If you think norovirus outbreaks occur mostly on cruise ships, you may want to think again, especially before dining out.

According to the Centers for Disease Control and Prevention’s (CDC) recent Vital Signs report, outbreaks of norovirus on cruise ships represent only about one percent of all reported norovirus outbreaks. Foodborne norovirus outbreaks can occur any place food is served.

The CDC analyzed 2009 to 2012 data through the National Outbreak Reporting System (NORS) and found that during the four-year period, a total of 4,318 norovirus outbreaks were reported to NORS, resulting in 161,253 illnesses, 2,512 hospitalizations, and 304 deaths.

Foodborne transmission was the primary mode reported in 1,008 (23 percent) norovirus outbreaks, representing 48 percent of the 2,098 foodborne outbreaks reported with a single suspected or confirmed cause during the four-year study period.

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Factors contributing to food contamination were reported in 520 (52 percent) of 1,008 foodborne norovirus outbreaks, among which infectious food workers were implicated as the source of contamination in 364 (70 percent). Bare-hand contact with ready-to-eat foods was explicitly identified in 196 (54 percent) of these outbreaks.

Ready-to-eat foods are foods that are ready to be served without additional preparation, such as washed raw fruits and vegetables for salads or sandwiches, baked goods, or items that have already been cooked.

Food service workers have been observed to practice proper hand-washing only one of four times that they should.

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Symptoms of norovirus include vomiting, diarrhea, and sometimes fever, although norovirus infections also can be asymptomatic, according to the CDC.

According to the CDC, each year an estimated 19 to 21 million cases of norovirus disease occur, including 1.7 to 1.9 million outpatient visits, 400,000 emergency department visits, 56,000 to 71,000 hospitalizations, and 570 to 800 deaths, which result in approximately $777 million in healthcare costs.

Rates of severe outcomes, such as hospitalization and death, are greatest in children less than five years of age, and in adults 65 years and older.

Norovirus is hard to kill. It remains on food, kitchen surfaces, and utensils. It can remain infectious on foods even at freezing temperatures and until heated above 140°F. Norovirus also stays on countertops and serving utensils for up to two weeks and is resistant to many disinfectants and hand sanitizers, according to the CDC.

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Weighing in on the report, Alissa Rumsey, a registered dietitian and spokesperson for the New York State Dietetic Association, told Healthline, “Foodborne illness is a serious problem. Have you ever had the “24 hour bug”? You may have had a bout of food poisoning. Proper hand washing is one of the keys to preventing contamination of food, especially when it comes to norovirus. Be sure to wash your hands thoroughly for 20 seconds with soap and water. This is important not only for restaurant workers, but in your own home as well. Rather than avoid certain foods, practice safe food handling instead.”

The CDC urge the food service industry to help prevent norovirus outbreaks by:

  • Ensuring that food service workers practice proper hand-washing and avoid touching ready-to-eat foods, such as raw fruits and vegetables, with their bare hands before serving them.
  • Certifying kitchen managers and training food service workers in food safety practices.
  • Requiring sick food workers to stay home, while providing paid sick leave, and utilizing on-call staffing to support compliance.