What you need to know about the 5-second rule


It’s definitely not OK to eat food off the floor, even if you’ve picked it up within five seconds of dropping it, according to researchers at Rutgers University.

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5-second rule debunked by researchers

We’ve all heard about the five-second rule, the notion that it’s safe to eat food that has fallen on the floor if you pick it up within five seconds. The rule is based on the belief that it takes bacteria five seconds to transfer from the floor to your food.

Rutgers researchers say that’s absolutely false. Bacteria can transfer in less than a second.

Researchers tested four surfaces – stainless steel, ceramic tile, wood and carpet – and four different foods — watermelon, bread, bread and butter, and gummy candy.

They also looked at four different contact times – less than one second, five, 30 and 300 seconds. 

According to the findings, watermelon had the most contamination and gummy candy had the least. Meanwhile, carpet had much lower bacteria transfer rates compared to tile and stainless steel.

“Transfer of bacteria from surfaces to food appears to be affected most by moisture,” said Donald Schaffner, professor and extension specialist in food science at Rutgers. “Bacteria don’t have legs, they move with the moisture, and the wetter the food, the higher the risk of transfer. Also, longer food contact times usually result in the transfer of more bacteria from each surface to food.”

While it’s true that more bacteria is likely to transfer the longer the food is on the floor, the type of food and the surface it fell on must also be considered, researchers emphasized. 

The bottom line from Rutgers is that bacteria won’t wait five seconds to spread, it can contaminate instantaneously.


Read more: 8 foods you should never reheat in the microwave

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