Ewww. Hand-dryers spread 27 times more bacteria than towels

Modern electric hand-dryers spread much more bacteria in public toilets than handtowels, according to British researchers. The University of Leeds team found the latest generation of “jet-air” dryers are far worse for spreading germs than the older, less-powerful “warm-air” models.

The researchers carried out detailed tests where they placed some harmless Lactobacillus bacteria on the hands of volunteers in public bathrooms, who then washed their hands. Later, they collected air samples to measure the germ count around the hand-dryers and the paper-towel rolls used by other volunteers to test the difference.

The bacterial counts from jet-air dryers were 4½ times higher than around warm-air dryers, but 27 times higher compared with the air circulating in the bathroom when paper towels were used.

Prof Mark Wilcox said: "Next time you dry your hands in a public toilet 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."

Increased dispersal of germs could play a role in worsening flu or novovirus outbreaks, along with the passage between people of Staphylococcus aureus and Escherichia coli.

Faster transmission “would appear to be more likely with jet-air dryers, particularly if these shower droplets towards the face of the user, although the magnitude of risk remains unclear”. Most worryingly, say researchers, the bacteria lingered in the air long after the volunteer had finished the usual 15-second drying time.