Aflatoxin B1 binding by dairy strains of lactic acid bacteria and bifidobacteria

Various food commodities including dairy products may be contaminated with aflatoxins, which, even in small quantities, have detrimental effects on human and animal health. Several microorganisms have been reported to bind or degrade aflatoxins in foods and feeds. This study assessed the binding of aflatoxin B-1 (AFB(1)) from contaminated solution by 20 strains of lactic acid bacteria and bifidobacteria. The selected strains are used in the food industry and comprised 12 Lactobacillus, five Bifidobacterium, and three Lactococcus strains. Bacteria and AFB(1) were incubated (24 h, +37 degreesC) and the amount of unbound AFB(1) was quantitated by HPLC. Between 5.6 and 59.7% AFB(1) was bound from solution by these strains. Two Lactobacillus amylovorus strains and one Lactobacillus rhamnosus strain removed more than 50% AFB(1) and were selected for further study. Bacterial binding of AFB(1) by these strains was rapid, and more than 50% AFB(1) was bound throughout a 72-h incubation period. Binding was reversible, and AFB(1) was released by repeated aqueous washes. These findings further support the ability of specific strains of lactic acid bacteria to bind selected dietary contaminants.