Survival Characteristics of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes in Pickling Solutions at 5°C

There has been a surge of interest in pickling at retail food establishments. We investigated the time to a 5-log reduction of E. coli O157:H7, Salmonella, and L. monocytogenes in organic acid solutions containing 25 mM fumaric acid, 5 mM benzoic acid and 2% NaCl, pH 3.8, at 5°C. E. coli O157:H7 survived significantly longer than L. monocytogenes or Salmonella (P < 0.05). Mean decimal reduction values ranged from 10.52 h for Salmonella in malic acid solution to 56.40 h for E. coli O157:H7 in citric acid. Across acid solutions, pH 3.8, we noticed some significant differences in survival, e.g., acetic acid was significantly more lethal than citric acid (P < 0.05) to E. coli O157:H7. No pathogen reduction was observed at 5°C over four days in acid solutions that did not contain added fumaric and benzoic acid. A retailer who formulates a pickling brine with 25 mM fumaric acid, 5 mM benzoic acid and 2% NaCl, with a pH of 3.8 or below, using citric acid as the acidulant, would establish a holding period of at least 282 h at 5°C to achieve a 5-log pathogen reduction. Similarly, a holding time of at least 237 h would ensure a 5-log pathogen reduction in acetic acid-acidified brine.