Photo by jeso

Never underestimate the lengths a college freshman will go to avoid a pile of dirty laundry. University of Alberta student Josh Le wore his tight-fitting raw-denim jeans every day for 15 months and one week with nary a spin cycle. On a lark, Le’s professor, Rachel McQueen, took bacterial counts from the pants before he threw them into the wash, then sampled the same jeans a couple of weeks later. The verdict: The bacterial growth on both versions was virtually the same—high, to be sure, but nothing that will kill you.

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“I expected to find some bacteria associated with the lower intestine such as E. coli, but was surprised to find there weren’t any, just lots of normal skin bacteria,” says McQueen, a professor of textile science in the Department of Human Ecology.

In this case, at least, the bacterial growth is no higher if the jeans aren’t washed regularly.

If you want to get down to the nitty gritty—and we do mean nitty gritty—the counts showed between 8,000 and 10,000 colony-forming units per square centimeter in the crotch area, 1,500 to 2,500 on the back, and 1,000 to 2,000 on the front. Translation? “This shows that, in this case at least, the bacteria growth is no higher if the jeans aren’t washed regularly,” she says.

Because most bacterial organisms are transferred to clothes from the person wearing them, McQueen adds, they shouldn’t pose a threat for healthy and unbroken skin. And unless you work in a hospital or kitchen, where sanitation is paramount, the environmental benefits of going longer between washes outweighs any potential risk.

Le isn’t about to go another year without dropping quarters at the laundromat. “Maybe more frequently than 15-month intervals between washes—but maybe less frequently than after every wear,” he says. “If anything, I learned that I’m much cleaner than I thought!”

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+ University of Alberta

[Via Physorg]