We live in a world obsessed with cleanliness and are constantly being told that bacterial danger lurks everywhere. But few of us give much thought to one of the dirtiest things we carry every day – our money. That money in your purse or wallet is teeming with life.
Each dollar bill carries about 3,000 types of bacteria on its surface. Most are harmless, but not all. DNA tests show that drug-resistant microbes on money can include traces of anthrax and diphtheria. In other words, your wallet is a portable petri dish.
The most common microbes on the bills, by far, are ones that cause acne. Others were linked to gastric ulcers, pneumonia, food poisoning and staph infections, the scientists said. Some carried genes responsible for antibiotic resistance.
There is also lots of bacteria that aren’t pathogenic: They simply like to hang out on people’s bodies. Some of these critters may even protect the skin from harmful microbes. Other money dwellers included mouth microbes and bacteria that thrive in our private parts because many people probably aren’t washing their hands after they use the bathroom.
Testing has also detected genes that make bacteria impervious to penicillin and methicillin. The latter make MRSA bacteria such dangerous pathogens.
Human touch compounds the problem. Bacteria can feed on the waxy residue of skin and oils that builds up on bills in circulation. We actually provide the nutrients when we handle the bank notes,
At this point, though, scientists don’t how important money is for transmitting pathogens and fueling disease outbreaks.
Would changing the material that paper money bills are made from help to keep them cleaner? The jury is still out.
Some countries, such as Canada, have started printing money on flexible sheets of polymer film, a fancy plastic. One study found fewer bacteria, in general, grew on these plastic bills than cotton-based ones, like the dollar and euro notes. But another study reported that microbes survive longer on polymer-based bills.
Until the ideal material gets figured out, the best protection against money’s invisible inhabitants is also the simplest one: Wash your hands after handling cash.