The most common foodborne viruses are single stranded RNA viruses which are adaptable and extremely resistant to environmental stress factors. Usual routes of food contamination are via stool material by persons shedding intestinal virus, or by saliva aerosols generated by shedding persons when coughing. Contamination of meat by animal viruses occurs when good hygienic and manufacturing practice fails. Once within food, viruses cannot replicate since they require living cells for this; hence food is not sensorily altered. Preventive measures in meat processing against pathogenic bacteria frequently have poor antiviral performance, while diagnostic techniques for viruses remain problematic.