Efficiency of Saccharomyces cerevisiae and lactic acid bacteria strains to bind aflatoxin M1 in UHT skim milk

The purpose of this study was to evaluate the ability of a Saccharomyces cerevisiae strain and a pool of three lactic acid bacteria (LAB) strains (Lactobacillus rhamnosus, Lactobacillus delbrueckii spp. bulgaricus and Bifidobacterium lactis), alone or in combination, to bind aflatoxin M-1 (AFM(1)) in UHT (ultra-high-temperature) skim milk spiked with 0.5 ng AFM(1) mL(-1). All the LAB pool (10(10) cells mL(-1)) and S. cerevisiae (10(9) cells mL(-1)) cells were heat-killed (100 degrees C, 1 h) and then used for checking the effect of contact time (30 min or 60 min) on toxin binding in skim milk at 37 degrees C. The mean percentages of AFM(1) bound by the LAB pool in milk were 11.5 +/- 2.3% and 11.7 +/- 4.4% for 30 min and 60 min, respectively. Compared to the LAB pool, S. cerevisiae cells had higher (P < 0.05) capability to bind AFM(1) in milk (90.3 +/- 0.3% and 92.7 +/- 0.7% for 30 min and 60 mm, respectively), although there were not significant differences between the contact times evaluated. When using S. cerevisiae + LAB pool, a significant increase (P < 0.05) was observed in the percentage of AFM(1) bound (100.0%) during 60 mm. Results of this trial indicate that heat-killed S. cerevisiae cells, alone or in combination with the LAB pool used, has a potential application to reduce the concentration of AFM(1) in milk. (C) 2012 Elsevier Ltd. All rights reserved.