Impacts of high-hydrostatic pressure on the organoleptic, microbial, and chemical qualities and bacterial community of freshwater clam during storage studied using high-throughput sequencing

Abstract

This study was to determine the effects of high pressure processing (HPP; 200–600 MPa for 3 min) on the microbial, chemical, and organoleptic properties and the bacterial flora of freshwater clam (Corbicula fluminea) during cold storage. The results indicated that with an increase in pressure, the expanding rate, moisture content, shucking ratio, pH, lightness (L*), and whiteness (W) increased, whereas redness (a*), yellowness (b*), aerobic plate count (APC), psychrotrophic bacteria count (PBC), coliform, and Salmonella spp. decreased. In addition, HPP treatment of >300 MPa on samples significantly retarded the increases in APC, PBC, coliform, Salmonella spp., and total volatile basic nitrogen and a drop in pH during cold storage. Results of organoleptic analysis showed that HPP at 300 and 500 MPa prolonged the shelf life from 6 days (control group) to 9 days and 12 days, respectively. High-throughput sequencing (HTS) revealed that HPP considerably changed the spoilage microflora in samples after 15 days storage and delayed the spoilage process. These results demonstrate that pressurisation at least 300 MPa for 3 min on clam samples were able to reach 100% shucking, inactivate microbial growth, and retard quality loss, while they effectively extended shelf life of freshwater clam during cold storage.