I dropped a piece of chocolate the other day, and briefly wondered just how many bacteria I had added to my tasty treat. But I saw no dirt, so went ahead and popped the chocolate into my mouth.
After all, my kitchen floor is pretty clean and the chocolate had been on the ground for less than five seconds.
The "five second rule" was therefore in my favour, obviously. We all know that rule, right? Any food picked up from the floor is perfectly fine to eat within five seconds of dropping it.
But was I right to eat it, or had I unwittingly stuffed my mouth full of tiny, harmful microbes?
http://www.bbc.com/earth/story/20160322 ... -the-floor