According to the Centers for Disease Control (CDC), noroviruses are the leading cause of reported foodborne disease outbreaks and food preparation in restaurants is the most common source of norovirus contaminated foods. The findings were published in the Morbidity and Mortality Weekly Report.

In this report, data on suspected and confirmed norovirus outbreaks from the National Outbreak Reporting System (NORS) spanning 2009–2012 was analyzed for epidemiological trends in the outbreaks. Forty-three states reported these outbreaks during the time frame with a total of 4,318 outbreaks resulting in 161,253 illnesses, 2,512 hospitalizations, and 304 deaths. While the primary mode of transmission of the norovirus was person-to-person (69%) occurring most often in long-term care facilities, foodborne transmission was the cause in 23% of the outbreaks and 48% of the total foodborne outbreaks reported with a single suspected or confirmed case reported. Among the 1,008 foodborne norovirus outbreaks, 90% had a food preparation area as the source of the outbreak with restaurants (64%) and catering or banquet facilities (17%) as the most common locations.

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Food workers infected with the norovirus were the source of contamination in 70% of the outbreaks where factors were reported; contact between bare hands and ready-to-eat foods were identified in 54% of these outbreaks as well. Thirty-two percent of all foodborne norovirus outbreaks were linked to at least one specific food item, where the food was contaminated during preparation in 92% of outbreaks and 75% were foods eaten raw. Of the outbreaks with a single implicated food, vegetable row crops like lettuce, fruits, and mollusks were attributed most often to the outbreak.

The CDC recommends that food workers adhere to hand washing guidelines and the proper utilization of gloves or utensils to avoid bare-hand contact with ready-to-eat foods. It is also advised that workers with norovirus symptoms wait until ≥48 hours after symptom resolution to return to work.

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