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Volume 9, 2009

Since its discovery in 1972, human noroviruses have emerged as the most commonly identi-fied foodborne cause of acute gastroenteritis (AGE). In the United States alone, some 23 mil-lion infections are estimated to occur annually, although this number may be grossly under-estimated. Transmission of the virus has been traditionally attributed to the consumption of contaminated food such as oysters, raspber-ries, lettuce and other ready-to-eat products. However, a closer inspection of these reports shows that the actual transmission of the virus may have less to do with food and more to do with person to person transmission.

Dr. Moshe Dreyfuss at Walden University re-cently attempted to determine if noroviruses are strictly foodborne or if they are spread in the same way as pandemic viruses, such as influenza and rotavirus. Nearly 12,000 re-ported foodborne outbreaks registered with the Foodborne Diseases Active Surveillance Network eFORS database between 1998 and 2006 were analyzed to determine the actual source and transmission of norovirus during each outbreak. Just over 23% were attributed to norovirus of which nearly 56% were con-firmed through laboratory diagnosis. The data showed several very interesting and thought-provoking outcomes. Most notably was that norovirus was identified in a food product or food ingredient in only 11% of cases. In contrast, 80% of cases were directly associated with an infected food handler. The other 9% of cases were due to cross-contamination of the virus through environmental surfaces. Another point of interest was the odds ratio (OR) for norovirus outbreaks, which was only 0.45 for food yet 3.40 for food workers. This demon-strates that the cause of an outbreak is approximately 7.5 times more likely to be contact from an infected food handler or from environ-mental transmission than from ingestion of contaminated food.

With the data supporting person to person transmission, Dr. Dreyfuss has proposed a model not unlike that of two known pandem-ic viruses, influenza and rotavirus. All three viruses have similar transmissibility through saliva, vomit or aerosols. As well they are able to survive, for at minimum, several hours in the environment and require low infectious doses to cause infection. Moreover, the fre-quency of infection of norovirus far exceeds the current capacity to accurately detect and track transmission (ironically, this fact has led to the recent decision of the World Health Or-ganization to stop testing specifically for the pandemic H1N1 virus). Thus, Dr. Dreyfuss sug-gests that noroviruses may be better thought of as a pandemic virus than a foodborne one.

The reality is that we may never hear reports of a norovirus pandemic, however, the infor-mation presented by Dr. Dreyfuss does high-light the importance of good environmental and hand hygiene in all areas where food is handled. Proper handwashing or the use of

alcohol based handrubs will effectively remove and/or inactivate the pathogen. In addition, some (but not all) surface disinfectants are effective against norovirus and can prevent indirect spread through environmental surfaces. These interventions have already proven to be effective in stemming the spread of norovirus during the course of outbreak and should be a mandatory component of any food han-dling service. Moreover, the human factor in the spread of norovi-rus can now be put into better focus and the model presented by Dr. Dreyfuss may assist in both increasing and maintaining hygiene compliance amongst food handlers.

References are available upon request.

Should Human Norovirus Be Considered aPandemic Pathogen?Jason TetroCentre for Research on Environmental Microbiology, University of Ottawa

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Influenza is spread from person to person via droplets when coughing or sneezing and by touching objects and surfaces that are con-taminated with the virus (e.g. doorknobs, tele-phones) and then touching their eyes, nose or mouth. The influenza virus may persist for hours in dried mucus and be transmitted by direct contact. It is spread very easily indoors, which is why it is so prevalent in the winter months in northern countries, when people spend more time together inside.

Measures to Reduce the Spreadof Influenza

• Clean hands thoroughly and frequently with soap and water or alcohol-based hand rub, especially after contact with the eyes, nose, mouth or secretions

• Avoid touching your eyes, nose and mouth

• Avoid handling soiled tissues or objects used by an ill person

• Cover coughs and sneezes with a tissue or with your sleeve; throw the tissue in the trash after use and clean your hands

• Get an influenza immunization

• Stay home from work or school when ill and limit contact with others to keep from infect-ing them

• Follow the recommendations of your local public health unit.

There is no evidence to suggest that wear-ing masks will prevent the spread of infection in the general population. Improper use of masks may in fact increase the risk of infec-tion. Masks do not act as an effective barrier against disease when they are worn for ex-

tended periods of time. In addition, removing your mask incorrectly can spread virus to your hands and face. There is no risk of infection from this virus from consumption of well-cooked pork or pork products.

Health Care Settings

In health care settings, Routine Practices should be used consistently with all patients including:

• Hand hygiene before and after all patient contact (hand hygiene information is avail-able on CHICA-Canada’s Hand Hygiene web-site)

• Appropriate use of personal protective

equipment (gloves, masks, eye protection) for contact with all patient secretions/excre-tions

• Disinfection of all equipment which is shared between patients with a disinfectant regis-tered for use against influenza A viruses

• Cleaning/disinfection of all patient contact surfaces after patient leaves an examining room or area with a disinfectant registered for use against Influenza A viruses.

Emergency Departments should apply screening to all patients who present with respiratory symptoms. Laboratory testing for Pandemic H1N1 2009 virus is not recom-mended for patients with mild illness. Speci-mens should only be submitted for testing where lab results are required for clinical man-agement of hospitalized cases of influenza-like illness (ILI) or where patients are at high risk for complications from influenza.

Influenza Prevention and Control MeasuresAcknowledgement to CHICA-Canada www.chica.org

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Does it surprise you that 10 million bacteria can fit on an object as small as a pinhead? And given the right conditions, those 10 million bacteria can double every 20 minutes and spread rapidly. Hands (and the people to whom they belong) are responsible for the dissemina-tion of an estimated 80 per cent of common infectious disease in the community, and 40 percent of food-borne illness.

The Public Health Agency of Canada reports approximately 10 mil-lion people suffer food-related illness each year. The majority of these illnesses last a short time and cause minor symptoms, such as nausea, vomiting and diarrhea. Controlling food-related illness is difficult because bacteria may survive food processing and foods may become contaminated during preparation, cooking or storage. While there are many instances in which food contamination can oc-cur during processing, almost half of all food-borne illness outbreaks are a direct result of hand contamination. For this reason, food safety experts advise hand washing procedures be implemented and strictly monitored. When done correctly, hand hygiene is the single most effective way to prevent the spread of communi-cable diseases.

Correct hand hygiene requires proper pro-tocol, an appropriate hand washing or cleansing agent, and compliance. High risk areas, for instance where food is processed or prepared, require the strictest level of compliance.

To effectively cleanse hands:• Place hands under water and apply soap;• Rub hands together for at least 15 seconds; • Wash hands thoroughly, including wrists, palms, back of hands and under fingernails, removing all dirt;

• Rinse with potable water from wrist to fingertips;• Dry hands completely with clean, good quality, absorbent paper

towel as it helps remove germs. Rather than rubbing, pat skin dry to avoid chapping and cracking.

ProtocolWhile common sense dictates hands should be washed before han-dling food, there are many other occasions when hands must be

washed when working in a food processing environment. This in-cludes after touching body parts; using a restroom; coughing, sneez-ing or using a tissue; changing tasks, especially if switching between working with raw meat and ready to eat or cooked foods; handling money, garbage, tools or equipment; touching dirty surfaces; pick-ing up something from the floor; and engaging in any activity that contaminates hands.

AgentWhen soap and water are not available or hands are not visibly soiled, use an alcohol-based hand sanitizer to cleanse hands. In ad-dition to improved spreadability, foaming formulations have been shown to provide superior compliance and efficacy. When combined with hand washing, the effectiveness of alcohol hand sanitizers is in-creased and can reduce the risk of infection by, on average, 20 to 40 per cent.

ComplianceEducation and training are vital to the success of a good food safety program. In any orga-nization, regardless of size, the instructor must ensure all em-ployees understand the basic principles of food safety as well as their responsibility in keeping food safe.

Food handling staff should receive additional instruction in personal hygiene and be required to undergo a test of their knowledge on the subject. Refresher courses should be given periodically. Also, par-ticular attention should be drawn to the need to report illness to a supervisor as soon as it occurs.

Although most people recover, the Canadian Partnership for Con-sumer Food Safety Education reports food-borne illness can result in chronic health problems in two to three per cent of cases. Health Canada estimates the annual cost related to these illnesses is as high as $14 billion and growing. The good news is infection control prac-tices and programs are not difficult to implement and manage and are proven to work. When it comes to food safety and reducing the risk of food-borne illness, education and awareness remains the best defense.

Hand Hygiene in the Food IndustryChristian DesRoches, Regional Sales Manager, Deb Canada

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Deb Canada eLearning

Influenza Prevention- Is Your Business Ready?Watch a 6-minute presentation on Influ-enza Prevention strategies for your work-place.

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Hand Washing For Kids!This 2-minute video helps teach kids the importance of hand washing and proper technique. For more information and resources, visit the Education Learning Zone section of this web site.

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Infection Control in the WorkplaceWatch a presentation on infection con-trol in the workplace practices.

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Point of Care eLearningWatch a presentation on infection con-trol in the healthcare environment.

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Deb Food IndustrySkin Safety ProgramWatch a presentation on the Deb Food Industry Skin Safety Program.

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Available through the Learning Zone at www.debgroup.com