NEW YORK -- We all know New York City streets are dirty. But how much of those germs are we carrying into our homes?
A study by a New York chemistry professor suggests something we should all be doing before stepping though the front door.
"Shoes off, please." It's a dreaded phrase for many house guests, but it's exactly what Dr. Alessandra Leri says hosts should demand.
"The most novel thing about our study is that people are tracking these things indoors on their shoe soles," said Leri, a professor at Marymount Manhattan College.
Leri co-authored a study about contaminants on Manhattan's sidewalks, specifically in standing water. It focused on the Upper East Side, where her office and lab are.
"We found astonishing levels of enterococci, which are a fecal indicator bacterium," said Leri.
In translation, your shoes can be dangerous once you walk in your front door.
"30,000 bacterial cells per 100 milliliter of water. The EPA has a benchmark that cities use to close beaches and that benchmark is 110 cells for 100 milliliters of water," said Leri.
Dogs in the city are part of a growing problem on our streets and sidewalks. In their defense, dogs are an easy target for blame in the study. But the ideas you may be conjuring up in your head weren't the types of messy sidewalks that were examined.
"We look for puddles where there's no evidence of feces, no residue. So they appear to be on sidewalk surfaces that are not fouled," said Leri.
Some bacteria found on our sidewalks can cause heart disease Unsurprisingly, E. coli was also found.
As for solutions, cleaner streets would help. But the best way to avoid this is by starting a new habit, if you haven't already.
"The easiest thing you can do to avoid tracking it into your home is to remove your shoes at the doorway and leave them there," said Leri.
In response to the study, the New York Department of Sanitation told CBS2 they remain dedicated to keeping the city clean, safe and healthy, and remind pet owners the law requires them to pick up after their dogs or be ticketed.
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