Dirtier than water: how to clean and how often to change your sponge to wash the dishes

It’s funny, but when we wash the dishes, are we really cleaning it or are we just making it even more dirty? Depends. About what? Of the state of the sponge that we use for the task. Yes, because depending on its wear and the way we maintain it, we could go from shiny dishes to real potty chairs.

am I exaggerating? Perhaps, if we allow ourselves to be carried away by what happens on a day-to-day basis in a good part of homes. Not so much if we stick to what studies indicate such as the one published in the journal Scientific Reports, where a team of German microbiologists performed a DNA analysis on sponges from different households. In them they detected 362 different types of bacteria, more than those that are usually housed in toilets. That can mean two things: either the Germans are dirtier than we think – not very likely – or the dishwashing sponges can be dirtier than your toilet.

Although most of these bacteria do not represent a greater risk, others with potential pathogens were detected, including staphylococci, salmonella and E. coli, which could cause problems in the body of varying severity, such as diarrhea, urinary infections, diseases respiratory and bloodstream infections.

“Despite common misconceptions, kitchen environments have been shown to harbor more microbes than toilets. This was mainly due to the contribution of sponges, which represent the largest reservoirs of active bacteria throughout the house”, indicates the German study.

Thanks for everything Bob.

What is this all about? According to another investigation, this time from the Department of Chemical Biological Sciences of the University of Sonora, in Mexico, the porous material with which the sponges for washing dishes are made and the humidity that lodges in them work as an incubator for microorganisms. The problem is that, when you use it again, you run the risk of spreading them across different surfaces.

“Moisture is what microorganisms like the most”, says the cook and science communicator Heinz Wüth. “But the sponges also accumulate organic remains from food, which is food for microbes.” In short, a perfect breeding ground.

The sponge for washing is not the only element that acts as a double agent in the kitchen. Absorbent sponge cloths, used to clean surfaces, also work as a incubator for bacteria. “The biggest risk there is biological cross-contamination. Many times, by occupying the cloth, more is being contaminated than what is being cleaned”, exposes Wuth.

We know: washing dishes can be a tedious task. That means that, on more than one occasion, the dirty crockery is left stacking in the dishwasher until the next day. If the sponge remains in the middle of all that accumulation of moisture and organic debris, we are playing with fire blight.

“The biggest cause of poisoning in homes is poor handling and poor hygiene,” adds Wuth. “It goes beyond how we prepare food: it has to do with how we clean surfaces and utensils,” says Heinz Wuth.

For example, says the cook, “if I have a very dirty sponge and clean a glass with it, even if I rinse it well, there is a small chance that the bacteria will remain there. And surfaces are more likely to cross-contaminate if a dirty cloth is used to clean them.”

According to the study published in Scientific Reports, cross-contamination could not only occur on the surfaces where the contaminated utensils are passed, but also on the hands of those who use them and in the foods that are prepared on them. This “is considered one of the leading causes of foodborne illness outbreaks.”

It is a mistake, therefore, to leave the sponge and the absorbent cloth in the same dishwasher, even more so in dirty water. In addition, the useful life of these products is shortened and they begin to generate aromas – a great sign of the proliferation of microorganisms – that are then transferred to the objects that are trying to be cleaned. “And no one likes to drink water from a glass that smells like a rotten sponge,” says Wuth.

Who cleans the cleaners? Photo: Marcos Maldonado/AGENCIAUNO

It may seem like a truism, but given the background that is exposed from science, it is better to go back to the first units of our cleaning manual, and recheck the practices.

First, the sponge, also known as a scouring pad —some of you may feel represented here—, which is usually used to clean dishes, cutlery and other tools such as pots, pans and pans. For this it is necessary to apply detergent or dish soap and water (hopefully hot). They can be found in various materials: there are natural fibers (such as luffa), or artificial fibers such as polyester or polyamide, the latter being the most common in homes and on the market.

“Sponges, in general, have a soft part and an abrasive part. The first is for general washing and the second is for when there is very stuck dirt. And for it to work, it has to be accompanied by a good dishwashing detergent. It is ideal to use hot water, because it removes dirt and grease more easily. Although it can also be used with cold water, there is no problem with that”, specifies Heinz Wuth.

Absorbent cloths, meanwhile, are usually made from natural cellulose fibers and are used for cleaning surfaces. They are not recommended for washing dishes, although, says Wuth, there are those who do use them for these purposes. The important point is that this type of utensil should be used for exclusive tasks. Using the same cloth to clean the floor, which got wet while you were washing the dishes, and then to dry the furniture next to the dishwasher is like organizing a convention of microorganisms in your counter.

The same warning goes for the kitchen sponge. If it is used for washing dishes, it remains only for that task.

It is normal to believe that the sponge, when used together with detergent and water, cleans itself automatically. The reality can always be more complex than it seems, because the sponge, as well as the absorbent cloth, also need and must be washed and sanitized frequently.

There is a myth that the sponge can be cleaned by putting it in the microwave for a few minutes. Which is somewhat true, according to Wuth. To do this, says the cook, you must ensure that there are no visible organic remains. “It’s three minutes at maximum power, and then let it rest for a minute,” he adds. This will allow you to keep it relatively clean for a couple of weeks.

If you use this method, make sure the sponge is dry. If it retains a lot of moisture, you could burn yourself when removing it from the microwave.

In any case, you should know that this is not a 100% effective method. The German study states that the microwave does not eliminate all the bacteria and microorganisms that are housed inside. To be exact, it would only take care of about 60% of these. The problem, more than the percentage, is that there is a possibility that the bacteria that survived this attack will become stronger and re-colonize the sponge.

Considering the above, if the sponge you have in the kitchen is smelly or expels aromas that are not typical of the detergent, it means that it is infected and that it is too late to put it in the microwave. Its only destination is the garbage.

More effective than the microwave is to do a job of washing and sanitizing. Understanding that washing, as Wuth teaches, is to remove the remains that are visible to the eye, and to sanitize do the same with those that are invisible to the eye.

First, the specialist recommends washing the sponge well, with the same detergent or soap that is used to clean the crockery. “And once it’s relatively well rinsed, you can add 70% (minimum) alcohol to make it disinfect.”

There are those who do this by immersing the sponge in a solution of water and alcohol. But it is better, according to Wuth, to do it with a spray or atomizer. That way, he says, less alcohol is wasted without losing effectiveness in sanitizing the sponge.

In the case of the absorbent cloth, after the respective washing with the detergent, it is also a good alternative to apply alcohol on both sides. And once both utensils have been washed, it is necessary to dry them, squeezing them to release the water and leaving them “drying” in the open air to remove all moisture.

Another method is the one suggested by the University of Sonora: consists of submerging the sponge for at least 30 seconds in a solution of water and chlorine (in a ratio of 9 to 1), and then letting it dry.

The washing and sanitizing methods allow you to give these implements a useful life of a few weeks. However, it would be a mistake to pretend that in this way they can be made eternal. Experts estimate that you should change them every 15 or 30 days, although it depends, says Wuth, on the use, intensity and amount of dishes that are washed daily, among other factors.

Microorganisms begin to appear from the first use, so it is important to constantly evaluate the status of these products, verifying that there are no alarm signals. For example, if the abrasive fiber begins to separate from the rest of the sponge, or if fiber balls or knots begin to form; if it begins to lose its original color, if it expels a bad odor, if it feels sticky to the touch or if you see black or white spots on its fiber. All these are signs that the sponge has already given everything it had to give and that, no matter how much love you have for it, it is better to retire it.

As these utensils are disposable -although it costs, you have to know how to say goodbye-, it is convenient to choose those that are biodegradable. Wuth, for example, recommends compostable cotton and natural fiber absorbent cloths, which can be disposed of in organic waste bins.

Sponges made with copper nanoparticles, meanwhile, have a higher antibacterial power than other materials, which gives them a longer useful life and prevents the appearance of bad odors.

You can also opt for brushes. “I highly recommend them, especially for people who don’t like to touch food with their hands while washing dishes. The good thing is that they do not retain water or damage delicate surfaces, such as Teflon. Also, they have quite a shelf life. I have had one for five years, because I disinfect it every six months”, closes Wuth.

*The prices of the products in this article are current as of September 7, 2022. Values ​​and their availability may change.

Leave a Comment

Your email address will not be published.