Colorado State University Extension
SafeFood Rapid Response Network
SAFEFOOD NEWS - Spring 2000 - Vol 4 / No. 3
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Effectiveness of Different Handwashing Regimens
A study published in the October 1999 issue of Dairy, Food and Environmental Sanitation examined the effectiveness of four different handwashing regimens at reducing a transient marker microorganism (E. coli) from hands.
The researchers worked with 20 people to evaluate four different configurations of products intended for use in hand cleansing, 5 subjects per regimen. The regimens consisted of the following:
- non-antimicrobial lotion soap (DermaPro®)
- an alcohol gel hand sanitizer (Purell®)
- an antimicrobial lotion soap (Micrell®)
- an antimicrobial soap plus application of an alcohol gel hand sanitizer (Micrell® and Purell®)
This study evaluated each handwashing regimen for its effectiveness at demonstrating immediate reduction of transient microorganisms (E. coli) as well as potential for further reductions with multiple applications. All four regimens were found to significantly reduce E. coli populations from the baseline values.
| Log Reductions from Baseline (E. coli) | ||
| Regimen | Baseline | Reduction from Baseline |
|---|---|---|
| 1 | 8.4 | 2.1 |
| 2 | 8.2 | 2.2 |
| 3 | 8.5 | 1.9 |
| 4 | 8.2 | 3.3 |
The most effective regimen, which demonstrated a high immediate reduction of the E. coli, with the potential for further reductions with multiple applica-tions, was the 2-step wash in which the antibacterial soap was followed by the hand sanitizer.
While the study suggests that antimicrobial soaps and alcohol gel hand sanitizers are effective methods to microbial control, they were no more effective than mechanically removing microorganisms from hands during handwashing with non-antibacterial soap.
Frequent handwashing with warm soapy water is one of the simplest and most effective steps to preventing foodborne illness. Regardless of the type of soap or method used, the most important point is to increase the number of people who wash their hands.
Note that in this study the participants using the alcohol gel hand sanitizer put on 2 applications per washing cycle and were instructed to allow their hands to dry for five minutes before sampling for micro-organisms -- probably not a practice easily duplicated in retail settings.
Source: Dairy, Food and Environmental Sanitation, Vol. 19, No. 10, pp. 680-684.
Updated Monday, August 29, 2011
