Survival Differences of Vibrio vulnificus and Vibrio parahaemolyticus Strains in Shellstock Oysters (Crassostrea virginica) from Harvest to Sale: A Risk Perspective

Abstract

As there is limited information on the risk for consuming market oysters contaminated with V. vulnificus and V. parahaemolyticus, the aim of this study was to estimate the risk associated with raw oyster consumption affected by contamination levels and temperature during postharvest and transportation. To evaluate the effect of the temperature during transportation from the Mandinga Lagoon to Mexico City on the growth of V. vulnificus and V. parahaemolyticus, a modified Gompertz model was fitted at ambient temperatures of 20.1, 25.6, and 24.4°C for 22 h in windy, dry, and rainy seasons, respectively. The risk was calculated using FDA/FAO/WHOv.2005 software. Results showed that the mean risk (cases per 100,000 servings) of a person acquiring V. vulnificus vvha+/cvgC infection by consuming raw oysters was 2.9 × 10 −6 , 4.7 × 10 −6 , and 4.3 × 10 −6 during windy, dry, and rainy seasons, respectively. Risk for consuming oysters during windy season at-harvest contaminated with V. parahaemolyticus tdh+ was 8 × 10 −6 and 7.8 × 10 −7 for consuming oysters at-market during rainy season contaminated with V. parahaemolyticus tdh+ and trh+. These results suggest that maintaining temperatures above 20°C during oyster storage and transportation increases the risk of infections by pathogenic strains. The results provide a benchmark information to establish strategies to improve public health.

Comparative Survival and the Cold-Induced Gene Expression of Pathogenic and Nonpathogenic Vibrio Parahaemolyticus from Tropical Eastern Oysters during Cold Storage

“…Oysters are sold live in the whole shell, fresh or refrigerated in sacks, shucked in the fresh form, or packaged and refrigerated in polyethylene bags. Oysters are sent packaged to nearby local markets, retail stores, restaurants, oyster bars, and purchased by street vendors mostly in the Metropolitan Area of Veracruz, which includes the municipalities of Veracruz, Boca del Río, and Alvarado [19].…”