Survival of Escherichia coli O157, Salmonella, and Listeria monocytogenes in Ethanol and Juice Mixtures at Ambient Temperature

Some bars and restaurants have begun displaying alcoholic fruit and vegetable cocktail mixes at ambient temperature. Operators often believe that ethanol makes this practice safe, and conversely, some regulators question the safety. It has been reported that ethanol may inhibit the growth of some bacteria at concentrations starting at 8–10% and may be biocidal at concentrations ≥30%. In this study, Escherichia coli O157, Salmonella,and Listeria monocytogenes did not grow in bananapuree, pear puree, orange juice, and apple juice cocktailmixtures prepared with ethanol concentrations from 10to 50% at 25°C. Inoculated pathogens were not detectedin juice plus ethanol at 40 or 50% after 48 h. Juices withethanol concentrations of 10–30% exhibited different logreductions over time for each of the pathogens introduced.This study has implications for how regulators assess therisk of ethanol juice mixtures held at ambient temperatureunder the U.S. Food and Drug Administration (FDA) FoodCode. Operators that desire to display ethanol and fruitjuice mixtures at room temperature need to ensure a pH< 4.2 or a combination of pH and water activity values based on Table B of the FDA Food Code, or they must keep the product under refrigeration at a temperature ≤ 41°F.