Aflatoxin M1 Detoxification Ability of Probiotic Lactobacilli of Indian Origin in In vitro Digestion Model

Aflatoxin M₁ (AFM₁) is known to be a potent carcinogen and continues to pose a public health concern through the consumption of contaminated dairy foods. It is anticipated that consumption of lactic acid bacteria capable of binding aflatoxins can reduce the risk of AFM₁ on human health to a certain extent. Seldom reports have hinted the possibility of using lactic acid bacteria for the biological detoxification of AFM₁. Hence, the present study was conducted to assess the ability of selected probiotic Lactobacillus strains for their AFM₁ binding ability in PBS and to reduce its bioaccessibility in artificially contaminated skim milk using an in vitro digestion model. Eleven tested probiotic strains illustrated various degrees of AFM₁ binding ability ranging from 4.13 to 64.16%. Five among the 11 probiotic strains were subsequently selected for detailed studies on the basis of highest binding potential after 24 h of incubation period. The stability of bacterial-AFM₁ complex was assessed by repeated washings with AFM₁ free PBS. The observation on bacterial-AFM₁ complex stability showed small release of AFM₁ in first and second wash (17.30 to 0.98%) where as none was detectable in the third wash. However, upon chloroform extraction, 88.57 to 92.30% of bound AFM₁ was released from the bacterial cells which indicate AFM₁ binding to the bacterial cell surface rather than absorption or degradation of AFM₁ by bacterial cells. During the in vitro digestion test in skim milk, bioaccessibility of AFM₁ was reduced to a scale of 32.61 to 52.84% in the presence of selected strains of probiotic lactobacilli. The present findings suggest that selected probiotic strains could be potentially used to mitigate the toxic effects of AFM₁ in the contaminated milk and milk products and thereby enhance food safety.