Mechanistic Insights into Aflatoxin B1 and M1 Degradation by Bacillus subtilis HNGD-Mq02 from Wheat Koji and Its Application in Food Detoxification

Aflatoxin B1 (AFB1), the most toxic and prevalent mycotoxin in food and feed, and its hydroxylated metabolite aflatoxin M1 (AFM1), common in dairy products, pose serious health risks. Effective degradation of these toxins is thus a key goal in food safety. In this study, Bacillus subtilis HNGD-Mq02 was isolated and assessed for its ability to degrade AFB1 and AFM1. Under optimal conditions (50 °C, pH 7), the fermentation broth achieved 94.06 and 98.26% degradation, respectively. Ultrahigh-performance liquid chromatography–mass spectrometry (UHPLC-MS) analysis confirmed that both mycotoxins were converted into less-toxic compounds. Zebrafish assays and Ames tests further verified the reduced toxicity of the degradation products. In practical application, the strain reduced AFB1 by 72.90% in corn flour and AFM1 by 42.25% in milk powder. Fermentation also led to partial improvements in nutritional quality. These results highlight the potential of B. subtilis HNGD-Mq02 for enhancing the safety and value of food and feed products.