Avoid eating food that has been on the floor even for an instant. Researchers found that bacteria can attach to food as soon as it hits the floor.

Many people believe in the "5-second rule" according to which food won't become contaminated with bacteria if you pick it up off the floor in 5 seconds or less. After scientists tested it, they found that the rule is mostly a myth. Bacteria can attach to food as soon as it hits the floor. And foods like an apple slice, i.e. with wet surface, can pick up bacteria more easily. While floors that look dirty are obvious hazards, even floors that appear clean can harbor bacteria.