Effect of pre-exposure to sodium chloride on the resistance of pathogens to thermal and acid stresses

Abstract

This study determined the effects of pre-exposures to sodium chloride (NaCl) on the survival of three pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes) when the organisms were subsequently treated with moderate heat (55C) or an organic acid (acetic acid). Pre-exposure to 5% NaCl especially increased the thermal resistance of E. coli O157:H7 and L. monocytogenes, whereas there was no significant increase in thermal resistance for S. Typhimurium. Pre-exposure to 10% NaCl reduced the resistance of the three pathogens to 1% acetic acid, and similar reductions in acidic resistance were observed in S. Typhimurium and L. monocytogenes samples that were pre-exposed to 5% NaCl. These results indicate that prior exposure to NaCl can affect the resistance of pathogens to environmental stresses. © 2010 Wiley Periodicals, Inc.