Effects of high hydrostatic pressure on inactivation, morphological damage, and enzyme activity of Escherichia coli O157:H7

High hydrostatic pressure (HHP) is a nonthermal processing technology that can maintain the original color, flavor and nutritional components of food during preservation. In this study, the mechanism of HHP to inactivate Escherichia coli O157:H7 was studied and clarified. Along with the increase of treatment pressure, the total number of viable bacteria decreased significantly (p < 0.05). Different HHP treatments destroyed the integrity of E. coli O157:H7 cell membrane and had a certain effect on the content and activity of the whole protein profiles. Scanning electron microscopy and transmission electron microscopy confirmed that HHP caused membrane damage of E. coli O157:H7. In addition, the effects of HHP on enzyme activity, glucose metabolism and iodonitrotetrazolium chloride metabolic reduction activity showed that HHP could interfere with glycolysis and tricarboxylic acid cycle pathway of E. coli O157:H7. In general, HHP has multiple targets for the inactivation mechanism of E. coli O157:H7.