Is there really poo everywhere? © DanBright

Is there really poo everywhere?

Gross alert - make sure you wash your hands before you eat as we all spread poo around no matter much you clean your bathroom.

It’s true. In 2018, London Metropolitan University conducted swab tests on the self-order touchscreens in eight McDonald’s restaurants and found faecal bacteria on all of them.

Advertisement

This isn’t because these restaurants are dirty: it’s because their customers are, and so are you. Every one of us has about 0.1 grams of poop trapped in our butt crack at any given time. This spreads to our clothes, then our hands and then to every surface we touch.

You can clean the bathroom as much as you want, but bacteria are distributed as a fine mist every time you flush the toilet and will hang in the air for up to two hours, waiting to land on the next person to walk in. And your kitchen sponge, which you use to clean the dishes, has twice as many bacteria per square centimetre as your bathroom.

In fact, every door handle, TV remote, keyboard, lift button, bus handrail and car seat has detectable amounts of either your poo, or someone else’s. Of course, poo has always been everywhere: we just didn’t have the tools to detect it until the 20th Century. And it’s nothing to worry about. If your immune system is working properly, the low levels of contamination present today aren’t enough to make you sick. But washing your hands before you eat in a public place is always a good idea.

Read more:


Advertisement

Subscribe to BBC Science Focus Magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun facts.