So how exactly do fecal particles end up in the hand dryers?
Researchers in CT say using hand dryers can blow bacteria throughout bathroom surfaces and your hands.
Paper towels or the electric hand dryer? These sterile plates were then cultured and 18 to 60 colonies of bacteria were found to grow on them. The results were published this month in the journal Applied and Environmental Microbiology.
Bacterial feces can become "aerosolized" from the flushing of toilets, one of the researchers told Newsweek.
While we might hope bathroom hand dryers are helping to clean and dry our hands, a new study has suggested that they are in fact covering them in poo.More news: Billy Mitchell stripped of all records on Twin Galaxies
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Now imagine a public restroom with many toilets releasing human waste bacteria into the air.
Some hand dryers like those made by Dyson do use HEPA filters. Within a large building, potentially pathogenic bacteria including bacterial spores may travel between rooms, and subsequent bacterial/spore deposition by hand dryers is a possible mechanism for spread of infectious bacteria including spores of potential pathogens if present.
The University of CT added paper towel dispensers to 36 of its bathrooms after completing the study, Newsweek reported.
What's unclear, they admit, is just why the air-blasted plates showed so many more spores. The hand dryers apparently not only blow out hot air, they also "suck in" air that's in the bathroom, the article states. Spore-forming colonies, identified as B. subtilis PS533 averaged ∼2.5-5% of bacteria deposited by hand dryers throughout basic research areas examined regardless of distance from the spore forming laboratory, and these were nearly certainly deposited as spores. But this study showed that adding the filters did not help.