Biological detoxification of Aflatoxin M₁ by lactic acid bacteria: experimental evidence from in vitro systems to fermented dairy products

This study evaluated the ability of various lactic acid bacteria (LAB) strains, in both viable and heat-inactivated forms, to reduce aflatoxin M₁ (AFM₁) levels in phosphate-buffered saline, MRS broth, and Karish cheese. Eight LAB strains were tested, including Lactobacillus acidophilus , L. salivarius , L. bulgaricus , Bifidobacterium lactis , and others. Viable cells exhibited strong detoxification efficiency, with L. acidophilus achieving the highest AFM₁ reduction (≈ 76%), followed by B. lactis and L. salivarius . Heat-killed counterparts showed minimal activity, confirming the essential role of metabolic processes in toxin removal. In MRS broth, a significant relationship was observed between pH decline and AFM₁ degradation; where up to 80% reduction occurred at pH 3.0 after 20 hrs, emphasizing the influence of acidic and enzymatic conditions. Application in Karish cheese demonstrated the practical relevance of LAB under real food conditions. Mixed cultures of S. thermophilus , L. bulgaricus , and L. acidophilus or L. salivarius reduced AFM₁ by 74–78% after 20 days at 4°C, accompanied by gradual acidification during ripening. These findings highlight the effectiveness of LAB, particularly multi-strain systems, as a natural and biotechnological approach for mitigating AFM₁ contamination and improving the safety of fermented dairy products.