OK, the headline might be a slight overstatement, but not much of one. At least in terms of the number of disease-causing bacteria, floors tend to be cleaner than kitchen counters and toilet seats cleaner than both. Seriously.
Pediatrician and medical professor Aaron Carroll talks about this below after briefly debunking the five-second rule yet again. (That's the nonsensical folk belief that if you drop something on the floor it takes five seconds for it to get contaminated, as if bacteria were too initially startled to jump on it, or something.)
As Carroll says, you can react to this information by obsessively cleaning everything, or you can recognize that germs aren't all that scary a menace. There are reasonable precautions you can take, especially washing your hands with soap and water a lot. (Following food preparation guidelines also makes sense.)