Quantitative risk assessment of foodborne pathogens in poultry production and processing based on microbial challenging tests and predictive models.

摘要

Experimental data were collected and predictive models were developed for microbial behavior of foodborne pathogens in poultry production and processing. The load of Salmonella Typhimurium in eggs, during hatching process was analyzed with high and low initial bacterial load of 6.0 and 3.5 log cfu/egg, respectively. The bacterial load in eggs reduced after holding at 4°C for 24 h and increased during incubation (17 d) and hatch (21 d). A predictive model was developed with modification to Gompertz function to describe the behavior of S. Typhimurium in broiler hatchery.;Thermal inactivation of Listeria in chicken breast meats was evaluated during cooking in an air-steam impingement oven at air temperatures of 177°C and 200°C, and air humidity of 70-75%. At both temperatures, after cooking for 10 min, no survivors were detected in chicken breasts from an initial level of 106 CFU/g. A predictive model was developed by integrating heat and mass transfer models with a pathogen inactivation kinetics model.;The effect of refrigeration and freezing temperatures (8 to -20°C) on survival, growth, and death of S. Typhimurium and L. innocua in raw chicken breasts, for storage up to 21 d was investigated. At storage time of 7 d, there was significant increase in the load of L. innocua at 4°C and 8°C, and that of S. Typhimurium at 8°C, from an initial level of approximately 4.5 log CFU/g. A predictive model was developed by modifying Weibull distribution function to analyze microbial behavior on chicken breasts under these storage conditions.;Finally, a quantitative microbial risk analysis model for exposure assessment of Salmonella during poultry primary processing was developed to assess the effect of different processing steps. Monte Carlo simulation was performed for a typical poultry processing scenario. Results from this simulation indicated that prevalence and level of Salmonella in broilers from arrival to chilling process was reduced from 30% to 14% and from 1,570 to 126 CFU/bird, respectively. Developed predictive models could be used as tools to analyze behavior of foodborne pathogens and could be embedded into a risk analysis model for quantitative microbial risk assessment in poultry.