Noroviruses (NoV) are the most common cause of infectious diarrhoea and vomiting in the community. They often cause outbreaks, especially in closed or semi closed communities. Like other organisms that affect the gut NoV can be passed from person to person, or be picked up from a contaminated environment or through eating food contaminated at source or by infected food handlers.

What is not reliably known is exactly how much norovirus infection is food-related as opposed to transmitted by other means. Estimates from international research groups of the proportion of NoV that is transmitted through contaminated food vary quite widely. Through a series of linked studies we will seek to answer the following major research questions:- (a) how much NoV is transmitted through contaminated food? (b) what is the role of infected food handlers in transmission? (c) is it possible to differentiate between infectious and non-infectious virus in a variety of food matrices?

Given critical data gaps identified in 2004, and the lack of progress in filling them so far, we will conduct fieldwork in three crucial areas – first to determine the prevalence of NoV contamination of three high risk food commodities on retail sale, namely oysters, salad leaves and soft berry fruits; secondly to assess whether or not the NoV found is likely to be infectious or not and thirdly to determine the prevalence of NoV contamination of the catering environment. These are essential data items for being able to conduct a quantitative microbiological risk assessment.

The FSA’s policy objective is to develop an evidence based approach to managing risks from, controlling the burden of, foodborne NoV disease as described in the FSA forward evidence plan 2012 and the FSA Science and Evidence strategy 2010-2015. Armed with the information generated from the research, the Food Standards Agency should be better equipped to formulate risk mitigation strategies and develop improved targeted risk management tools.