Enteric viruses: Noroviruses and hepatitis A virus have been implicated in several large outbreaks of food-borne illness due to bivalve mollusc consumption in Australia and worldwide. These viruses persist and remain viable in oysters for long periods of time, and are not efficiently removed by depuration [36,37]. Levels do not necessarily always correlate with counts of faecal indicator organisms, so monitoring of water quality may not entirely control the food safety risks due to these hazards. The infectious dose is presumed to be low [9]. Light cooking does not inactivate noroviruses [38,39], and hepatitis A virus has significant heat stability [40].
