Fate of mycotoxins during beer brewing and fermentation

Mycotoxins are frequent contaminants of grains, and breweries need, therefore, to pay close attention to the risk of contamination in beer made from such grains as barley and corn. The fate of 14 types of mycotoxin (aflatoxins, fumonisins, ochratoxin A, patulin, trichothecenes, and zearalenone) during beer brewing was investigated in this study. Malt artificially spiked with each mycotoxin was put through the mashing, filtration, boiling and fermentation processes involved in brewing. After brewing, the levels of aflatoxins, ochratoxin A, patulin, and zearalenone were found to have decreased to less than 20% of their initial concentration. They had been adsorbed mainly to the spent grain and removed from the unhopped wort. Additionally, as zearalenone was known, patulin was metabolized to the less toxic compound during the fermentation process. The risk of carry-over to beer was therefore reduced for half of the mycotoxins studied. However, attention still needs to be paid to the risk of trichothecene contamination.