A very important thing that we can all do to lower our exposure to toxins - heavy metals, pesticides, etc., is to take off our shoes at the door. A recent study highlighted another great reason to leave our shoes at the door - poop!
The bottoms of our shoes can have fecal matter on them, with especially high levels if you live in a densely populated city such as New York City. The sidewalks have lots of microbes, lots of E.coli! Pet dogs defecate on the sidewalks in NYC, and even if the owners pick up the stools (as they should) - some residue stays. Which then people track into their homes on the bottom of their shoes.
The study found high numbers of microbes on outdoor sidewalks, but also on people’s shoes, indoor floors, and carpets. If you live in New York City and wear your shoes indoors, you will absolutely be contaminating the surfaces with the fecal matter. Not good for young children playing on the floors.
The researchers found that carpeted areas have way, way more fecal matter than bare floors.
From The Smithsonian: Shoes Carry Poop Bacteria Into NYC Buildings, Study Finds
People walking down New York City’s streets might unknowingly be bringing home unwelcome visitors: microscopic fecal bacteria. A study conducted on Manhattan’s Upper East Side found high concentrations of the bacteria not only on outdoor sidewalks, but also on people’s shoes, indoor floors and carpets.
“We found numbers of bacteria that were absolutely astonishing,” Alessandra Leri, a chemist at Marymount Manhattan College, tells the New York Post’s Emily Lefroy.
The findings, published January 31 in the journal Indoor and Built Environment, suggest that perhaps leaving shoes at the door when entering someone’s home is a good idea. “Taking your shoes off is a no-brainer,” Leri, the study’s lead author, tells Gothamist’s Jaclyn Jeffrey-Wilensky. “Shoe soles are disgusting.”
The study measured levels of enterococci, bacteria that live in the intestinal tracts of warm-blooded animals and are therefore found in their fecal matter. Enterococci indicate the presence of fecal matter in water and the possible presence of pathogens, according to the Environmental Protection Agency (EPA).
The researchers used pipettes to collect samples of water from puddles on sidewalks near Marymount’s campus. They only sampled puddles that did not contain any visible signs of poop, Leri tells Gothamist. They found concentrations of about 30,000 bacteria cells per 100 milliliters of water—the EPA shuts down beaches with more than 110 cells per 100 milliliters of water, Leri tells CBS News’ Doug Williams. The researchers also found E. coli, according to the publication.
Next up for examination were shoes and floors. The researchers let sterile liquid wash over shoe soles to capture their bacteria and used tape to collect samples from a university building’s floors.
They detected the highest amounts of enterococci in the building’s entryway and smaller amounts on interior floors. And carpets had more bacteria than bare flooring: While a carpeted entryway had around 22,000 enterococci per square meter, uncarpeted floor in the same area had only 100 per square meter, according to Gothamist. On shoes, they found between 15 and 2,000 enterococci per 100 milliliters of water, per the pblication.