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.
Keywords: Aflatoxin M1; Bioaccessibility; ELISA; Food safety; Lactobacillus; Probiotics.