Explain how viruses contaminate food.

Viral gastroenteritis affects people all over the world. In the U.S. the most common foodborne viral agents are Hepatitis A, Norovirus, and Rotavirus. Viral gastroenteritis outbreaks can occur in institutional settings, such as schools, child care facilities, and nursing homes, and can also occur in other group settings, such as banquet halls, cruise ships, dormitories, and campgrounds.

Water, salads, shellfish, iced drinks, and other ready-to-eat foods are the most sources of viral foodborne illnesses. The points of potential contamination determine the appropriate intervention strategy for preventing a viral foodborne disease. Food may be contaminated at the Source (i.e. polluted shellfish beds, vegetable growing fields, or during processing). Shellfish may be contaminated by sewage, and persons who eat raw or undercooked shellfish harvested from contaminated waters may get diarrhea. Drinking water can also be contaminated by sewage and be a Source of spread of these viruses.

Preventing this type of contamination requires monitoring of water overlying shellfish beds and providing sanitary facilities for food workers and enforcement of sanitary practices. Food may also be contaminated while being prepared for consumption; uncooked foods will remain infectious. For example, a food handler who has viral gastroenteritis could transmit viral agents to food if they do not wash their hands regularly after using the bathroom.