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For his study, Peters collected one thousand beer samples from 47 countries – mainly Europe. He determined the concentrations of mycotoxins – toxins produced by fungi – in the various beers. Deoxynivalenol (DON) is one of the more prominent mycotoxins. ‘Nearly every beer contains DON’, explains Peters. ‘But on average, the levels are higher in craft beers.’ The concentration of DON was above the permitted levels in 22 craft beers. Peters: ‘The substance is not extremely toxic, but it supresses the immune system and can cause nausea and diarrhoea.’
Brewing process
According to Peters, these higher concentrations could be caused by the brewing process. The standard process involves water, malted barley, hop and yeast. It’s the malted grains in particular, like malted barley, that are prone to mycotoxin contamination. Brewers use relatively more malted barley for the stronger beers, such as the popular craft beer style imperial stout, which can result in higher concentrations of mycotoxins in the beer. The darker malts also seem to contribute to higher mycotoxin levels. Furthermore, craft breweries often add myriad other ingredients that could be contaminated, such as coffee, cacao, tobacco, liquorice, fruit and a range of spices.
Certificate
‘The European Union has legislation regarding the maximum permitted levels of mycotoxins, but these only apply to the raw materials, not the beer itself’, Peters explains. He pleads for more transparency on the part of the suppliers of raw materials. ‘It would be much better if a certificate not only stated that the levels are below the allowed maximum, but also what levels have been measured. A brewer could then use this information to calculate how much of that ingredient can be used safely. Another option would be for craft brewers to test their beer before putting it on the market, but that is not financially viable for many of the starting and smaller breweries.’
Popularity
This is the first time such a large-scale study has been performed into mycotoxins contained in craft beer. Peters: ‘Many studies have been carried out into industrially brewed beer. However, we were curious about craft beer because we see its popularity skyrocketing.’ That is also the reason it is so important to keep an eye on the quality, he adds. He would like to repeat the study in a few years, to see how the situation has developed. ‘I am a lover of craft beer myself, and I always bring a few sample pots whenever I go to a craft beer festival. That is also how we collected most of the craft beer samples for this study.’