Related: 5-second rule backed up by science
The Associated Press reported that the findings were published in September's American Society for Microbiology journal, "Applied and Environmental Microbiology."
To test the rule, researchers tested four surfaces and four different foods: stainless steel, ceramic tile, wood and carpet, and watermelon, bread, bread and butter and gummy candy, respectively. They also used contact times of less than one second, five seconds, 30 seconds and 300 seconds.
Findings said that moisture contributes most to bacteria transfer. The gummy candy had the least amount of contamination and watermelon had the most.
The study also found that the longer food is on the ground, the more time it has to collect more bacteria, so if you must eat that piece of candy that fell on the floor, be quick about it.