A recent study published in the Journal of Food Protection has found that bacteria can thrive in non-alcoholic beers, presenting potential food safety risks. Researchers examined the effects of antimicrobial variables such as storage temperatures, pH levels, and ethanol concentrations on bacterial populations in non-alcoholic beer. Their findings highlight that while low-alcoholic beers inhibit bacterial growth, non-alcoholic beers allow it.
Traditional alcoholic beers have long been considered resistant to foodborne pathogens due to their intrinsic properties and manufacturing processes. These include factors like ethanol content, hops bitter acids, acidic pH, dissolved carbon dioxide, anaerobic conditions, and low sugar content. Coupled with pasteurization, wort boiling, filtration, and refrigerated storage, instances of beer-related food poisoning are uncommon.
Studies have indicated that ethanol concentrations of 3.5% – 5% can effectively prevent the growth of most common food pathogens. However, certain bacterial strains can survive in full-strength beers, typically due to poor refrigeration over an extended period.
In recent years, there has been a shift in consumer demand from alcoholic beers to low- (<2.5% ABV) or non-alcoholic beers (<0.5% ABV), driven by factors such as demographics, religious preferences, social regulations, health concerns, and calorie management.
Low- and non-alcoholic beers, with ABV levels below 3.5%, may be susceptible to pathogenic growth if bacterial contamination occurs during production. Unfortunately, research on the association between foodborne pathogens and beer has primarily focused on traditional alcoholic varieties, leaving a significant knowledge gap regarding non-alcoholic beers.
The recent study aimed to investigate the impact of ethanol concentration, storage temperature, and pH on the growth of strains of Escherichia coli (E. coli), Salmonella enterica, and Listeria monocytogenes in low- to non-alcoholic beers.
To conduct the study, non-alcoholic canned beers with baseline ethanol and pH concentrations were adjusted using sodium hydroxide and ethanol. The beers were prepared in sterile containers with varying pH and ethanol levels and inoculated with the bacterial strains. The samples were then stored at controlled temperatures for 63 days, and periodic sampling was conducted to assess pathogen growth or die-off.
The research findings revealed that E. coli and S. enterica could survive in low- and non-alcoholic beers under various conditions. However, L. monocytogenes was less resilient, with its population declining below detectable levels within a few days.
In non-alcoholic beers, pH levels were associated with reductions in microbial populations across the tested strains. At lower temperatures, pH 4.20 resulted in a decrease in E. coli population size, while pH 4.50 reduced S. enterica population size. L. monocytogenes remained below detectable levels at all pH values, though lower pH levels led to more rapid population reduction. At higher storage temperatures, E. coli and S. enterica populations continued to grow, while L. monocytogenes showed significant declines.
In low-alcoholic beers, all microbes experienced population declines at lower temperatures. At higher temperatures, E. coli and S. enterica populations decreased but persisted in low numbers throughout the study. In contrast, L. monocytogenes population sizes rapidly dropped below detection limits.
The study concludes that alcohol content and storage temperature are critical factors influencing bacterial growth in low- and non-alcoholic beers. Non-alcoholic beers are particularly susceptible to microbial growth compared to their low-alcohol counterparts.
These findings highlight the importance of implementing rigorous quality control measures during the production of non-alcoholic beers to minimize the risk of bacterial contamination. Manufacturers should consider the impact of factors such as ethanol concentration, storage temperature, and pH levels to ensure the safety and quality of their products.
1. Source: Coherent Market Insights, Public sources, Desk research
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