The so-called “five-second rule” for food that is dropped on the floor has been scientifically debunked according to Lindsey Stevenson, nutrition and health specialist, University of Missouri Extension.
A recent study from Tufts University Friedman School of Nutrition Science and Policy conducted an extensive test, 2,500 measurements to be exact, on the idea that food touching the floor for no more than a few seconds is still safe to eat.
“No matter how clean you think your floor is, germs or bacteria are everywhere. It’s important that we don’t let those germs into our bodies because they can lead to illnesses, especially for the youngest and oldest members of our society, or those with compromised immune systems,” said Stevenson.
In the Tufts study, researchers dropped various food items on different surfaces for anywhere from less than a second up to five seconds. They then measured the food items for bacterial contamination.
Of the foods tested, watermelon soaked up the most bacteria while gummy candy picked up the least. Similarly, tile or steel flooring transferred bacteria more readily than carpet.
While the study did find that longer contact on contaminated surfaces increased the transfer of bacteria to the food item, the results also show that the type of surface and food matter.