Purpose: The goal of this study was to develop a farm-to-table quantitative microbial risk assessment (QMRA) model to analyze the public health burden through consumption of fresh pork in the U.S.
Methods: T. gondii prevalence in pigs was described by a weighed prevalence and bradyzoites concentration was calculated in each pork cut (picnic, butt, ham, loin and belly) of an infected pig. A logistic regression and a log-linear regression were developed to model the reduction of T. gondii during moisture enhancement and home cooking, respectively. A Beta-Poisson dose response model was developed by using the experiment data of mice orally infected with Type II strain. The QMRA model was developed in a Monte Carlo probabilistic framework to account for uncertainty and variability in model parameters and input variables.
Results: The mean probability of infection per serving of fresh pork products ranges from 2.4 × 10-7 to 6.69 × 10-6, corresponding to 136,470 new infections annually in general population. Approximately 1,059 new infections occurred each year in pregnant women, which associated with 346 congenital toxoplasmosis cases per annum. Sensitivity analysis suggested that cooking is the most important parameter impacting human health risk.
Significance: This study addressed the disease burden of T. gondii infection and quantified the effects of processing on the viability of cysts, which provides the scientific basis for risk management and also could serve as the baseline model for the QMRA of T. gondii in other meats.