We have all, at one point, dropped food on the floor and then sneakily put it back in our mouths. After all, there’s an age-old principle that says you can eat the food you dropped on the floor so long as you pick it up within five seconds (or less!). Whether you believe the “five-second rule” or not, scientists have actually tried to shed some light on the topic.
According to Anthony Hilton, a germ expert, and professor at Aston University in the United Kingdom, there is little to be concerned about if the food is on the floor momentarily. However, you can never be 100 percent sure.
“Eating food that has spent a few moments on the floor can never be entirely risk-free,” he tells the Evening Standard. “Obviously, food covered in visible dirt shouldn’t be eaten, but as long as it’s not obviously contaminated, the science shows that food is unlikely to have picked up harmful bacteria from a few seconds spent on an indoor floor.”
However, Hilton adds, “That is not to say that germs can’t transfer from the floor to the food.”
Hilton, along with other researchers at Aston University, found that there are certain kinds of food you can eat beyond five seconds — in fact, some of these foods are safe to eat even if they’ve been left on the floor for up to 30 minutes! “Rigid food” like biscuits, cookies, sandwiches, dry toast, and chocolate can be on the floor for half an hour with “little increased risk of attracting germs,” according to the study.
“Dry foods, hard foods are really quite low-risk,” Hilton told Daily Mail. “Not only do they not pick up much bacteria on impact with the floor, but they do not get any additional contamination over time.”
Certain types of food like cooked pasta, chips, donuts, sweets, and buttered toast are more likely to pick up bacteria the longer they are left on the floor. “It is less safe to leave damper, stickier foods, which pick up more after falling and more over time,” Hilton said. “The five-second rule probably does still apply to them.”
The kind of floor where the food is dropped is also important. Food dropped on laminated or tile becomes more contaminated than those dropped on the carpet. But across all types of flooring, the food dropped picked up fewer than .0004 percent of the average 10 million bacteria found on a family floor.
“Our research has shown that the nature of the floor surface, the type of food dropped on the floor and the length of time it spends on the floor can all have an impact on the number that can transfer,” Hilton said.
It is important to note that researchers examined the bacteria on kitchen, dining, and living room floors in 40 family and student homes in Birmingham, UK. So it can be said that it is generally safe to follow the five-second rule and eat food that has been dropped on the floor — as long as it’s on a residential floor that is cleaned thoroughly at least once a week.
“The chances of anyone getting ill from dropping food on the floor at home are infinitesimally small,” Hilton said. He presented the study’s findings at The Big Bang Fair — a celebration of science, technology, engineering, and maths (STEMS) for young people — in March 2017.
She adds that foodborne illnesses can have varying onset, between 24 hours to a week, so you probably won’t think the food you picked up last Wednesday is related to your being unwell the following weekend.
“Err on the side of safety,” says Frechman.
If you’re feeding your child and the food drops on the floor, should you believe the five-second rule, pick it up and feed it to her? The American Academy of Pediatrics offers food for thought in an article on HealthyChildren.org: “Children are guaranteed to spend quite a lot of time on the floor. And unless you have an unrealistic notion that you’re always going to be able to keep your floor-crawling hands out of his mouth until they’ve been washed, it begs the question of what’s difference between having one’s hand or one’s food spend time on the floor before finding their way into one’s mouth?”
What do you think, moms and dads? Do you believe in the five-second rule?