Norovirus (Norwalk virus)
Foodborne illnesses

Food Safety


Norovirus (
Norwalk virus) is usually associated with poor personal hygiene and contaminated soils or water. Because Norwalk is a virus, it does not grow or reproduce in food. However, when food is contaminated with the virus via hands, soil or water, it is not easily killed by cooking. Because viruses cannot be isolated readily or detected in contaminated food, preventive controls are extremely important.


Norwalk virus is characterized by nausea, vomiting, diarrhea, abdominal pain, headache and low-grade fever. Symptoms usually appear 24-48 hours after infection, and may persist for as long as 1-2 days.


Man is the only known source of the virus. The virus is found in the feces of an infected person and is shed in human waste.

Mode of Transmission

Poor personal hygiene/lack of handwashing after toilet use and consumption of contaminated water supplies are the most common mode of transmission. Raw shellfish harvested from contaminated waters, contaminated ready-to-eat foods, eggs and even ice have caused Norwalk virus outbreaks.


  • Food-protection education

  • Good personal hygiene and handwashing

  • Food and water from reputable sources

  • Washing raw vegetables


FDA’s Bad Bug Book


National Restaurant Association