Colorado State University Extension
SafeFood Rapid Response Network


SAFEFOOD NEWS - Fall 1998 - Vol 3 / No. 1

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Frequent Handwashing... The Best Defense

How significant is cleanliness in foodborne disease prevention? A review of surveillance data for U.S. foodborne disease outbreaks over a five-year period by the Centers for Disease Control and Prevention found that poor personal hygiene was a contributing factor in over a third of those outbreaks for which contributing factors were reported. Clearly, consumers, as the last stop in the progression of food from farm to table, can play an important role in protecting themselves.

But, don't most people wash their hands? Not as often as they think they do, it seems. In a nationwide survey conducted in 1996 by Wirthlin Worldwide for the American Society for Microbiology, 94% of 1,004 respondents claimed they always washed up after using the restroom. However, an observational study of over 6,000 adults in public restrooms in five large cities in the U.S. found that only 68%, in fact, did so. Women were more likely than men to wash after using the restroom (74% versus 61%).

In another study, the Food and Drug Administration found that 20% of those observed did not wash their hands before preparing food and 16% did not wash cutting boards used to prepare raw meat or poultry before they used them to prepare other foods.

Frequent handwashing can even translate into fewer sick days. For example, in one study of 305 Detroit school children, children in those classes where teachers had them wash their hands four times a day (on arrival, before lunch, after recess, and before leaving) had 24% fewer sick days due to respiratory illness and 51% fewer days lost because of stomach upset than did children in classrooms without scheduled handwashing.

For best results, hands should be washed with warm, soapy water for at least 20 seconds before preparing or eating food, after touching raw meat, poultry or fish, after using the restroom, after changing diapers or helping a child at the toilet, after touching a pet, and whenever hands come in contact with body fluids.

Which type of soap is best? In an a recent study, plain, antimicrobial, E2-rated hand soaps (a USDA classification requiring equivalency to 50 parts per million chlorine), and instant hand sanitizers were evaluated for their effectiveness. Results showed that all three types of hand soaps were effective in reducing bacteria on hands when used with a 20-second wash procedure, with the E2 soaps being most the effective. The use of instant hand sanitizers, on the other hand, actually resulted in a significant increase in bacterial numbers on hands.

Sources: 1) Pat Kendall, September 1998, Column on Handwashing, Target of Food Safety Campaign. 2) Miller, et. al., "A Field Study Evaluating the Effectiveness of Different Hand Soaps and Sanitizers," Dairy, Food and Environmental Sanitation, 1994, Vol. 14, No. 3, pp. 155-160.

Updated Monday, August 29, 2011