So, you bought an ice cream. And you dropped it on the ground. And its sprinkles are now as smashed up as your heart. Or you spent hours boiling that mushroom risotto down, and the friggen cat tripped you up and the pan slipped out of your hand and went flying into the kinda-dirty sink.
The five-second rule — the notion that if you pick something up off the ground within 5 seconds you can still eat it without being gross or infected with bacteria — will not save you. The myth has recently been debunked.
If you’re not a subscriber of the American Society for Microbiology‘s journal, maybe you haven’t heard that some scientists at Rutgers University in New Jersey felt the need to categorically prove that 5 seconds is long enough for bacteria to contaminate your ill-fated food item.
In fact, not even The Flash could recover their food off the ground in time to prevent contamination: it’s instantaneous. The less time on the ground the better, but, there is no “no harm done” rule for floor-fallen food.
The study wasn’t the first to prove this, but, it was the most thorough:they dropped a variety of food types onto various surfaces, and measured bacteria rates after 1, 5, 30 and 300 seconds of exposure with their surface. And they conducted 2,560 tests.
No food was safe, and, the wetter the food (like their watermelon test-subject) the worse the contamination. Ditto for the harder the surface: ceramic tile and wooden flooring transfer more bacteria, and transfer it more quickly. .