Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2015
Publication Date: 4/17/2015
Citation: Sheen, S., Cassidy, J.M., Scullen, O.J., Uknalis, J., Sommers, C.H. 2015. Inactivation of Salmonella spp. in ground chicken using High Pressure Processing. Food Control. 57:41-47.
Interpretive Summary: High pressure processing (HPP) is a green and sustainable non-thermal means to reduce harmful bacteria in foods. Salmonella contamination of poultry meat is a common foodborne illness risk for Americans. At moderate operating conditions (e.g. 450MPa, 4 degree C, 10 min), a five log reduction (100,000 cells per gram of food) of Salmonella spp. can be achieved in poultry meat (e.g. ground chicken). The results of this study will allow regulatory agencies and the food processing industries to conduct risk analysis and provide safer meat to consumers. Consumers, especially those who are immuno-compromised (e.g. cancer patients, diabetics, and the HIV/AIDS population) will benefit from having more information about foods treated with alternative processes which kill harmful bacteria such as Salmonella. Food processors and risk assessors will be able to provide safer ground poultry meat to consumers.
Technical Abstract: 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 five-isolate cocktail of Salmonella spp. in ground chicken (95 percent lean) using HPP at refrigeration temperature (4 – 6 degree C) was studied. More than 5-log CFU/g inactivation was achieved at 450 MPa for 10 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).