Here's exactly how germy your damp bath towel is (and how often you should wash it).

“Pick your damned towel up of the floor and PUT IT IN THE WASH.”

We all heard that sentiment plenty as teenagers. And science is, yet again, proving we deserved it.

In soon-to-be-published research, Dr Charles Gerba, a microbiologist at the University of Arizona, has discovered that nearly 90 per cent of bathroom towels are contaminated with coliform bacteria – microscopic organisms that can indicate the presence of disease-causing bacteria in water.

Perhaps most unsettling about the study is that Dr Gerba reportedly found that roughly 14 per cent carried E. coli. Yes, E. coli as in the bacterium found in the digestive tract of humans and animas. E. coli as in the kind spread by faeces.

Oh, and he also found Salmonella.

According to TIME, Dr Gerba explained that bathroom towels serve as an ideal breeding ground for such bacteria, as the room is often dark, damp, and your hands are routinely exposed to faecal organisms.

Every time you dry yourself without having thoroughly washed, you’re transferring those organisms from your skin onto the fabric, where it flourishes in the petri-dish-like conditions.

“After about two days, if you dry your face on a hand towel, you’re probably getting more E. coli on your face than if you stuck your head in a toilet and flushed it,” Dr Gerba told the outlet.

Listen: Your pillows are also pretty gross. (Post continues below…)

According to TIME, Dr Gerba observed that the numbers of E. coli bacteria correlated with how often the towels were washed. That two-day mark he mentioned is key, as is a hot cycle.

That’s a conservative approach and, let’s be honest, pretty unrealistic for the majority of families. Thankfully most experts agree that a weekly wash is sufficient, as long as the towel stays completely dry between uses. Be sure to give it a whiff, too, because if a musty odour develops, then you’ve left it too long.

It’s important to note, that if you wash yourself and your towels properly, they’re unlikely to make you ill. But having studied germs for over three decades, Dr Gerba isn’t taking any chances.

After years wiping his face on a towel every morning, he’s now switched to paper towels.

“Some people say that’s not environmentally friendly,” he told Good Housekeeping, “but you’ll sure use a lot of toilet paper if you get diarrhoea!”

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