Colorado State University Extension
SafeFood Rapid Response Network
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Hand Hygiene Revisited: Another Look at Hand Sanitizers and Antibacterial Soap
Edited by: Mary Schroeder, M.S., R.D. & Pat Kendall, Ph.D., R.D., Colorado State - Spring 2004
Typically, people carry between 10,000 and 10 million bacteria on each hand. We all know the importance of good hand washing in reducing harmful microorganisms on the skin, but what about those times when there is no access to hand washing facilities or not enough time to wash thoroughly? Can a hand sanitizer (alcohol gel) serve as a suitable alternative to hand washing?
How do hand sanitizers work?
Hand sanitizers (alcohol gels) have gained popularity because they are convenient and easy to use. The majority of hand sanitizers contain ethanol or isopropanol, or a combination of these two products. Most brands also contain a moisturizer to minimize irritation to the skin. Alcohol works immediately and effectively to kill bacteria and most viruses. Solutions containing 60-95% alcohol are most effective. Higher concentrations are less potent because proteins are not denatured easily in the absence of water. Alcohol gels work by stripping away the outer layer of oil on the skin, thereby destroying any "transient" microorganisms present on the surface of the hands. After use, re-growth of bacteria on the skin tends to occur slowly, thereby effectively keeping "residual" micro-flora that reside in deeper layers of skin from coming to the surface. To be most effective, a dime-size dollop of alcohol gel should be rubbed into the hands for 30 seconds. If hands are dry after only 10-15 seconds, it is likely that not enough sanitizer was used.
A Substitute for Handwashing?
Research has shown that hand sanitizers can be as effective as hand washing only in certain situations. The type of soil which may be present on hands can significantly alter their effectiveness. Because dirt, food or anything else on your hands can make the alcohol less effective, it is important to first wash hands with soap and water. Some confusion has occurred as a result of the 2002 Centers for Disease Control and Prevention (CDC) guidelines "recommending alcohol-based gel as a suitable alternative to hand washing for health-care personnel in health-care settings." Because many healthcare workers routinely must clean their hands multiple times per hour, the use of alcohol gels while moving between patients has been shown to favorably impact hand-cleansing adherence by staff due to time saved over traditional hand washing methods. However, the guidelines apply only to hospitals and clinics. These are not appropriate for and do NOT apply to those in foodservice settings.
Food Establishments vs. Healthcare Settings
The CDC guidelines for hand hygiene in healthcare settings do not apply to those in foodservice primarily because the types and levels of soil on the hands are quite different. The types of pathogens most commonly transmitted by hands in health-care settings (primarily lipophilic, nosocomial pathogens) differ from those in retail and food-service settings, where fecal bacteria and enteric non-lipophilic viruses, such as Norovirus are more of a concern. Food workers often have wet hands and hands contaminated with proteinaceous and/or fatty materials, which can significantly reduce the effectiveness of an alcohol gel. Therefore, soap, friction and running water still remain most effective in removing the types of pathogens food workers might encounter. Both the FDA Model Food Code and the Colorado Retail Food Establishment Rules and Regulations make the provision that hand sanitizers may be used by food workers in addition to, but not in place of proper hand washing. Because hand sanitizers are considered to be a food additive, only products approved by the FDA can be used.
Antimicrobial Soaps
Now let's throw antimicrobial soaps into the mix. How do they rate over plain soap and water or alcohol gels? Antimicrobial soaps contain an antiseptic agent to help lower the number of microbial flora. Triclosan is the most commonly used chemical ingredient in antimicrobial soaps. A key factor in its effectiveness is that it must be left on the skin long enough to work, as in a good 30-45 second scrub. Companies have not published information on what combination of triclosan concentrations and washing times are most effective, so it is difficult to know which brands work best. Also, there is concern that use of antimicrobial soaps may lead to bacterial resistance. While in theory this remains possible, research thus far has not found evidence that this is happening.
General Public
At home, plain soap and water is adequate for most consumer uses. There are situations, however, when antiseptic hand products are advised. Elaine Larson at the Columbia University School of Nursing in New York recommends taking the extra precaution of using an alcohol gel or antibacterial soap for those in the following situations:
- Close physical contact with persons at high risk for infection (such as newborns, the very old, or immunosuppressed);
- Direct physical contact with someone having an upper respiratory infection, skin infection or diarrhea;
- Work settings where infectious diseases are commonly transmitted, such as child-care centers, preschools, prisons or chronic-care residences.
Bottom Line
Hand washing guidelines for healthcare workers should not be confused with recommendations for food workers or the general public. For everyone, washing hands with soap and water (whether plain or antimicrobial) is still a must. Hand sanitizers should primarily be used only as an optional follow-up to traditional hand washing with soap and water, except in situations where soap and water are not available. In those instances, use of an alcohol gel is certainly better than nothing at all.
Sources:
- Hand Hygiene in Retail & Food Service Establishments. FDA/CFSAN Food Service Safety Fact Sheet. May, 2003. vm.cfsan.fda.gov/~comm/handhyg.html.
- CDC Guideline for Hand Hygiene in Healthcare Settings. Morbidity and Mortality Weekly Reports (MMWR) October 25, 2002.
- Larson, E. Hygiene of the Skin: When is Clean Too Clean? Emerging Infectious Diseases. Vol.7, No.2 Mar-Apr 2001.
- Paulson, D.S. Comparison of Hand washing Products. Dairy, Food and Environmental Sanitation. 14: (9):524, 1998.
