Have you heard of the “Five Second Rule”? Honestly I thought it was something my in-laws invented. The way it goes is – you drop food on the floor and if you pick it up right away – you can still eat it. Now, while many of us would just throw the food away, new research has found that there is some truth to the “Five Second Rule”.
Anthony Hilton, a microbiology professor at Aston University in England researched the transfer of germs such as E. coli and Staphylococcus aureus from flooring surfaces to foods dropped for 3 to 30 seconds. His team found that germ transfer is poor with surfaces such as carpeting and greater for laminate or tiled surfaces. Germ transfer is also greater after five seconds of exposure, especially to moist foods. Professor Hilton stated that while “Consuming food dropped on the floor still carries an infection risk, it very much depends on which bacteria are present on the floor at the time”.
An earlier research study conducted at the University of Illinois, Urbana-Champaign also
looked at the “Five Second Rule” and found that when university floors were swabbed for microorganisms, it was difficult to isolate them. Most pathogens like salmonella, listeria, and E. coli need moisture to survive. So the take away from these studies is “There is a Five Second Rule” in food safety. If you drop dry food on dry surfaces, and if you keep your floors cleaned regularly, you are probably safe to eat it. Especially if it was only on the floor a few seconds, but moist foods or those foods dropped on moist surfaces are more likely to have picked up the transfer of potentially harmful germs.
While I’m not likely to use the “Five Second Rule, the next time my in-laws call it out and grab a cookie that was dropped to the living room carpet, I won’t think they are crazy. Dry foods on recently cleaned dry surfaces are unlikely to pass bacteria, but especially moist foods on moist surfaces can be harmful to your health. For more information on food storage and safety check out the factsheets on http://go.osu.edu/foodsafety.
Writer: Lisa Barlage, Extension Educator, Family and Consumer Sciences, Ohio State University Extension, Ross County.
Reviewer: Melinda Hill, Extension Educator, Family and Consumer Sciences, Ohio State University Extension, Wayne County
Office on Women’s Health, U.S. Department of Health and Human Services, http://womenshealth.gov/news/HealthDay/index.html.