You’re eating ice cream on a cone and it fell to the floor. Would you pick it up and eat it? If it were a piece of biscuit that fell to the floor, would your answer be the same? Would you apply the ever-popular 5-second rule that says if the food touched the floor for less than five seconds, it’s still safe to eat?
There are two not-so-old studies on the safety of eating food that had fallen to the floor.
In a 2014 study at the Aston University’s School of Life and Health Sciences, “the transfer of the common bacteria Escherichia coli (E. coli) and Staphylococcus aureus from a variety of indoor floor types (carpet, laminate and tiled surfaces) to toast, pasta, biscuit and a sticky sweet when contact was made from 3 to 30 seconds” was monitored.
Conclusion? When contact lasts longer than five seconds, bacteria is more likely to transfer if food fell on laminated or tiled flooring, and less like to transfer if the food touched carpeted floor.
In a 2016 study at Rutgers, 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.”
The finding? The wetter the food, the higher the risk that bacteria will transfer to it from the floor. Among the four foods tested, watermelon was the most contaminated. But that’s not all. Like the earlier Aston finding, the Rutgers researchers found that carpeted floor is slower to transmit bacteria to food because of its “topography”. Because carpet is not smooth like laminated wood or tile, less surface area of the food gets in contact with the floor.
Read both studies to see if the 5-second rule is true or plain BS. The links are provided above.