Inactivation mechanism of Vibrio parahaemolyticus via supercritical carbon dioxide treatment

•Vibrio parahaemolyticus was treated at different conditions of supercritical CO2.•Exploring inactivation mechanism combined with the changes in the physical and chemical indexes.•Severe damage to key substances and structures is considered to be the inactivation factor.

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 40 min), pressures (10-25 MPa), 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 25 MPa treatment for 40 min 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.

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