According to the Centers for Disease Control and Prevention (CDC) norovirus is the leading cause of outbreaks from contaminated food in the United States. About 50% of all foodborne illness (food poisoning) outbreaks are caused by norovirus with most occurring in food service settings. Infected workers are often the cause of these outbreaks by touching ready-to-eat foods with their bare hands. However, any food served raw or improperly handled after cooking can become contaminated with norovirus.
Norovirus spreads very easily and it only takes a small number of the viral particles (as few as 10 to 100) to cause illness. The virus is present in feces (stool, poop) or vomit in very high levels, so exposure to even a very, very small amount of these substances can cause illness. The virus can become airborne which can occur with vomiting. Airborne norovirus can land on surfaces that others may touch and then touch their mouth thus contaminating themselves. The virus can survive for extended periods of time on surfaces and in food.
The CDC outlines three main ways the virus is transmitted.
Let's examine these in terms of a foodservice setting:
- Eating or drinking contaminated foods or liquids. In this case, an infected worker may have a small amount of poop or vomit on their hands and then proceed to prepare food that is served to a customer.
- Touching surfaces or objects contaminated with the virus, then putting your fingers in your mouth. Here a customer may have vomited in the restroom, spewing vomitus onto surfaces in the bathroom. If the vomit was not properly cleaned up a worker could touch these surfaces contaminating their hands and then contaminate the food, they are preparing.
- Having direct contact with an infected person. In this case, a foodservice worker may not have any symptoms but be living with someone who has norovirus. They may be coming to work since they are not sick but may be shedding the virus in their feces during this time. People are most contagious when they are sick and for at least three days and possibly up to two weeks after recovery.
Other facts about norovirus
- Symptoms generally occur within 24 hours of exposure and include severe vomiting (often projectile), diarrhea, nausea, low grade fever & chills, headache, and muscle ache.
- Norovirus is hard to kill. It can remain infectious in food at freezing temperatures and until heated above 140°F. It can survive on surfaces for up to two weeks. It is not necessarily destroyed by many common disinfectants and hand sanitizers.
- It can enter your place of business through employees, customers, or food contaminated at its source. The foods most often implicated in an outbreak include ready-to-eat foods such as salads, sandwiches, bakery items, leafy greens, fresh fruit, or shellfish harvested from contaminated waters.
As owner/manager/person in charge (PIC) in a foodservice operation, you must take steps to prevent a potential norovirus outbreak in your facility. The Food and Drug Administration (FDA) Food Code specifically addresses the following about norovirus:
Employee Illness
As the PIC it is your responsibility to train employees about the causes of foodborne illness, their job responsibilities in terms of potential for causing a foodborne illness, and reporting requirements of specific symptoms, diagnosis, and exposures to norovirus and other foodborne illnesses. Likewise, employees share in this responsibility and as a condition of employment, they must fully understand and adhere to these guidelines.
Things to consider in your employee policies
- Include the "Conditional Employee or Food Employee Reporting Agreement" from the FDA Employee Health and Hygiene Handbook in the hiring process and review with all employees on a regular basis.
- Through training, help employees understand the importance of reporting symptoms of vomiting, diarrhea, a diagnosis of norovirus, or if they live with someone who has been diagnosed and how working when sick can place others at risk for a potential illness.
- Display posters on preventing food contamination and reportable illness symptoms.
- As the PIC be aware of signs that may indicate illness such as frequent trips to the bathroom, cold sweats or chills, vomiting and others.
Additional prevention measures include
- Practice proper hand hygiene – employees must understand the importance of proper handwashing as a key control in preventing the spread of any type of microorganism. Training on handwashing techniques and times when handwashing should occur is essential. As the PIC monitoring of handwashing and retraining or reminders are essential.
- No bare hand contact with ready to eat foods – monitor that employees are using gloves correctly or using another appropriate barrier to prevent bare hand contact.
- Wash fruits and vegetables and cook seafood thoroughly – wash fruits and vegetables under running water before preparing or eating. If quick steaming oysters or shellfish, the final temperature may not reach 145°F. Norovirus can survive temperatures as high as 140°F therefore always check the final cooked temperature with a calibrated thermometer.
- If for any reason you think food may have been contaminated with Norovirus, throw it out.
- In addition to food contact surfaces, keep common surfaces clean and disinfected such as door handles, tables, chairs, elevator buttons, drinking fountains, railings, condiment stands, and other similar touch points.
Clean Up for Vomiting and/or Diarrheal Event
The FDA Food Code requires food service operations to have written procedures for cleaning up vomit and diarrhea. This is critical to minimize further contamination to food, surfaces, and people. The procedure should designate specific individuals responsible for cleaning up after such an event. These employees must have access to the proper equipment and be trained on the procedure.
Norovirus is resistant to many common disinfectants; therefore, it is important to use an EPA registered disinfectant. Clean up kits are available for purchase or you can make your own. These kits allow for easier access and rapid response. The Pennsylvania Department of Agriculture "Clean Up for Vomiting and Diarrheal Event in Retail Food Facilities" provides detailed information on supplies needed for making a kit as well as specific clean up procedures.
Do not let your operation be the cause of a norovirus outbreak! Take the time to develop policies and procedures that address this issue and educate your employees about the important role they play in preventing the spread of this nasty virus. Not only will they be protecting the health of the customers they serve and their own health, but they will also be protecting their livelihood from the financial burden and loss of reputation a foodborne illness outbreak could have on the operation.
References
Centers for Disease Control and Prevention (April 2019). Norovirus
CDC Vitalsigns™ (December 2019). Preventing Norovirus Outbreaks: Food service has a key role.
Fraser, A. (April/May 2019). Cleanup during a Norovirus Outbreak in a Foodservice Establishment. FoodSafety Magazine.
National Restaurant Association Educational Foundation. (2018). 7th Edition ServSafe Manager includes 2017 Food Code Updates.
