Food that touches the ground for even five seconds is contaminated, so the 'five-second rule' should be changed to 'zero-second rule, warn scientists at Clemson University.
Food scientist Paul Dawson and his students at Clemson determined that the new rule should really be zero seconds, which means that if your food touches the ground, it should not then touch your tongue.
In their work, they determined that salmonella and other bacteria can live for a month even on dry surfaces and will immediately be picked up by food that falls on it.
The Chicago Tribune, which reported on the findings on Monday, noted there is a vast body of research on the consequences of noshing on fallen food.
Two Connecticut College students sprinkled apples and Skittles in the college dining hall to determine how long it took before the foods picked up bacteria.
Their research concluded it took apples a full minute and the candy was safe for at least five minutes.
Other researchers have also noted that where you drop food matters, reports the Daily Telegraph.
Kitchens are literally breeding grounds for bad things because of the types of germs that are found in them, according to University of Colorado School of Medicine professor Harley Rotbart.
Bacteria from uncooked meat tends to collect in kitchens which is generally more dangerous than bacteria that are found in dirt.
In other words, you are probably better off enacting the five-second rule in your yard than in your kitchen.
And similarly, for obvious reasons, bathrooms, too, should be considered zero second zones.
The study appeared in an article in this month's National Geographic.