No harmful bacteria found in jeans not washed for 15 months: study

EDMONTON – A University of Alberta student has discovered through science that a current fashion trend is safe, but can be a little stinky.

Josh Le donned the same pair of skin-tight jeans for 15 months without washing them. The idea was to break in the raw denim so the fabric would hug the contours of his body, leaving distinct wear lines and creases.

Curious about the health risks of wearing such a grubby garment, Le asked his textile professor to test the jeans for bacteria before he washed them for the first time.

The results showed high counts of five different kinds of bacteria in the denim, but nothing that posed a health hazard.

“I was blown away. I thought there would be a lot more bacteria than was present,” Le said Wednesday. “It sort of shows that it is OK to not wash jeans.”

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Raw or dry denim is not washed or treated with chemicals when it is manufactured. The dark indigo pants are as stiff as cardboard. It’s trendy to wear the tight jeans without washing them in the hope the indigo will wear away at stress points in the fabric. When the jeans are finally washed, they leave wear patterns that are as personal as a fingerprint.

Human Ecology professor Rachel McQueen said the highest recordings of bacteria were found in the crotch of the jeans at 10,000 units per square centimetre, with lower readings in the back and front of the pants.

But the colonies were normal skin bacteria and did not include dangerous E. coli.

“I didn’t see any evidence of those, but that could be very unique to Josh. I mean, he wore underwear, which can be helpful,” she said.

Le said some of his friends were disgusted by his jeans experiment, but others were very understanding.

He said his dingy denim even became a good way of meeting new people.

“Some people really liked it, but some people were completely grossed out by it,” he said. “I was able to meet a lot more people and have a lot of good conversations. It was like, ‘hey, nice jeans.'”

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Despite his best efforts to keep his jeans clean, Le said he still managed to spill food on them. He also wore them on hot days. He figures he wore them well over 200 times during the experiment.

He acknowledged the denim did get pretty ripe. His solution was to toss them in his freezer whenever they got too smelly.

“There were times when it had a bad odour, like in the seventh month,” Le said. “That’s when I threw it in the freezer and magically when it came out it was odourless.”

McQueen said what was most surprising was a second test she did on the jeans after they were washed and Le wore them again for another 13 days. The results were about the same.

She said while the bacteria didn’t pose a risk for a healthy, strong young person, she recommends that people wash their jeans more often – at least once a month.

“I would suggest washing your jeans more frequently. But that is more for control over the odour,” she said.

“If people are just being lazy, perhaps odour could become a problem and they may lose friends rather than gain friends.”

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