Suppression of fungal contamination by Pythium oligandrum during malting of barley

Abstract

Fungal contamination of malting barley can contribute mycotoxins and potentially compromise beer quality. Several physical, chemical and biological treatments during the malting process have been developed to decrease fungal contamination. Anti-fungal treatments using microorganisms are desirable because they typically exhibit environmental sensitivity and sustainability, but their efficiency can be affected by the complexity of microbial interactions, as well as by undesirable side effects. We therefore sought a more effective bio-fungicide that is applicable in the malting process. This work describes the application of RT-PCR to quantify the anti-fungal potential of oomycetes Pythium oligandrum on barley naturally or artificially contaminated with three Fusarium species. The suppression of fungal contamination by P. oligandrum during malting was statistically more effective than by Geotrichum candidum, with the exception of barley artificially contaminated with Fusarium oxysporum. For P. oligandrum, addition into the third steeping water was significantly more effective than application at the beginning of germination. © 2018 The Institute of Brewing & Distilling.