New research by the University of Westminster, commissioned by ETS, the European Tissue Symposium, suggests that single use towels are the most hygienic way to dry hands after visiting the washroom. Despite a trend for sophisticated drying machines in recent years it appears that traditional single use towels offer an unsurpassed level of hygiene when drying hands after visiting the washroom.
The study was undertaken by leading microbiologist Keith Redway and looked at the potential for microbial contamination from hand drying and the potential risks for the spread of microbes in the air, particularly if hands are not washed properly.
Public health concern
“These findings clearly indicate that single-use towels spread the fewest microbes of all hand-drying methods,” said Keith Redway. “Cross contamination in public washrooms is a legitimate public health concern. The extent to which jet air dryers disperse microbes into the washroom environment is likely to have implications for policy guidance to facilities managers operating in a wide range of environments from sports venues and airports through to schools and hospitals.”
Paper towels, a textile roller towel, a warm air dryer and a jet air dryer were compared using three different test models: acid indicator using lemon juice, yeast, and bacterial transmission from hands when washed without soap.
The University of Westminster scientists found that the jet air dryer spread liquid from users’ hands further and over a greater distance – up to 1.5 m – than the other drying methods. They also recorded the greatest spread of microbes into the air at both near and far distances for each of the tested models.
Levels recorded at close distance for a jet air dryer revealed an average of 59.5 colonies of yeast compared with an average of just 2.2 colonies for paper towels. At a distance of 0.2 m the jet air dryer recorded 67 colonies of yeast compared with only 6.5 for paper towels. At a distance of 1.5 m the jet air dryer recorded 11.5 colonies of yeast compared to zero for paper towels.
Spread of microbes affecting adults and children
The peer-reviewed study also looked at the body height at which microbes were spread by air dryers. It found the greatest dispersal was at 0.6 – 0.9 m from the floor. This is worrying since it equates to the face height of small children who might be standing near the dryer when a parent is drying his or her hands.
This suggests that parents should take care to keep children away from the direct air stream of jet air dryers in washrooms to ensure that they are not unintentionally contaminating youngsters.
- Due to their air flow, electric hand dryers show a greater potential for the dispersal of microbial contamination on the hands at different heights and to greater distances than towels; a jet air dryer showing the greatest potential.
- The visualization of the air flow from a jet air dryer helps explain the results of this study. Claimed air speeds for jet air dryers of over 600 kph are likely to increase the risk of transmission of viruses and other microbes from the hands of users to other occupants of public washrooms and into the washroom environment.
ETS is the European Tissue Paper Industry Association. The members of ETS represent the majority of tissue paper producers throughout Europe and around 90% of the total European tissue production. ETS was founded in 1971 and is based in Brussels.
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