Think Following the "5-Second Rule" Keeps Food Safe? Think Again!

Research reexamines the "5-Second Rule"


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Image Source, This content is subject to copyright.

When food falls on the floor, it’s always a judgment call as to whether that food goes into your mouth or into the trash. And many of us, when making that call, defer to the so-called “five-second rule” — that long-standing and widely accepted notion that if food spends five seconds or less on the floor it hasn’t had enough time to be contaminated by whatever bacteria is on the floor. But is the five-second rule based on any actual facts, or is it just a myth that we perpetuate every time we let our kids pick up and keep sucking on that lollipop they dropped?

Turns out, scientific research on the topic has been pretty limited ... until now, that is. A team of researchers at Rutgers University’s School of Environmental and Biological Sciences put a variety of foods — watermelon, bread, bread with butter, and gummy candy — through their paces. They dropped them onto four different surfaces — carpet, stainless steel, ceramic tile and wood — and left them for less than one second, five seconds, 30 seconds and 300 seconds. All of the 128 possible scenarios were repeated 20 times; in the end, the researchers had a total of 2,560 data points to analyze.

Watermelon got the germiest after even a brief time on the floor, and the gummy candy picked up the fewest contaminants. Both bread and the bread with butter fell somewhere in the middle of the contamination continuum. But what was most interesting is that although all the foods picked up more bacteria the longer they sat on any of the four surfaces, they weren’t totally bacteria-free even after just a few seconds of contact. “Some transfer takes place ‘instantaneously,’” the researchers wrote, “disproving the ‘five-second rule.’”

So, sorry kids, but that fallen lollipop should probably go into the trash — unless you want to suck down a bunch of bacteria along with your candy.

Sally Wadyka is a Boulder, Colorado-based journalist who writes about nutrition, health and wellness.

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