In the Journals

Restroom hand dryers spread more bacteria than paper towels

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November 26, 2014

The use of air-powered hand dryers may spread more airborne bacteria than paper towels, according to data.

Researchers from the University of Leeds simulated restroom hygiene scenarios by contaminating hands with the harmless bacteria Lactobacillus. Participants dried their hands with jet air dryers, warm air dryers and paper towels, before 120 air-samplings were collected and measured in close proximity to and 1 meter away from hand drying.

Airborne bacteria counts after jet air dryer use were the highest (70.7 CFU), reduced with warm air dryer use (15.7 CFU; P=.001), and lowest after paper towel use (2.6 CFU; P<.001). A difference also was seen when towel drying was compared with warm air drying (P=.001).

A similar pattern was observed for counts 1 meter away, while visualization experiments replacing water with paint demonstrated that the greatest liquid dispersal came from the jet air dryer. Forty-eight percent of the bacteria was collected more than 5 minutes after drying, and was still detectable after 15 minutes.

“Next time you dry your hands in a public [restroom] using an electric hand dryer, you may be spreading bacteria without knowing it. You may also be splattered with bugs from other people’s hands,” Mark Wilcox, MD, said in a press release. “These findings are important for understanding the ways in which bacteria spread, with the potential to transmit illness and disease.”

Disclosure: The researchers report no relevant financial disclosures.

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