Study Finds Nonalcoholic Beer Can Harbor Bacteria

A new study in Frontiers in Microbiology found that non-alcoholic beer can either suppress or support dangerous bacteria depending on how it is formulated, adding fresh evidence to a category that has grown quickly as drinkers cut back on alcohol.

The research tested a model non-alcoholic beer against Salmonella enterica serovar Javiana, Escherichia coli O157:H7, Listeria monocytogenes, Pseudomonas aeruginosa and Bacillus cereus over 60 days. Scientists varied pH, carbonation and antimicrobial ingredients to see which combinations were enough to keep the microbes from surviving or multiplying. The work matters because removing ethanol also removes one of beer’s main safety barriers, forcing brewers and regulators to rely more heavily on recipe design and process controls.

The study found that pH was the most important factor. At lower acidity, the other hurdles worked better together. Carbonation at 1.5 volumes of CO₂ was especially effective against Salmonella and E. coli, while lower carbonation levels allowed those bacteria to survive and in some cases grow. Hop-derived compounds added another layer of control, especially against Gram-positive bacteria such as Listeria and B. cereus. Some formulations pushed pathogen counts below the limit of detection, a drop of more than 3 log units.

By contrast, higher-pH treatments without added hurdles were far less protective and could support pathogen survival. That finding is significant for non-alcoholic beer, where commercial products can vary widely in acidity and carbonation. The researchers noted that some products on the market reach pH 5.0, above the level generally recommended for safer production.

To run the experiment, the team prepared 20 model beers using dry malt extract and then adjusted them with citric acid, carbonation and either iso-α-acids or potassium sorbate. They also tested two alternative approaches: kettle souring and chitosan addition. Each bottle was inoculated with a cocktail of the five bacteria and stored at room temperature while samples were checked on days 1, 7, 14, 28 and 60.

The findings come as non-alcoholic beer sales continue to rise in the United States and abroad. Brewers have been expanding the category to meet demand from consumers who want fewer calories, less alcohol or no alcohol at all. But the shift has created new food safety questions because many of the assumptions that apply to regular beer do not automatically carry over when ethanol is removed.

The authors said their results offer practical guidance for producers and process authorities evaluating microbial risk in non-alcoholic beer. In particular, they argued that formulation choices such as pH target, carbonation level and preservative use should be treated as core safety decisions rather than only flavor or shelf-life decisions.

The study also has implications for draft products and cold-filled beverages that may not receive a terminal heat treatment. In those cases, the paper suggests that validation through challenge testing may be needed to show that a given recipe can reliably control pathogens under real storage conditions.

For brewers, the message is direct: non-alcoholic beer is not automatically safe because it looks like beer. Its safety depends on how much acidity it has, how much carbon dioxide is dissolved in it and whether it contains antimicrobial compounds that can help hold back bacteria over time.