Effects of a Commercial Heat-Shock Process on Vibrio vulnificus in the American Oyster, Crassostrea virginica, Harvested from the Gulf Coast

Abstract

Oysters (Crassostrea virginica) harvested from the Gulf Coast, containing 102 to 104 most probable number (MPN) per gram of Vibrio vulnificus, were subjected to a commercial heat-shock process. After 1 to 4 min at internal oyster meat temperatures exceeding 50°C, shellstock oysters were shucked, chilled, washed, and packed. V. vulnificus and total bacterial levels in Gulf Coast oysters were significantly reduced from 1 to 4 logs in the finished product. Similar reductions were not observed in shellstock oysters that were subject to conventional processing. Under the National Shellfish Sanitation Program, heat shocking is an acceptable process to use to assist in the shucking of shellstock. This research revealed that the heat-shock process may also serve to significantly reduce V. vulnificus in summer Gulf Coast oysters.