You may have heard of the 5 second rule when it comes to dropped food on the floor - but have you heard of the lightning 5 second rule?

A new study appears to validate what every 12-year-old knows: If you drop food on the floor, you have five seconds until it becomes contaminated.

When your favourite food hits the floor, it feels like instant heartbreak. That's when the five-second rule swoops in like a ...