Use Microwave To Kill Bacteria On Sponges

For as long as I can remember, after I started my own household, I have heard the debate over using dish cloths as opposed to sponges. These are things that I have heard and I cannot vouch for their validity or medical soundness. I have always gone the route of the dish cloth. I have friends that have always gone the route of sponges.

When I have been at my friends’ houses, and have been in their kitchens, I have always glanced at their sponges. Except for when they were new, I have yet to see one that did not look absolutely disgusting. The sponges always have small pieces of food caught in the little holes that are in the sponges. Dish rags, however, don’t have little pieces of food caught on or in them. Why?, you might be asking. Because there are not three dimensional holes in dish rags like there are in sponges. Granted some of the dish rags are stained from various types of food, but being stained is not the same thing as having food actually caught on or in the dish rags. The sponges actually have food caught in them, not just caught on them, and yes the sponges are stained too. Seeing the sponges like this just turns my stomach.

Apparently there has been enough debating about the sponges versus the dish rags, that studies have been done to find out about bacterial growth in both of them. The findings were conclusive that as a whole the dish rags did not have the same types or amounts of bacteria as the sponges did. The reason being that the dish rags are washed in the laundry every few days. The sponges, on the other hand, do not typically get washed in the laundry at all. I guess most women don’t think that it is necessary to keep their sponges clean. After all, they clean dishes only when they are in the dish water, and wipe off counters and stoves. How can either one of those activities possibly get the sponges dirty? Right? Well, the bacteria is on the counters, the stoves, the drain boards and dish drainers, etc. There is not much of anything that you can touch in a kitchen that does not have bacteria on it. And the longer the bacteria is on whatever it is on, without being cleaned and sanitized, the more the bacteria will grow. There in lies the reason why the sponges have so much more and worse bacteria than the dish rags. Not as much bacteria can grow on the dish rags in the few days in between them being washed in the laundry as sponges that barely get washed at all.

But have no fear. Those of you that use sponges do have a way to get rid of the bacteria. Moisten the sponges and put them in the microwave on high for at least two minutes. According to their findings, this should kill almost all of the bacteria that is present in the sponges. If you don’t think that two minutes is long enough, then you can moisten the sponge again and put it back into the microwave for another two minutes. I have read this is a few places, but I thought that copying the results of a study that was in would give even more proof.

The study and results are below.

According to, “Microwave Sterilizes Sponges”

In the study, published in the Journal of Environmental Health, researchers evaluated the effects of zapping sponges and plastic scrubbing pads in the microwave on bacteria and viruses.

The sponges and scrubbing pads were soaked in wastewater containing a dangerous mix of fecal bacteria, E. coli, and bacterial spores. Bacterial spores are more difficult to kill.

The results showed that two minutes in the microwave at full power killed or inactivated more than 99% of all the living germs and the bacterial spores in the sponges and pads, including E. coli.

After an additional two minutes — a total of four — none of the bacterial spores survived.

Before you zap your sponges in the microwave, researchers offer the following advice:

Microwave only sponges or plastic scrubbers that do not contain steel or other metals.
Make sure the sponge or scrubber is wet, not dry.
Two minutes should be enough to kill most disease-causing germs.
Be careful in removing the sponge from the microwave because it will be hot and should not be handled immediately after zapping.

Bitton recommends that people microwave their sponges according to how often they cook, with every other day being a good rule of thumb.”