It Could Be a Dirty Idea to Use a Hand Dryer
Written By:Ashish Gaur
17 Sep, 2010 - 06:38pm
It might be better to not wash your hands than using a hand dryer to dry them. According to a study hand dryer are unhygienic and moisture left after partially drying your hands with an electric dryer makes the spread of bacteria more likely. Researchers also concluded paper towels were the most effective means of reducing the risk of infection after washing.
The study was carried out by researchers from the University of Bradford and the Microbiology Department of Dyson Limited. It was published in the Journal of Applied Microbiology. The researchers recruited 14 adult volunteers to take part in their two-part study. In the first part, volunteers were handled with fresh raw chicken and then were asked to wash their hands with an unmedicated liquid soap. They then dried their hands in a variety of ways with conventional warm-air hand dryers, the newer ultra-rapid hand dryer or by allowing the hands to air-dry naturally. After drying, volunteers pressed their fingertips onto sterile foil, and tests were carried out to assess the number of bacteria transferred.
Researchers found that the average amount of bacteria transferred to the foil sheets after the ultra-rapid dryer was lower than after use of the conventional warm-air hand dryers used for 10 seconds or unassisted air drying for 10 seconds. There was no statistically significant difference in bacterial transfer after using the conventional dryers for 10 seconds and air drying hands for 10 seconds. However, using the conventional warm-air hand driers for 30-35 seconds, the levels of bacteria transferred after drying were not significantly different from after using the ultra-rapid dryer.
In the second part, researcher studied whether hand rubbing affected the results of hand washing and drying. This part of the study compared the two conventional warm-air hand dryers (with and without hand rubbing), the newer ultra-rapid hand dryer, and drying the hands with paper towels. The researchers found that people who rubbed their hands while using the conventional hand driers for 15 seconds, fewer bacteria were removed than if they kept their hands still during drying. If the hands were kept still while using the conventional dryers, the amount of bacteria removed was similar to the amount removed using the ultra-rapid drier for all regions of the hand tested.
The researchers concluded that effective hand drying is important to reduce the transfer of remaining bacteria from the hands onto other surfaces after hand washing. They say that rubbing hands during warm-air hand drying removes the benefits of hand washing. According to them faster drying time means that people are more likely to dry their hands, and therefore reduces bacterial spread. But, this study did not compare the amount of bacteria on the hands without any washing and after washing and drying.
Whatever it may be, effective hand washing is very important to reduce the risk of passing on infectious agents, so studies looking at the best way to reduce bacterial transfer are useful.