Inactivation mechanism of Vibrio parahaemolyticus via supercritical carbon dioxide treatment.

The effects of supercritical carbon dioxide (SC-CO2) treatments on Vibrio parahaemolyticus cells were determined using viable plate count method at different treatment times (10 and 40min), pressures (10-25MPa), and temperature (40°C). Using the changes in the physical (absorbance, transmission electron microscope and contents of fatty acids) and chemical indexes (pH value, activity of Na+K+-ATPase, SDS-PAGE) were for further understand the mechanisms of bacterial inactivation under SC-CO2. The result showed that 25MPa treatment for 40min in 40°C could significantly (P<0.05) enhance inactivation of V. parahaemolyticus. The pH value and activity of Na+K+-ATPase of SC-CO2 treated groups significantly (P<0.05) decreased compared with blank group. Damage to the cell membrane and cytoplasmic components can be observed on transmission electron microscope images. Results of SDS-PAGE and UV-absorbing substances also showed that the leakage of proteins and cytoplasmic materials increased with the SC-CO2 treatment time and pressure. Therefore, our results indicate that SC-CO2 can be applied to inactivate V. parahaemolyticus by causing a low pH, as well as severe damage to key substances and structures.