There’s no science behind the five-second rule, long invoked by parents to allow their kids to “safely” eat food they dropped on the floor, according to a report in Feedstuffs on new research published in the journal Applied & Environmental Microbiology.
Turns out that bacteria can transfer to food dropped on the floor no matter how quickly it is picked up. “Donald Schaffner, Rutgers professor and extension specialist in food science, found that moisture, the type of surface and contact time all contribute to cross-contamination. In some instances, the transfer begins in less than one second,” said Feedstuffs.
The study concluded that watermelon had the “most contamination and gummy candy the least.” Schaffner noted that “[b]acteria 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.”
Carpet proved to be the safest surface in terms of contamination, and tile and stainless steel had much higher “transfer rates.” Wood was “more variable” than the other surfaces. “The topography of the surface and food seem to play an important role in bacterial transfer,” Schaffner said.