Effect of inactivation on microorganisms in pickled cowpea by high hydrostatic pressure

The objective of this study was to explore the application of high hydrostatic pressure (HHP) sterilization in Sichuan pickled industry and to improve the microbial safety. The effect of different salt concentration in pickled cowpea, treatment pressure and treatment time on bactericidal effect of HHP were investigated, and the preserved performance of pickled cowpea treated by HHP was studied. The results showed that salt concentration of 4.2% was superior to salt concentration of 4.2% in pickled cowpea on bactericidal effect by HHP, so HHP was more suitable for picked cowpea with lower salt concentration. With the increase of treatment pressure and treatment time, the lethality for microorganisms raised gradually, but the pressure had more significant effect to mortality of microorganisms than treatment time. The reduced the amount of total plate counts were respectively 5.45, 5.52, and the molds and yeasts wasn’t observed in samples treated by 300, 400MPa for 30min. Treatment at level of 300～400MPa could effectively reduce the amount of coliforms and improve the preserved performance of pickled cowpea.