However, the scientists noted that most of the genera of bacteria discovered was not harmful. The pathogens that were found were most concerning, because those can cause infections among humans.
"Kitchen sponges are likely to collect, incubate and spread bacteria from and back onto kitchen surfaces, from where they might eventually find their way into the human body," the study said. "Direct contact of a sponge with food and/or the human hands might transfer bacteria in and onto the human body, where they might cause infections, depending on their pathogenic potential."
Although many boil or microwave sponges to rid of toxins, analysts found that the latter method only kills 60 percent of bacteria. Plus, the bacteria could increase after cleaning, because the microbes re-colonize.
To minimize the spread of germs, researchers suggests that people replace their sponges at least once a week.