PLANNING MATERIALS
Ecolab Customers, please contact your Ecolab representative to request helpful planning materials such as:
- Cleaning Procedures to help minimize risk
- Product Suggestions
If you are not currently an Ecolab customer, contact Customer Service.
Background
Noroviruses (previously known as Norwalk-like viruses) are widely known for causing outbreaks of illness among large numbers of people on cruise ships. Since the original Norwalk virus was identified in 1968, there has been increasing recognition of norovirus as an agent of viral gastroenteritis traced to restaurants and catered meals, nursing homes, schools and camps. The Centers for Disease Control and Prevention (CDC) estimate that at least 50 percent of foodborne outbreaks in the United States are attributed to norovirus with 10 percent from cruise ships, 36 percent in restaurants and catered meals, 23 percent in nursing homes, and 13 percent in schools. While the source of a majority of cases is unknown, foodborne (source of 39 percent of cases), water (3 percent of cases) and person-to-person spread (12 percent of cases) may be involved.1 Norovirus is also an increasingly common cause of gastroenteritis outbreaks in Europe2 and other countries.
Symptoms and disease process
Noroviruses cause acute gastroenteritis: nausea, frequent and violent vomiting, and/or diarrhea. Other symptoms include low-grade fevers, chills, headaches, muscle aches and fatigue. Onset occurs in as little as 12 hours from exposure, but commonly takes 24 to 48 hours after ingesting the virus. The illness usually lasts one to two days, and in most cases recovery occurs without problems unless the person becomes dehydrated from the illness. This is a higher risk in very young, elderly or immunocompromised persons.
Noroviruses are extremely contagious due to the low infectious dose of as few as 10 to 100 viral particles. This means that low-level contamination of food and water can lead to outbreaks. People may infect others by shedding the virus from the time they start feeling ill until at least three days – and possibly up to 2 weeks – after recovery. There are presently no vaccines to prevent infections and no antiviral medicines available that treat norovirus infection. The Center for Infectious Disease Research and Policy provides additional information of clinical interest on symptoms and disease.3
Primary routes of transmission
Noroviruses are present in feces or vomit of infected people at very high levels (millions per gram), which is why it is essential that ill people are prohibited from handling food. Most foodborne outbreaks of norovirus illness are likely caused by direct contamination of food by a food handler before its consumption. Norovirus particles can be carried by aerosols over distances longer than three feet to land on surfaces.4 Others may become ill by touching these contaminated surfaces and then touching their mouths, or having direct contact with an infected person.
Outbreaks have frequently been associated with consumption of ready-to-eat foods, including various salads, sandwiches and bakery products. Liquid items (e.g., salad dressing or cake icing) that allow the virus to mix evenly have also been implicated as a cause of outbreaks. Additionally, food can be contaminated at its source, as oysters from contaminated waters have been associated with widespread outbreaks of gastroenteritis. Other foods, including raspberries and salads, have been contaminated before widespread distribution and subsequently caused extensive outbreaks.5 A large norovirus outbreak, likely involving person-to-person spread, impacted more than 1,000 people in the Houston Astrodome when it housed Hurricane Katrina evacuees. Inadequate sanitary conditions, the lack of adequate hand-washing facilities, delays in cleaning and decontaminating soiled areas and bedding, and close proximity of people contributed to the spread.6
Norovirus cannot be detected by standard culture methods, but only by more complex techniques such as microscopic examination or by polymerase chain reaction, so researchers have used feline calicivirus as a surrogate in studies that examine inactivation techniques.
Control
The primary control of norovirus relies on the exclusion of ill individuals from food and hospitality settings. Food handlers who have recently recovered from norovirus illness should be given non-food handling tasks.
Normal cleaning and sanitizing procedures are typically not sufficient to inactivate the virus; rather, aggressive disinfection protocols are needed. Prompt attention to disinfection is needed to reduce the magnitude of norovirus outbreaks. For cleanup of vomitus or other body excretions, personal protection equipment and a biohazard clean-up kit is very useful to minimize further spread of the virus.
In general:
- Cover material with tissue or paper toweling until clean-up detail arrives.
- Wear disposable gloves and face mask when cleaning the spill.
- Follow Biohazard Clean-up Kit instructions:
- Sprinkle adsorbent material on body fluids.
- Pick up with scoop and place in disposal bag.
- Apply a properly registered disinfectant per label instructions.
- Wash hands thoroughly after removing protective equipment.
Hand hygiene is critical to help prevent and control of virus outbreaks. This is a primary transmission mode and must be judiciously implemented. Washing well and often is the best control. The CDC recommends use of an alcohol-based hand sanitizer7 along with hand washing using the following procedure8:
- Wet your hands with warm water.
- Apply a generous amount of soap.
- Rub hands together for 20 seconds.
- Rinse hands.
- Dry hands with a paper towel
- Use the paper towel to turn off the faucet and open the door.
Food items that may have become contaminated with norovirus should be immediately discarded. The virus does not multiply in foods or in the environment, but can persist on contaminated surfaces and survives freezing. Norovirus is also relatively heat stable, though cooking foods to 70°C (158°F) for five minutes or boiling for one minute was shown to destroy feline calicivirus,9 the surrogate for norovirus.
For assistance with this topic or other food safety questions for your operation, please Contact Us.
References and Further Information
1Centers for Disease Control and Prevention specific information on Norovirus
2Lopman BA, Reacher MH, van Duijnhoven Y, Hanon F-X, Brown D, Koopmans M. Viral gastroenteritis outbreaks in Europe, 1995-2000. Emerg Infect Dis. 2003 Jan
3Center for Infectious Disease Research and Policy (CIDRAP) information of clinical interest
4Siegel JD, Rhinehart E, Jackson M, Chiarello L, and the Healthcare Infection Control Practices Advisory Committee, 2007. Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings, June 2007. http://www.cdc.gov/ncidod/dhqp/pdf/isolation2007.pdf
5MMWR, June 2001; Vol. 50, No. RR-9:1-18.
6MMWR, Oct 14, 2005; Vol 54(40);1016-1018
7CDC - Norovirus
8CDC - Handwashing
9Doultree, J.D., J.D. Cruce, C.J. Birch, D.S. Bowen, and J.A. 1999. Marshall. Inactivation of Feline Calicivirus, a Norwalk virus surrogate. Journal of Hospital Infection 41:51-57.
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