Germapalooza: How to Keep Kitchen Sponges Clean


Germs may be lurking in your trusty kitchen sponge, but you can take measures to kill the bacteria.“Germs may be lurking in your trusty kitchen sponge, but you can take measures to kill the bacteria.iStockphoto/Thinkstock

Think fast: What’s the most germ-infested room in the house? If you guessed the bathroom, you’re wrong. The kitchen earns the distinction, largely because of the sponges we use to clean our dishes and countertops.

Sponges are excellent at absorbing and retaining liquid, which is great for cleaning kitchen surfaces and soaking up spills, but those same properties can also be problematic when it comes to germ control. When a wet sponge sits, harmful bacteria can multiply, and when you go to wash your dishes and counters, you could be spreading around dangerous pathogens. When you use a sponge to clean up food waste, the sponge accumulates microorganisms and stores them in its little nooks and crannies — which is why the U.S. Department of Agriculture (USDA) reports that using old sponges can lead to food-borne illness.

"A sponge that’s been in use for no more than two or three days in a kitchen will harbor millions of bacteria,” explained Elizabeth Scott, co-director of Simmons College’s Center for Hygiene and Health in the Home in a recent New York Times article. That can be a serious problem if you happen to pick up salmonella or E. coli with your sponge, because any time you use that sponge, you could potentially disperse dangerous bacteria around the kitchen.

Reading this might make you want to order takeout or go to a restaurant just to avoid the kitchen sink, but that isn’t the solution. People have been preparing food for eons without poisoning themselves and their loved ones, and there’s no reason you shouldn’t be able to as well. You don’t even need to toss those kitchen sponges, as long as you can clean them properly.

Keep reading to learn what types of bacteria are hiding in your sponge and what you can do to fight them.


  1. What Are Common Kitchen Bacteria?
  2. How to Prevent Bacteria on Kitchen Sponges
  3. What Are Some Good Ways to Kill the Bacteria?
  4. Are There Different Types of Sponges That Harbor Less Fungi or Bacteria?

What Are Common Kitchen Bacteria?

Most kitchens are swimming in bacteria, and it isn’t just the kitchen sponge that’s to blame. A recent survey by the Hygiene Council found that the average kitchen drain has 567,845 bacteria per square inch (second only to the toilet).

Of course, not all bacteria in the kitchen or elsewhere are dangerous — some can even be beneficial. But MSNBC reports that the reason we worry about germs is because uncooked meats and raw fruits and vegetables can carry very dangerous pathogens, like E. coli, salmonella and campylobacter, to name a few.

So why is the kitchen such a nurturing environment for microorganisms? The introduction of raw meats and fish, along with fruit and vegetable residues, is where the problem starts.

Every time you bring home a bag of groceries and prepare a meal, you’re unleashing loads of bacteria in your home. For example, if you decide to cook a chicken you’ll need to clean it, cut it and cook it, and during every step of the process you could be spreading potentially dangerous pathogens all over the kitchen. If you grab a saltshaker without washing your hands, you could transfer a fresh load of bacteria onto its surface. Even when you go to wash your hands, you’ll likely leave some raw chicken residue on the faucet.

Food residues adhere to your hands, hand towels, kitchen utensils and countertops; and the bacteria can survive for several hours or days. Water is the key element that enables germs to thrive and multiply, which is why the sink area is ground zero for bacteria in the kitchen. Every time you clean your countertops or wash your dishes, you are filling up the pores of the sponge with food-borne bacteria, CBS reported. And if the sponge stays wet, the bacteria could remain there for days.

Do we have your attention yet? Read on to learn some valuable tips on how to prevent bacteria from hiding in your sponge.

What’s in That Sponge?

Most sponges (kitchen sponges, that is — not the sea creatures) are made of a combination of cellulose from wood pulp, hemp fiber and sodium sulfate. DuPont developed the technology in the 1940s.

How to Prevent Bacteria on Kitchen Sponges

Now that we’ve stoked your germophobia, let’s talk about some solutions. Food poisoning often results from improperly handling raw foods and inadvertent cross-contamination, which can involve the kitchen sponge. The main thing to remember is that because bacteria thrive in moist environments, keeping the sponge and the area surrounding the sink dry will create a less hospitable environment for them. So every time you clean a countertop or do the dishes, remember to thoroughly wring out the sponge so it can dry faster.

The next line of defense is, of course, soap. Antibacterial soap has become clouded with controversy in recent years, because many scientists argue that antibacterial soap kills beneficial bacteria while aiding the rise of superbugs, against which we have little defense.

Antibacterial dishwashing soaps are specifically designed to kill bacteria that make their home in sponges, but the jury is still out on their actual effectiveness. For example, a study conducted in 2002 at a Dutch university tested antibacterial soap’s ability to kill various microorganisms in kitchen sponges. It found that the soap ended up killing many of the innocuous bacteria, but that more dangerous bacteria — like E. coli and salmonella — survived. The results of that study are exactly what antibacterial skeptics are afraid of: a soap that kills beneficial bacteria while leaving dangerous germs stronger than ever.

What Are Some Good Ways to Kill the Bacteria?

Since it was discovered that kitchen sponges tend to host large colonies of bacteria, a handful of home remedies for killing the germs have been introduced in recent years. Let’s take a look at some of the more popular home remedies:

  1. Wash the sponge in the dishwasher: The most obvious way of cleaning the sponge is to toss it in the dishwasher with the dirty dishes, but there has been little proof that the method actually works. During a TV appearance, Sharon Franke, the kitchen technology and appliances director at Good Housekeeping Research Institute, explained that putting sponges in the dishwasher isn’t the best course of action because the water in the dishwasher probably doesn’t get hot enough to kill all the bacteria.
  2. Put the sponge in the microwave: A 2007 University of Florida study found that nuking kitchen sponges for about two minutes in the microwave was enough to effectively sterilize the sponge and kill all bacteria in it. Many news outlets reported the findings without mentioning that sponges should be wet before putting them in the microwave, prompting many people to zap dry sponges, which is a serious fire hazard. The University of Florida later issued an advisory that sponges should be completely wet and have no metallic content before they are put in the microwave.
  3. Dip the sponge in bleach: Chlorine bleach is one of the most widely used household disinfectants because it is tried-and-true. Experts recommend regularly soaking sponges in a bleach solution that is heavily diluted with water. When working with bleach, it’s a good idea to wear rubber gloves and be careful not to breathe in fumes.
  4. Dip the sponge in lemon juice or vinegar: If you (understandably) feel a bit queasy about using bleach in the same area where food is prepared, you might want to try dipping your sponges in lemon juice or regular old white vinegar. Several studies back it up, proving that vinegar is an effective way of killing bacteria. The U.S. Department of Agriculture (USDA) recommends dipping sponges in lemon juice for about one minute to disinfect them.

What Is Chlorine Bleach?

Chlorine bleach, or sodium hypochlorite, is a common household cleaner that’s made from mixing chlorine gas with sodium hydroxide. It’s found in tap water and swimming pools because it’s an effective disinfectant.

Are There Different Types of Sponges That Harbor Less Fungi or Bacteria?

Considering the risks, is it even worth the trouble to keep that germy sponge around? Most kitchen sponges are made of cellulose, an organic compound made from a mixture of wood and cotton fibers. Cellulose is good at soaking up liquid, which is useful for cleaning up spills, but that same property is what makes sponges an excellent refuge for germs. We also use sponges because they’re cheap and easy to find (just about every grocery store or neighborhood pharmacy stocks them). But they aren’t the only option available.

Dishrags are commonly used to clean dishes and counters, and — although many of the same studies that have found high levels of bacteria in kitchen sponges also found similarly high levels in dishcloths — they’re generally considered to be slightly less bacteria-filled. For example, a recent New York Times article observed that dishcloths "become saturated with bacteria, although since they dry more quickly than sponges, bacteria are less likely to breed." Dishcloths dry faster because they are thinner and easier to wring out than sponges — and they’ll probably get washed more often to keep them from looking so gross.

For a quick-drying tool, you might be better off moving away from sponges and dishrags and trying something less absorbent. For example, scouring pads (which are often paired with kitchen sponges) effectively remove food from dishes and kitchen surfaces, but they are less absorbent, and as a result, they tend to dry faster. A variety of plastic and synthetic dishwashing tools, like cleaning brushes, are also available at most grocery stores. As with sponges, other types of cleaning tools should be disinfected regularly.

For lots more information about keeping kitchen sponges clean, read on.

Lots More Information

Related Articles

  • What’s cleaner — a toilet bowl or a kitchen sponge?
  • Is antibacterial soap any better than regular soap?
  • How does chlorine bleach work?
  • 10 Ways to Clean the Kitchen with Lemon Juice
  • Home Cleaning Tips


  • Hesser, Amanda. "Squeaky Clean? Not Even Close." New York Times. 2004.
  • Hitti, Miranda. "Top Spots for Bacteria at Home." WebMD. 2007.
  • Hoover, Aaron. "Researchers: Microwave oven can sterilize sponges, scrub pads." University of Florida News. 2007.
  • Kusumaningrum, et. al. "Effects of antibacterial dishwashing liquid on foodborne pathogens and competitive microorganisms in kitchen sponges." Journal of Food Protection. 2002.
  • "Microorganisms in Kitchen Sponges." Internet Journal of Food Safety. 2005.
  • "Mystery solved: How bleach kills germs." Reuters. 2008.
  • Neal, Rome. "Ways To A Safe Kitchen." CBS News. 2004.
  • "People, only zap wet sponges to kill germs." Reuters. 2007.
  • Sharma, Manan, Mudd, Cheryl and Eastridge, Janet. "Effective household disinfection methods of kitchen sponges." 2008.
  • "Soap up! The 12 germiest places in your life." TODAY Health. MSNBC. 2008.
  • Technical Foam Services, Ltd. "How synthetic cellulose sponges are made." 2010.


Please enter your comment!
Please enter your name here