Virus risk in the food supply chain

Enteric viruses are an important food safety concern and have been associated with many foodborne disease outbreaks. Norovirus and Hepatitis A virus have been implicated in majority of outbreaks; however, other foodborne viruses such as Hepatitis E virus, Sapovirus and Rotavirus can also present a risk to humans. Viral foodborne disease outbreaks have typically been associated with foods served raw including shellfish, fruits and vegetables. The contamination of food by viruses can occur anywhere in the supply chain. Unlike bacteria, viruses cannot replicate in food, so the ability of a contaminated food to serve as a vehicle for infection depends on virus stability and host susceptibility. The burden of foodborne enteric viral disease is often difficult to estimate as many illnesses are mild and go unreported. Molecular assays have been developed for foodborne viruses, and the sensitivity of theses assays has significantly improved throughout the last decade. Surrogate viruses are often used in laboratory research to further understand virus behavior as many foodborne viruses are difficult or impossible to culture outside a human host. This review provides an overview of the epidemiology and detection of foodborne viruses, and most summarizes the state of the science in quantitative microbial risk assessment as applied to foodborne viruses, including the use of viral surrogates.