Scientists Prove 5-Second Rule Is Real (Sometimes)

We’ve all heard of the five-second rule: You drop a piece of food on the ground, and you have five seconds to pick it up and eat it. If you get it in that amount of time, it’s still okay to eat. Right?

Many of us think of this concept as a joke — an excuse people make when they really, really want to eat something, but it’s accidentally hit the ground. If we say, “5-Second Rule” and quickly snatch it back up, we justify in our heads that the food item is still fine to eat. Assuming, of course, there’s nothing gross clinging to that item.

Now a new Discovery Science Channel show, The Quick and the Curious, took the “Is 5 Second Rule Real” theory to task. They brought in NASA engineer Mark Rober, who offers cookies to passersby. But in order for them to get the cookie, he first drops it to the ground (in a park, no less) and then asks them to take a bite. Some turn down the snack, while others grab it. But is that action bravery, a safe risk, or just plain stupidity?

It all has to do with the 30-second moisture rule. Whenever a piece of food is dropped on the ground, small amounts of bacteria will jump on immediately. Moist food is more likely to present a problem because bacteria, such as E.coli and listeria, love wet environments.