Strategies to reduce norovirus (NoV) contamination from oysters under depuration conditions. (September 2020)

• Record Type: Journal Article
• Authors: Younger, Andrew D.; Neish, Anna; Walker, David I.; Jenkins, Kaitlyn L.; Lowther, James A.; Stapleton, Tina A.; Alves, Mickael Teixeira
• Is Part Of: Food and chemical toxicology. Volume 143(2020)
• Publication Date: 2020-09
• Subjects: Pacific oysters -- Norovirus -- Depuration -- Purification; Toxicology -- Periodicals; Food poisoning -- Periodicals; Food Poisoning -- Periodicals; Toxicology -- Periodicals; Toxicologie -- Périodiques; Intoxications alimentaires -- Périodiques; Food poisoning; Toxicology; Periodicals; Electronic journals; 615.9
• DOI: 10.1016/j.fct.2020.111509
• Languages: English
• ISSNs: 0278-6915

Abstract

Abstract: Depuration of oysters can effectively reduce levels of E. coli, however, may not be effective in safeguarding against viral contamination (EFSA, 2012). These trials assess the removal of Norovirus Genogroups I and II (NoV GI and GII) and F + RNA bacteriophage genogroup II (FRNAP-II) from oysters under depuration using molecular and viability assay methods. Our results show consistently better removal of NoV GII compared with Nov GI. We found approximately 46% removal of NoV GII at 18 °C after 2 days and 60% after 5 days compared with a maximum of 16% NoV GI removal. Twice the rate of NoV GII removal was achieved at 18 °C compared with 8 °C after 5 days. Results suggest better NoV removal when depuration water salinity is close to that prevailing in the harvesting area. Trials investigating algal feeding, light/dark and disturbance from pump vibration did not show any significant effect. We found that FRNAP-II was more readily removed than NoV. No significant difference was found between the rate of removal (as measured by RT-qPCR) and inactivation (as measured by bioassay) of FRNAP-II. This indicates that reduction in FRNAP-II may be primarily due to physical removal (or destruction) rather than in situ inactivation of the virus.