Danni and Krystyna determine if food that’s fallen on the floor is safe to eat if you pick it up within five seconds. Our test dummies Aj, Fabiana, and Spencer take pizza and bagels to Prospect park intentionally drop them on different surfaces. We thenswab them for bacteria and bring the swabs to the Columbia University Lab to develop on petri dishes for 72 hours. Once they develop Dr. Susan Wittier helps us determine what bacteria is present on food after five seconds of exposure on different surfaces.