Why do feet stink?
Ed Clausen, professor of chemical engineering, replies:
If the smell of your shoes knocks you off your feet, you’ve probably wondered just what makes those sneakers stink.
Your fetid feet are fermenting. You have more than 250,000 sweat glands in each foot, so perspiring piggies produce up to a pint a day. It’s not the sweat that stinks, though. It’s the byproduct of the bacteria that are feeding off the sweat. The bacteria cells eat and then excrete an organic acid. That’s what smells.
So it all comes down to bacteria poop … that and the sealed-off sweat stuck inside your shoes and socks. Other parts of your body, such as your hands, have a similar number of sweat glands. But your palms aren’t putrid because that dampness dissipates. The clammy conditions of your shoes and socks create a feeding frenzy at the bacteria buffet.
Bacteria love dark, damp places. Fermentation is just what happens when a microorganism breaks down a substance, producing a byproduct. Sometimes, as with beer and wine, we want those byproducts.
Only science could connect booze and shoes.