Doctor reveals why the 3-second rule could be a big mistake
Rachael Davis
Featured Image Credit: Indeed/Getty Images
The pandemic made many of us considerably more contamination-conscious, but it doesn’t take many tube journeys with people sneezing into open space to realise it wasn’t a universal effect.
Some have even taken it upon themselves to lower their personal biosecurity in response to the pandemic, as if to prove it was all a lot of fuss over nothing. There’s nothing like pointlessly contracting norovirus to stick it to the Man!
That section of society will no doubt proudly scoop up some food they’ve dropped on the floor, then scarf it down whilst dubiously claiming it will be ‘good for their immune system’.
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They will likely cite a particular urban legend while they're at it: the three-second rule.
The legend has it that food can’t be contaminated with floor-borne nasties until three seconds have elapsed, making food saved in that window safe to eat.
As with most nonsense proliferated in primary school playgrounds, it’s not exactly scientifically-robust.
A doctor has stepped in to clarify why eating food off the floor isn’t a great idea, along with whether there's much truth to the popular urban legend.
Dr Zoe Williams made an appearance on ITV’s This Morning to attempt to put the myth to bed, and she came armed with results from a study conducted by Manchester Metropolitan University.
The experiment involved dropping various foods on the floor at three, five and ten-second intervals. They were then checked for contamination with bacteria that had been deliberately applied to the floor under lab conditions.
"There was a slight difference depending on the amount of time, so there is a thread of truth that the quicker you pick it up, the less contaminated it might be,” explained Williams. “But what they actually found was that it depends more on the type of food."
Essentially, foods that were higher in sugar or salt were more challenging for bacteria to quickly contaminate. The contamination rate also depended on whether the food was wet or dry, with wet stuff being much more effective at picking up bacteria.
Do with this information what you will, but do bear in mind that most floors are dirtier than one used under these specific lab conditions, you never know what nasties might be on the floor, and your immune system is regularly in action throughout the day regardless of how many gross habits you might have.
If you want to strengthen your immune system, then you’re better off with regular exercise, a balanced and vegetable-heavy diet, managed stress, consistent hydration, and good sleep rather than throwing all caution to the wind.
As for Dr Williams’ take on the results: "As a doctor, I have to say I cannot say it is safe to pick up food off the floor, but it largely depends on the floor, doesn't it?”