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Cambridge University Science Magazine
According to the research, 87% of people would eat food dropped on the floor, or already have done so. Of the women surveyed 81% said that they would follow the 5 second rule. The team led by Professor Anthony Hilton of Aston University, looked at the transfer of commonly found bacteria E.coli and S.aureus from a variety of indoor floor coverings (such as carpet, laminate and tiles) to a variety of foodstuffs over a time period of 3 to 30 seconds.

Professor Hilton says: "Our study showed surprisingly that a large majority of people are happy to consume dropped food, with women the most likely to do so. But they are also more likely to follow the 5 second rule, which our research has shown to be much more than an old wives tale.”

Although the risk of bacterial infection depends in part on how clean the floor is, the study had two main findings. Firstly, the amount of bacteria transferred from the floor to the food increases with time in contact- increasing after 5 seconds, and secondly that the type of floor covering also plays a role.

The best flooring proved to be carpet over laminate or tiles and was facilitated by moist over dry food types. So the next time you drop a piece of toast, it may be worth making your five second rule decision based on whether it landed butter side up or down.