How to Tell When Mushrooms Go Bad

Updated on March 16, 2016
Image edited with text.
Image edited with text. | Source

Mushrooms are an iffy food for a lot of people. After all, they're fungus, and no one really wants to think that they're willingly eating fungi. However over the years, many have grown increasingly more interested in cooking and consuming mushrooms. They're a low-calorie food item that works great in many vegetarian and ethnic dishes, helping to add texture and flavor without making you put on the pounds.

If you're still hesitant about trying them, it could be because you're afraid of getting sick. After all, they are associated with the psychedelic and poisonous properties of some specific types. You might think that if your mushrooms go bad, you're going to go on a bad trip.

The truth is that bad mushrooms can make you very sick. However, the risk is very low if you're eating store-bought or farm-fresh. There's even less of a risk if you eat them cooked. Still, you obviously don't want to eat bad food. You don't want to take any chances.

Here's what to look for when a mushroom is turning and how to properly store them to prevent spoilage.

Have They Gone Bad?

The answer is yes, if:
They smell bad/funny
They're wrinkly
They're growing dark spots
They're slimy
They're older than two weeks
They're getting darker
Use your best judgment. Sniff, eyeball, and poke at your mushrooms to determine whether they're edible or not. Use this cheat sheet if you need help, but always err on the side of caution.

How to Tell if Your Mushrooms Have Gone Bad

If your mushrooms have dark spots on them, they've gone bad. Make sure you throw these out!
If your mushrooms have dark spots on them, they've gone bad. Make sure you throw these out! | Source

Here are some obvious and not-so-obvious signs that your mushrooms need to go in the trash:

  • They're slimy. The number one rule-of-thumb when it comes to detecting freshness is that when mushrooms are slimy, they're not good to eat anymore. This could be from sitting in the fridge for too long. While they aren't definitively dangerous at this point, it's still a good common kitchen practice to toss them.
  • They have wrinkles. Sometimes mushrooms don't get slimy but they do dry out and get wrinkles. While it's okay to dry out your mushrooms a little bit (since they are fairly moist vegetables anyway), you don't want your mushrooms too wrinkly. So if they're shriveled up looking, it's a safer bet to toss rather than consume.
  • They're darker or have dark spots. Dark spots are a sign that they're starting to go bad. The best thing that you can do is to keep an eye on your mushrooms throughout the time they're in the fridge. If you see them getting darker or developing dark spots, it's time to use them or lose them.
  • They've been around for two weeks or more. The general consensus in terms of shelf life/storage time with mushrooms is around two weeks in the fridge. Of course, use your best judgment and common sense. If they look, smell, and feel fine, they're probably still safe to eat.
  • They emit an odor. Your mushrooms shouldn't have a noticeable or strong odor. If you can smell them, they've gone bad. Of course, if you're sticking your nose right up to them, you'll get a scent, but it should be light and subtle. If you pick up the bag, open it, and have to turn your head, then you've got bad mushrooms.

Proper Storage Techniques

An ideal way to store mushrooms is to simply keep them in their original sealed container until you're ready to eat them.
An ideal way to store mushrooms is to simply keep them in their original sealed container until you're ready to eat them.

How can you properly store mushrooms so that their shelf life can be optimized? Here are a few tips to consider:

  • Let them breathe. Store mushrooms in a way that allows them some air without drying out too much. A paper bag inside the refrigerator is one common way.
  • Plastic bags and paper towels. Another way to keep mushrooms relatively fresh is to store them in plastic bags lined with paper towels to capture the moisture. Make sure you change the towels regularly if you aren't using them right away. Find different ways of cooking them so that you use them up in your meals before they go bad!
  • Keep them in their sealed wrap. One of the most effective storage techniques is to simply keep them in the sealed containers/bags that they come in. Make sure you don't open the container or tamper with them (there's no need to transfer them) until you're ready to use them.
  • Freezing. If you want to freeze up some mushrooms for use later on, this is possible. However because mushrooms retain so much water, it's much more difficult to freeze them when raw. If you're going to do so, make sure you freeze them on parchment paper and then quickly transfer to an air-tight bag with as much air as possible pressed out. The best way is to first cook—either blanch, saute, or steam—the mushrooms and then pack them into airtight containers or freezer bags, whichever has less air.

Remember, being afraid that your mushrooms are going to go bad isn't a good reason not to eat them. Use some common sense, look out for the obvious signs, and enjoy what this fungus can add to your recipes!

Questions & Answers


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    • Spanish Food profile image

      Lena Durante 11 months ago from San Francisco Bay Area

      These are great tips. I'm one of those people who can't eat mushrooms unless they're the right texture, so I'm sensitive to only buying them very fresh and using them right away. As long as they don't get overcooked, I can enjoy them.

    • profile image

      Karen flynn 19 months ago

      Want to know why every time I marinate and grill Portabellas the skin on top is like leather. Have to peel it off.

    • profile image

      Jane 19 months ago

      I washed my large portable las and they drained pink on the towel. Is that OK?

    • profile image

      perg 20 months ago

      Thank you for your answer about how long to keep mushrooms. It was VERY HELPFUL!!! :)

    • profile image

      Eh 22 months ago

      Eh, they always end up with dark spots and go slimy in places, but I've always still eaten them. They still taste fine when cooked, and I'm not dead so.

    • profile image

      Smackdaddy442 2 years ago

      Are they talking bout morels or just mushrooms in general cause i need to know how to tell for morels. I let them soak for 2 days but i usually only do it for 1 and they smell bad now but look the same as before so idk

    • profile image

      Mushmush 2 years ago

      I have a package still wrapped and presliced but dated for yesterday. They have very light spots, no slime, no wrinkles. They have a tinge smell of fish but if brought right to nose. Is this okay?

    • janshares profile image

      Janis Leslie Evans 2 years ago from Washington, DC

      Very helpful hub about whether the mushrooms can still be eaten safely or not. I'm always trying to figure this out. Even if they are a little slimy, I rinse them, cook them, and they are just fine. Thank you for this informative hub. Glad it's still in circulation. Voted up and useful.

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      jordan 2 years ago

      i left mine out of the fridge for two days and I’m not sure if they’re bad or not :( some smell and some don’t.. any ideas?..

    • profile image

      trippy 3 years ago

      When you take then out the bag, eat them, and see little green men dancing around and you join them and... Oh wait I'm on the wrong page.... Whoops

    • profile image

      Kane 3 years ago

      Mushrooms collect bacteria and other harmful fungus contaminations very easily especially wild ones. Be very careful and do your research if your new to the fungi family. Good luck everyone!

    • profile image

      tina d. 4 years ago

      One week after washing n storing in fridge they were slimy n smelld fishy. Thanx for the heads up :) didn't wanna gamble so i tossd em. Will try paprr bag nxt time.

    • profile image

      GraveDigger 4 years ago

      Life is a cycle. I imagine JJ has a fairycircle of mushrooms growing overtop of where he is buried.....

    • profile image

      shroomgobbler 4 years ago

      Poor JJ... he was so young and full of promise..

    • profile image

      Rei shi 4 years ago

      Recently I ate two handfuls of steamed champignons, they had gone quite dark. The next day my urine was very acidic (I test it every morning) and my mood subsequently awful. I also didn't sleep well through the night; woke up around 3am, something that happens when the liver / gallbladder is out of whack. The liver processes toxins, so it might well be related to the mushrooms I ate. I had brushed off most of the dark areas though.

      Because the mushroom body has such a moist and soft structure, I think it's very hospitable for new invaders (other fungi, moulds, yeasts, parasites?), and easy for them to enter. After the mushroom has fulfilled its purpose of dropping spores, it's discarded by the mycelium network, so it would be logical that other organisms will come in to compost it. But our bodies shouldn't be composted yet! (Which is what happens when we're infested with candida & other anaerobic opportunistic organisms).

      Good reasons to be very careful about this issue. I say throw away if even a bit suspicious.

    • profile image

      Milesy 4 years ago

      I'm still worried about JJ, it's put me right off my 2 week old slimy mushrooms, that's for sure.

    • profile image

      Tina 5 years ago

      My portabella mushrooms smelt fishy so I googled it and this post came up. I decided to throw them away!!

    • profile image

      anonymous 5 years ago

      Helpful info.

    • profile image

      jazz 5 years ago

      i think jj

    • profile image

      tebeth 5 years ago

      hey alicia! totally agree. i wont buy anything including meat from walmart. all their stuff spoils within a day

    • Seek-n-Find profile image

      Jenna Ditsch 5 years ago from Illinois

      Thank you for sharing--I was on the line about weather to use my bellas or not and your hub helped me decide--NO!

    • profile image

      5 years ago

      I bought some mushrooms from Walmart Wednesday mine are starting to get dark spots still in bag don't know if slimmy let me go check...OK nevermind,they are partically frozen so they are good. My fridge is way too cold but I will try the garlic clove thing. Thanks for the good article.

    • profile image

      alicia 5 years ago

      I bought a pack of regular mushrooms from walmart yesterday and opened them to fry up today and they are already slimy. (Previously i had washed and dried them which seems to work as long as they are not too far gone). However, i realized most every time i buy these from walmart (they seem fine at the store) they barely last even one day. Any one else have the same problem? Plus, i was reading the posts and noticed that poor jj never checked back

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      Lavender 5 years ago

      They smell so bad. I used half the pack and refrigerated the rest. It's been about two weeks, so I definitely won't be using these.

    • profile image

      bob 5 years ago

      Well I've just this minute ate a mushroom & egg toasty & realised the mushrooms smelled & tasted funny half way through eating them! Hopefully I'm not gonna be ill later... Fingers crossed.

    • profile image

      aDORKableChic 6 years ago

      Great info! Fresh mushrooms are my favorite but every time I eat them I get a knot in my stomach for hours. I'm not allergic so who knows! I'm very careful and only eat them within a few days of being brand new, really crisp and white so I must just be the type with a sensitive stomach to mushrooms. It won't stop me though!

    • profile image

      LJ 6 years ago

      I spent half an hour washing the slime off my mushrooms, cut off all the dark spots but still wasn't convinced - they had almost a licorice smell, so I have just chucked them into the bin, don't want to take chances..!

    • Goldentvmemories profile image

      Goldentvmemories 6 years ago from London.

      Very interesting - may have saved me from an upset tummy. Love mushrooms - really missed them on Atkins! That's something I won't be doing again - EVER! :-)

    • profile image

      Bree 6 years ago

      Just threw out some in a plastic bag I brought three days ago. They smelled like dead fish as the other blogger said. I never made them before. I wanted to try something new. I can't eat something that smell like that.

    • profile image

      katia 6 years ago

      For those who doesn't know...oi read various articles abt how mushrooms r good to prevent cancer. I read various articles abt how women who eat mushrooms every other day can prevent from breast cancer. I do...I never get sick....

    • profile image

      Anna 6 years ago

      I remember my Mom always used to cook her fresh mushrooms with one whole clove of garlic in the pan, she said that if the mushrooms were bad or poisonous that the garlic clove would turn brown, and if the mushrooms were fine the garlic clove would stay the same color. Old wives tale Im not sure but it worked everytime, we never got sick from mushrooms :-)

    • stevebruton profile image

      stevebruton 6 years ago

      Thank you very much for the information i keep an eye on my mushroom pretty much so i don't get sick

    • profile image

      Jackie 6 years ago

      I've had some go slightly slimy, but when I washed and dried them, they were like new. However, I only had them for a little over a week. They were fine. Still be careful.

    • profile image

      Rv 6 years ago

      I froze a box in the freezer,, when I put it n the pan it smelled like dead fish... I went on and made my stir fry.. But thought afterwards, should I throw it away??

    • profile image

      Mushroom baby 6 years ago

      Smazette popped out me, a mushroom baby!!!

    • aleesya hanee profile image

      aleesya hanee 7 years ago

      white mushroom will take time 3 day to changes..

    • WannaB Writer profile image

      Barbara Radisavljevic 7 years ago from Templeton, CA

      Interesting hub. I'm afraid I have eaten mushrooms that were getting dark spots and a bit on slimy side. I used them in a stir fry and nobody had a tummy ached afterward. I had washed them well and scraped the surfaces. I have to admit they are much more appetizing fresh.

      AS to Appleby's, it's a place to watch out for whether you are eating mushrooms or not. I know a few people who have reported feeling sick after eating there, including my husband.

    • profile image

      Helltd351 7 years ago

      I love my mushrooms, I cooked some buttered mushrooms for dinner tonight, but as I was short on fresh ones I ventured deep into my fridge and going some older ones in a bag. I could not say exactly how old they were but they could have even been a month old. They were in a paper bag most were quite dried up but some were a slight bit slimy but as I was going to cook them well I thought I would be ok. Well the mushrooms are having the last laugh now as I have been glued to the toilet for 12 hours now! Don't eat suspect mushrooms, it's not worth it!

    • profile image

      Afd 7 years ago

      I would eat more but I haven't got mushroom! Oh pleaaassee!!

    • profile image

      billy  7 years ago

      i like um oh yes i do

    • eilander1542011 profile image

      eilander1542011 7 years ago from Everywhere

      Awesome hub! The best part about it is that reading it immediately prevented me from utilizing some mushrooms in a a salad I was making, that had most definitely gone bad. My night ended well with no unwanted trips to the bathroom. Thank you. :)

    • profile image

      Iain 7 years ago

      Well, I'm none the wiser. Most of the mushrooms in the two tubs I bought has gone slighlt brown after storing them for a couple of days, but also has a moisture on them. I chicked out any obviously bad ones and washed the others until the slimey feeling had gone. Gonna cook them for a good long time with butter/spread and at a high temperature so hopefully that will ward off any likely bugs?

    • profile image

      jstlistnin 7 years ago

      i'm drying wild mushrooms when I came across this site. Found a whole fairy ring of 75 parasol mushrooms. Ate a few last night at a get together everyone survived and wanted more! slimy would be the only way i'd toss them

    • jayantsingh99 profile image

      jayantsingh99 7 years ago from Chennai

      Really good information...thanks for the info. Very useful.

    • profile image

      jar-one 7 years ago

      When they are solf. They are too old to eat. Just cook and eat them fresh.

    • RoseGardenAdvice profile image

      RoseGardenAdvice 7 years ago from San Francisco

      I could never figure out when mushrooms are bad...thanks for the info. Very useful.

    • K9keystrokes profile image

      India Arnold 7 years ago from Northern, California

      I learned a great deal about mushrooms here. Really good information and safety practices KV. Voting up!

    • profile image

      Blake 7 years ago

      I went to Applebee's and ate the Weightwatcher points Portobello Mushroom Chicken sandwich. and the sandwich digested but not the mushrooms. A couple hours later I felt like I had a knot in my stomach, this lasted for several hours even after I had eaten again. Until i threw up. Everything that i threw up had digested and puree'd in my stomach exept for the mushrooms that came back up. i felt better until I had to throw up again. I am feeling better now that I think I've got most of them down the toilet.


    • profile image

      smazette 8 years ago

      I am 24 weeks pregnant and have just cooked arriabata and added three bought mushrooms. After eating most of them I realised the offensive smell was the mushrooms and stopped.I was given them and have no idea how old they are and i think they are normal shop bought. Do I need to panic?

    • profile image

      Si Lossibin 8 years ago

      If your mushrooms go blue when you touch them or break them open, then you got the best mushrooms!

    • profile image

      Brian 8 years ago

      I sure do hope JJ is alright.

    • profile image

      JJ 8 years ago

      I'm eating mushrooms right now that are right on the border according to these posts! They are slimy had a couple of black spots and are about two weeks old. I check back in a couple hours...hopefully.

    • Hendrika profile image

      Hendrika 8 years ago from Pretoria, South Africa

      I never leave mushrooms more than two days! Not only because I'm scared they will go off, but because I love them so and eat them all before the two days are over.

    • Richard Armen profile image

      Richard Armen 8 years ago

      I personally usually do a week because I would get weirded out if I ate them after that.

    • profile image

      GerryG 9 years ago

      I sauté baby bellas along with sliced potato, oinion and green pepper as an accompaniment to eggs for breakfast once a week. The bellas last up to two weeks, and I slice and use them even when they are all shriveled up. Thus far, the shrivelled ones have the most intense flavor!

    • jGaunt profile image

      jGaunt 9 years ago from London

      I got sick from eating mushrooms once and the doctor told me you really have to watch the mushrooms. Because they are prone to giving you problems if you aren't careful.

      But I do love mushrooms.

    • hot dorkage profile image

      hot dorkage 9 years ago from Oregon, USA

      A lot of these things happen if you dry your mushrooms. And some wild mushrooms are slimy right from the getgo. I have successfully reconstituted shriveled agaricus bisporus (that's the typical white button you buy in the grocery store.) and of course dried shiitakes are a big item in our cuisine because it's often difficult to get them fresh.