7. The Five Second Rule
This little chestnut rears its head whenever someone somewhere drops something extremely delicious-looking on the floor. But throw that sucker away, because as Dr. Roy M. Gulick said "the five-second rule probably should become the zero-second rule." Dammit. In a 2007 study, 99 percent of salmonella bacteria immediately clung to bologna dropped on wood and tile. A British study using cookies and jam sandwiches had slightly different results, but the water, sugar and salt content of the food can determine how much bacteria can kick around. We're not gonna take chances on this one.