Norovirus

What It Means

Norovirus is a highly contagious virus that is the leading cause of foodborne illness in the United States, responsible for an estimated 19 to 21 million cases of acute gastroenteritis each year. The virus causes inflammation of the stomach and intestines, leading to symptoms including nausea, vomiting, diarrhea, and stomach cramping. Symptoms typically appear 12 to 48 hours after exposure and last 1 to 3 days, though some people may be contagious for several days after symptoms resolve. Norovirus is particularly associated with food contamination by infected food handlers, as the virus is easily transmitted from person to person and can contaminate food at any point during preparation or serving. Foods most commonly associated with norovirus outbreaks include leafy greens, fresh fruits, shellfish (especially oysters), and any food handled by an infected person. Unlike bacterial pathogens, norovirus is not always detected through routine food testing and contaminated products are less frequently subject to FDA recalls compared to bacterial contamination. However, norovirus contamination of commercially distributed foods, particularly shellfish harvested from contaminated waters, can trigger recalls. The virus is resistant to many common disinfectants and can survive on surfaces for extended periods. Prevention focuses primarily on proper handwashing, keeping sick food handlers away from food preparation, and adequate cooking of shellfish.