There's Some Science Behind the 5-Second Rule
You're safest if carpet was involved, says study
By Kate Seamons, Newser Staff
Posted Mar 14, 2014 11:59 AM CDT
Carpet is safer than tile, it seems.   (Shutterstock)

(Newser) – The five-second rule: old wives' tale or science? According to a professor of microbiology at Birmingham, England's Aston University, the answer is ... it depends on whether you're in your bedroom or kitchen. Anthony Hilton and his biology students looked at two types of bacteria (E. coli and Staphylococcus aureus) on three flooring options: carpet, laminate, tile. Toast, pasta, a cookie, and a "sticky sweet" were dropped on the various surfaces and rested there for 3 to 30 seconds. When it came to the transfer of bacteria, both time and flooring type played a role.

Bacteria were least likely to hop aboard the fallen bite if carpet was involved; when "moist" foods hit laminate and tiled surfaces, bacteria was more likely to transfer when contact was made for more than 5 seconds. The upshot, per Hilton: "We have found evidence that transfer from indoor flooring surfaces is incredibly poor." That's likely welcome news to the 87% of people the students surveyed who reported a willingness to adhere to the five-second rule. Writing for Forbes, Alice Walton notes that the findings should be taken with a grain of salt—preferably one not dropped on the floor. She points out that the study doesn't seem to have been peer-reviewed or accepted for publication anywhere. (A previous report on the topic noted that food dropped on the sidewalk was likely safer to eat than that on the kitchen floor.)

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Showing 3 of 11 comments
Mar 23, 2014 3:36 PM CDT
wait, it's the TWO second rule? So I can slow down!
Mar 14, 2014 6:39 PM CDT
I think I'll take the article's word for it, which is good news. I am clumsy for sure, and I do follow the five second rule with dry foods and toothpicks. It's a matter of common sense.
Mar 14, 2014 3:28 PM CDT
When MythBusters Jamie Hyneman and Adam Savage bit into the same popular presumption, they realized that different foods produce a smorgasbord of results. Comparing the bacteria colonies picked up by dry saltines and wet pastrami after the sodium-rich snackshung out on a contaminated floor for a few seconds, Jamie and Adam noticed the moist sausage scooped up far more flora. When the MythBusters then analyzed food-free contact plates that had spent two- and six-second intervals on a contaminated surface, the "five-second rule" quickly crumbled. Even if something spends a mere millisecond on the floor, it attracts bacteria. How dirty it gets depends on the food's moisture, surface geometry and floor condition - not time. That spells sad news for clumsy eaters everywhere: The "five-second rule" myth is busted.