A Carlsbad woman did a little science experiment in a public bathroom that has people stunned.
Nichole Ward claims on her Facebook page that she put a Petri dish under a hand dryer in a public bathroom for a period of three minutes. She said three days later, an alarming amount of microorganisms grew.
On Thursday, the Carlsbad mom told NBC 7 on the phone she conducted the experiment as a microbiology student, after her professor told the class to put a Petri dish in a place of their choosing for a few minutes. She chose a hand dryer in a Carlsbad restroom.
"And you think you’re walking out with clean hands," Ward wrote in her Facebook post.
The photo posted shows the Petri dish filled with giant globs of cultures that are held with blue rubber gloves.
"This post is simply for awareness not to instill fear," she added.
As of Thursday, the post had been shared over 550,600 times. It had 143,000 likes and dozens of comments.
Horrified Facebook users commented that it was gross and eye-opening.
NBC 7 asked experts about the contents of the Petri dish, and whether people should be alarmed based on what was shown in the picture.
"I can tell you that hand dryers can be very unsanitary as they blow bacteria from hands all over the bathroom," said Tracey Brown, professor of biology at Cal State University San Marcos. From what I know, the most sanitary way to dry is actually to use paper towels to completely dry your hands as the rubbing action helps (after washing correctly of course) dislodge bacteria."
Victor Nizet, MD, a professor and infectious disease expert at University of California, San Diego Scool of Medicine said bacteria are everywhere and most are harmless or even beneficial to us.
"You can’t tell from this photo alone which type of microbes are growing on the petri dish," said Nizet. "You could leave an open petri dish just about anywhere for three days and something would grow on it, so the fact that bacteria and fungi grew after the dish was placed under a hand dryer isn’t surprising."
However, he added that the photo raises an interesting question of whether bathroom hand dryers spread pathogenic microbes. He said scientists don't know right now.
"It’s a hypothesis that could be tested in a scientifically controlled way—for example, by comparing the results from this one hand dryer to what might grow after exposure to multiple hand dryers with and without HEPA filters, and compared to control petri dishes that are just left open in the bathroom and petri dishes that are exposed to a hand dryer located outside a bathroom," said Dr. Nizet.