Production of viable but nonculturable state in Salmonella isolates by combination of acidity, osmotic pressure and freezing

This study aimed to investigate the production of viable but nonculturable (VBNC) state in food-borne Salmonella strains by the combination of environmental conditions, including acidity, osmotic pressure, and freezing. Three cocktails of Salmonella serotypes (S. Typhi, S. Typhimurium, and S. Enteritidis) with the origin of beef and mutton were used in this study. The plate counting method and bacterial resuscitation were used to evaluate the VBNC state. The obtained results showed that the freezing induced the VBNC state in S. Typhi, S. Typhimurium, and S. Enteritidis. Acidic condition (pH 4.5) alone caused the death of all three Salmonella serotypes, but the combination of freezing, osmotic pressure, and low pH induced VBNC state in all three serotypes. The results can be used as base of further researches in this field.