The richer, better-developed and more economically-independent a country is, the fewer bacteria you will find on its money. The material used to produce banknotes and the age of the money (whether it is creased or not) also affect the level of contamination. Banknotes harbouring alarming concentrations of pathogenic bacteria were not found in any of the world’s countries. These are the findings of research carried out by ten universities and knowledge institutes in as many countries. Researchers from Wageningen University, a part of Wageningen UR, examined banknotes in the Netherlands.
A total of 1,280 banknotes were collected from a range of food outlets, including shops and snack bars. They were then subjected to a thorough examination in order to identify bacteria. The countries where the research was conducted were Australia, Burkina Faso, China, Ireland, Mexico, the Netherlands, New Zealand, Nigeria, the United Kingdom and the United States. The Dutch branch of the study was headed by the Wageningen food microbiologist, Dr. Rijkelt Beumer.
The researchers recently published their findings in Foodborne Pathogens and Disease.
Creased
The research showed that the age of bank notes was a contributory factor. As notes become older they also become more creased, and dirt and bacteria tends to collect in the creases.
The material used to produce the banknotes is also important. Cotton is used in most banknotes. Although this initially makes it difficult for bacteria to take hold, the researchers only found a quarter of the bacteria on banknotes manufactured on a polymer substrate basis (such as the Australian dollar) as they did on banknotes made from a cotton-based material.
The researchers also found a strong correlation between the number of bacteria per square centimetre on a banknote and a number of indicators of economic wealth in the various countries. The lower a country scores on the ‘index for economic independence’, the more bacteria that are found on its banknotes. The ‘index for economic independence’ measures factors such as entrepreneurial freedom, freedom of trade, monetary freedom, fiscal freedom, freedom from government intervention, and the level of absence of corruption. It would be safe to assume that a country with a low score on this index will have older banknotes than a country with a high score.
Not pathogenic
The researchers only found low concentrations of pathogenic bacteria on the banknotes, and there was no evidence of alarming high numbers anywhere. To be on the safe side, they still recommend that food service should be separated from cash transactions, and preferably carried out by different people. Another option could be to handle food with one gloved hand, and money with the other. This would probably be difficult in certain locations, such as markets. But the risk of becoming ill would be considerably lower if everyone were to wash their hands before eating or preparing food.