Saccharomyces cerevisiae strains and the reduction of Aspergillus parasiticus growth and aflatoxin B 1 production at different interacting environmental conditions, in vitro

Abstract

The effect of Saccharomyces cerevisiae RC008 and RC016, previously selected based on their aflatoxin B1 binding ability and beneficial properties, against Aspergillus parasiticus under different interacting environmental conditions was evaluated. Studies concerning the lag phase, growth rate and aflatoxin B1 production were carried out in vitro under different regimes of aw (0.95 and 0.99), pH (4 and 6), temperature (25 and 37°C), and oxygen availability (normal and reduced). Both yeast strains showed great antagonistic activity at pH 4, decreasing growth rate compared with the control. The RC008 strain showed the greatest inhibitory activity at all assayed conditions. A. parasiticus produced large amounts of AFB1in vitro. A significant decrease of AFB1 levels in comparison with the control were observed with yeast interaction. Differences between control and treatment values ranged from 130 to 5400 ng ml-1. S. cerevisiae RC008 and RC016 could be considered as effective agents in reducing growth and AFB1 production at different interacting environmental conditions, related to that found in stored feedstuff. The importance of the present work lies in the search for live strains with both probiotic and biocontrol properties able to prolong the safe storage of feedstuff and exert beneficial properties after animal consumption and which could be included in a novel product for animal feed.