Mitigation of aflatoxin B 1 in fish feed by peroxidase from soybean meal.

Potential of the enzyme peroxidase (PO) from soybean meal to mitigate aflatoxin B (AFB) in fish feed was evaluated. Reaction parameters studied in the wet stage of the feed production process were enzyme activity (0.01-0.1 U/g), temperature (20-36 °C), time (0-8 h) and humidity content (40-70%). Feed was produced in conformity with the National Research Council and spiked with AFB at 10 ng/g. Any residual concentration of AFB in the diet was extracted by the QuEChERS method and quantified by a liquid chromatograph with a fluorescence detector. AFB mitigation of 90% was reached when feed production conditions were 0.035 U/g, 32 °C, 6 h and 70% humidity. Therefore, application of PO to the feed industry may be considered a promising tool for mitigation of AFB, considering its toxicity and frequent occurrence. In addition, it guarantees safe food for consumers of fish farming products, as AFB can bioaccumulate in the food chain. It also provides an alternative use for soybean meal that would previously be discarded.