Viruses are the smallest of the foodborne microbial contaminants. They are packets of infectious genetic material wrapped with an outer layer of protein. Most experts believe that viruses are the most common cause of foodborne illness
There are 2 main viruses in food that are involved with food poisoning. Hepatitis A & Noroviruses. The foods that seem to be most responsible for viral infection are those with little to no processing. These include foods such as oysters, clams, mussels and scollops as well as fresh produce (salads and fruits).