“Five second rule,” you might think to yourself as you scoop that cheese puff off the floor. Don’t be ashamed—turns out there may be some truth behind the imaginary time limit we’ve set to determine when it’s still OK to eat food that’s fallen to the ground. Research out of Aston University’s School of Life and Health Sciences suggests there is scientific evidence to support the idea that you can safely eat food that has been in contact with the ground for five seconds or less.
In the study, a team of final-year biology students, led by Anthony Hilton, a professor of microbiology, watched how bacteria like e.coli and staphylococcus aureus (which causes staph infections) transferred from common indoor flooring surfaces like carpet, tile and laminate to foods such as toast, pasta, biscuits and a “sticky sweet.” The exposure times ranged in duration from three to 30 seconds.
The research showed that time is a significant factor in determining the likelihood that bacteria will transfer to food. It also showed that the surface on which the food was dropped has an effect on the transfer of bacteria. Bacteria is least likely to transfer from carpeted surfaces, whereas a laminated or tiled surface is most likely to transfer bacteria to a “moist food” making contact for more than five seconds.
“Consuming food dropped on the floor still carries an infection risk, since it depends heavily on which bacteria are present on the floor at the time; however, the findings of this study should bring some slight relief to those who have employed the five-second rule for years, despite a general consensus that it is purely a myth,” Professor Hilton said in a press release.
Still, you might want to avoid grabbing that sticky sweet cinnamon bun off your carpet—unless you want a mouthful of hair, that is.