A gastric acid condition enhances the microbial killing effect of ethanol

Abstract

Tolerance to extremely low pH (< pH 3) is a crucial strategy that enables microorganisms to survive in the human stomach cavity. We found that the killing effect of ethanol on dormant cysts of soil protist Colpoda cucullus, and pathogenic bacteria such as Klebsiella pneumoniae and enterohemorrhagic Escherichia coli O157 was enhanced under stomach acid's low pH condition. This result suggests that gastric-acid-tolerant microorganisms can be partly killed by drinking alcoholic beverages during meals.

Keywords: Acid-tolerant microorganisms, ethanol, bactericidal effect.