NOTES and coins are not nearly as dirty or germ-ridden as people think, a study has shown.
The research, conducted over a year, found low levels of common bacteria on the currency traded through food outlets in Australia and New Zealand.
However, the number of bacteria was so insignificant that it would be impossible for them to cause diarrhoea, vomiting or the other gastrointestinal symptoms they are usually believed to cause.
Dr Frank Vriesekoop, of the University of Ballarat, who led the research team, said the study proved that fears about currency hygiene were unwarranted.
"There's been so much hype," Dr Vriesekoop said, "but, in fact, the chances of you picking something up from your cash are virtually non-existent."
His team of researchers collected more than 800 coins and notes from outlets where shop assistants handled food and cash.
On the 20 cent and $1 coins and $5 and $20 notes, they found the extremely resistant spore bacillus, which causes gastroenteritis, and the opportunistic organism staphylococcus, commonly found on the skin.
The intestinal bacteria E. coli, which causes diarrhoea, was present on some notes, and salmonella bacteria on a few coins.
Coins were far less dirty than notes, probably because some organisms cannot survive on metal.
The team said the Australian currency was marginally cleaner than that of New Zealand.
Researchers also found that credit cards had the same levels of bacteria as hard currency.
The research is part of an international study that is expected to prove that the polymer notes used in this part of the world are far less bacteria-prone than paper notes.
Early results from the Middle East, in particular, showed "extremely dirty paper notes", but it was too soon to draw conclusions, Dr Vriesekoop said.