Science - November 17, 2005

Commentary/ Dirty dishcloths

Dishcloths in student houses contain billions of bacteria, announced the Dutch consumers’ association this week. Most students have no idea when they last washed the cloth. One student dishcloth contained about eight billion bacteria, two thousand times more than a dishcloth in a family house. Is this worrying news?

Wb asked Dr Rijkelt Beumer, food microbiologist and the Dutch dishcloth expert:

‘Funny you should call. We did the research ourselves. We collected thirty dishcloths, including ten from student houses in Wageningen, ten from families with children, and ten from elderly households.

‘Families with children generally change their dishcloths about every one and a half days, the elderly about every two days, and students often don’t know when the cloth was washed for the last time. We found all kinds of bacteria, including Staphylococcus aureus, which has quite a bad name because it is capable of making toxins. But I wouldn’t worry that much about it, as it only does this where it has no competition, which is not the case on a dishcloth. We also found Bacillus cereus, also pathogenic but not terribly dangerous. We did not find salmonella bacteria. You do find salmonella on a dishcloth that has just been used to wipe a surface where infected chicken was prepared, but once the cloth dries they decrease rapidly in number.

‘Would I be worried if I lived in a student house? No, not really. Most of the bacteria are harmless. It wouldn’t be a good idea to wipe a baby’s face with one of the dishcloths, but a healthy student is unlikely to become ill from the bacteria we found. I wouldn’t worry. What is not a good idea is to use the same dishcloth for the kitchen and the toilet. This way you can spread noroviruses for example. These can cause serious stomach flu, the winter vomiting disease. One gram of excrement easily contains a billion noroviruses, and you only need a few to become sick.

‘To be honest, I don’t change the dishcloth every day at home. Mostly it lies there for a couple of days until it starts to stink. I always defend what I do by saying I know all about these matters and know what is dangerous and what not. What we definitely don’t do is use the same cloth for the toilet.’

Korné Versluis

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