'Five second' rule on dropped food unsafe

CHICAGO, July 17 (UPI) -- The "five second" rule that says quickly retrieved dropped food is all right to eat should be a "zero second" rule because of bacteria, food scientists say.

Clemson University food scientist Paul Dawson found that salmonella and other dangerous bacteria can remain alive up to four weeks on dry surfaces -- like floors -- and can be instantly transferred to dropped food, the Chicago Tribune reported Thursday.

Location, not time, is the critical factor, researchers say.

Brushing off a bagel you dropped on the sidewalk and eating it is probably safe because the pavement is cleaner than a kitchen floor in terms of the kinds of bacteria found there, Dr. Harley Rotbart, a professor of microbiology and pediatric infectious diseases at the University of Colorado, said.

"The kitchen floor, however, is probably a zero-second zone because the bacteria from uncooked meat and chicken juices are more hazardous than the 'soil' bacteria outside," said Rotbart.

Bathroom floors are also zero-second zones because they're "a great potential source of bacteria and shorter-lived viruses that can cause gastrointestinal illness if ingested," Rotbart said.