When it comes to your home, you might expect the highest number of microbes will be found in the bathroom. You just might be wrong.

As a professor of microbiology, I pretty much practice what I preach, and I am probably into more disinfection and sanitizing in my own house than most of you would be. But even I can overlook the smallest things that have the potential to be extremely dangerous, like a kitchen sponge. 

I went to the kitchen this morning and there was a terrible odor. Upon investigation, it wasn’t coming from the garbage receptacle but from a small kitchen sponge. I went to my computer and began to research microbes that can contaminate kitchen sponges.

The kitchen sponge is the perfect cleaning tool, and the harder you scrub, the more you spread the pathogens. Bacteria love to hide and grow in the kitchen sponge. One researcher, Dr. Linchong You from Duke University, described the kitchen sponge as a perfect apartment complex for bacteria, in which they have their own free delivery of food and water from the spills we wipe up.

A study in Scientific Reports that outlined research from Furtwnagen University in Germany found 362 different species of bacteria isolated from kitchen sponges. PubMed Central published a study conducted in 10 kitchens in the United States; it found that 67 percent of the tested sponges were positive for Escherichia coli and fecal coliforms. Fifteen percent were contaminated with Salmonella. Sponges also tested positive for Campylobacteria, Enterobacteria, Klebsiella, Proteus, yeasts, molds and more. These names might have no meaning for you, but the microbes can be pathogenic. A National Science Foundation study of 22 families over a one-month period (NSF 211) found that 75 percent of the household sponges and dish clothes had coliform bacteria (E. coli), indicating fecal contamination.

Remember, chicken, meat and vegetables brought home from the supermarket are not sterile. You prepare these dishes on the kitchen surfaces, uncooked, and then you clean the surface with the kitchen sponge.

When we use a contaminated sponge with our hands, it can cross contaminate our hands and any surface it touches, 

Researchers found that recommended cleaning methods, such as microwaving a sponge, only kills about 60 percent of microbes, and resistant strains recolonize. Why even bother? Online I found a pack of 50 kitchen sponges for $14.95. You can probably do better at other locations.

At the end of the day, clean your kitchen surfaces with a disinfectant like Clorox wipes and dry with toweling. Throw out the kitchen sponge.

Michael Kossove is a professor emeritus and adjunct professor of microbiology at Touro University, School of Health Sciences, NY.