New York University’s (NYU) aptly titled ‘Dirty Money’ project has found 3,000 different types of bacteria dwelling on $1 bills, and even though researchers found microbes causing concern, people shouldn’t walk around fearful of handling cash.

The study is yet to be published, but some of the findings have already leaked out. It’s been known for years that minted monetary means could carry diseases and traces of narcotics. Several studies have confirmed this, but the Dirty Money project shows precisely what crawls around in our wallets.

NYU director, Jane Carlton, was thrilled and amazed at the university’s findings: “We actually found that microbes grow on money.”

Carlton and her colleagues only looked at 80 $1 bills when they were searching for microscopic forms of life on money via DNA. The study found 1.2 billion DNA segments on the money, only half of which are human. Also Staph, E. Coli, and the bacteria that cause ulcers were found.

“Microbes are so important, are very ubiquitous and they surround us all the time. We did find certain microbes that we might be a little concerned about, but that doesn’t mean that people should be unduly concerned,” Carlton said.

The amount of DNA data discovered required approximately 320 gigabytes of digital storage. This is roughly equivalent to the amount of storage space required to hold an entire library of traditional medical texts.

Bacteria weren’t the only thing researchers found. They also found viruses, fungi, plant pathogens, a very small amount of anthrax, diphtheria, and from the animal kingdom there was DNA from horses, dogs, and even two samples of white rhino.

This latest study adds to what’s already known about other substances found on cash. A British study from 2010 said that every single bank note in the UK is contaminated with cocaine within weeks of entering circulation.

The problem with drug-laced cash in the UK is so widespread that police no longer bother testing money for traces in criminal investigations as every note tests positive for cocaine. It takes just two weeks for a new bank note to pick up the drug, either because it’s handled by someone using it to do a line or two, or it’s contaminated by rubbing against other currency.