Removal of aflatoxin M1 from milk and aqueous medium by indigenously isolated strains of W. confusa H1 and L. plantarum S2

Employing LAB and/or their metabolites to reduce aflatoxins from food products is one of the fascinating areas of research. Therefore, in the present work an attempt was made to study the effect of isolated lactic acid bacteria (LAB) on the reduction of aflatoxin M1 (AFM1) from phosphate buffer saline (PBS) and reconstituted skim milk (RSM). Out of 68 isolates, nine strains of LAB isolated from food products were examined to bind and reduce AFM1. The isolates were incubated with AFM1 at different time and temperature (24 h, 48 h, and 72 h at 37 degrees C and 4 degrees C) and later the residual toxin in the supernatant was determined. The preliminary results through thin layer chromatography (TLC) revealed that all isolates were able to bind AFM1 in PBS. However, based on the intensity of spots observed in TLC sheets, it was indicated that two isolates, H1 and S2 genotypically identified as W. confusa and L. plantarwn shown better AFM1 binding ability as compared to other isolates. Further, the heat treated cells of both the selected strains did not show significant difference to AFM1 binding ability as compared to live cells. Results of high performance liquid chromatography (HPLC) observed that W. confusa H1 and L. plantarwn had shown 78% and 72% AFM1 binding in PBS at 37 degrees C after 72 h. There was a significant difference (P < 0.05) in AFM1 binding ability of L. plantarum S2 at 37 degrees C & 4 degrees C, but such difference was not observed for W. confusa Hl. Moreover, these isolates also observed reduction of naturally present AFM1 in 10% RSM. This is the first study reporting the AFM1 binding capability of the genus Weissella (strain W. confusa H1) and Enterococcus durans. These results showed that indigenous strains of LAB are able to bind AFM1 effectively.