The primary contamination of food occurs when the animal which is going to be killed has already a virus disease. Meat and organs may then carry the virus. The secondary contamination of food occurs during processing, transportation and storage through dirt and smear infections. Virus carrier of hepatitis - A virus may contaminate food handling food in restaurants. Water which bears viruses is the most common cause of contamination when used in the production of food or used in cleaning of tools and equipment.
Enteroviruses are the most important group of water-borne viruses.
The HAV is a heat resistant RNS from the family of the Picornaviridae . The HEV is supposed to be a member of the Calici - group . It is a RNS - virus, its incubation is about 40 days. It causes a high mortality between pregnant by first infection. It is very frequent in India and Mexico.