Think about it. Whether you have a lot of it or hardly any, money is one of the dirtiest things you're likely to handle every day.
Kids, and even some adults, stuff their shoes with money, and a few women will pull wads of cash out of their undergarments. You really don't know where that dime or dollar has been, or what nasty stuff might be on it.
That legal tender in your wallet has been passed around from hand to hand, person to person and possibly traveled the world and back.
So, how worried should you be?
Experts say your mother was right when she warned you to not put money in your mouth. But while there is plenty of grime and dirt on our American currency, there's not enough to kill you, said Yvette McCarter, professor of pathology at the University of Florida College of Medicine at Jacksonville and director of the clinical microbiology lab.
"Mostly, there will be normal skin and environmental stuff on the money," McCarter predicted.
Really? Is that all? In this era of worries over infections and germs - witness the rise in popularity of anti-bacterial soaps and headlines seemingly every other day about food-borne illnesses - we wanted to know for sure.
We collected cash - paper money and coins - from fast-food restaurants, banks and other local businesses until we had a variety of crumbled, soiled and marked-up money, including a yellowed dollar bill from 1969.
Next step was McCarter's lab for testing, to see what sorts of diseases, bacterium, perhaps traces of drugs and other icky stuff we've been carrying around in our pockets.
In her lab, McCarter "pressed" the money onto Mueller-Hinton agar plates - sort of like petri dishes, where bacteria can grow and be analyzed. She added a few drops of normal saline liquid and told us to come back the next day for the results.
It wasn't nearly as bad as we feared. The results were right there, exactly as she predicted - normal skin and environmental stuff in quantities far too small to cause an outbreak. No Ebola. No flesh-eating bacteria. No swine flu.
That doesn't mean you should let your guard down. While our sample turned out to be relatively "clean," consider this: In a similar 2001 experiment, researchers from the Wright-Patterson Air Force Base Medical Center in Dayton, Ohio, exchanged 68 new dollar bills for old, worn ones with people at a grocery store and a sporting event.
The findings, reported in an ABC News segment, showed five of the bills contained bacteria that can cause an infection like influenza in healthy people, 59 contained bacteria that can cause serious illness in those with weak immune systems, and four were relatively germ-free.
The researchers found that while money contaminated with bacteria can spread these organisms, the risks to the average consumer are low - and perhaps there's more bacteria on that shopping cart you are pushing.
That's exactly what Noel Gomez said of our experiment, too.
"The organisms isolated from [your] project represent a small number of other potential bacteria that might have been found," said the UF & Shands Clinical Microbiology lab supervisor. "It's possible that bacteria such as E.coli and pathogens such as MRSA [flesh-eating bacteria] can be found on money. One thing to consider, though, is that most bacteria die on most surfaces within hours if not given a food source and proper temperatures in which to grow."
However, Gomez added that if E.coli and MRSA were found in large quantities on heavily soiled paper money, and a person handling that money immediately touched an open sore, there would be a greater chance that person might get an infection.
Because the UF & Shands lab doesn't test money for traces of drugs, and the Florida Department of Law Enforcement's lab was too busy testing regular cases, we were unable to see if there were illegal drugs on our cash. However, other studies have found traces of cocaine on a lot of money, particularly $20 bills.
A little bacteria isn't necessarily a bad thing, McCarter said.
"Frankly, there's more things to worry about than the bacteria on money," she said. "It's good to be aware of what's in our environment, new organisms and infections. But, since we were born we've been exposed to normal, everyday bacteria and it's not enough to worry about. Besides, there's probably more bacteria on your toothbrush than on your money."
Tell that to Sophia Huland, a teller at the SunTrust Bank branch in the Modis Building downtown. She and fellow colleagues work in a hands-on, people-based business handling money from various sources every day.
Even though Huland said her bank promotes a healthy and sanitary work environment by providing hand-sanitizer bottles at each workstation, and by following a "bank-industry rule" to refuse to accept currency that is visibly contaminated, she and the others still remain proactive about how they handle incoming currency.
"Sometimes, if the money looks really worn or soiled, we'll accept it and then put it off to the side and it's flagged so that it doesn't get back into circulation," she explained.
Huland recalled one unnerving incident at a South Carolina bank where she worked.
"A client came in to exchange money his dog had swallowed and later expelled," said Huland. "Although he said he washed off the feces, I was horrified."
So how can you keep yourself safe from dirty money?
McCarter advises using common sense and washing your hands after handling money. But, she says if you forget, don't fret, a little "normal flora" or good bacteria is actually good for us every now and then as it helps keep the other crud away.
Want another option?
You could move to Japan, where money is "laundered," literally.
One of Japan's leading banks, Sanwa, installed its first "clean ATM" machine at a branch in Tokyo in the mid-1990s. The ever-appreciative and clean-seeking Japanese flocked to the wonder machine, for the potential to have the cleanest money ever. Customers would insert their yens into the machine, which would then be treated to a heat process of 392 degrees, claiming to kill 90 percent of germs and bacteria before dispensing back to customers.
"What a novel idea," said McCarter. "Except, the minute you pick up that paper money again, it becomes contaminated with your normal flora!"
So much for clean money.
As for Gomez, he sized up that getting germs from money won't be a problem for him. Why?
"Because I always use a debit card."
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