Scientists Prove The '5-Second Rule' When You Drop Food On The Floor Really Does Work

Parents, relax.

Research from England’s Aston University suggests that eating food that has fallen on a ground is safe if you retrieve it quickly. It gives a scientific basis to the old urban myth of the “5-second rule”.

The study, by final year biology students from the School of Life and Health Sciences at Aston University in Birmingham, monitored 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.

Food picked up a few seconds after being dropped was less likely to contain bacteria than if left for longer periods.

The study found that:

  • Time is a significant factor in the transfer of bacteria from a floor surface to a piece of food.
  • The type of flooring the food has been dropped on has an effect, with bacteria least likely to transfer from carpeted surfaces and most likely to transfer from laminate or tiled surfaces to moist foods making contact for more than 5 seconds.

So if it makes you feel better, despite the Vegemite stains on the carpet, your toast is actually safer to eat than if it lands of a timber floor.

Anthony Hilton, Professor of Microbiology at Aston described the transfer of bacteria as “incredibly poor” from carpet.

“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,” Professor Hilton said.

The students also surveyed people who applied the 5-second rule and Prof. Hilton said “a surprisingly large majority” of people were happy to eat things that fell on the ground and that women led the way.

“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’ tail,” he said.

The survey showed that:

  • 87% of people surveyed said they would eat food dropped on the floor, or already have done so
  • 55% of those that would, or have, eaten food dropped in the floor are women
  • 81% of the women who would eat food from the floor would follow the 5 second rule

[Dropped ice cream photo: Shutterstock]

Read more about the study here.

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