UK researchers have found there may be some scientific basis to the “five second rule”, an urban myth that suggests it’s okay to eat food you’ve dropped if you pick it up within five seconds.
Until now, it’s been unclear about whether it actually limited the germs you ingest, but research from Aston University’s School of Life and Health Sciences have studied the transfer of common bacteria Escherichia coli (E. coli) and Staphylococcus aureus between various floor surfaces and foods.
They compared carpet, laminate and tiled surfaces that had toast, pasta, biscuits and sticky sweets dropped on them for different lengths of time, between three and 30 seconds.
They found time was a significant factor for the transfer of bacteria from floor to food.
But the type of flooring also had an effect .Carpet is less likely to facilitate a bacteria transfer than laminate or tiled surfaces.
The worst scenario is moist food dropped onto a hard floor for more than five seconds.
Study leader Anthony Hilton, a professor of Microbiology at Aston University emphasised that there was a risk inherent in eating anything from any type of floor.
“Consuming food dropped on the floor still carries an infection risk as it very much depends on which bacteria are present on the floor at the time; however the findings of this study will bring some light relief to those who have been employing the five-second rule for years, despite a general consensus that it is purely a myth,” he said.
The researchers surveyed people who adhere to the five-second rule and found 87 percent of those surveyed said they would eat food dropped on the floor, or already have done so –– and 55 percent of those were women.
“Our study showed surprisingly that a large majority of people are happy to consume dropped food, with women the most likely to do so,” he said.
“But they are also more likely to follow the five-second rule, which our research has shown to be much more than an old wives tail.”
Julian Rood, a professor of microbiology at Monash University, said that the most important factors for bacteria transfer is the type of food and where it was dropped.
“A piece of bread and butter landing butter side down is more likely to pick something up than a potato chip dropped on a floor,” he said.
“The more bacteria that are on the floor in the first place, the more are going to be transferred to the food. The second issue is whether it’s moist and likely to make significant contact. The greater the surface area, the more bacteria that will be picked up.”
Professor Rood advised people to exercise caution.
Source: Science Daily Author