Go ahead, eat that cookie

Health facts come and go: One minute fiber wards off cancer, the next minute it’s ... well, fiber. Now one of the most famous health rules we live by is hanging by a thread: The 5-second rule, which states that you can eat a cookie that fell on the floor if it touched the ground for 5 seconds or less. Turns out this is wrong! The correct time is more like 30 seconds.

Thus concluded Molly Goettsche and Nicole Moin, two students at Connecticut College in New London, Conn., after empirically testing the rule with Skittles candies and apple slices. The foodstuffs were dropped onto floors then left for 5, 10, 30 and 60 seconds, and 5 minutes. Then surfaces were tested for presence of bacteria by swabbing the foods and culturing the swabbings on agar plates.

Result for the Skittles: Bacteria were detected at 5 minutes.

Result for apple slices: Bacteria were not detected at 30 seconds or less but were detected at 1 minute. (The bacteria probably stuck easier to the apple because the slices, unlike the Skittles, were wet.)

Read the whole release at https://aspen.conncoll.edu/news/3464.cfm.

— Rosie Mestel