You won’t like hearing this but your kitchen sponge has more bacteria than a laboratory petri dish! One study from overseas suggests sponges are dirtier than toilets! Hard to believe, not sure I believe that one!
Anyway, sponges massively attract and absorb and spread germs that contaminate the counter, kitchen appliances you use them on, and also the dishes you wash.
So if you’re worried about catching food poisoning from undercooked meat, the odds are far, far higher if you clean your dishes with an old sponge! I say that because about 5% of raw chicken sold in supermarkets may be contaminated with Salmonella, according to the latest data. Compare that with a microbial paradise living in your sponge which houses up to 54 billion bacteria in every cubic centimeter! To get a visual on how many microbes take up residence in 1 cubic centimeter, it’s the size of a sugar cube! Your kitchen sponge is much bigger than that!
Today we will explore what is living in your sponge, but first, you can throw it out now if you’d like to because it’s probably older than a week, which is about how long they stay ‘fresh.’ We can’t buy a new one every week, so let’s think this through together.
Duke University biomedical engineers have proved that your kitchen sponge is a delicious housing community for germs, and it incubates the pathogens better than a traditional agar plate. The publication can be found in the peer-reviewed journal, Nature Chemical Biology and researchers concluded with:
“Partitioning promotes the persistence of populations with negative interactions but suppresses those with positive interactions. For a community consisting of populations with both positive and negative interactions, an intermediate level of partitioning maximizes the overall diversity of the community. Our results reveal a general mechanism underlying the maintenance of microbial diversity and have implications for natural and engineered communities.”
In short, they’re saying that a sponge is a great communal space for nasty organisms!
It’s not because you keep it dirty, I bet you don’t. I bet your sponge appears pretty clean. It’s because of all the nooks and crannies in a sponge compared to a petri dish! It allows the microbes to swarm around and multiply very quickly.
Don’t X Out This Page Yet
Before you say, “eew” and X this page, please hear me out. The reason I find this topic so critical for readers is that when illness strikes, we often look outside our home, for the cause of distress. For example, if you get a tummy ache with diarrhea, most people assume it was from the food consumed at the last meal… whether that meal was eaten at a restaurant or at home.
But I bet it never enters the mind of anyone that the transmitted bug for said “stomach flu” came from a sponge. Perhaps you or the restaurant washed the utensils with a filthy sponge. The mind just doesn’t go there, does it? It will assume that the food itself was the culprit. Until maybe today. I submit to you that you might be ‘eating’ microscopic bacteria off that freshly washed plate or spoon, and it could be responsible for the food poisoning. Depending on the organism transmitted from the sponge, one may experience far more than the expected mild gastroenteritis cured by Pedialyte! The catastrophic illnesses from microbes found in a sponge are meningitis, pneumonia, high fevers, bloody diarrhea, and life-threatening blood poisoning.
1. Campylobacter Has Been Isolated
But for most of us, we will live out our entire life and never know we have this bug! It lives on your sponge. You may be washing dishes with this and putting it all over your dishes. The word “campylobacter” means “curved bacteria.” This organism will cause diarrhea. People typically get an infection of this from undercooked (or raw) chicken, unpasteurized milk, or raw alfalfa sprouts that carry it. This organism, like many others discussed in my blog, may also be found in contaminated lettuce or other vegetables, especially if they are not washed well.
Those who become ill from this can expect loose stools, abdominal pain, fever, and feeling queasy. It’s usually self-limiting, however, seek medical attention if you see blood in the stool.
People who get infected may also get it from undercooked chicken, raw milk, or contaminated lettuce. In recent times, we see many people getting very sick, and many recalls associated with lettuce, so if you’re interested in other salad greens, read my other article, The 9 Most Delicious Lettuce Alternatives.
2. Enterobacter cloacae is in a Sponge
Germophobes beware, this guy lives in your gut as part of your normal intestinal flora! It’s not considered dangerous unless you become immunocompromised. It’s also a common nosocomial infection… the kind you get while you’re in the hospital. Then it will rise with all its glory and attack your skin, respiratory tract, internal organs, and blood. It can cause endocarditis. In some rare cases, it can lead to pneumonia, septicemia (blood poisoning), severe urinary tract infections, and even meningitis. By the way, septicemia is the medical term for blood poisoning by bacteria. There’s an absolutely bizarre CASE STUDY of a 52 yo woman whose rotator cuff (shoulder) got infected with this organism.
3. E. coli is Present in a Sponge
This organism is extremely common and ubiquitous. It is often associated with food poisoning and in my humble opinion, sponge-related illness! People who become infected with E. coli have the usual stomach complaints that look like food poisoning. To be clear, E. coli can be transmitted from raw or undercooked ground beef, raw milk, some cheese, or contaminated vegetables.
Most cases include a mild fever, painful stomach cramping, diarrhea (often tinged with blood), and nausea/vomiting. Weakness and dehydration occur as well. These symptoms may resolve on their own unless you are weak or otherwise chronically ill.
If that’s the case, the rare life-threatening complications include kidney failure, bloody stools, and dangerous thrombocytopenia. You may not recognize the symptoms at first, and thus wait too long, so let me ensure your safety by telling you about the late-stage problems associated with life-threatening E. coli infections:
- Shortness of breath
- Unexplained, easy bruising
- Weak or decreased urine outflow
- Pink tinge in the urine (indicates blood)
- Pale skin, including the loss of rosy cheeks and pink inside your lower eyelid
- Nosebleed or gum bleeding
E. coli is usually self-limiting and the symptoms are mild. You just have to rest, replenish with water and electrolytes, and over a week introduce bland foods into your diet. It can cause dehydration and fatigue. In 2021, we saw an exponential spike in cases worldwide due to contaminated food, especially onions, PACKAGED SALADS, and other vegetables grown in and out of the USA. Read my other article, How to Recognize and Treat Food Poisoning, to see how crazy the uptick in food poisoning was in 2021. It’s much worse this year too!
4. Klebsiella Can be Found in a Sponge
This organism is another opportunistic pathogen, meaning it lives inside the normal flora of the gut, but it will become stronger in people who have poor immune function. It is also common as a nosocomial infection during a hospital stay. Unfortunately, a sponge is home sweet home to this bug, and sadly, it can evade many of our strongest antibiotics. A severe infection of this may be hard, if not impossible to treat because it can be a superbug, therefore resistant to traditional antibiotics. The severity of infection and prognosis depend of course on the person’s age, medical history, severity, and time frame of illness. The organism can cause “Klebsiella pneumoniae” as well as very severe urinary tract infections, septicemia and skin/soft tissue infections.
5. Moraxella osloensis is Also Found in Laundry
This organism is probably the most popular one that you’ve encountered, but never heard of! It’s the bacteria that causes a musty, moldy odor in LAUNDRY, maybe laundry that is wet. You know what I’m referring to if you do the laundry in your household. Moraxella is found in tremendous amounts in a sponge according to this paper entitled, Moraxella Species Are Primarily Responsible for Generating Malodor in Laundry. It also lives in your sponge. The illnesses associated with M. osloensis include skin lesions, meningitis, osteomyelitis, endocarditis, urethritis, and joint arthritis. In kids, you might see oral mouth sores (stomatitis) or impetigo if they happen to get infected.
6. Salmonella Could Be Inhabiting Your Sponge
An intestinal infection of salmonella is termed “salmonella enterocolitis” and it causes fever, diarrhea, and painful abdominal cramps. If you catch this from something you ate (or through sponge cross-contamination), the symptoms may begin same day, in 4 to 6 hours. In other cases, it may take up to a week to show symptoms. Salmonella has nothing to do with salmon, you don’t get it from eating fish! It’s a common microorganism that actually is found in humans (and animals) and lives symbiotically with our microflora. It is shed through our elimination processes, specifically #2.
People mostly get this from contaminated food or water, but again, a sponge will harbor salmonella and if you don’t know that, you could be washing your utensils, plates and glasses and transmitting it everywhere. By the way, iguana and turtle lovers can get it from their pets. Snakes as well!
Like the other germs discussed today, salmonella is already in “the host” meaning it’s in you. So it can become opportunistic and deadly if you have a weakened immune system or a cytokine storm. Other candidates for serious infections include people who take a lot of antibiotics or those who have Crohn’s disease or ulcerative colitis (UC). Those last two intestinal conditions can be very serious and are autoimmune-driven. My close friend Janet just suffered the loss of her precious daughter-in-law who succumbed to UC at the age of 58, and her family is never going to recover! While this has nothing to do with a sponge, I am mentioning it because our gut is often the most important, and yet most under-cared-for area to focus on with health challenges.
Here’s something interesting on the topic of GI disorders such as UC or Crohn’s… it almost always impacts the skin. Sometimes that’s the first place people ‘see’ a symptom that is associated with their gastrointestinal tract! For that reason, I wrote an article about the connection between GI problems and skin health. You can read, Save Your Skin with Probiotics at your leisure.
Of interest is a species called Salmonella typi, which lives in humans very commonly. It’s passed around people through contaminated food or water. This is the organism that leads to typhoid fever!
5 Things You Should Never Do With Your Sponge
- Never cross-contaminate. For example, do not clean the dish that held your raw meat while it was marinating, and then use the same sponge to clean your forks, and drinking glasses.
- Never clean the sink, or countertop, and then use the same sponge to clean your dishes.
- Never leave your sponge in a puddle of water at the bottom of the sink. It will get moldy and fungus. You should at the very least, microwave it for 2 minutes on high, then let it dry every time you use it.
- It’s ideal to use dish gloves when washing dishes, that way you’re not contaminating anything with the germs that are under your fingernails or on your skin. They’re comfy too, and allow you to turn up the heat of the dishwater.
- Don’t recycle it. Regular kitchen sponges are almost always made of plastic which doesn’t break down, and cannot be recycled. Regular sponges should go into the trash. I’m concerned that my information today will make you want to discard your plastic sponges more frequently than you currently do, like once a week! And while that’s good for your health, it’s bad for Earth.So rather than do that, save yourself the money, and consider alternatives to plastic sponges since they are just piling up at the bottom of our oceans and destroying our beaches (and our bodies due to microplastics). There’s an interesting National Geographic article on this topic if you’re so inclined.
Sponges made from cellulose (or some other plant-based degradable material) will be marked as such on the packaging, and can be recycled when you’re done with them, however, are often biodegradable, so they can go in your recycling or compost bin when you are done with them.
Staphylococcus is Another Pathogen to Consider
One of the most common pathogens in the world, this is responsible for causing skin and soft tissue infections. The clinical presentation is usually red, swollen cutaneous lesions, sometimes there is pus or drainage. Staph is all over your body anyway, it lives on people. It’s always on our skin, but you obviously don’t want to lick it off your freshly washed spoon that was cleaned with a disgusting sponge! A staph infection that begins to take over can cause impetigo which can then crust over. It may cause cellulitis infections which can be very dangerous in the elderly.
It’s terrible to see this, but we are seeing an unprecedented degree of infections of Staph in people, and the organism is getting into the bones, heart, lungs and other tissues causing life-threatening infections.
Up to 7 percent of sponges and dirty dishrags have been found to harbor the flesh-eating MRSA bug – short for methicillin-resistant staphylococcus aureus (MRSA).
Two other organisms that live on a sponge include Proteus and Acinetobacter species if you care to look those up.
Does microwaving a Sponge Work?
Maybe, maybe not. It depends on who you ask. According to this PAPER, regularly sanitized sponges have higher percentages of bacterial pathogens than those that had never been cleaned! It’s mind-boggling but one explanation is that microwaving kills the more susceptible microbes, allowing more dangerous ones to take over their space in the sponge. But whether or not this is the reality of it isn’t clear because they weren’t actually growing the pathogens, they were looking at DNA sequences which aren’t the same. And other research suggests that microwaving is okay, and preferable.
So if you’re asking me, and I think you are, then I say YES! Microwaving will massively reduce the microbial load. It will certainly weaken and sometimes kill certain types of bacteria, but not all. So this is a good recommendation from a general standpoint. It may reduce colonies of some species of E. coli, Staph, and Salmonella organisms, we know that much. Microwaving will also often diminish a smelly odor on a sponge because it is killing off some of the Moraxella species. Another advantage of disinfecting your sponge in the microwave is that it extends the life of one sponge, so it saves money.
A STUDY from 2007 did find that microwaving helps and can kill up to 99.9% of the germs they tested, meaning this method is more effective than dishwashing it. Not all microwaves are up to snuff! Certain microwaves may require more time to sufficiently kill bacteria, or may not have wattage high enough to completely eliminate bacteria.
Some of the older ones will require you to heat them for a long time because they have low wattage. Newer microwaves with higher wattage may have sufficient power that you only need to microwave it for 1, or perhaps 2 minutes to sufficiently kill the organisms. Do WET the sponge first, do not put it in dry.
Does boiling work? Maybe a little, but microwaving is better than boiling it.
Alternatives to a Sponge
There are many options if you are grossed out about using your sponge. Like one of my friends Jason said, “It’s a love-hate relationship.”
- Scrub brush – These will also harbor bacteria, but you can dishwash a plastic scrub brush, and their housing ability doesn’t come close to the nooks and crannies of a sponge! So they’re a level up. These are ideal for cleaning pots and pans, cast iron skillets, and thermoses. are more hygienic than a plastic sponge.
- Silicone brush – These are easy to wash and have the same advantages as a scrub brush (see #1 above), but they last longer.
- One-time use metal scrubbies – If you’re using this once, or even twice in a day, you can toss it out and it won’t harbor anything. Metal is less hospitable to the plastic in a regular plastic sponge with all the nooks and crannies.
- A dishwasher – The advantage of this is you’re sterilizing everything pretty much, however, the chemicals in dishwashing soap, and drying agents have their own downside!
- Microwave a wet sponge – You can continue using a sponge, but microwave it with every use, or at least several times a week. Wet it before microwaving. This can reduce the number of bacteria in your sponge significantly. See more about microwaving a sponge above.
- Hot soapy water for 15 minutes – I will often do this. I keep one side of my sink very clean and fill it with hot, soapy water with all the dishes in it. I use comfortable dishwashing gloves so that the water I fill the sink with is super hot. After 10 – 15 minutes of soaking, you can pull up a dish, and it is virtually clean! I use my gloves to ‘scratch’ off any lingering residue, and add more soap if needed to make it squeaky clean.
If I use a sponge, and I do at times, it is less than a month old and gets microwaved at least once a week. If you try this method, the key is to keep that side of the sink perfectly clean, and sanitized frequently, so it isn’t harboring pathogens when you fill the sink with hot, sudsy water!
- Launder your dish rags or in hot water if you use them to wash dishes. Same recommendation if you use “Norwex” clothes. My friend Anna uses those, I had to look them up but they look pretty cool! Still, you have to sanitize those frequently.
- AIRNEX biodegradable sponges or alternatively, sponges made by Soap Lift® are two different brands of eco-friendly sponges! They were not part of the study I’ve cited so there isn’t any data on them. But just upon visual inspection, it’s clear they will not house as many germs as a regular sponge. So they are definitely NOT as bad a breeding ground as a typical plastic kitchen sponge. These brands are two of my favorite sponges because at least when you throw them out, you don’t feel guilty about it, and they clean dishes really, really well!
Summarizing the Sponge Dilemma
Sponges are a microbial hot spot for dangerous organisms! Diseases may be transmitted from a seemingly clean-looking sponge to a person. The person may or may not realize their symptoms are caused by the sponge, and may assume it’s foodborne. They cause various symptoms that are difficult to differentiate clinically from other diseases. In other words, your doctor’s gonna have a tough time discerning your illness from many others, so the clinical presentation of diarrhea, fever and fatigue is going to look like a lot of things! This is why a detailed history of the past week of events will be important to your physician.
Microwaving a sponge may or may not help, it depends on the research you believe. Using brushes may be a great option since they do not contain nooks and crannies where a cornucopia of microbes flourish. If you use sponges now to clean your dishes and kitchen surfaces, replace them more frequently. Even better, consider one of the 7 alternatives that I’ve listed above. Thanks for reading this and forward this article to a friend if you think they could benefit. Also, keeping your immune system in tip-top shape helps you fight the germs that you encounter on a daily basis, even those transmitted from a sponge. Your body is always fighting for you so don’t obsess about this too much. The related articles below will help you with your immune function.
Related Articles of Interest
Suzy Cohen, has been a licensed pharmacist for over 30 years and believes the best approach to chronic illness is a combination of natural medicine and conventional. She founded her own dietary supplement company specializing in custom-formulas, some of which have patents. With a special focus on functional medicine, thyroid health and drug nutrient depletion, Suzy is the author of several related books including Thyroid Healthy, Drug Muggers, Diabetes Without Drugs, and a nationally syndicated column.