Scientists confirm dad’s common sense: 5-second rule totally legit

A British microbiologist has concluded that food dropped on the floor is okay to eat as long as you pick it up really fast. Other researchers aren't so sure.

Parents, rejoice: The 5-second rule, it turns out, is totally legit.

In one of those satisfying moments where science confirms common sense, a British microbiologist from Aston University in Birmingham, England, has come to the conclusion that food from the floor is okay to eat as long as you pick it up really fast.

“The findings of this study will bring some light relief to those who have been employing the five-second rule for years, despite a general consensus that it is purely a myth,” says Prof. Anthony Hilton, who led the important effort.

Mr. Hilton and his grad students of course simply formalized an experiment that takes place every day across the world, as fumbling toddlers, clumsy pre-adolescents, and insouciant teenagers scatter their Cheerios and strawberry chunks about them and then happily munch them up. In most parental experiences, the food-from-the-floor moments don’t seem to lead to subsequent throwing up, leading to the innate conclusion that the 5-second rule works.

Not everyone agrees. A very similar study by Clemson University researchers in 2007 came to the opposite conclusion – that contamination of food-on-the-floor is immediate. Thus, Clemson urged the “zero-second” rule for cookies on the floor.

However, that Clemson study seems not to have had much of an effect on food-from-the-floor trends.

Indeed, the British researchers included a poll that also seemed to confirm the obvious: 87 percent of people say they are “happy to consume dropped food,” in the words of the report, and 55 percent of those people (wait for it) are women. (Kids were apparently not asked, but let’s just throw a guess out there: roughly 100 percent have eaten off the floor.)

The researchers did note, however, that time can be a “significant factor” in the proper digestibility of food-on-the-floor. Also, the study says, “The type of flooring food has been dropped on has an effect, with bacteria least likely to transfer from carpeted surfaces and most likely to transfer from laminate or tiled surfaces to most foods making contact for more than 5 seconds.”

Final takeaway: Dropped cookie on the carpet? Go ahead and eat it. Blob of mac-and-cheese on the kitchen tile? Maybe you should just toss that. Or let the dog find it.