The risk of Vibrio parahaemolyticus infections associated with consumption of raw oysters as affected by processing and distribution conditions in Taiwan

Abstract

The steadily increased consumption of raw oysters in Taiwan warrants an assessment of the risk (probability of illness) of raw oyster consumption attributed by Vibrio parahaemolyticus. The aim of this study was to estimate the risk of V. parahaemolyticus infection associated with raw oyster consumption as affected by various factors such as prevalence and contamination levels of V. parahaemolyticus and the time and temperature during postharvest processing and transportation. The risk was calculated using @Risk software with input including the initial levels and prevalence of total and pathogenic V. parahaemolyticus, temperature and time during processing and transportation, growth/inactivation models of V. parahaemolyticus in raw oysters, raw oyster consumption, and a dose response model. Results show that the mean probability of a person acquiring V. parahaemolyticus infection by consuming raw oysters is 8.56 × 10−5 (95% CI: 0.000–0.4.5 × 10−3) per serving of oyster, and the incidence rate was 0.28 case per 100,000 people in Taiwan. Sensitivity analyses showed that the contamination levels and prevalence of virulent V. parahaemolyticus and the processing and transportation temperatures are significant risk-contributing factors. This study suggests that maintaining temperatures below 12 °C during oyster processing and transportation could significantly reduce the annual incidences of V. parahaemolyticus infections. The findings provide a benchmark information for the regulatory agency and oyster processor in Taiwan to design control measures to protect the consumers against V. parahaemolyticus as it is one of the most prevalent foodborne pathogens in Taiwan.