If you really had to try and make yourself sick, licking the hand-rail at your local railway station would seem like the best (and worst) way to do it – but science is discovering that public transport isn't as dirty as you may think.
New research from the Harvard Chan School of Public Health has found that using Boston's subway system would give you the same amount of bacteria as shaking hands with someone.
In fact, almost all of the bacteria that the researchers found (and to be honest, there was a lot) were simply from normal human skin, and extremely unlikely to be capable of making you sick.
"We were surprised to find that the microbes that we collected of surfaces that people touch—and sometimes sneeze on—had low numbers of worrisome pathogens or antibiotic resistance genes," said senior author of the study Curtis Huttenhower.
"They're exactly what you'd run into shaking somebody's hand."
To reach this conclusion, the scientists had to get their hands dirty – sampling everything from handrails to train seats, ticket machines and even the yellow "do not cross" lines on the station floor.
An icky job, mind you, when you consider that almost 1.3 million people ride on the Boston subway every day.
After taking 100 samples, the researchers went back to the lab to give them a treatment of shotgun metagenomics sequencing – which despite sounding like a hillbilly experiment – is actually the most accurate way of separating the different strains of bacteria.
The results showed that the "dirtiness" of the surface depended highly upon what it was made of – porous surfaces like foam grips and cloth seats held the most bacteria between their tiny fibres.
"I didn't expect the overhead grips to have that much DNA on them, because they're relatively small and seem to be used less often," said Tiffany Hsu, who led the study.
"But porous surfaces can collect microbes more efficiently than something solid like a metal pole."
Most of the bacteria found on public surfaces was skin and oral associated microbes (transferred by touching or sneezing), however the researchers also found amounts of vaginal microbes on the subway seats, which can be transferred through clothing.
For Huttenhower, this research explains that while we are right to avoid licking anything at the train station, it's far less harmful to hop on public transport than we might've first thought.
"We were surprised by how normal a lot of the samples looked," said Huttenhower.
"Even when we looked closely, there was nothing unusual or dangerous about the microbes we found. It shows that, in the absence of something like flu season, all of the germs you run into, even in a crowded environment like the [Boston Subway System], are normal."RELATED: Catching the bus the unhappiest way to commute