A new study finds that compared to regular-strength beers, low- and no-alcohol beers may be breeding grounds for foodborne pathogens such as E. coli and salmonella, which may be introduced during production, storage or pouring. Driven by the rise of wellness culture, the global beverage industry has seen a shift toward producing low- and no-alcoholic beverages, including beer. In the US, UK and Australia, brewers can label beer as "alcohol-free" if it contains less than 0.5% alcohol by volume (ABV).
There are clear benefits to drinking non-alcoholic or low-alcohol beer; it contains vitamins and minerals, and studies show it has cardiovascular benefits compared to regular beer. However, a new study from Cornell University researchers finds that removing alcohol from beer may create a perfect environment for the growth of foodborne pathogens introduced during manufacturing, storage or pouring.
"When you remove the alcohol, beer is no longer beer in the traditional sense," said Randy Worobo, one of the study's co-authors. "We suspected that foodborne pathogens could grow in the absence of alcohol, and we were right. At this point, alcohol-free beer must be considered in the same way as food and ensure that all parameters that keep the product safe are met."
Traditional beer contains several factors that prevent the growth of pathogens. Ethanol concentration, bitter acids produced by hops, low pH, high concentrations of carbon dioxide, low oxygen and lack of nutrients all help keep beer free of pathogens.
Ann Charles-Vegdahl, another author of the study, said: "Craft makers of non-alcoholic beers sometimes follow traditional beer brewing processes. But ultimately, brewers add additional flavoring and aroma substances - such as hops - to non-alcoholic beers, which has the potential to introduce contamination."
The researchers took samples of beer with an alcohol content of less than 0.5% (no alcohol) or 3.2% (low alcohol) and spiked it with three foodborne bacterial pathogens: E. coli, salmonella and listeria. Beers with three different pH values (4.20, 4.50, and 4.80) were prepared and stored at two different temperatures (39°F (4°C) and 57°F (14°C)) for two months.
E. coli and salmonella can grow and survive in beer at both temperatures, regardless of pH and whether the beer has low or no alcohol. When stored at 57°F, populations of both bacteria doubled at all pH conditions tested. Listeria was not detectable at either temperature.
Based on their findings, the researchers recommend pasteurizing low- and no-alcohol beers to commercial sterility standards and considering sterile filtration and the addition of preservatives to reduce microbial risks. Additionally, they say serving alcohol-free beer on draft from kegs or kegs may increase the risk of pathogens and recommend regular disinfection of kegs, pipes and beer taps.
"Without alcohol in beer, a lot of the safety net against foodborne pathogens is lost," Worobo said. "Without the protection provided by alcohol, manufacturers must consider how pathogens can sneak in from the raw product during processing."
The research was published in the Journal of Food Protection.