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 1 (AFB 1 ) 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 1 at 10 ng/g. Any residual concentration of AFB 1 in the diet was extracted by the QuEChERS method and quantified by a liquid chromatograph with a fluorescence detector. AFB 1 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 1 , considering its toxicity and frequent occurrence. In addition, it guarantees safe food for consumers of fish farming products, as AFB 1 can bioaccumulate in the food chain. It also provides an alternative use for soybean meal that would previously be discarded.