BACKGROUND Aflatoxin B-1 (AFB(1)) is the most commonly occurring and the most toxic of all aflatoxins (AFs). It is responsible for liver cancer in animals and it is listed as a Group I carcinogen by the International Agency for Research on Cancer. Thus, it is necessary to find decontamination methods that show efficiency, specificity, low cost, and that allow the disposal of contaminated raw materials into the environment. This study evaluated the effects of enzyme concentration, pH, temperature and reaction time on AFB(1) biotransformation by commercial peroxidase (POD) in a model solution (100 mmol L-1 phosphate buffer). RESULTS When 0.015 U mL(-1) was used to treat 0.5 mu g L-1 of AFB(1), at pH 7.0-8.0 and 30-40 degrees C, for 8.0 h, the AFB(1) biotransformation reached its maximum (97%). K-M value of POD for the biotransformation of AFB(1) was 0.0160 mu mol L-1 (5 mu g L-1) with a V-MAX of 6.4 mu mol L-1 min(-1), which were determined based on Lineweaver-Burk's plot. POD (0.015 U mL(-1)) effectively reduces AFB(1) (97%) and M-1 (65%) in UHT milk and AFB(1) (24%) in lager beer samples acquired in markets of Rio Grande-RS (Brazil). CONCLUSION The use of POD may be a strategy to mitigate the impact of AFs found in food to reduce the risk of consumer exposure. (c) 2018 Society of Chemical Industry