The five-second rule: why you can’t always use it for food dropped on floor
Watermelon that slips through your fingers shouldn’t be eaten, but spilt gummi bears fare a little better in new research on how quickly bacteria latch on to food that lands on the floor
Is it OK to eat food that has fallen on the floor – as long as you pick it up within five seconds?
The short answer: not true. Sometimes bacteria transfer from floor to food in less than a second.
The facts: We’ve all heard the “five-second rule” of food hygiene, which is probably as scientific as watching viral cat videos on Facebook. Well, a new study by researchers at Rutgers University has scientifically proven the rule wrong. It turns out bacteria may transfer to food that has fallen on the floor no matter how fast you pick it up.
Donald Schaffner, professor and extension specialist in food science, found that moisture, type of surface and contact time all contribute to cross-contamination. In some instances, the transfer begins in less than one second. The study appears online in the American Society for Microbiology’s journal, Applied and Environmental Microbiology.
“The popular notion of the ‘five-second rule’ is that food dropped on the floor, but picked up quickly, is safe to eat because bacteria need time to transfer,” Schaffner says, adding that while the pop culture “rule” has been featured by at least two TV programmes, research in peer-reviewed journals is limited.
“We decided to look into this because the practice is so widespread. The topic might appear ‘light’ but we wanted our results backed by solid science.”