Application of yeasts and yeast derivatives for the biological control of toxigenic fungi and their toxic metabolites

Abstract

Mycotoxins, the metabolites of toxigenic fungi are important contaminants of food and agriculture industry throughout the world. Among the different strategies to minimize the mycotoxins synthesis and decontamination of food; yeasts and their derivatives are used as efficient biological control agents. In this study, cell walls (CW) of six yeast strains; two commercial baking {Saccharomyces cerevisiae (Sc 1 and Sc2)}, two low-fermenting (Candida intermedia and Lachancea thermotolerans), and two non-fermenting (Cyberlindnera jadinii and Candida friedrichii) were explored to inhibit A. flavus growth, aflatoxin (AF) synthesis and remove mycotoxins from contaminated buffers (at pH 3, 5 and 7) and milk. The volatiles of non-fermenting yeasts showed a significant inhibitory effect on of A. flavus growth (up to 79%) and aflatoxin synthesis potential. The highest mycotoxins binding activities of Sc strains were noted against ochratoxin A (92%), AFB2 (66%), AFG2 (59%) and AFB1 (31%). The highest and lowest binding activities occurred at pH 7 and pH 3, respectively. On the other hand, all yeast CWs significantly (44%–54%) reduced aflatoxin M1 (AFM1) from contaminated milk. These results show clearly that yeasts (particularly Sc) can be used as efficient biocontrol and decontamination agents in food industry or the management of mycotoxin contamination.