I suppose it depends on what has touched the Bank notes in the first place. Like, a newly created bank note wouldnt have much germs on it, but bank notes passe by drunk people in pubs probably have a lot more!! lol

1) "Transmission of microorganisms is possible from any place where they are attached. How many will be transferred from coins or notes depends on a series of factors such as the number of organisms present and their ability to survive in such a dry environment, in which many will die. The form of contact also makes a difference, whether it be by touching contaminated money, which can transfer the organisms to the hand, or the "hoovering" that occurs when people snort drugs through a banknote. The latter is obviously a more direct way of carrying germs into your nasal passages. The number of individual viruses or bacteria needed to make you ill also counts. For viruses, it can be as high as 100,000 or as low as 10. One more factor is whether any germs taken in from money will have easy access to the site in the body where they can thrive. In a recent microbiological investigation of money in the Netherlands it was observed that coins may harbour up to 1000 bacteria, and paper money a few million. Of course this depends on the type of material the money is made of: coins usually carry few microorganisms, which is also the case for some materials used in producing paper money. We have very little reliable data about which viruses are present, although results on that topic may be available next year." Source and further information: http://www.newscientist.com/blog/lastword/2007/09/filthy-lucre.html 2) "Evils of money: now it's the germs The University of California at San Francisco microbiology lab performed cultures on currency from more than a dozen urban sources, including an ATM, coffee house, deli, donut shop, fast-food chain, grocery store, newsstand, pharmacy, post office, snack bar, two butchers and a bagel shop." "Plentiful bacteria flourished -- both harmless and disease-causing. Concentrating only on pathogenic varieties, Lowe found about 18 percent of coins and 7 percent of bills grew disease-causing bacteria. Most contaminated samples grew Staphylococcus aureus, a ubiquitous bug that colonizes in skin and nostrils. Two cultures grew bacteria found in the digestive tract: Escherichi coli and Klebsiella enterobacter. Colonies were light to moderate." Source and further information: http://archive.southcoasttoday.com/daily/02-98/02-04-98/b05he066.htm 3) "Coins are more sanitary than notes and harbor fewer germs. Studies show that 94% of all $1 notes carry germs that could cause serious infections (Staph, e coli, etc). Copper (the main alloy in $1 coins) is an anti-microbial, which means it can kill dangerous microbes as the coin is passed from one person to the next. Peter Ender, chief of infectious diseases at Dayton's Wright-Patterson Air Force Base collected 69 $1 notes from businesses in Dayton and found five had bacteria (Staphylococcus aureus and Klebsiella pneumoniae) that could infect healthy people if the notes touched the mouth or an open cut. Another 59 notes had a variety of germs that "have been known to cause significant infections in those with depressed immune systems." His findings were presented to the American Society of Microbiology meeting in Orlando in May 2001." Source and further information: http://marketplace.publicradio.org/display/web/2008/07/23/dollar_coins/ 4) Further information: - "Germs on currency? Dirty money is a myth": http://www.nzherald.co.nz/personal-finance/news/article.cfm?c_id=12&objectid=10390688 - "FIGHT FOR CLEAN MONEY.; Expert Says Soiled Bills Carried Diphtheria Germs a Month." http://query.nytimes.com/gst/abstract.html?res=980DE4D6163DE733A25757C2A9649C946497D6CF