Students and scientists at Aston University’s School of Life and Health Sciences in Birmingham, England have tested the so-called “five second rule” and found it does apply in real life. That rule, which was most likely coined as tongue-in-cheek, states that if food is dropped on the floor and left there for less than five seconds, bacteria don’t adhere to it and it’s safe to eat.
The findings suggest that many foods (not all) that are picked up just a few seconds after being dropped are less likely to harbor bacteria than food left on the floor for longer periods of time. [Editor’s caveat: I think it depends on how often your floor is cleaned, if animals walk on the kitchen floor, and if you go into the kitchen wearing shoes you wear outside. Kitchen floors can harbor pathogenic bacteria that will make you sick.]
The study found that “time is a significant factor in the transfer of bacteria from a floor surface to a piece of food, and the type of flooring the food is dropped on has an effect.” Bacteria are least likely to transfer from carpeted surfaces to food than from tiled or laminate surfaces. The type of food dropped also makes a difference. A food such as toast picks up fewer bacteria than foods such as spaghetti coated in sauce.
While this study is interesting, mostly because it found that 87% of people surveyed said they would eat food dropped on the floor, we can’t recommend it. It’s better to just stay safe and throw away dropped food. If you get sick from food dropped on the floor, it will be for longer than five seconds.
