Five-Second Rule ‘More Than Old Wives Tale,’ Scientists Find

NIH, cell day
Under the microscope, an E. coli cell lights up like a fireball. Each bright dot marks a surface protein that tells the bacteria to move toward or away from nearby food and toxins.
(Image credit: Derek Greenfield and Ann McEvoy, University of California, Berkeley.)

Is food dropped on the floor gone forever? Some people swear it’s not, citing the five-second rule, an urban myth that food is safe to eat if it has only been on the ground for only seconds because germs have yet to “latch on” to the item.

A team of researchers tested the rule by allowing toast, pasta and even a “sticky sweet” to touch different floor types where E.coli and Staphylococcus aureus could be transferred in a span of anywhere from 3 to 30 seconds.

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Nina Sen
Nina Sen is a frequent contributor to Live Science’s Life’s Little Mysteries series: an exploration and explanation of our world’s phenomena, both natural and man-made. She also writes astronomy photo stories for Live Science's sister site Space.com.