Dirty Money?

Dirty money usually is associated with illegal transactions but in this case it is referring to the bacteria living on currency.In a new study, Frank Vriesekoop and other researchers compared the germ populations found on bills of different countries. Vriesekoop is a microbiologist at the University of Ballarat in Australia. He led the study, which compared the germ populations found on money gathered from 10 nations. The scientists studied 1,280 banknotes in total; all came from places where people buy food, like supermarkets, street vendors and cafes, because those businesses often rely on cash.

Overall, the Australian dollars hosted the fewest live bacteria — no more than 10 per square centimeter. A square centimeter is a unit of area that is almost equal to the size of the nail on a child’s index finger. Chinese yuan had the most — about 100 per square centimeter. (Imagine 100 germs on your fingernail!)

Most of the germs on money probably would not cause harm. While six types of currency were germier than the United States dollars, U.S. dollars were the most likely to carry E. coli, a bacterium that usually lives in the intestines of animals (including humans). E. coli is largely responsible for food poisoning: People who eat food contaminated with this germ can get very sick.

Source: sciencenews.org 1/19/11