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Science: yep, there is poop on your shoes

The scoop on poop: 93 percent of shoes carry fecal matter, according to research by the University of Arizona. (John Loo / Flickr)

There is almost definitely poop on your shoes, and you’re getting it all over the floor.

That’s the groundbreaking discovery teams of scientists from around the nation have made after more than 20 years of research. A series of studies dating from 1996 to today have analyzed the soles of America’s shoes and concluded, nearly definitively, that there is fecal matter on almost all of them.

The facts on fecal matter and footwear

Muddy Shoes

90 percent of the bacteria on your shoes is transferred onto a clean tile floor on first contact, according to a 2016 study. (Max Pixel)

96 percent of shoes, after two weeks of normal use, will become contaminated with coliforms and E. coli bacteria, suggesting that they’ve been in contact with feces.

That was the discovery Dr. Charles Gerba, a microbiologist at the University of Arizona, made in 1996, kicking off what no one could have expected would be years of actual scientific research into poop on shoes.

Shortly after, Dr. Gerba managed to get a bit more specific with his numbers. After a month of normal use, he discovered, 93 percent of shoes will be carrying fecal matter.

The revelations only got worse from there. In 2016, Dr. Gerba and his team managed to show that, in addition to feces, there are 440,000 units of bacteria on the soles of the average pair of shoes. And 90 percent of that bacteria transfers directly onto a clean tile floor the second you put your foot down.

There are some serious problems with that bacteria, too. Just last year, Kevin Garey of the University of Houston took up Dr. Gerba’s cause for himself and found that 26 percent of shoes worn inside the home are contaminated with clostridium difficile, a bacteria that can cause explosive diarrhea.

C. diff, as the bacteria is better known, can kill, and there’s a lot of it on your shoes. In fact, according to Garey’s research, there is three times a much of it on contaminated shoes than there is the average bathroom.

What’s the scoop on all that poop?

Fecal Matter on Shoes

Is it time we start leaving our shoes outside? (pxhere)

All that research is adding up to a lot of worries about the American habit of leaving our shoes on indoors. It has a lot of people wondering: are we putting our lives at risk?

The short answer, according to most experts, is “no”.

“Microbes exist all around us,” Nottingham Trent University’s Michael Loughlin told The Independent. “The risk posed by bacteria on the soles of shoes is very low.”

While there certainly is poop – and therefore, bacteria – on our shoes, Loughlin explained, the same could be said about almost everything. And Dr. Gerba has made a career out of doing just that.

Dr. Gerba, the man behind most of the research, specializes in identifying bacteria on household objects. He has earned the nickname “Dr. Germ” for his penchant for pointing out just how many germs are on everything we own — and not just shoes.

The household object with the most germs per square inch, according to Dr. Gerba, isn’t your shoes. It’s your cell phone. 94.5 percent of cell phones used by health care workers, he says, are contaminated with bacteria.

But that bacteria isn’t always a bad thing. Most scientists today believe in what’s called the “hygiene hypothesis”: the idea that bacteria makes our bodies stronger.

If you are worried about the bacteria and fecal matter on your shoes, the solution is simple. Dr. Gerba’s 1996 study also revealed you can get 90 percent of that poop and bacteria off of your shoes just by washing them with detergent.

More to the story

Dave & Dujanovic talked about this story on the air, and Debbie Dujanovic revealed that, when she was growing up, her parents required her to wear shoes inside the house.

If you missed the show live, you can still hear everything they had to say on the Dave & Dujanovic podcast.

Dave & Dujanovic can be heard weekdays from 9 a.m. to noon on KSL Newsradio. Users can find the show on the KSL Newsradio website and app, as well as Apple Podcasts and Google Play.

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