The 5 second rule: fact or fiction?

When it comes to oral satisfaction, pretty much everyone knows the infamous "5 second rule".

For any readers who either are inhumanely non-clumsy or don't eat food it can be summarised by saying that if you drop your lovely delicious cream bun onto the floor it is medically, socially and morally acceptable to pick it up and continue eating it as long as it has only been on the floor for 5 seconds or less. Any more than that- if you're not prepared to throw away your hard-earned food - and you risk dirt, disease, death and derision from the floor filth getting onto your sustenance and into you.

After finishing their theses at Connecticut College, biology students Molly Goettsche and Nicole Moin wanted to do something "light-hearted and fun". Unfortunately it seems they couldn't get their hands on recreational drugs right away, so instead they decided to test the premise of the 5 second rule using cold hard science.

In what seems like a rather apparatus free, and some would say uncontrolled, experiment they selected two types of food to represent "wet" and "dry" categories; namely apple slices and the colourful e-number extravaganza sweets known as Skittles. They went to the college dining hall and joined the messy student eaters in dropping their food on the floor.

Unlike the other hoi polloi gorging themselves, Molly and Nicole actually picked up their dropped food. As the rule relates to time, the food items were left on the floor for differing amounts of time - 5, 10, 30, 60 and 300 second intervals. The potentially-dirty food was then swabbed and the resulting mix placed onto agar plates in order to promote the growth of any bacteria that might have been picked up.

The results came in. Food that had been on the floor for 5, 10 or 30 seconds showed no bacterial contamination at all. The wet apple slices that had been on the floor for a minute however did gain bacterial growth, as did both types of food after they had been left lying around for 5 minutes.

Their conclusion?

…you can wait at least 30 seconds to pick up wet foods and more than a minute to pick up dry foods before they become contaminated with bacteria.

NB: Before consuming Mars Bars that have been lodged in dog dirt for just 59 seconds, it should be noted that this result conflicts somewhat with a similar experiment done by the Mythbusters which found "that the amount of bacteria that was picked up depended on the moisture of food, the surface geometry of food, and the location that it was dropped on, but there was no correlation to the amount of time it was dropped.".

The Poorhouse would likely risk it anyway though.


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