Effectiveness of Hot Water Pasteurization for Thermal Inactivation of Listeria on Fully Cooked and Vacuum Packaged Chicken Breast Meat Products

摘要

In this study, fully cooked chicken breast strips were surface inoculated with heat-resistant Listeria innocua at an initial level of approximately 107 CFU/g, Individual inoculated chicken breast strips were vacuum packaged followed by thermal treatment in a water bath at 60, 70, 80, and 90 deg C for different treatment times (20 s to 30 min). The cell number of L innocua in chicken breast strips after hot water treatment was determined using cultural plate count method with modified Oxford (MOX) agar overlaid with tryptic soy agar (TSA). A 24 h enrichment procedure at 37 deg C was followed to check the survival of L. innocua. Our results showed that, when heated at 60, 70, 80, and 90 deg C, the bacteria reduction in log CFU/g was 5.0 after 12 min,3.4 after 4 min, 2.6 after 2.3 min and 2.8 after 2 min, respectively. Enrichment data indicated that the 7 log (CFU/g) reduction of L. innocua in chicken breast products occurred at 30, 10, 7 and 5 min for hot water treatment at 60, 70, 80, and 90 deg C,respectively. A primary model was developed based on the Weibull function to predict the survival of L. innocua at each heating temperature. The root mean square errors (RMSE) of the model and plot of predicted versus observed data showed a good fit andprediction of the model. The results indicated that post-package hot water treatment could be an effective intervention strategy to control Listeria in RTE poultry products. The results from this study would be useful for poultry processors to evaluatepost-cooking treatment of RTE poultry products and provide consumers with safer foods.