title: Survival of Normal and Chlorine-Stressed Pathogenic and Non-Pathogenic Vibrio parahaemolyticus Under Adverse Conditions.
abstract: BACKGROUND
  Vibrio parahaemolyticus is an important human pathogen which can cause gastroenteritis when consumed in raw or partially-cooked seafood. The pathogenesis of V. parahaemolyticus is based on the presence of virulence factors: the thermostable direct hemolysin (TDH) and TDH-related hemolysin (TRH), encoded by the tdh and trh genes, respectively.
  
  
  OBJECTIVE
  The present study aimed to evaluate the survival of normal and chlorine-stressed cells of pathogenic and non-pathogenic V. parahaemolyticus under adverse conditions.
  
  
  METHODS
  Normal and chlorine-stressed cells of pathogenic and non-pathogenic V. parahaemolyticus were subjected to environmental stresses such as low storage temperature (4°C and -18°C), high incubation temperature (50°C) and high NaCl content (20%). Viable counts were then made at various time intervals by surface plating on TSA-2.0% NaCl, and the survival rates of the cells were determined and compared.
  
  
  RESULTS
  Findings of the current study revealed that the normal cells of pathogenic and non-pathogenic V. parahaemolyticus, as well as the chlorine-stressed cells of both strains behave similarly under adverse conditions. In addition, chlorine stress increased the susceptibility of pathogenic and non-pathogenic V. parahaemolyticus to incubation at 4°C, and the presence of high NaCl content in the medium. However, chlorine stress did not significantly affect the thermal tolerance of pathogenic and non-pathogenic V. parahaemolyticus, and the susceptibility to incubation at -18°C.
  
  
  CONCLUSIONS
  Chlorine-stressed cells of V. parahaemolyticus were more susceptible to adverse conditions than the non-stressed ones. Pathogenic and non-pathogenic strains showed the same survival characteristics under the adverse conditions. These results should be considered in the development of food preservation measures.
authors.affiliation: Department of Food Hygiene, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, IR Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Zarei
authors.affiliation: Department of Food Science and Technology, College of Agriculture, Shiraz University, Shiraz, IR Iran.
authors.forename: Mohammad Hadi
authors.initials: MH
authors.lastname: Eskandari
authors.affiliation: Department of Food Science and Technology, College of Agriculture, Shiraz University, Shiraz, IR Iran.
authors.forename: Somayeh
authors.initials: S
authors.lastname: Keshtkaran
keywords: Chlorine; Stress; Survival; Vibrio parahaemolyticus