We have all done it before (even those who don’t want to admit it): dropped something delicious on the floor and quickly picked it up, hurriedly exclaiming “five second rule!” and proceeding to eat the tasty morsel. While nobody was actually sure if the rule was correct, now we can all rejoice as new research has revealed that the period of time food is left on the floor is an important factor when it comes to the transfer of bacteria.
The study conducted at Aston University’s School of Life and Health Sciences discovered that food contained much less bacteria when picked up almost immediately, as opposed to food that was left for a longer period of time.
Led by Professor of Microbiology Anthony Hilton and conducted by final year biology students at Aston University in Birmingham, England, the research monitored the transfer of the common bacteria Escherichia coli (E. coli) and staphylococcus aureus from various indoor floor types that included carpet, laminate and titled surfaces. A range of foods were used in the tests such as: toast, pasta, biscuits, ham, dried fruit and sticky dessert, while the time the food was left on the surfaces ranged from three – 30 seconds.
Researchers found that time was a significant factor in bacterial transfers, with the type of flooring used also having an effect on the results. They found for example that bacteria has less chance of sticking to the food on carpet as opposed to when dropped onto a laminate or tiled surface. When food was moist and left on the floor for more than five seconds, this also increased the chances of bacteria transfer.
The study also included a survey and found that 87% of people would eat food that has fallen on the floor, with 55% of these people women.
While the study has provided some evidence to support the “five second rule”, as Professor Hilton says, “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”, there are also other factors besides the length of time to consider when deciding whether or not to eat food that has been on the floor. Factors such as the type of bacteria present on the floor at the time also plays an important role.
So it is still important to be smart when deciding whether or not you really need that piece of food that has just been on the floor.