Norovirus in shellfish are the main cause of human gastroenteritis outbreaks worldwide. So Commission Regulation (EC) No 2073/2005 on microbiological criteria for foodstuffs gave attention to shellfish safety criteria. In order to establish the purification times, in addition to the conventional bacterial fecal indicators is necessary demonstrating the presence of NLVs by harmonized sampling frequencies at Community level. Finally it's confirmed the need of new safety criteria for pathogenic viruses in live bivalve molluscs by official analytical methods. The official method to research norovirus in live bivalve molluscs has been validated by the ISS. The Real Time RT PCR protocol resulted provided of efficiency to research NLVs. The PCR protocol was applied and further validated during a national monitoring carried out testing norovirus presence in shellfish collected from harvesting areas and bought at retailers located in Southern Italy. Finally, for determining shellfish purification times and establishing new criteria of classification for seawater in harvesting areas, a bioaccumulation study was carried on French oysters living in seawater contaminated by Norovirus spp.