The research findings are likely to have implications, particularly in the healthcare sector, when it comes to examining the overall cost benefits of replacing paper towel dispensers with warm air hand-driers
, particularly the comparatively recent innovation of "jet-air" driers.
was led by Professor Mark Wilcox of the University of Leeds’ School of Medicine. It found that both warm-air and jet-air driers spread bacteria into the air and on to nearby users.
In the case of jet-air driers, the scientists found airborne germ counts were 27 times higher compared with the air around paper towel dispensers.
To conduct their study, the researchers used an innocuous bacterium known as Lactobacillus
, a bacterium not normally found in public restrooms. The bacteria were used to replicate conditions where hands had been poorly washed.
Tests for Lactobacillus
in the air close to driers after washing and hand-drying had occurred established that the bacterium must have come from test subjects’ hands during drying. Air samples were taken both from the immediate vicinity of hand driers and also at distances of one and two metres away.
These tests showed air bacterial counts close to jet air dryers were four-and-a-half times higher than around warm air dryers but 27 times higher compared with samples of residual air tested after paper towels were used for hand drying. Not only that but the bacteria persisted in the air well beyond the 15 second hand-drying time used in testing. Almost half (48 percent) the Lactobacilli
were collected more than five minutes after drying ended. The researchers also found Lactobacilli
were still present in the air close to hand-driers some 15 minutes after hand drying.
Commenting on the research teams findings, Professor 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.
“These findings are important for understanding the ways in which bacteria spread, with the potential to transmit illness and disease.”
The University of Leeds’ research was funded by the European Tissue Symposium
and was published in the Journal of Hospital Infection and presented at the Healthcare Infection Society
(HIS) International Conference in Lyon, France.