In some cultures, with the Japanese being the most prominent, wearing shoes inside the house is heavily frowned upon. Now, there is mounting scientific evidence that this practice of removing shoes may have far greater benefits than simply appeasing a Japanese host.
Researchers at the University of Arizona found a shocking truth. There are, on average, nearly 421,000 different bacteria present on the bottoms of 96 percent of shoes. Basically, your shoes are a petri dish you walk on.
Among these bacteria are Klebsiella pneumoniae (which causes urinary tract infections), Serratia ficaria (which causes respiratory infection) and a whole lot of E. coli.
E. coli is no fun. It can cause serious digestive issues and, in extreme cases, can even result in potentially lethal kidney damage.
The major source of E. coli on your shoes? Trace fecal matter from public restroom floors.
Sadly, even if you visited only the most immaculate public toilets, there's plenty of animal fecal matter on the ground/sidewalk/road. It's everywhere.
Interestingly enough, public restroom floors have around two million bacteria per square inch, while the average toilet seat only comes in at 50 per square inch! You should be way more worried about the floor than the seat.
Not only did researchers find bacteria on the shoes, they found that that bacteria gets tracked over long distances via your shoes to then potentially contaminate your personal space. The transfer of bacteria from shoe soles to home floors was anywhere from 90-99 percent. Other studies
have found that other toxins like lawn chemicals, coal tar from asphalt roads and gasoline and other chemicals in rainwater can all be tracked into your home via your shoes as well. Though the risk of illness from these is comparatively small, it can potentially build up over time with prolonged exposure.
So are we all supposed to live in a world full of plastic booties for our shoes?
Thankfully, no. Machine washing your shoes with detergent on a semi-regular basis should help drastically reduce bacteria. Cleaning your home floors and carpets is also recommended (especially steam cleaning).