In vitro ability of nonviable cells of lactic acid bacteria strains in combination with sorbitan monostearate to bind to aflatoxin M1 in skimmed milk

Abstract This study aimed to evaluate the in vitro ability of heat-killed (HK) and acid-killed (AK) cells from three commercial strains of lactic acid bacteria, alone or in combination with sorbitan monostearate (SM), to bind to aflatoxin M1 (AFM1) in skimmed milk at concentrations of 0.05, 0.2 and 0.5 ng mL-1. The stability of the AFM1-bacterial cell bonds and the cell wall and exopolysaccharides (EPS) contribution to AFM1 decontamination were also investigated. Compared with HK cells, AK cells exhibited higher binding capacities in milk containing the highest AFM1 level, with maximum removal of 81.4, 56.8, and 50.8% by Lactococcus lactis ssp. cremoris, Lacticaseibacillus rhamnosus (formerly Lactobacillus rhamnosus), and L. lactis ssp. lactis at 1010 cells mL-1, respectively. The combination of HK cells with SM increased the AFM1 binding capacity, although no effect was found regarding AK cells. SM treatment also enhanced the stability of the AFM1 bond formed with both HK and AK cells. Cell wall isolates and EPS were the major components involved in the AFM1 binding process. Combining SM with HK cells is an interesting approach to reduce AFM1 levels in milk, although further studies are needed to optimize the adsorbing process.