Binding rather than metabolism may explain the interaction of two food-grade Lactobacillus strains with zearalenone and its derivative ά-zearalenol

Abstract

The interaction between two Fusarium mycotoxins, zearalenone (ZEN) and its derivative ά-zearalenol (α-ZOL), with two food-grade strains of Lactobacillus was investigated. The mycotoxins (2 μg ml-1) were incubated with either Lactobacillus rhamnosus strain GG or L. rhamnosus strain LC705. A considerable proportion (38 to 46%) of both toxins was recovered from the bacterial pellet, and no degradation products of ZEN and ά-ZOL were detected in the high-performance liquid chromatograms of the supernatant of the culturing media and the methanol extract of the pellet. Both heat-treated and acid-treated bacteria were capable of removing the toxins, indicating that binding, not metabolism, is the mechanism by which the toxins are removed from the media. Binding of ZEN or α4́-ZOL by lyophilized L. rhamnosus GG and L. rhamnosus LC705 was a rapid reaction: approximately 55% of the toxins were bound instantly after mixing with the bacteria. Binding was dependent on the bacterial concentration, and coincubation of ZEN with ά-ZOL significantly affected the percentage of the toxin bound, indicating that these toxins may share the same binding site on the bacterial surface. These results can be exploited in developing a new approach for detoxification of mycotoxins from foods and feeds.