A study by UK's Aston University discovered that food plucked off the floor within a few seconds is less likely to contain bacteria than if left to languish for longer.
The findings suggest there may be some scientific basis to the five-second rule according to which it is fine to eat something that has had contact with the ground for only five seconds or less.
"Consuming food dropped on the floor still carries an infection risk as it very much depends on which bacteria are present," said Professor Anthony Hilton, a professor of microbiology at the university, who led the research.
"However the findings of this study will bring some light relief to those who have been employing the five-second rule for years.
"We have found evidence that transfer from indoor flooring surfaces is incredibly poor, with carpet actually posing the lowest risk," Hilton said.
The study monitored the transfer of E coli and Staphylococcus aureus from a variety of carpet, laminate and tiled surfaces to toast, pasta, biscuit and a sticky sweet when contact was made from three to 30 seconds, 'The Times' reported.
It found that time was a significant factor in the transfer of germs.
The study found moist foods, including pasta and sweets could be picked up within the five-second window but after five seconds the risk of bacteria transfer increased.
The type of flooring also plays a part - with bacteria most likely to transfer from laminate or tiled surfaces to moist foods.
The study also found that women were more likely to pick up dropped food than men.