News - January 18, 2007

Pecunia non olet

Money is clean, concluded Wageningen microbiologists after making a round of market stalls and shops. They found most bacteria on the money at the cheese-seller’s, but if you bear in mind that millions of bacteria live on your hands anyway, and a lettuce leaf is home to at least ten million microbes, a eurocent is almost sterile.

The researchers examined 270 coins and 120 banknotes, and found that numbers of bacteria on coins varied between 10 and 1000. The numbers on banknotes varied between 250 and 25,000. There are more living organisms on banknotes because coins are too smooth for bacteria to be able to stick to them.

That they found the most bacteria on money in the cheese shop comes as no surprise to Rijkelt Beumer, the man behind the research. One gram of cheese contains a billion bacteria. In addition to doing a number count, Beumer also looked for dangerous bacteria on the money. The results were reassuring; they found no salmonella. They did find gut bacteria here and there, but in such small numbers that Beumer could not make a reliable count.

The reassuring message was world news in the Netherlands this week. The research was reported in nearly all Dutch newspapers.