Before you reach into your pocket, bag, purse or wallet for some cash … you might pause for thought about the bacteria, yeasts, fungi, cysts and ova of intestinal parasites that could be lurking there.
All the above are commonly found on money worldwide – but which types of cash are the filthiest? In a comprehensive roundup of global research into money and its disease-causing potential, researchers Emmanouil Angelakis, Esam I Azhar, Fehmida Bibi, Muhammad Yasir, Ahmed K Al-Ghamdi, Ahmad M Ashshi, Adel G Elshemi and Didier Raoult have examined various physical forms of cash to determine which might be the most problematic.
They note that paper (i.e. cotton and linen based) notes are particularly bad (in Ghana, 100% of the currency notes tested were found to be contaminated with one or more bacterial species). Plastic (i.e. polymer) notes were considerably cleaner (polymer-based banknotes from Australia and New Zealand presented less than 10/cm2 bacteria). And coins – particularly those rich in copper, were also less contaminated than the paper (possibly due to the antibacterial properties of some metals).
The research team suggest that :
“The capacity of banknotes, coins and fomites* to serve as sources of pathogenic agents represents a major challenge in the 21st century. It is possible that the replacement of cotton-based banknotes by substrate material can play an important role in the reduction of bacterial concentration.”
REFERENCE: ‘Paper money and coins as potential vectors of transmissible disease’ in Future Microbiology (2014) 9(2), 249–261
*NOTE: A ‘fomite’ is any non-living entity that can transmit disease – like, say, a church font, or a doorknob.
BONUS: A look at another type of dirty money