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T2-07 Quantitative Risk Assessment of Toxoplasma gondii Infection through Consumption of Fresh Pork in the United States

Sunday, July 26, 2015: 10:30 AM
C125 - C126 (Oregon Convention Center)
Miao Guo , University of Maryland , College Park , MD
Elisabetta Lambertini , University of Maryland , College Park , MD
Robert Buchanan , Center for Food Safety and Security Systems, University of Maryland , College Park , MD
Jitender Dubey , U.S. Department of Agriculture , Beltsville , MD
Dolores Hill , U.S. Department of Agriculture , Beltsville , MD
H. Ray Gamble , National Academy of Science Fellowships Office , Washington, D.C.
Jeffrey Jones , Centers for Disease Control and Prevention , Atlanta , GA
Abani Pradhan , Center for Food Safety and Security System , College Park , MD
Audio File Recorded Presentation
Introduction: Toxoplasma gondii is one of the leading foodborne pathogens in the U.S. The Centers for Disease Control and Prevention (CDC) reported that T. gondii is one of three pathogens, which together account for >70% of all deaths due to foodborne illness in the U.S. Consumption of undercooked pork products in which T. gondii has encysted is a common transmission route for human infection.

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.

Back to: Technical Session 2 – Modeling and Risk Assessment
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