Food and water contamination by human viruses is a great health problem. These viruses are shed in stools. Norwalk-like viruses, hepatitis E virus, poliovirus, echovirus, hepatitis A virus, rotavirus, astrovirus, enteric adenovirus and parvovirus B19 have been described. The most important ones are Norwalk-like viruses, rotavirus and hepatitis A virus as reported in epidemiological surveys. The most frequently implicated foods are shellfish (bivalve mollusks) harvested from waters contaminated with human sewage, as well as water itself. The other source of infection is the handling of food in poor hygienic conditions. In this case contaminated foods are vegetables, sandwiches, fruits, pastries that are soiled. The detection of viruses in foods is difficult for several reasons: Virusfood interactions make difficult the concentration and the purification of viruses, several virus species are difficult or unable to grow in cell culture, furthermore viruses are present in the sample in very low amounts. Molecular techniques are therefore the methods of choice for detecting these viruses, especially the polymerase chain reaction which is often described. Another possibility consists in a fecal viral indicator. Bacteriophages seem to be the most promising in this respect.