Aflatoxin B_1 Binding Capacity Of Autochthonous Strains Oflactic Acid Bacteria

摘要

Some foods are prone to contamination with aflatoxins, with detrimental effect on human health. Lactic acid bacteria have been reported to bind aflatoxins and remove them from foods and feeds. Reduction of aflatoxin B_1 (AFE_1) from the liquid media by the autochthonous lactic acid bacteria (Lactobacillus casei, Lactobacillus plantarum, and Lactobacillus fer-mentum) isolated from traditional Iranian sourdough and dairy products is reported in the current study. The effect of incubation time on the binding capacity of the strains to AFB_1 was also investigated. Duplicates of individual bacteria with population equivalent to 2 × 10~(10) CFU/ml were incubated in the presence of AFB, at 37℃ for a period of 72 h, and the amounts of unbound AFB_1 were quantitated by reverse-phase high-performance liquid chromatography. All the strains were capable of removal of AFB_1, and the reduction of AFB_1 ranged from 25 to 61% throughout the incubation period. Removal of AFB_1 was a rapid process, with approximately 61 and 56% of the toxin taken instantly by L. fermentum and L. plantarum, respectively. Binding was of a reversible nature, and some of the bound AFB_1 was released into the media by the repeated centri-fugation and resuspension of the cell pellets. The stability of the bacteria-toxin complex was strain dependent, and L. casei was a stronger binder of AFB, compared with the other bacteria. No toxin release was observed after 24 h. These findings tend to suggest that certain novel probiotic bacteria with high aflatoxin binding capacity could be selected for detoxification of foods.