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The 5-Second Rule: Fact or Fiction?

By: Wellness Committee Co-Chair Punita Patel

November 14, 2017

Let’s admit it. We have all done it — dropped a delicious morsel on the floor, picked it up, wiped it off, and then put it in our mouth.

In 2016, researchers at Rutgers University in New Jersey found that bacteria can contaminate food in less than one second! The research study leader, Dr. Donald Schaffner, says that bacteria transfer from surface to food instantaneously. When researchers evaluated the transfer of bacteria from surface to food, they concluded that the longer the food item was exposed to “dirty” surfaces and the more moisture present, the worse the spread of the germs. Therefore, the wetter the food, the higher the risk of bacteria transfer from the surface to the food. This was reported in Applied and Environmental Microbiology.

In 2017, germ expert Professor Anthony Hilton, from Aston University, said, “food is unlikely to have picked up harmful bacteria from a few seconds spent on an indoor floor.” A good test is to see if it is visibly contaminated with dirt. If so, don’t eat it. If no visible dirt is seen, then the chances of ingesting harmful bacteria are very low. Dr. Hilton suggests that dry foods and hard foods are especially at low risk for bacterial contamination even if left on the floor longer than five seconds. He added, “It is less safe to leave damper, stickier food, which pick up more after falling and more over time, so the five-second rule probably does still apply to them,” reported the Daily Mail. “However the chances of anyone getting ill from dropping food on the floor at home are infinitesimally small.”

Dr. Hilton’s research also suggested that it's safest to eat food dropped on carpeted floors, as this had the lowest bacteria levels after three-and-a-half minutes. But if you drop food on a laminated or tiled kitchen floor, it’s worth picking it up quickly (or perhaps just binning it).

While you can never guarantee that eating dropped food will be risk-free, chances are there’s little to worry about if it is on the floor only briefly. Now that’s some serious food for thought!


Rossman School, nestled on a 20-acre campus in Creve Coeur, is an independent preparatory school for students in Junior Kindergarten (four years old) through Grade 6. The school’s mission is to provide a strong, well-balanced education in a nurturing school community committed to excellence. Dedicated to developing personal, nurturing relationships with each child, Rossman’s experienced educators provide a solid foundation in academics, athletics and arts while emphasizing strong character development and leadership skills.​ Request a free Rossman School brochure here

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