Can You Clean a Kitchen Sponge and Make it Bacteria Free?

Posted by Eric Troy on 14 Jul 2014 00:07

If you use a kitchen sponge to clean your kitchen counters or to hand-wash dishes, you probably know that sponges get very nasty very quickly. They also quickly become little germ factories so that you end up doing nothing more than spreading bacteria over your kitchen or dishes, etc. Now, the truth is that once kitchen surfaces or other surfaces are dry most all of the bacteria, if not all of it, dies.

You may have been told that viruses, on the other hand, can survive virtually forever on surfaces or in the air but the truth is that viruses need a host organism to reproduce and have a limited lifespan on kitchen surfaces.

Humidity plays a role in the lifespan of both bacteria and viruses. However, how long they can survive depends on the particular bacteria or virus. HIV, despite the widespread fear of toilet seats and other surfaces, dies very quickly outside the body and sunlight will do an instant number on it. Flu virus can hang around for days or weeks. E coli is pretty resilient, as well. But on a dry kitchen counter-top which has been wiped "clean" there is really not much to fear. Your body or clothes, full of skin cells and fluids, are a different matter. But the kitchen sponge? May as well have a germ factory in your house. Full of moisture and edible goodies. As well, even if it doesn't stink, it is probably still germy.

Even if you're not worried about the things you use the sponge on, you may be worried about getting all those germs on your hands and then transferring that to your mouth or eyes, accidentally. So, most of us replace kitchen sponges often. But, if you're like me, you feel guilty using a lot of disposable items like kitchen sponges, paper towels, etc.

There's good news. To some extent, you can clean your sponge and render it germ-free. This doesn't mean you can keep it forever but you can certainly sanitize it and make it a little safer for everyday use. There are good ways and bad ways to do this. A popular method being passed around the internet is to use a dishwasher.


Using a Dishwasher to Sanitize Sponges and Other Cleaning Implements

This seems to be very popular, as long as you have a synthetic cellulose sponge. Some home dishwashers (like mine) have a Sani-Rinse setting which uses a very hot water rinse to sanitize dishes. The food code would have such temperatures be at least 180° for mechanical methods and 171° for hot water immersion. The sani-rince cycle on home dishwashers will probably not get that hot. Maybe up to 160 or 165°F. However, this may not matter. Dishwashers just won't clean inside porous surfaces. All the little bits of crud will probably not even wash off the surface of the sponge, let alone be removed from the crevices and holes. And, although you would think the high heat drying cycle would kill all the microbes, it will not dry out a sponge.

I cannot guarantee you that your dishwasher will not kill all the germs in your sponge, but there certainly is no guarantee it will. It will remain sopping wet, and cruddy bits of gunk will remain in it and any bacteria that survive will start having a party and give birth to millions of little bacteria monsters. Also, do you really want to put a nasty sponge in with your dishes? On other hand, do you want to use all that energy to clean just a couple of sponges, plastic pot scrubbers, and/or brushes, etc.? This doesn't seem green, to me. Despite all this, I suspect a dishwasher is a better method than most people use, which is nothing.

O-Cedar Kitchen sponge

O-Cedar Kitchen Sponges rinse clean and the scrubber won't
scratch Teflon coated nonstick pans.

O-Cedar Kitchen sponge

O-Cedar Kitchen Sponges rinse clean and the scrubber won't
scratch Teflon coated nonstick pans.

Washing With Hot Soapy Water

A combination of soap and warm or hot water does a great job of decimating bacteria. However, washing a sponge in soapy water will not sanitize it completely. The presence of soapy water residue inside the sponge and on its surface will likely impede microorganisms, but have you noticed how hard it is to wash soap out of a sponge? If you are using it with dish-washing liquid to clean dishes, this may not matter to you. But if you are using it for other purposes, you are probably not going to want a sponge full of soap. I shudder, personally, at using a sponge to clean dishes. I prefer a clean dishrag that I use a couple of times and then launder thoroughly. So, given this, here is how I would propose you prolong the life and cleanliness of a kitchen sponge, if you are inclined to do so:

Rinse in Water Thoroughly After Use

Each time you use your sponge, rinse it in water by immersing it or getting it thoroughly water-logged, squeezing out the water and then repeating, while rubbing with your hands. This serves to remove some of the bits of food and other contaminants from the sponge.

Spray or Soak in White Vinegar for Everyday Maintenance

Vinegar is a great disinfectant. After rinsing your sponge thoroughly soak it with white vinegar and let it sit for a minute or two before squeezing it out and allowing it to dry throughout, preferably on a warm window-sill.

Boil, Microwave, or Bleach for Thorough Sanitizing

To completely sanitize, but not necessarily remove all residues, food bits, etc. (see these are two different things), immerse a sponge in boiling water for a few minutes, or in pure household bleach. You can also put a WET sponge in a microwave and heat it on high for one to two minutes (there may be a slight odor). OR, soak the sponge in a bleach solution of at least 10% bleach for five minutes. This will thoroughly sanitize the sponge. Make sure that if you use bleach to sanitize a sponge not to then use the bleach along with an ammonia cleaning agent, as this will produce a poisonous gas.

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