91快活林

Despite the rising popularity of hand dryers in public restrooms the research shows traditional paper towels do the job better – and leave behind less bacteria.

The scientists are now calling on hospitals and other health care facilities to consider withdrawing air dryers altogether.

The research was conducted by Biomedical Science BSc(Hons) graduate Samantha Crockett, now  Senior Quality Assurance Microbiologist with GlaxoSmithKline, and Biological Sciences BSc(Hons) graduate Gregory Andreou, a microbiologist at Industrial Microbiological Services Limited. They were led by Dr Sarah Pitt, Principal Lecturer in the university’s School of Pharmacy and Biomolecular Sciences in Moulsecoomb, 91快活林.

It concluded that paper towels were more effective and efficient although they may have a larger carbon footprint than air dryers – the paper goes through a recycling process, is recycled and supplies are regularly being transported by road. Dryers, once fitted, need electricity but little maintenance.

The research was conducted when the graduates were studying at the university and their findings have been published in The Journal of Infection Prevention.

Samantha Crockett

Gregory Andreou

Dr Pitt said: “Hand hygiene is a key tool in infection control and while methods of hand washing have been widely researched, there have been fewer studies investigating the effectiveness of available ways to dry hands in public areas. 

“Our study compared the efficacy of using paper towels, warm air dryers and jet air dryers after hand washing in terms of microbiological effectiveness and potential for dispersal of pathogens.” 

Microbial flora on palms and fingertips of 30 volunteers were sampled on nutrient agar plates (which grow colonies of bacteria) before washing hands and after drying with the three methods.

Total colony forming units were recorded and the walls around the three dispensers and dryers in female and male washrooms were also sampled for the presence of viable microorganisms.

The results were stark: Volunteers using paper towels were tested before washing and after drying and the result showed a marked reduction in bacteria, whereas there was a marked increase in bacteria using air dryers. Those using jet dryers showed no marked change.

In scientific terms, the results showed that colonies were “significantly reduced” after drying with paper towels but were “significantly increased” after using warm air dryers, and there was no difference with jet air dryers.

Dr Pitt said: “Some dispersal of organisms was detected on the washroom walls, with the least distribution around paper towel dispensers and there were unusual opportunistic pathogens (microorganisms that can cause disease) isolated from inside the jet air dryers.

“The conclusion is that paper towels are more effective at drying hands than warm air dryers and jet air dryers, they are more likely to be used appropriately and they lead to minimal dispersal of microorganisms from wet hands. 

“That is why we would recommend hospitals, in particular, should consider switching from air dryers to paper towels.

Dr Sarah Pitt

“The results show that while hand washing is important in reducing transmission of potentially pathogenic microorganisms, it is also vital that hands are dried properly. This study supports the idea put forward by previous authors that paper towels are the best hand drying method. The reasons for this are because they provide the most effective means to dry hands in microbiological terms and drying is likely to be carried out properly without need for special instructions.

“In addition, paper towel dispensers minimise the spread of organisms from wet hands during the drying process.

“However, using hand towels can be seen as wasteful (even when the paper is recycled) and jet air dispensers in particular have been shown to have a lower carbon footprint.

“Paper dispensers must be replenished regularly, which requires ordering of towels and employing a person to do it. This could be perceived as costly and there is a risk of some time periods when no towels are available.

“And an air dryer should not need daily checks, so may be preferred in a healthcare setting. However, in a busy environment, professionals and patients may not take sufficient time to dry their hands adequately which may contribute to the spread of infection. Therefore, the conclusion of these findings are that paper towels are preferable in public health terms.”