Dirty digital

Germy phoneWhich payment system is the most germ-free?

In the wake of New York University’s 2014 Dirty Money Project, the switch from paper to digital currency was probably welcome news for germophobes. That was the study that revealed that some 3,000 varieties of bacteria hang out on the average American dollar bill. 

Most of the bacteria, of course, are benign. Indeed, we should thank our lucky stars that there are such things as benign and, often, helpful bacteria, since, according to the National Institute of Health, trillions of them—up to six pounds worth—make a living hanging out on our bodies every day.

Some people unwittingly up the germ count on their currency through their creative choice of “wallet.” Fed up with disgustingly sweat-soaked currency, owners of a Kentucky store announced they would no longer accept cash pulled from a bra, sock, or shoe. The announcement brought a brief surge in business from visitors who came to gawk at the rather blunt sign announcing the policy. The resourceful, defiant customer, however, needed only to retrieve ill-cached cash while out of view.

Not all the little bugs are benign. Paper currency also carries microbes that have a habit of causing diphtheria, gastric ulcers, food poisoning, and, according to an article in TIME, “a smudge of anthrax and diphtheria.” They are, however, relatively few in number and, either way, are unlikely to make you sick. Provided, the article advises, you resist any urge to lick your currency. 

Are plastics more germ-free than currency?

Certainly germophobes were pleased when payments began moving from cash to plastics. After all, paper currency is made from fibers that provide a rich environment in which germs can flourish. Plastic, not so much. Or so one would suppose from studies showing that fewer bacteria dwell on Canada’s polymer film currency than on paper currency. Last year none other than MarketWatch said, “If you want to avoid bacteria, you might be better off paying with plastic than dollar bills.”

Not so fast. MarketWatch and other publications reporting on the matter did not define fewer in “fewer bacteria,” nor did they place the word significantly in front of it. But they did point out that bacteria live longer on polymer film than on paper currency.

Missing definitions and modifiers side, contrary to what one would suppose, it turns out that plastic cards are dirtier than currency. A study by the University of Texas and CreditCard.com found, “Credit cards led all payment methods in the detection of a few particularly infamous bacterial species.” 

Again, there’s no need to panic. As with paper, the odds of picking up diseases from a credit card, provided one avoids licking it, are low.

How germ-free is your smartphone?

At last, contactless payment systems arrived to assuage the fears of the most ardent germophobe. Just wave your smartphone over the payment terminal and—voila!—payment is complete. No handling currency. No handling a card.

Except, once again, not so fast. Germs love to transfer from finger to finger via terminal touch pads. They also hitch rides from one person to another on the stylus you use to sign. 

Besides which, there’s the fact that smartphones are by no means germ-free. In fact, they’re worse. According to another TIME article

Research has varied on just how many germs are crawling on the average cell phone, but a recent study found more than 17,000 bacterial gene copies on the phones of high school students. Scientists at the University of Arizona have found that cell phones carry 10 times more bacteria than most toilet seats … Studies have found serious pathogens on cell phones, including Streptococcus, MRSA and even E. coli.

Fecal bacteria like E. coli frequently hitch rides on phones that owners bring with them into restrooms. Of course, that could only happen if someone were to be holding a smartphone while flushing. We know that no one ever does that.

Just to add to the ick factor, I might also point out that, unlike currency and credit cards, a phone is something you hold against your face. You know, as in near your mouth. Yum.

Since plastics carry more germs than paper bills, and smartphones pack more germs than plastics, what do health experts advise? 

Oddly enough, their advice is the same that Hungarian physician Ignaz Semmelweis was mocked for proposing in 1847, only to be vindicated years after his death: Wash your hands.

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