Germs (细菌) on Banknotes
People in different countries use different types of money: yuan in
China, pesos in Mexico, pounds in the United Kingdom, dollars in the United
States, Australia and New Zealand. They may use different currencies, but these
countries, and probably all countries, still have one thing in 1 : germs on the banknotes.
Scientists have been studying the germs on money for well over 100 years. At the
turn of the 20th 2 , some researchers
began to suspect that germs living on money could spread disease.
Most studies of germy money have looked at the germs on the currency
3 one country. In a new study, Frank
Vriesekoop and other researchers compared the germ populations found on bills of
different 4 .
Vriesekoop is a microbiologist at the University of Ballarat in Australia. He
led the study, which compared the germ populations found on money 5 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, 6 those businesses often rely on cash. Overall, the
Australian dollars hosted the fewest live bacteria—no more than 10 per square
centimeter. Chinese yuan had the 7 —about 100 per square centimeter. Most of the germs on money probably would
not cause harm. What we call "paper money"
8 isn’t made from paper. The U.S. dollar, for example, is
printed on fabric that is mostly cotton. Different countries may use different
9 to print their money. Some of the
currencies studied by Vriesekoop and his team, such as the American dollar, were
made from cotton. Others were made from polymers. The three
10 with the lowest numbers of bacteria
were all printed on polymers. They included the Australian dollar, the New
Zealand dollar and some Mexican pesos. The
11 currencies were printed on fabric made mostly of cotton.
Fewer germs lived on the polymer notes. This 12
suggests that germs have a harder time staying alive on polymer
surfaces. Scientists need to do more studies to understand
13 germs live on money—and whether or not we need to be
concerned. Vriesekoop is now starting a study that will
14 the amounts of time bacteria can stay alive on different
types of bills. Whatever Vriesekoop finds, the fact remains:
Paper money 15 germs. We should wash
our hands after touching it; After all, you never know where your money’s been.
Or what’s living on it.