Resistance of acid-habituated Escherichia coli to organic acids and its medical and applied significance

Escherichia coli grown in broth initially at pH 5.0 (pH 5.0‐grown organisms) survived exposure to inorganic acid or to acid pH plus organic acid which prevented subsequent growth by pH 7.0‐grown organisms. This resistance of pH 5.0‐grown organisms to organic acids was observed at acid pH with lactic, propionic, benzoic, sorbic, trans‐cinnamic and acetic acids. Such resistance might allow acid‐habituated organisms to survive in acid foods or at body sites such as the urinary tract where organic acids are present at acid pH.