We’ve all heard of the 5-second rule: if a piece of food drops on the floor, it’s safe to eat if you grab it in five seconds or less. That may not be true, though, according to an article on the Medical News Today website.
Researchers at Rutgers University decided to test the rule. They used four types of surfaces: stainless steel, ceramic tile, wood, and carpet. They also choose four kinds of food: watermelon, bread, bread with butter, and gummy candy. Finally, they tested four different contact times: less than a second, five seconds, 30 seconds, and 300 seconds.
They cultivated bacteria similar to salmonella and spread it on the different surfaces, allowed it to dry, then dropped each food on each surface for each designated time period. The results: the bacteria was able to contaminate the food almost instantly in every case, although with different degrees of contamination. Watermelon soaked up the most bacteria because of its moisture; the gummy treats were affected the least due to their hard surface.
Nonetheless, the scientists are confident that their findings disprove the 5-second rule. So you’re probably safer throwing out any food that hits the floor.