Five-second rule

The five-second rule, or sometimes the three-second rule, is a food hygiene myth that states a defined time window after which it is not safe to eat food (or sometimes to use cutlery) after it has been dropped on the floor or on the ground and thus exposed to contamination.

There appears to be no scientific consensus on the general applicability of the rule, and its origin is unclear. It probably originated succeeding germ theory in the late 19th century. The first known mention of the rule in print is in the 1995 novel Wanted: Rowing Coach.