A man drops a brownie on the floor. If he picks it up within five seconds, should he still eat it? Two U.S. students claim the answer is yes.

In fact, they say he could wait half a minute.

The students, who are seniors at Connecticut College, studied the five-second rule as part of their microbiology class.

"It is an eye-opener," student Molly Goettsche told ABC News. "There may be a little more time than just seconds."

First they dropped Skittles candy and apple slices on the school's dining hall floor for different lengths of time.

Then they swabbed the food for samples and checked for any bacteria.

Their conclusions may be a relief to those who rescue fallen food: it took more than 30 seconds for bacteria to cultivate on the apple slices, which represented wet food.

As for the Skittles, which stood in for dry food, it took longer than a minute.

But despite their findings, the students said they would never eat anything that's hit the ground.

"I don't know if I would ever eat off that floor," said Goettsche.

High school student Jillian Clarke conducted a more exhaustive study in 2003, and her research earned her an Ig Noble award -- a parody of the Nobel Prize -- the following year.

She traced the five-second rule to Genghis Khan. But the Mongol leader, known more for his military tactics than passion for science, thought food could be left on the floor for half a day.

Like the Connecticut College students, Clarke found that dry food dropped on clean floors did not pick up a noticeable amount of bacteria.

However, when she dropped food on floors contaminated with E. coli, the bacteria latched onto the food in less than five seconds.