Is the ‘5 second rule’ real? Scientist says it’s all about location

TORONTO – When microbiologist Jason Tetro accidentally drops a piece of his meal onto the floor, the first thing he considers is location.

When it comes to the “five-second rule,” the Canadian scientist says some areas, like the kitchen, are off limits when it comes to eating off the floor. The living room? That might just be a passable area.

“If you happen to drop your apple or something onto a surface that you don’t normally see pathogens, then it’s not really going to be a problem,” Tetro explained.

“If it’s the middle of the living room, there’s really no problem. However, if it’s in the bathroom, especially if you don’t flush with the lid closed, then it’s likely you might pick something up,” Tetro warned.

Our biggest concern? Fecal bacteria that’s most often lurking by the toilet. Then there’s the E. coli, salmonella and campylobacter– all food-borne pathogens that you could find in your kitchen.

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“If you haven’t washed your floors in the kitchen for, say, a month, and you cook chicken every single day, there’s a good likelihood you’ll have salmonella or campylobacter on the floor,” Tetro said.

He pointed to research that suggests a small floor space could be covered with up to 10,000 germs.

Tetro’s comments come on the heels of a new British study that says there may be some scientific basis to the “five second rule.” It all depends on the surface your food is falling on and how long that sad piece of meat has been sitting on the dirty floor.

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Dr. Anthony Hilton and his team at Aston University looked at how certain germs – E. coli and staphylococcus aureus – transferred from a variety of indoor floor types like carpet, laminate, and tiled surfaces. Toast, pasta, cookies and a sticky sweet were each dropped on the different surfaces for between three to 30 seconds.

Turns out, carpeted surfaces are the best to work the five second rule on. Hardwood floor, laminate or tiled surfaces make exposure to germs much easier.

Moist foods, like cooked pasta or sticky treats, were also more likely to pick up bacteria compared to dry food, like a piece of toast.

No-go zones

Tetro says that bathrooms and kitchens are no-go zones. Tables in restaurants might even be worse off: they’re wiped down with dishcloths that could be laced with bacteria. In previous studies, Tetro swabbed tables and found they’re more germ-infested than the floor.

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“So what ends up happening is you expose yourself to a whole variety of germs that your body may not be used to. Next thing you know, you have stomach rumblings and you’re feeling awful,” he explained.

His rule of thumb? If you drop a piece of your meal, take a second to ask yourself what location you’re in, then take another second to consider the surface area. Finally, take the last three seconds to pick it up and make your own decision.

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According to Hilton’s research, Tetro says that hardwood floors or ceramic tile almost guarantee some transfer of germs. In other textures like carpet, clothing or upholstery, bacteria could get trapped in the surface area and transfer – whether it’s five seconds, 30 seconds or an hour – may not happen at all.

“The five second rule is a general rule to follow but it’s better to make sure you know your environment, location, surfaces and your own health status before you make that decision,” Tetro said.

Hilton’s research follows a 2007 study done by researchers in South Carolina. The strange thing is, they found opposite findings, or a “zero second rule” even after using nearly identical methods of investigation.

carmen.chai@globalnews.ca
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