Why does our kitchen sponge smell like mildew after less than a week?

August 13, 2007 9:10 PM

Our kitchen sponge starts to smell like mildew after less than a week of normal use. We use a standard "scrubby" sponge that has an abrasive side and an absorbent sponge side. Has anybody else experienced this problem, and if so, what did you do about it, or do you have any general advice about keeping sponges from mildewing quickly?

Both my wife and I make a point of always wringing the extra water out after each use, and store the sponge on the edge of our stainless steel sink. We never had this problem before we moved to our current home; sponges would generally take a month or more to get nasty in all our previous residences. We can't figure out what could be causing this premature bacteria growth! Our water (chlorinated municipal water supply!)? Mold spores floating through our house? (We do live in the Pacific Northwest, but keep our house well heated and don't otherwise have a mold problem.)

We've considered keeping the sponge in a dish of dilute bleach water between uses, but would prefer to not have a ubiquitous bleach presence in the kitchen. We've also tried several different brands of sponge, and only use the sponge for washing dishes and wiping the counters down.

posted by ezrainch to Home & Garden (37 answers total)

After using it, rinsing it in very hot water and squeezing it, pour a little white vinegar on it and squeeze it out again. Microbes that grow happily in an acid environment are generally pretty benign, and tend not to smell.
posted by flabdablet at 9:14 PM on August 13, 2007

You can always run the sponge through the dishwasher. Keep 2 on hand; one to have out while the dishwasher is running. Rotate as neccesary.
posted by rossination at 9:15 PM on August 13, 2007

do you have any general advice about keeping sponges from mildewing quickly?

Either "zap" your sponges periodically in the microwave -- or, wash them in your dishwasher.
posted by ericb at 9:18 PM on August 13, 2007

Just out of interest, are you using Dawn detergent? I've found that there's something in that soap that causes a really bad smell to linger on sponges.
posted by aberrant at 9:24 PM on August 13, 2007

If you keep it dry that is odd. Make sure you get the soap out, at the can slow drying. Most of the funk bacteria should not thrive dry. Did you change sponge brands, detergent or anything else? I guess testing your water wouldn't hurt, but I doubt that is the answer.
posted by caddis at 9:28 PM on August 13, 2007

Yeah, I just nuke mine... soak 'em pretty good and zap them until they steam. Let them cool, and they're fresh and ready to go.

Note that this isn't perfect sterilization unless you really blast it, but it'll be sterile faster than it would in boiling water, because of the steam.

As far as WHY you're having the problem... have you considered having a water test done? You might have some bacteria source that's close enough that it doesn't die from the chlorine before it gets to your sink.

Could also just be hiding in scratches in your sink. You could try a very through scrubbing of all surfaces anywhere near the sink, using a bleach solution that you let sit for a few hours afterward, at least on the stainless. (might not be good on the countertops.) Can't hurt, might help.

You can also find stink-free sponges that won't grow bacteria, if you look a little.
posted by Malor at 9:46 PM on August 13, 2007

bleach is your best bet here, and it's probably already under the sink! Just scour the sink with a little comet, and the residual bleach will keep the sponge bleachy enough to keep ott clean.
posted by skybolt at 10:12 PM on August 13, 2007

Are you sure it's actually drying out enough? Maybe your old sink had a sponge storage spot that allowed for greater air flow underneath the sponge (one of those ribbed inset molded things on ceramic sinks). Maybe your stainless steel sink just creates too much of a block against the side of the sponge for air to circulate. Try hanging the sponge or creating an air gap underneath it?
posted by otherwordlyglow at 10:20 PM on August 13, 2007

Pick up one of these. You can usually find them at Bed Bath and Beyond or a kitchen store like Sur La Table. The sponge holder thingy really does make a difference and it's not that obtrusive.

I tend to toss my sponges after a couple weeks. It's just easier to buy a whole pack of them from Costco and grab a new one once it starts to get funky. It's just not worth the grossness factor for me to try and get it clean. Especially after scrubbing out scrambled eggs or melted cheese from dishes.

If you do try zapping your sponge in the microwave, make sure it's wet first. There were several news reports a few months back about people putting dry sponges in their microwaves and then having them catch fire.

If you're not keen on keeping a diluted bleach wash around your food, try this stuff. I use it around my kids, my dogs, and it's not overwhelmingly 'bleachy'.
posted by dancinglamb at 10:37 PM on August 13, 2007 [1 favorite]

How is the ventilation in your kitchen? Kitchens get humid when you are cooking and washing dishes, and if the humidity lingers, you'll get mildew everywhere.
posted by happyturtle at 11:18 PM on August 13, 2007

It could be because of the weather; bacteria grow faster when it's warmer.

I used to use combination sponge/nylon-mesh, er, sponges but the plastic sponge kept getting stuff growing in it. Nylong scouring pads - without the sponge - used in the same way, though, don't funk up since they dry faster and rinses more thoroughly than a sponge.
posted by porpoise at 11:27 PM on August 13, 2007

Don't microwave them too much, though. They start to disintegrate easily after a point.
posted by rhizome at 12:06 AM on August 14, 2007

1 tablespoon of bleach per gallon of water makes an excellent sterilizing solution.
posted by Cool Papa Bell at 12:14 AM on August 14, 2007

but would prefer to not have a ubiquitous bleach presence in the kitchen

whoops, sorry...
posted by Cool Papa Bell at 12:14 AM on August 14, 2007

We had the same problem and my mom insisted that it was the dishwashing liquid as she had the same problem until she switched. I think we were using Joy, but it may have been Dawn as mentioned above. We switched to Palmolive and have never had the problem again. Odd, I know! We're in PNW as well, if the local water is part of the oddness.
posted by girlhacker at 12:15 AM on August 14, 2007

Like dancinglamb, I store my dishwashing sponge upright, but aside from that the easiest, cheapest, and least toxic disinfectant you can find is simple distilled white vinegar. I buy it in bulk bottles and use that to refill a few spray bottles that I keep under both kitchen and bathroom sinks. Just wring excess water from the sponge, spray a few times, then wring again. I use also use it on my kitchen's laminate counters, the stove, and all glass surfaces instead of Windex.

Yes, it stinks. But once the vinegar odor fades so do any other stinky odors, because it's also a natural freshener. (Some people cut the vinegar with water, which makes it less overpowering, but I prefer to use it full strength.)

(As long as I'm here, I'm going to evangelize: vinegar is god's own cleaning fluid. Blend half a cup with a teaspoon of olive oil and you've got wood polish. Add a quarter cup to the wash and it'll remove stains and soften your clothes. Drink it to gird your loins before battle and apply it to any resultant sword wounds. You get the picture.)
posted by melissa may at 3:20 AM on August 14, 2007 [2 favorites]

and only use the sponge for washing dishes and wiping the counters down

You wash the sponge off and wring it out after wiping down the counters, right? Because otherwise there's all sorts of nastiness on counters that will simply thank you in kind appreciation for conglomerating all their friends together on to a nice, inert, damp surface.

Also, you don't have to keep the sponges in a pool of bleach. You can just get yourself some generic kitchen cleaner (Fantastic with bleach or whatever your flavor of choice is)--just make sure it's got bleach on the ingredients list. Keep it near the sink and give the sponge a couple of sprays after using it.

That way you don't have to worry about leaving bleach out 24/7, and that should end your mold problem. At least, with the sponges. Living in the PNW, you'll be seeing a lot more of your green and black fluffy friend.
posted by Civil_Disobedient at 5:05 AM on August 14, 2007

I found I could never keep sponges getting nasty, so I followed the advice in Home Comforts and bought a big stack of waffle-weave cotton dishtowels to use instead. I find they work just as well or better than a sponge, and I use them once then put them in the laundry hamper. We have a separate nylon scrubbie for when scrubbing needs to happen.
posted by MsElaineous at 5:52 AM on August 14, 2007 [1 favorite]

Bleach evaporates out of solution fairly quickly, and doesn't do well in sunlight (hence the opaque bleach containers). Leaving a dish of bleach water out will result in a mildly bleachy-smelling container that is largely full of water by the next day.

Try using some sort of mild countertop spray (my wife prefers Mrs. Meyers) when you wipe things down. No bleach, food-safe, but it helps kill the baddies and doesn't seem to impart any sort of nasty odor to the sponge.
posted by caution live frogs at 5:56 AM on August 14, 2007

I'm having a similar problem, and have traced the problem to using well water which doesn't have the same chemicals as treated city water. I haven't found a good solution yet.
posted by Classic Diner at 6:19 AM on August 14, 2007

I'm with the vinegar-ites. Small spray bottle in the kitchen to zap sponges and cutting board.
posted by desuetude at 6:27 AM on August 14, 2007

If all else fails, these antimicrobial sponges seem to work well, even when left moist.
posted by caddis at 7:03 AM on August 14, 2007

I, like others, have ditched using sponges altogether for exactly this reason. I didn't find washing sponges worked particularly well so I bought a pack of the waffle weave dish clothes (I bought my at K-Mart). They go in the washing machine just fine, do a good job cleaning the regular stuff and are a renewable resource! We use a scrubber for the stubborn food.
posted by bluesky43 at 7:22 AM on August 14, 2007

I've always used a Tuffy scrubber -- just like my mom does! -- because it is durable but lets the air circulate. It's nothing but mesh; it doesn't have a sponge in the middle. It's also gentle enough to use on nonstick surfaces, but gets stuck-on stuff off like a steel wool scrubber. You can run it through the dishwasher (usually only needs it after a huge greasy scrub), and it lasts forever. Plus it doesn't collect soap (thus taking forever to rinse out).

I've found that not only are sponges super grody, they disintegrate really easily. Plus if you use the kind with the green abrasive side, those tend to collect grease and rub off into little twisty balls or whatever. The Tuffy never dies until it snags on something, and even then it usually takes a few weeks to unravel :)

My only lament is that I haven't been able to find them at the store nearest my house.

Another option is something like this, with or without the soap dispenser. Same idea -- nylon bristles are easier to wash, thoguh the bristles collect grunge a bit more than the Tuffy does.
posted by Madamina at 7:22 AM on August 14, 2007

Oh, and if you're looking for something more like a rag, something you can use for wiping down counters and the like, try Handi-Wipes. Same general idea; you can put them in the dishwasher (or regular laundry) as well. It's synthetic and has little holes, so hanging it over the faucet is basically all you need to keep it reasonably dry.
posted by Madamina at 7:31 AM on August 14, 2007

About a year ago I had the same exact problem. I searched askmefi and found this solution. I went with the Brawny DuraFresh sponges because they don't contain anti-bacterial chemicals. Rather, they're made to resist housing bacteria.

They really do do the trick. I was going through a sponge every few weeks. I've been on the same Brawny sponge for over six months!
posted by funkiwan at 9:04 AM on August 14, 2007

I disagree with the suggestions of anti-microbial sponges. Using those in your kitchen sponge is a lot like trying to manage your front yard by sterilizing everything down to bare dirt. It requires such intensive chemical use you risk poisoning yourself, and when, as happens inevitably, something does manage to grow in despite, it will be the most noxious of weeds.

Also, the ubiquitous anti-microbial is triclosan, which has such a similar structure to dioxin (the most poisonous component of Agent Orange) that it makes me nervous.

To extend the analogy of the lawn a bit, I like the vinegar idea, but only if you go down to your 'local food co-op' and buy one of the several vinegars they sell which contain living cultures of acetobacter (aka Mother of Vinegar), on the general principle that if something you don't like is growing somewhere, first try growing something you like better. Make sure you shake the bottle enough to get the Mother of Vinegar out onto the sponge.
posted by jamjam at 9:11 AM on August 14, 2007

Microwave your damp sponge on high for two minutes. This will kill all the pathogens. In my opinion, this is your best option.

Chemical sanitation with bleach will work but then you've got exposure problems. It's not great stuff to handle and you don't want to consume any.

The only other sanitizers worth using are hydrogen peroxide (30%+) and the quaternary ammonium ("quant") compounds. Quants are used in most of the antibacterial soaps and other products that you can buy. Again, you want to limit injestion of both of these.

Vinegar is good for dissolving stuff, but it's not a particularly good sterilizer (acetic acid has to be fairly strong to be effective). It's mild in the regular 5% form, but "mild" and "sterilizer" are essentially opposites.
posted by bonehead at 9:19 AM on August 14, 2007

Try keeping your sponge in a soap dish. The kind with little pegs that keeps the soap/sponge well-raised and dry.

And, try the twelve-for-a-buck cheap-o sponges and tossing them out whenever it seems even a little past its best before. Environmentally friendly it isn't, but it beats trying to de-funk a $3 sponge that should really be in the trash.
posted by kmennie at 9:21 AM on August 14, 2007

Every night, before I turn on the dishwasher, I place the sponge in the top rack.
posted by GarageWine at 10:36 AM on August 14, 2007

I don't have a dishwasher, so I wash them in the washing machine. I have about fifty or so of them in circulation. After two days +/- of dishwashing, I get a clean sponge and start using the two-day-old sponge for counters. I wash a load of sponges, kitchen rags (which I need for washing cast iron pans--sponges retain too much soap), and dish towels every two to three weeks. Light bleach. The sponges last for years and actually they work better when they're a little worn.
posted by Don Pepino at 11:40 AM on August 14, 2007

Seconding the microwave method. Minute and a half works for me. (Rinse it when you take it out - but watch out. Ees hot.)
posted by eleyna at 1:08 PM on August 14, 2007

coming to this a little late, but we stuck the suction-cup holder to our kitchen window (conveniently located above the sink). After wringing it out there aren't any drips, and the sun coming through the window completely dries that sucker out. Of course, this will only work for you if you have a nearby window....
posted by dogmom at 1:09 PM on August 14, 2007 [1 favorite]

1. 2nd dogmom's suggestion, the sunlight should dry the sponge faster and help prevent mildew
2. rotate and wash in dishwasher as others have suggested
3. use a washcloth; they dry faster, are reuseable and washable, and you can have tons of them in a drawer to rotate daily (I personally use washcloths and never have a stinky one)
posted by bugsoup at 10:54 PM on August 14, 2007

The point of vinegar in the sponge is not to sterilize, but to make the environment acidic enough that what does grow will tend to be inoffensive organisms that outcompete the stinkies. And it does that very well. If the vinegar happens to come preloaded with suitable acid-loving bacteria, so much the better, but ordinary white vinegar works fine too.
posted by flabdablet at 1:53 AM on August 15, 2007

I'm quite puzzled. I never have this problem with foam rubber sponges. However, this problem is typical of cellulose sponges. Foam sponges last months for me, I use them until the nylon scratchy surface wears out.
posted by Goofyy at 7:00 AM on August 15, 2007

Sponges are little apartment houses for bacteria and molds. I have come to find sponges repulsive, even when they're not overtly smelly. Use dishcloths instead and launder them in hot water (and bleach if necessary) every few days.
posted by bad grammar at 6:39 PM on August 15, 2007