ECJ EUROPEAN Cleaning Journal

Paper money harbours thousands of germs and other microorganisms, according to a study. And common viruses can live on paper money for 10 days or more.

A team of researchers spent a year collecting US dollar bills from dozens of New York City banks and swabbing them.

Microorganisms of human origin including skin bacteria, oral bacteria, and even vaginal bacteria were discovered in the banknotes' fibres. Also present were some non-human DNA from pets and indoor fungi.

"A lot of people aren't washing their hands and they're at a restaurant where money is going back and forth," said Susan Whittier, microbiologist at New York-Presbyterian and Columbia University Medical Centre. "You don't know who's touched it."

Common viruses such as the flu can live on paper money for 10 days or more, according to research. And banknotes may stay in circulation for between five to 15 years depending on their denomination.

A second study discovered that the bacteria that causes acne were among the most common microorganisms on banknotes. Researchers from the University of Hong Kong collected paper bills from hospitals and metro stations as part of the study. Around 36 per cent of the bacteria on the notes were pathogenic and capable of infecting humans.

Experts have also discovered that the ability of bacteria to grow on money depends on the material the notes are made of plus the geography of the region concerned. For example, the Hong Kong researchers found more marine bacteria on their own samples than scientists who conducted another study in central India, far from the ocean.