Norovirus-the Most Common Foodborne Illness

Pamela Schmutz,
Home & Garden Information Center

You may have heard of E. coli and Salmonella as common causes of foodborne illness. However, these two bacteria do not cause most cases of illness. According to the Centers for Disease Control and Prevention (CDC), over half of all cases of foodborne illness are caused by noroviruses. Noroviruses can easily spread anywhere people gather, if good hygiene practices are not followed, such as on a cruise ship. Of 660 norovirus outbreaks confirmed by the CDC between 1994 and 2006, 36% were from long-term care facilities, such as nursing homes, 31% were from restaurants, parties and other events, 20% were from vacation settings, including cruise ships, and 13% were from schools and community settings.

Noroviruses are very contagious. You can get it from another person, by touching a contaminated surface, or by consuming contaminated food or water. About 25% of norovirus cases are foodborne. Food can become contaminated when an infected food worker handles it during preparation or service. Any food eaten raw, such as leafy greens, fruits, shellfish, and ready-to-eat foods that are handled a lot, are common sources. Symptoms usually begin about 12 to 48 hours after exposure and include stomachache, diarrhea, vomiting and nausea. 

The best way to prevent the spread of noroviruses is by scrubbing all surfaces of your hands with soap and water for at least 10 seconds, then rinsing thoroughly under warm, running water, and completely drying with a clean paper towel. Alcohol-based hand rubs, such as hand sanitizers, can be used between hand washings. Because it is still uncertain how effective alcohol-based hand rubs are against noroviruses, it is best not to use them as a substitute for soap and water hand washing.

To read about Clemson University’s role in a USDA-funded grant to study noroviruses, see For more information on noroviruses and foodborne illnesses, see HGIC 3720, Foodborne Illnesses: Viruses.

Source: Centers for Disease Control and Prevention. March 2011. Updated Norovirus Outbreak Management and Disease Prevention Guidelines.

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