BARFBLOG: Handwashing for nerds: Are those Dysan jet dryers better than paper towel?

12.nov.09
barfblog
Doug Powell

Amy, Sorenne and I spent a long last weekend in San Francisco, where Amy
conferenced, I had some meetings, but mainly just hung out with the kid
(three pirates and a little girl, right).
The washrooms at the San Francisco airport featured the Dysan airblade,
billed as the "fastest, most hygienic hand dryer." Says so right on the
machine. And it's certified by NSF as "tested, certified, hygienic."
Says so right on the machine.
My bowels are in a state of flux when traveling so I had several
opportunities to try out the newfangled machinery, that sounds like an
airplane is taking off below your fingertips.
We have maintained, based on our reading of the available literature,
that proper handwashing, entails:
* wet hands with water;
* use enough soap to build a good lather;
* scrub hands vigorously, creating friction and reaching all areas of
the fingers and hands for at least 10 seconds to loosen pathogens on the
fingers and hands;
* rinse hands with thorough amounts of water while continuing to rub
hands; and,
* dry hands with paper towel.
Water temperature is not a critical factor -- water hot enough to kill
dangerous bacteria and viruses would scald hands -- so use whatever is
comfortable.
The friction from rubbing hands with paper towels helps remove
additional bacteria and viruses. 
I did a cursory search to find some data on the Dysan thingy, and found
a study comparing paper towel, regular blow dryers, and a Dysan-type jet
dryer that was published in 2008.
Those authors state:
"The jet air dryer showed that there were significant differences
(although not as great as for the fingerpads) between the towels and
both types of dryer. Again, the superior performance of the towels in
reducing bacterial numbers was confirmed. As for the fingerpads, the jet
air dryer performed better than the warm air dryer in not increasing
mean bacterial count on the palms as much but this difference was not
significant.
"Therefore, the manufacturer's claim that the tested JAD is the "most
hygienic hand dryer" is confirmed, especially for fingerpads and
assuming that the term "hand dryer" refers to electric devices only
because its performance in terms of the numbers of all types of bacteria
remaining on the hands of users compared to paper towels was
significantly worse. ...
"It is well known to microbiologists that air movements encourage the
dispersal and transmission of microorganisms and increase the chances of
the contamination of materials or persons in any situation. This makes
paper towels, where little air movement is generated, the most hygienic
option tested in this respect followed by the warm air dryer and,
lastly, the jet air dryer."
The friction from rubbing with paper towel is particularly effective at
reducing microbial populations; yet many of these public bathrooms have
signs proclaiming that electric dryers of whatever kind are better, and
save the trees. Oh, and I should hear from someone at Dysan or NSF -
public claims need to be backed with public data.
Maybe I'll just stay at home.
http://en.wikipedia.org/wiki/Dyson_Airblade
http://www.europeantissue.com/Files/positionpapers_and_studies/090402-2008%20WUS%20Westminster%20University%20hygiene%20study,%20nov2008.pdf
http://barfblog.foodsafety.ksu.edu/2008/02/articles/handwashing/dude-wash-your-hands/