FEATURE


epidemic, then that contamination is going to be in the air for at least 15 minutes – and some viruses are very infectious, you only need 10 particles for infection.


“With warm air dryers and paper, there was much less contamination in the air. There was some, that’s inevitable, but it was very low over the whole time period.”


While the research makes some interesting points regarding the dispersal of germs, there is a school of thought that would argue that, in an ideal world, if people washed their hands properly then there wouldn’t be quite as much of a spread, as there would be less bacteria on the hands to begin with.


However, as Keith pointed out: “unfortunately a lot of people don’t wash their hands at all well.


“You’re supposed to take ‘x’ number of seconds to wash your hands, but often it’s just a cursory thing so people can tell themselves that they’ve washed their hands and that they’re a hygienic person.”


Another argument suggests that, as one of the main ways in which germs are transferred is through contact, either from person to person or via a surface, one of the easiest ways to spread these germs is through having wet hands. Therefore if your hands are dried properly, the contamination risks are reduced. Keith does agree with this point, and admits that when it comes to physically drying the hands, paper and jet air dryers are on a par.


He explained: “When the jet air dryers first came out, I tested them for how efficient they were at drying the hands, and I was very impressed. They produced 95% dryness – and you never get 100% – in 10 seconds, which is the same as you’d get with paper.


“It’s good, because if the hands aren’t dried properly they’ve got more chance of transferring contamination and infection, but there’s more to it than just getting hands dry.”


Keith added that while they may be efficient at drying hands, more problems can arise if the jet air dryers are used incorrectly. “A lot of the public


56 | Tomorrow’s Cleaning June 2016 IN THE WASHROOM AFTER HAND DRYING POTENTIAL FOR VIRUS DISPERSAL MS2 bacteriophage virus WWW.EUROPEANTISSUE.COM AVERAGE TOTAL NUMBER OF VIRUS PARTICLES AT DIFFERENT DISTANCES JET AIR DRYER VIRUS PARTICLES 3005 1.00 m 2.00 m 3.00 m 1.00 m AVERAGE TOTAL NUMBER OF VIRUS PARTICLES AT DIFFERENT HEIGHTS JET AIR DRYER VIRUS PARTICLES 2219


Height in metre 1.65


1.35 VIRUS PARTICLES 34 0.45 0.15


Average total number of viral particles on 90 mm agar plates of a bacterial lawn at a set height and at different distances from hand-drying devices used to dry the hands of participants after contamination with a bacteriophage suspension.


WARM AIR DRYER VIRUS PARTICLES 104 2.00 m 3.00 m 1.00 m WARM AIR DRYER


Height in metre 1.65


1.35 VIRUS PARTICLES 2 0.45 0.15 PAPER TOWEL VIRUS PARTICLES 15 2.00 m 3.00 m


Average total number of viral particles on 90 mm agar plates of a bacterial lawn at different heights at a set distance from hand-drying devices used to dry the hands of participants after contamination with a bacteriophage suspension.


PAPER TOWEL


Height in metre 1.65


1.35


0.45


0.15


HAND DRYING IS AN IMPORTANT PART OF HYGIENE Average total number of virus particles counted in air after 15 minutes: JET AIR DRYER 44 VIRUS PARTICLES WARM AIR DRYER 0.8 VIRUS PARTICLES PAPER TOWEL 0.4 VIRUS PARTICLES


A 2008 study by the University of Westminster showed that paper towel and a Jet Air Dryer were equally efficient at drying the hands of users, all of them achieving 90% dryness in approximately 10 seconds. However, the results showed that a Warm Air Dryer was considerably less efficient (i.e. slower) than paper towel or the Jet Air Dryer and took over 4 times as long to achieve 90% dryness of the hands. Redway K.F. & Fawdar S. (2008) A comparative study of three different hand drying methods: paper towel, warm air dryer, jet air dryer.


Kimmitt, P.T. & Redway, K.F. (2016). Evaluation of the potential for virus dispersal during hand drying: a comparison of three methods. Journal of Applied Microbiology. 120, 478-486.


seem to think that the jet air dryers are more hygienic because you don’t touch anything, but what they don’t appreciate is that things spread in the air. But even with that, we’ve sampled the surface areas and they’re heavily contaminated.


“Although if you use them correctly you don’t touch anything, a lot of people do – particularly if they’re in a rush.


“I’ve done a few observations in Euston station where people are rushing to catch a train and you see them touching the bottom. We did some studies with a fluorescent dye, where we put the dye on people’s hands and showed that they did touch the insides quite frequently, so there is a contamination risk there.”


So while the results of Keith’s study point to paper towels as the most hygienic method of drying hands, Keith has stressed that his research is predominantly for the more sensitive environments, where the risks of infection are higher.


He said: “One of the criticisms of this study is that we used artificial contamination of the hands at quite a high level, but it’s been shown that sometimes that will occur, particularly with people that have had diarrhoea and fecal contamination, and they haven’t washed it properly.


“But I’d emphasise that the study is a model, and what it is showing is the


potential risks. We’re quite careful to say that we don’t want to ban jet air dryers completely, but they shouldn’t be in sensitive locations where cross- infection is particularly important – that would be hospitals, clinics, food preparation areas, restaurants, possibly schools and care homes.”


Although the study itself was independently carried out by the University of Westminster, the findings have been greeted with a positive reaction from the European Tissue Symposium (ETS). Following the publication of the findings, Roberto Berardi, Chairman of the ETS, said: “Our industry places great emphasis on hygiene and studies have consistently shown that single use towels offer the most effective way to limit the spread of microbes in the washroom.


“This latest research not only focuses on viruses for the first time, but it was also undertaken, independently from ETS, by microbiological experts at the University of Westminster and thus serves to further, autonomously, underline our message.”


It remains to be seen whether the latest research from Keith and his team will spark some kind of response from jet air dryer manufacturers, but one thing is for sure – the debate certainly shows no sign of slowing down just yet.


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