When it comes to handwashing hygiene, drying your hands doesn’t just remove water, drying your hands should also remove bacteria. That’s why the method you use to dry your hands is very important.
Dr. Karl Kruszelnicki holds degrees in mathematics, biomedical engineering, medicine and surgery. Kruszelnicki, who is best known as an author and science commentator on Australian radio and television, advises readers to use paper towels to dry their hands over warm-air dryers.
“Washing the hands, and then using paper towels or continuous-loop cotton towels reduced the bacterial count by about 45–60 per cent. But washing, and then using a warm-air dryer actually increased the bacterial count by an average of 255 per cent.”
Kruszelnicki claims researchers found bacteria were already inside warm-air dryers, thanks to the warm moist environment. Every single warm-air dryer they tested had high bacterial counts on the air inlet, while 97 per cent had them on the outlet nozzle surfaces as well.
Kruszelnicki warns that warm air blowing over poorly washed moist bacteria-laden fingers in a grimy public toilet is an ideal way to spread bacteria and other germs through the air, in an aerosol of tiny droplets.
Drying your hands removes the bacteria floating in the thin layer of water on your hands. If you just let your hands dry slowly in the air, the bacteria remains on your skin.
According to Kruszelnicki, with a paper or cloth towel you can apply mechanical friction to your hands which is a vital part of the hand-cleaning process.
A towel soaks up the water and the bacteria end up in the bin. You can dry 90 per cent of the surface area of your hand within 10 seconds with a towel. But a warm-air dryer cannot dry your hands within 10 seconds because of the inept and weak wind velocity.
Kruszelnicki says the most important lesson to take from this is to get into the regular habit of washing and drying your hands. Drying your hands on your jeans or hair is better than not drying them at all.
So if you’re using a washroom facility that has no paper towels and only a warm-air dryer, it’s better to dry your hands on your clothes than leave them wet, or use the warm-air dryer.
“Warm-air dryers were NOT installed to improve hygiene. They are purely a cost-cutting measure. Anything else they tell you is a lot of hot air.”
The bottom line is that in most cases our immune systems are resilient enough to keep the numbers of these bacteria low.
“Furthermore, the overwhelming majority of these bugs are fairly harmless. They don’t usually include the real nasties like salmonella, shigella, campylobacter, hepatitis A or B, the SARS coronavirus, or the virus that causes meningococcal disease.”