Scientists from the University of Leeds have found that high-powered jet-air and warm air hand dryers can spread bacteria in public restrooms. Airborne germ counts were 27 times higher around jet air dryers in comparison with the air around paper towel dispensers.
The research team, led by professor Mark Wilcox of the School of Medicine, contaminated hands with a harmless type of bacteria called Lactobacillus, which is not normally found in public bathrooms. This was done to mimic hands that have been poorly washed. Subsequent detection of the Lactobacillus in the air proved that it must have come from the hands during drying. The experts collected air samples around the hand dryers and also at distances of one and two metres away.
Air bacterial counts close to jet air dryers were found to be 4.5 times higher than around warm air dryers and 27 times higher compared with the air when using paper towels. Next to the dryers, bacteria persisted in the air well beyond the 15 second hand-drying time, with approximately half (48 percent) of the Lactobacilli collected more than five minutes after drying ended. Lactobacilli were still detected in the air 15 minutes after hand drying.
Wilcox notes, “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. These findings are important for understanding the ways in which bacteria spread, with the potential to transmit illness and disease.”
The research, funded by the European Tissue Symposium, was published in the Journal of Hospital Infection and presented at the Healthcare Infection Society (HIS) International Conference in Lyon, France.
A spokesman for Dyson, which makes jet hand dryers, said: “This research was commissioned by the paper towel industry and its flawed. “They have tested glove covered hands, which have been contaminated with unrealistically high levels of bacteria, and not washed.”