You drop your sandwich on the floor, it's okay to eat it if you pick it up in five seconds, right?  U.T. Health Sciences Medical School Microbiologist Kevin Morano says it's not about the time, it's about the concentration of bugs.  That means it's really about where you drop that food.

“It depends,” Morano says.  “If you drop it on a dry floor it's perfectly fine.  If you drop it on the bottom of a bathroom stall, I probably wouldn't even go five seconds.”

He says there are two main threats -- bacteria like staph or MRSA.

“Those guys are particularly nasty,” he says.  “They're all over the place.  And, if you got enough of them on your food, you could have a problem.”

The other bacteria which could make you sick are e. Coli or salmonella.  But, for the most part, there’s not much of a threat.

“In most locations where you drop things,” he explains.  “The concentration, the density of germs is really quite low.”