Why Do Sponges Start Smelling Bad? – Explained!

The function of kitchen sponges is to keep our dishes and kitchen surfaces clean. However, the sponges begin to emit unpleasant odors relatively quickly after we start using them.

Have you ever wondered why kitchen sponges get smelly so quickly and if there is anything you can do about it? The purpose of my post is to shed light on the possible causes of the foul smell of kitchen sponges.

Substances created as a result of the activity of microorganisms cause the unpleasant smell of kitchen sponges.
Sponges are made of porous materials so that they can absorb and retain large amounts of liquid.

The moisture, food particles, and dish soap residue in the sponge provide ideal living conditions for various bacteria, yeast, and mold.

How can you clean a kitchen sponge?

Boiling is one of the methods of disinfecting kitchen sponges. The easiest way to boil the sponge is in the washing machine, together with kitchen towels. Afterward, it is very important to dry the sponges. Just like our clothes, sponges are best dried in the hot sun or in a clothes dryer.

Many people put the kitchen sponge in the dishwasher to clean it, which can be effective if you use a hot water cycle and then dry the sponge.

A popular way to disinfect sponges is to put them in the microwave, which can destroy more than 90 percent of bacteria through high heat. However, caution is important when disinfecting a sponge in the microwave, as it can easily catch fire if it is not soaked with water.

The methods of disinfecting kitchen sponges listed here kill most of the bacteria, but the result is only temporary. They will start breeding again in a short time if the conditions become suitable for them.


Can a dirty kitchen sponge make you sick?

Contaminated kitchen sponges can be sources and spreaders of microorganisms, as well as foodborne illnesses.

Microorganisms living in kitchen sponges pose the greatest danger to young children, the elderly, and people with compromised immune systems. Regular and proper kitchen hygiene practices are very important in preventing foodborne illness.

Raw meat, fish, poultry, and eggs pose a health risk in the kitchen. Therefore, it is absolutely not recommended to use again the sponge that was used to clean the tools and surfaces used during their processing.

When should you throw out a kitchen sponge?

It is best to change the kitchen sponge weekly, do not wait for it to smell unpleasant or become slimy. At that point, it is better not to try to save or clean it, but to buy a new one.

Why you shouldn’t leave a sponge in the sink?

The dish sponge cannot dry out if it is kept in the kitchen sink all the time. Moisture favors the growth of microorganisms. According to a study, most pathogenic microorganisms live in the kitchen sink, dishcloths, and sponges, including Listeria, Salmonella, and Escherichia coli.

After each use, wring out the sponge well and dry it. The best way to store a dishwashing sponge is in a wire basket so that air can circulate on all sides.


However, there are safer dish and kitchen cleaning methods and tools that should be considered.

Don’t keep your kitchen sponge in the sink

What tools can we use instead of a dish sponge?

1. Dishwasher

The most efficient way to wash dishes is to use a dishwasher, which ensures adequate cleanliness for dishes with hot water cycles and strong detergent. Another advantage of the dishwasher is that it requires less water than manual dishwashing.

2. Dish brush

For manual dishwashing, it is better to use a dish brush, as a smaller number of microorganisms remain in it than in sponges. This is probably due to the faster drying time.

However, it is important to clean the food residue from the brush after use. A 2022 research funded by the European Commission recommends the use of brushes instead of sponges for washing dishes.

3. Silicone dish scrubber

Dish brush in a plate
A dish brush is more hygienic than a sponge.

The advantage of silicone dish scrubbers is that their material is non-porous, so it does not retain as many bacteria as a sponge, so it does not become smelly. The silicone dishwashing tools are easy to keep clean and can be washed in the dishwasher.

4. Wet wipes

For cleaning kitchen surfaces, countertops, cabinet doors, and refrigerators, it is best to choose wet kitchen wipes and paper towels, which are thrown away after one use.


By using disposable wet wipes, we can prevent the spread of bacteria to other surfaces and to the rest of our living space. Eco-friendly wipes made from biodegradable materials are also available.

Final thoughts

Due to the porous structure of the kitchen sponge, it can contain a large amount of moisture, which, together with food residues, creates a suitable breeding ground for various microorganisms.

Substances produced by bacteria are responsible for the development of unpleasant odors in the majority of cases.

If you wash the food residues from the sponge well and then dry it, you can slow down the deterioration process. Nevertheless, it is recommended to change the kitchen sponge every week, even if it does not look dirty yet.

If your sponge already smells, it is best not to try to save it, but to throw it away. Time to buy a new one.

For more information on food safety, please read my article on the benefits of good food hygiene.



My name is Debora, the founder of My Delicious Sweets, and a qualified confectioner with broad experience in the confectionery industry. On my blog, I will share important, interesting, and fun facts about food, along with some of my favorite recipes.

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