Objective: We explored the mechanism of the microbial inactivation by high hydrostatic pressure.
Methods: We investigated the effect of ultra high pressure treatment on inactivation of Vibrio Parahaemolyticus cells, and the damages inflicted on the microstructure and the membrane proteins of the Vibrio Parahaemolyticus cells.
Results: The result indicated that after pressure treatment at 100 MPa, 200 MPa and 20 degrees C for 10 min, the viable cell was reduced to 60% and 15.3% respectively, viable cell counts were not detected following pressure treatment at 300 MPa and 20 degrees C for 10 min. High pressure treatment at 300 MPa also caused changes in the microstructure of the cell, such as the cell wall of Vibrio Parahaemolyticus was shrunk, breached and cytoplasm leaked out, the layer structure of cytoplasm disappeared, and a large electron transmission area appeared in the cell after compression, the membrane disappeared, the nucleoids condensed and the proteins aggregated after compression. At the same time, the membrane proteins of cells were damaged, and the cell membrane permeability increased, resulting in leakage of the cell.
Conclusion: This study showed that the damaged cell membrane was the major reason of the mechanism of microbial inactivation by high hydrostatic pressure.