Plastic or paper: How clean is the new polymer fiver?

This May, paper five pound notes will cease to be legal tender. And since the average fiver has at least 136 exchanges a year, we thought we’d find out how clean the new polymer notes are, so you know just what you’re putting your hands on.

When the new polymer five-pound notes entered circulation last September, they did so under a rhetoric of numerous benefits. The Bank of England claimed that the new notes would provide a better alternative to their previous paper counterparts.

The new polymer notes would be stronger, making them more economical in the long run and have more security features, making them more difficult to counterfeit. More so, because of the nature of the material, the Bank of England also claimed the new notes would be cleaner.

In particular, they said: “Banknotes, like any other surface that large numbers of people come into contact with, can carry bacteria. However, the risks posed by handling a polymer banknote are no greater than those posed by touching any other common surface, like handrails, doorknobs or credit cards.”

However, whilst the general belief around the new notes tended to agree with the Bank of England’s claims, certain studies went against the consensus.

In 2013, shortly after the Bank of England began a public consultation on the move to polymer notes, the Daily Mail reported on a study which claimed that polymer notes would be a “breeding ground for superbugs”. The study, which was conducted by Turkish and Dutch scientists, found that polymer notes would provide a home for diseases such as E. coli and MRSA.

To discover whether the claims of the polymer note’s cleanliness were true, we turned to Wickham Laboratories. The lab tested a number of the polymer notes in a thorough investigation, which examined the level of contamination of the new five-pound polymer note, after it had been in circulation for two weeks with real life handling scenarios.

To begin with, the lab took nine brand new five pound notes out of circulation and sanitised them with a 70% isopropyl alcohol spray. Afterwards, the notes were individually placed into a sterile stomacher bag, to clean them of any microorganisms, then given to nine different members of Wickham Laboratories staff.  

The staff members handling the notes, stored them as they would with their regular money, i.e. in a wallet, purse or pocket. Throughout a two-week period the staff members handled the money outside to simulate real transactions and also exchanged the notes six times on prearranged dates between different members of staff.

After the notes had been handled for two weeks, staff at Wickham Laboratories then tested the notes to calculate the amount of bacteria present.

The staff found that all of the nine five pound notes were contaminated with bacteria and the microbial load obtained from the nine notes varied from 31 colony forming units to 4600 colony forming units.

However, whilst this sounds like the notes are riddled with diseases, the actuality of the situation is far different. Each of the notes contained similar type of bacteria, all of which were gram positive organisms.

The good news for us is that gram positive organisms are generally considered  to be the helpful, probiotic bacteria, that helps us digest food.

Two of the most common bacteria found on the notes were organisms regularly found in soil, dust, water and air. The most common bacteria, micrococcus luteus, is also a normal bacterium of human skin.

Thankfully there was no indication of faecal organisms or ‘coliforms’ on the notes, perhaps indicating that those handling them had good hygiene or that the polymer note doesn’t provide favourable conditions for this  group of bacteria to survive.

The results drawn from Wickham Laboratories, aligns with other studies’ results that show less bacteria on polymer notes, when compared to paper notes. It’s also possible that the polymer note provides poor bacterial adherence, due to its smooth and non-absorbent surface.

Either way, you can rest easy knowing that when someone gives you a plastic fiver, it won’t be crawling with deadly bacteria or superbugs.

You can find the full study by Wickham Laboratories here.