Norovirus is a major cause of acute gastroenteritis in Europe. The virus is readily transmitted from person to person so outbreaks can easily become large, as shown in the outbreak that occurred in a Dublin Hotel just before Christmas. In this instance, around 580 people reported illness after attending events in the hotel. Food and water can also be sources of norovirus infection when they are either contaminated with faecal matter or cross-contaminated by food handlers.
A major issue for the Authorities and the industry in Ireland surrounds decisions regarding the safety of oysters when they are found to contain norovirus genome copies but are nevertheless compliant with all applicable control requirements. In this context the FSAI requested advice from the European Food Safety Authority (EFSA) on the public health risks associated with establishing standards for noroviruses in oysters.
EFSA concluded that norovirus is highly infectious and low doses can result in disease. However, it noted that the amount of virus detected in oysters linked to human illness could vary greatly. It also concluded that norovirus genetic material was frequently detected in European oysters even when they complied with existing control standards.
The opinion went on to recommend that risk managers should consider establishing an acceptable limit for norovirus in oysters that are intended to be harvested and placed on the market in the EU.
