It's time to retire the five-second rule | Science News

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It's time to retire the five-second rule

Bacteria jump quickly onto dropped food

11:53am, September 23, 2016
peanut butter and jelly sandwich face down on the floor

DON’T EAT THAT  Wet foods that fall on the floor pick up bacteria quickly, a new study suggests.

For some dropped foods, the five-second rule is about five seconds too long. Wet foods, such as watermelon, slurp up floor germs almost immediately, scientists report online September 2 in Applied and Environmental Microbiology.

Robyn Miranda and Donald Schaffner of Rutgers University in New Brunswick, N.J., tested gummy candy, watermelon and buttered and unbuttered bread by dropping morsels onto various surfaces coated with Enterobacter aerogenes bacteria. Food was left on each surface — stainless steel, ceramic tile, wood and carpet — for time periods ranging from less than a second to five minutes. Afterward, the researchers measured the amount of E. aerogenes on the food, harmless bacteria that share attachment characteristics with stomach-turning Salmonella

As expected, longer contact times generally meant more bacteria on the food.

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