You’ve dropped a delicious morsel of food on the floor. If you pick it up within 5 seconds is it still clean and safe to eat? Many adults have been presented with this dilemma. Not the case with children, who don’t think twice about popping the fallen food straight into their mouth. Now science can tell you just how risky this scenario is. The research was led by Professor Donald Schaffner, of Rutgers University in New Brunswick, NJ and the findings were published in the journal Applied and Environmental Microbiology. According to the Centers for Disease Control and Prevention in the USA, approximately one in six people get sick every year from foodborne illness. That’s around 48 million people. Bacterial cross-contamination from surfaces to food can cause foodborne disease. Prof. Schaffner said the 5 second rule exists because people realise that bacteria need time to transfer. But can they do it in 5 seconds? The researchers that conducted this study were very thorough; they used four different surfaces: stainless steel, carpet, ceramic tile and wood. They used four different foods: watermelon, gummy candy, bread and bread with butter. Lastly, they used four different contact times: less than 1 second, 5 seconds, 30 seconds, and 300 seconds. The type of bacteria they used is Enterobacter aerogenes, which is a close relative of Salmonella. Here is what they found: bacteria can contaminate a food instantaneously. Watermelon developed the most contamination, while gummy candy had the least. Here are some quotes from the researchers: "Bacteria don't have legs, they move with the moisture, and the wetter the food, the higher the risk of transfer. Also, longer food contact times usually result in the transfer of more bacteria from each surface to food. The 5 second rule is a significant oversimplification of what actually happens when bacteria transfer from a surface to a food. Bacteria can contaminate instantaneously." You probably had a feeling this was the case all along. Now you know that it’s never OK to eat food that has dropped on the floor. Of course, eating it will not guarantee that you’ll get sick. That really depends on the type of bacteria living on the floor at the time. Reference: