Is it possible to disinfect a sponge in a microwave: a scientific view

It is believed that sterilizing a kitchen sponge in the microwave destroys all microorganisms that remain in the porous material, and, accordingly, extends the life of the sponges. Let's try to figure out whether this is really so and whether any processing is needed at all.

Why sterilize a kitchen sponge?

It would seem that if you conduct a large-scale laboratory study, then the least amount of bacteria can be found on a kitchen sponge. Firstly, she is touched only with clean hands, and secondly, she is constantly “washed”. However, this is a mistaken impression.

Microbiota colonies

Microbes and bacilli reach the sponge in different ways.

• Primary contamination occurs at the production stage - microorganisms that live in the air and are on the surface of factory equipment penetrate into the pores of the foam rubber. However, this is not scary, because there are exactly the same invisible roommates in every house and apartment.
• Subsequently, bacteria are introduced inside during washing of utensils that were used for cutting raw meat or fish. No less dangerous are utensils that have been in contact with raw dairy products purchased at spontaneous markets.
• Also, some bacteria come from leftover food, especially if they have begun to decompose.
• If one of the family members has infectious diseases transmitted by airborne droplets, pathogenic microbes remain on the plates and cutlery, which subsequently penetrate into the porous material of the sponge and can begin to reproduce.

During a study conducted by scientists from the University of Furtwagen (Germany), 362 types of bacteria were found on kitchen sponges. This is even more than on a toilet brush.

Other microorganisms

In addition to bacteria, yeast and mold fungi live and feel free in the thickness of the foam rubber. Depending on what types of fungi have colonized the sponge in a particular case, they can be much more dangerous than other microorganisms. In addition, they are incredibly difficult to fight, and when they enter the body, many types of mold (for example, the notorious Aspergillus) cause irreversible changes, even lethal.

Sterilizing sponges in the microwave

To kill the pathogenic microflora that lives inside the dishwashing sponge, housewives use a very simple method - processing in the microwave. This procedure is carried out once every three days or more often if necessary.

Process description

Before proceeding directly to sterilization, the sponge is “washed” with dishwashing detergent or simple laundry soap. This is not necessary in order to remove some of the microbes mechanically, but in order to wash out the remaining food from the pores. If you place a sponge in the microwave without first cleaning it, it will acquire a persistent unpleasant odor (in this case it will have nothing to do with the activity of bacteria).

The next steps look like this:

1. The sponge is soaked in clean water.The more liquid the material absorbs, the higher the chance that everything will go according to plan and that you will not have to buy a new microwave oven.
2. The sponge is placed on a plate (it should be ceramic, glass or made of special plastic).
3. A cup two-thirds filled with water is placed next to the sponge - this is a precaution designed to prevent the accumulation of unused magnetic energy inside the device.
4. Turn on the microwave for 1–2 minutes. It is advisable to set the power to 750 Watts or more.
5. When the oven turns off, you need to wait until the sponge has cooled down a little, since its temperature will be 100°C, and only then remove it and put it back in place.

During sterilization, do not leave the microwave. Despite the fact that the water with which the sponge is soaked protects it from melting, sometimes the foam rubber still begins to “melt” - in this case, you should immediately turn off the heating.

Of course, you should not treat metal scrapers in this way - sparks will appear inside the microwave.

Is there an effect?

Some people who are unfamiliar with the operating principles of a microwave oven endow this device with truly fantastic qualities. Unfortunately, this is just a heating device, and its effect on microflora is exaggerated. In essence, the process described above imitates steam sterilization - it has a detrimental effect on most microorganisms known to science.

However, this effect is achieved not only and not so much due to the presence of steam. The heating temperature is of great importance - if water boils at 100°C in a microwave, then in an autoclave the thermometer shows no lower than 130°C.The processing time also differs - a kitchen sponge spends several minutes in the microwave, while sterilization in an autoclave takes at least half an hour.

It turns out that such a short-term treatment in a microwave oven can kill only the least resistant microbes. They, as a rule, do not pose any danger to humans and are part of the natural microflora.

Consequences of sterilization

Housewives, sterilizing a kitchen sponge in the microwave, hope that this will protect them from pathogenic microflora and the diseases caused by it. In fact, the degree of risk increases - since weak microbes did not survive the steam treatment, space was freed up inside the pores, which was immediately occupied by stronger and more dangerous microorganisms.

In most cases, a sponge removed from the microwave is stored in the same place where it was before, that is, in close proximity to the sink. There, bacteria receive an ideal environment for reproduction, because they are warm and humid, which means that after just a couple of hours, a seemingly harmless piece of colored foam becomes a household bacteriological weapon.

How to properly treat a sponge?

To disinfect a kitchen sponge, it should be soaked in a 20% solution of sodium hypochlorite (popularly called bleach), and then processed in an autoclave. However, it is unlikely that foam rubber will withstand such abuse, and the cost of the procedure will be several times higher than the price of a new clean sponge. Therefore, you should not sterilize at home - it is better to simply throw away the used item.

Whether to continue sterilization in the microwave after reading this article is up to everyone to decide for themselves. However, you should never forget that the price of a piece of foam rubber and human health are incomparable.