A study conducted by the University of Westminster in London reported that warm air hand dryers increase bacteria counts by up to 254 per cent, as well as contaminating the surrounding area with bacteria too. The study assessed warm air hand dryers, paper towels and the latest models of ‘jet’ hand dryers, with all three producing radically different results.

Of the three, the most successful method was to use paper towels, with a reported reduction of up to 77 per cent of hand bacteria. The researchers also commented that paper towels will not spread bacteria around the room in the way that air hand dryers will.

“The superior performance of paper towels over the two types of dryer in reducing the numbers of bacteria was shown with both the finger pads and the palms of the subjects,” said Keith Redway, lead author.

“Using paper towels results in a significant decrease in the numbers of bacteria on the hands, a clear advantage compared with the increases observed for both types of electric hand dryer tested in this study,” added Redway. “In addition, paper towels are far less likely to contaminate other washroom users and the washroom environment.”

By far the worst method was the traditional design of warm air hand dryer which increased palm bacteria counts by up to 254 per cent and finger tip counts by 194 per cent. The newer design of jet air hand dryers increased finger tip bacteria counts by 42 per cent and palm counts by 15 per cent, much less than the older designs of hand dryer, but still an increase.

The concern is that users will leave washrooms with a greater amount of bacteria, like Staphylococcus aureus which causes food poisoning, on their hands than when they entered, with serious consequences for workers in the food industry, or health care.

“The presence of any type of Staphylococcus aureus on the hands of a worker in the food industry or medical field should be taken seriously as should any increase in its numbers caused by particular hand drying methods,” concluded Redway.

Image: Steve Johnson/ Flickr

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