isfahan market

Hydrogen peroxide is commonly used as disinfectant for sterilization of food contact materials. In dairy industry, contamination of milk with H2O2 residue is likely due to its leakage from the disinfected surfaces resulting in development of oxidative spoilage of milk. Since no report has been documented on the prevalence of such contamination in food stuff in Iran, this study aimed to measure the prevalence of H2O2 in sterilized milk samples, collected from Isfahan market in 2013.
A total of 20 tetra-pack sterilized milk samples from 7 different brand were randomly collected from the market. All the samples were 250ml in volume. In order to measure the H2O2 concentration a colometric method was adapted based on catalase reaction and measurement of light absorption at 400nm.
H2O2 residue was detected in all tested samples ranging from 0.14-1.62 ppm. Fifteen samples (75%) contained H2O2 levels greater than its regulated level by international organization (0.5 ppm). Accordingly, the results of one-sample t-test showed that the average amount of detected H2O2 concentration in the tested sample is higher than the standard value.
Regarding the H2O2 contamination of the tested milk samples revealed in this study and due to lack of any regulation limit for H2O2 in sterilized milk in Iran, presentation and documentation of standards introducing reliable method for detection and monitoring of H2O2 in the sterilized milk along with its limits is highly recommended.