Quantitative evaluation of the risk of Vibrio parahaemolyticus through consumption of raw oysters (Crassostrea corteziensis) in Tepic, Mexico, under the RCP2.6 and RCP8.5 climate scenarios at different time horizons

Abstract

Little is known about the impacts on public health of pathogenic Vibrio parahaemolyticus under different climatic scenarios and future time horizons. A simulation model was developed based on the Monte Carlo method to evaluate the effect of the factors that contribute to the growth of Vibrio parahaemolyticus from its estuary environment to its end consumption in different seasons, climatic scenarios and time horizons. The factors that most contribute to risk of gastroenteritis were postharvest time, season, time horizon and the climate scenario. The predicted risk increases with postharvest time, nearing a plateau of 0.010 after 36 h when risk is 5 times higher than that at 0 h postharvest. There are significant differences in risk among the seasons: in summer the risk is almost double that in winter, and in fall it is higher than in spring. The time horizon significantly affects the predicted risk, increasing 1.12 times from 2020 to 2100. There is significant evidence that the climate scenario affects predicted risk per serving: risk in the RCP8.5 scenario intensifies to 11 times that in the RCP2.6 scenario. Moreover, the effectiveness of mitigation measures to reduce the level of Vibrio parahaemolyticus in raw oysters was evaluated with respect to the official Mexican norm NOM-242-SSA1-2009. Using as reference the risk of becoming ill in summer from consuming recently harvested oysters with no mitigation in any climate scenario and time horizon, immediate refrigeration would reduce risk of disease by 37%. In contrast, depuration would reduce it by 94%, and freezing, heat treatment and thermal shock would reduce it by almost 100%.