Mycotoxins transmitted into beer from contaminated grains during brewing

Area of Science:

• Food Science
• Mycology
• Toxicology

Background:

• Mycotoxins, toxic secondary metabolites produced by fungi, can contaminate agricultural commodities like grains.
• Beer production involves processes that may lead to the transfer of mycotoxins from raw ingredients into the final product.

Purpose of the Study:

• To investigate the potential transmission of specific mycotoxins (aflatoxin B1, ochratoxin A, zearalenone, deoxynivalenol, fumonisins B1 and B2) into beer during brewing.
• To assess the survival of citrinin during the mashing step.
• To determine the occurrence and levels of these mycotoxins in beer from different geographical regions.

Main Methods:

• Studies involved adding known mycotoxins at various brewing stages to track their fate.
• Analysis of beer samples from different regions (Africa, Europe, Canada) for the presence of mycotoxins.
• Utilized chromatographic methods (including liquid chromatography and thin-layer chromatography) for mycotoxin detection and quantification.

Main Results:

• Aflatoxin B1, ochratoxin A, zearalenone, deoxynivalenol, and fumonisins B1/B2 can be transmitted from grains to beer.
• Citrinin is degraded during the mashing process and does not survive.
• Deoxynivalenol was found with high incidence in Canadian and European beers, sometimes exceeding 200 ng/mL.
• Ochratoxin A was rarely detected above 1 ng/mL, but trace levels were common with sensitive methods.
• Aflatoxins were prevalent in African beers but not detected in European beers; zearalenone was also largely absent in European/Canadian beers.

Conclusions:

• Mycotoxin contamination of beer is a potential risk originating from raw materials (malted grains or adjuncts).
• The brewing process significantly impacts the survival and presence of different mycotoxins.
• Regional differences in brewing practices and raw material sourcing contribute to varying mycotoxin profiles in beer.