Abstract:

Objective: The objective of this study was to observe the susceptibility of Vibrio parahaemolyticus to variousenvironment stresses as influenced by high hydrostatic pressure treatments. Methods: A pressure-sensitive strain ofV. parahaemolyticus (ZJGSMC001) isolated from seafoods was repeatedly treated with high hydrostatic pressures rangingfrom 80 to 250 MPa, and the surviving cells were selected as pressure-resistant strains (ZJGSPR001). The tolerance ofV. parahaemolyticus to subsequent adverse conditions was investigated in the pressure-sensitive strains as well as the pressureresistantstrains. Results: When exposed to a pressure of 250 MPa, the survival of pressure-resistant strains was 2 (lg (CFU/mL))higher than that of pressure-sensitive strains. When exposed to low temperature (1 ℃) and high temperature (45 ℃), pressuresensitivestrains could not survive, while the pressure-resistant ones grew well and still survive at 1 ℃or 48 ℃. Pressuresensitivestrains could not grow at high salt concentration such as 11.5 g/100 mL NaCl. However, pressure-resistant bacteriacould survive and grow well. Pressure-resistant strains were more resistant to organic solvent and organic acids comparedto the pressure-sensitive ones. When exposed to alcohol (12%), acetone (9%), toluene (0.75%), citric acid (3 mg/mL)and lactic acid (1.5%), the pressure-sensitive bacteria were totally dead, while the pressure-resistant cells remained alive.Conclusion: The pressure-resistant V. parahaemolyticus is more tolerant to environment stresses such as temperature, NaClsolution, organic solvent and organic acids than the pressure-sensitive strains.

Key words: Vibrio parahaemolyticus, pressure-resistant bacteria, environmental stresses