Using of Lactobacillus and Bifidobacterium strains for detoxification of some mycotoxins

In this study, the ability of some Lactobacillus (Lb. acidophilus NCC 12, Lb. acidophilus NCC 36, Lb. acidophilus NCC 68 and Lb. rhamnosus) and Bifidobacterium (B. bifidum Bb 13 and B. bifidum NCC 381) to bind aflatoxin M1 (AFM1) and ochratoxin A (OTA) in phosphate-buffered saline (PBS) and food model was investigated. The binding abilities of AFM1 by viable test strains at 108 and 107 CFU ml-1 in PBS were ranged from 10.22 to 26.25% and from 0 to 5.02%, respectively, depending on contamination level and incubation period. While B. bifidum Bb 13 was the best binder, the poorest removal was achieved by Lb. acidophilus NCC 68. The binding capacities of heat-killed bacteria in PBS were found to range from 14.04 to 28.97%. The binding abilities of AFM1 were found to range from 7.85 to 25.94% and from 12.85 to 26.27% for viable and heat-killed bacteria in reconstituted milk, respectively, within 4 h. No significant differences (p 0.05) in AFM1 removal ability of both viable and heat-killed bacteria were observed between PBS and reconstituted milk, except for heat-killed Lb. acidophilus NCC 68 for 10 ng ml-1. The toxin concentration had no effect on the removal of AFM1 levels by both viable and heat-killed bacteria in reconstituted milk. When washing the bacteria/AFM1 complexes, 5.62-8.54% of AFM1 was released back into the solution. In contrary, binding process was irreversible in reconstituted milk. The binding abilities of OTA by viable (108 CFU ml-1) test strains were found to range from 4.43 to 20.71% and 15 to 23.40% for PBS and white wine, respectively. While Lb. rhamnosus was the most efficient binder in PBS, Lb. acidophilus NCC 36 bound more OTA than other strains in white wine. A significant decrease (p 0.05) was observed in the percentage of OTA removal by test strains at 107 CFU ml-1 in PBS when compared to activity at 108 CFU ml-1. Heating of the bacterial strains improved their ability to remove more OTA from PBS (9.60-25.17%) and white wine (15.24- 26.11%). The toxin concentration had no effect on the removal of OTA by viable and heat-killed bacteria in white wine. While OTA bound strongly by Lb. acidophilus NCC 12, Lb. acidophilus NCC 36 and Lb. rhamnosus in white wine, OTA was released in the range of 1.91-7.06% of bound OTA by other strains back into the white wine. Keywords: aflatoxin M1, ochratoxin A, Lactobacillus, Bifidobacterium, binding