Submitted to: United States Japan Natural Resources Protein Panel
Publication Type: Other
Publication Acceptance Date: 11/30/2002
Publication Date: 11/1/2003
Citation: KINGSLEY, D.H. VIRUS AND VIBRIO INITIATIVES WITHIN THE USDA MICROBIAL FOOD SAFETY RESEARCH UNIT. UNITED STATES JAPAN NATURAL RESOURCES PROTEIN PANEL. N1-N13 Interpretive Summary:
Technical Abstract: Safety concerns associated with the consumption of molluscan shellfish include biotoxins, chemical pollutants, microbial, and viral pathogens. The USDA Microbial Safety of Aquaculture Products Center of Excellence within the Microbial Food Safety Research Unit is located on the campus of Delaware State University in Dover DE. This unit has active research projects involving V. vulnificus, and environmentally-persistent viruses such as hepatitis A virus and the Norwalk-like viruses. Research on V. vulnificus has focused on the identification of virulence proteins and on developing an understanding of the mechanisms of bioconcentration and persistence within shellfish tissues. Current findings indicate that for oysters (Crassostrea virginica), a virulent strain of V. vulnificus depurates less efficiently than an avirulent isolate, with the virulent strain showing a 3-log10 reduction after six days and the avirulent strain showing a 4-log10 reduction over the same period. Viral pathogens, which replicate in the human gut, are a persistent problem due to sewage release in estuarine waters. Virus-related research has focused on mechanistic characterization of virus persistence within shellfish meats, the development of highly sensitive virus extraction and detection methods for shellfish, and the evaluation of high hydrostatic pressure processing for the sanitization of raw shellfish for human consumption. Specific accomplishments of the viral research project include development of a sensitive viral RNA extraction method for shellfish which can detect less than 1 plaque forming unit of hepatitis A virus and less than 25 RT-PCR units of Norwalk virus within 30 ml of seeded shellfish extracts. Also, inactivation of hepatitis A virus and feline calicivirus from 7- log10/ml stocks to non-detectable levels using high hydrostatic pressure has been demonstrated.