Abstract
The effect of low pH on survival and growth of C. jejuni and C. coli were studied in Brain Heart Infusion broth acidified with hydrochloric, acetic, citric, maleic, succinic, malic or lactic acid. The survival and growth of C. jejuni and C. coli at low pH depended in the type of acid present. The cells of C. jejuni and C. coli died within 3 h at pH 4.0 adjusted with each organic acid at either 10 or 25°C. In broth adjusted to pH 5.0 with lactic or acetic acid, the cells decreased in number within 24 h and 48 h, respectively, at 10°C. At pH 5.0 adjusted with other acids and at 10°C, the cells survived over 48 h. The cells of C. jejuni held for 48 h at 25°C decreased in number in broth adjusted to pH 5.5 with any organic acid. C. jejuni and C. coli grew at pH 5.7 acidified with hydrochloric, citric, succinic, malic or lactic acid; however they failed to grow at the same pH value acidified with acetic or malic acid. The lowest pH at which C. jejuni and C. coli grew in these acids was 6.5.
