Viruses as causative agents of foodborne diseases

Viruses (particularly noroviruses and hepatitis A virus) are important causes of growing numbers of foodborne diseases. They are highly resistant to environmental conditions and can persist for extended periods in the environment and in food. The principal sources of viral contamination of food include human or animal faeces and untreated sewage, infected food handlers and animals carrying zoonotic viruses (e.g. hepatitis E virus). Ready-to-eat food prepared by infected food handlers and bivalve molluscs often consumed raw or undercooked are categories of food particularly associated with viral foodborne illnesses. The detection of viruses in foodstuffs is usually based on molecular biological methods, though standardised methods of testing are not yet available. The regular monitoring of foodborne viruses is not required by law, but recommendations and procedures for the prevention of viral contamination are included in the Codex Alimentarius.