Inactivation of Salmonella spp. in ground chicken using high pressure processing

High Pressure Processing (HPP) is a safe and effective process for improving the microbial safety and shelf-life of foods. Salmonella is a common contaminant in poultry meat and is frequently responsible for foodborne illness associated with contaminated poultry meat. In this study the inactivation of a fiveisolate cocktail of Salmonella spp. in ground chicken (95% lean) using HPP at refrigeration temperature (4-6 degrees C) was studied. More than 5-log CFU/g inactivation was achieved at 450 MPa for10 min. In contrast, HPP treatment at 250 MPa or 350 MPa (single-cycle, 15 min) inactivated 0.5 log or 1.7 log CFU/g, respectively. The multiple-cycle HPP mode at 250 or 350 MPa (3-cycle with 5 min/cycle) showed higher cell reduction at 1.3 or 3.3 log CFU/g, respectively. HPP at 550 MPa for 10 min may reduce the cell counts, initially at 8.5 log CFU/g, to below the detection limit (1.0 log CFU/g) in current study. The images (electron microscopy) of the HPP shocked cells were examined for structural damage, which demonstrated that Salmonella cells may still look intact (with damages on rough/irregular surface at 450 MPa stress) under Scanning Electron Microscopy (SEM), but have significant damage internally (voids and uneven mass distribution patterns) under Transmission Electron Microscopy (TEM). Published by Elsevier Ltd.