Abstract:In this study,total RNA,instead of genome DNA,was extracted from pressurized cooked ham and then performed with RT-PCR-denaturing gradient gel electrophoresis(DGGE) analysis to explore whether this molecular method was feasible to reveal the active species in the samples.Sliced vacuum-packed cooked ham were high pressure treated at 400 MPa and 600 MPa for 10 min at room temperature(22 ℃) and then stored at 4 ℃.Directly RNA extraction from meat samples and RT-PCR-DGGE analysis was performed at storage time 1,30,60,90 days(after HPP).Results showed that the major spoilage bacteria in the samples were largely inactivated by HPP and that higher level of pressure leaded to better effect.The microbial diversity of HPP samples during the whole refrigerated storage was extremely simple.Only Weissella viridescens survived the HPP of 600 MPa for 10 min at 22 ℃ and Weissella viridescens coupled with Leuconostoc mesenteroides survived the HPP of 400 MPa for 10 min at 22 ℃.The RNA-based DGGE method adopted is shown to be an efficient tool for the detection of active bacteria in pressurized cooked ham.
