It's not just an old wives' tale or urban legend after all - the legendary five-second food drop rule is apparently legit, according to a new study.
Anthony Hilton, Professor of Microbiology at Aston University in Birmingham, England, and his team did the Mythbuster thing, and found that the time spent by a piece of food lying on the floor was a significant factor for the transfer of bacteria.
Hilton and his team dropped various pieces of different kinds of food such as toast, pasta, biscuits, ham, dried fruit and various sticky foods to an assortment of indoor floor surfaces, which included carpet, laminate and tiled surfaces and let them lay there from 3 to 30 seconds. They then monitored the transfer of the common bacteria E. coli and Staphylococcus aureus from the floor to the pieces of food, factoring in the time duration in which the food was left on the floor.
The researchers have found that time duration was significant in the amount of bacteria that was eventually transferred from the floor to the piece of food. Sticky food had increased chances of picking up bacteria from the floor if they were left there for more than five seconds. The type of flooring was also a factor in the transfer, as they have found that carpeted surfaces were least likely to transfer bacteria onto food, while laminated or tiled surfaces can transfer bacteria onto dropped food if the food is kept in place for more than five seconds.
The popular TV show Mythbusters already did a previous "busting" of the "myth" of the five-second rule, and their findings did not show any significant different in the amount of bacteria transferred on fallen food that remained on the floor between two and five seconds. However, this new study has proven that the myth is actually not a myth.
The research team also conducted a survey asking people if they would eat food that had had fallen on the floor. They found that 87% of people surveyed said they would, and 55% percent of these were women. Furthermore, 81 percent of these women said they follow the five-second rule. The results of the study have been published in the Journal of Applied Microbiology.
However, Hilton explained that this does not mean that people can just eat food off the floor if it has been there less than five seconds. He warns against the risk of infection because floors are generally not clean.
"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 but 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," Hilton told Science Daily.