How to Tell When Mushrooms Go Bad

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!

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Comments 56 comments

Karen flynn 6 weeks ago

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

Jane 7 weeks ago

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

perg 8 weeks ago

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

Eh 4 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.

Smackdaddy442 6 months 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

Mushmush 6 months 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?

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janshares 17 months 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.

jordan 17 months 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?..

trippy 19 months 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

Kane 20 months 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!

tina d. 2 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.

GraveDigger 2 years ago

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

shroomgobbler 2 years ago

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

Rei shi 2 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.

Milesy 2 years ago

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

Tina 3 years ago

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

anonymous 3 years ago

Helpful info.

jazz 4 years ago

i think jj

tebeth 4 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

Seek-n-Find 4 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!

4 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.

alicia 4 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

Lavender 4 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.

bob 4 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.

aDORKableChic 4 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!

LJ 4 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..!

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Goldentvmemories 4 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! :-)

Bree 4 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.

katia 4 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....

Anna 4 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 5 years ago

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

Jackie 5 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.

Rv 5 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??

Mushroom baby 5 years ago

Smazette popped out me, a mushroom baby!!!

aleesya hanee profile image

aleesya hanee 5 years ago

white mushroom will take time 3 day to changes..

WannaB Writer profile image

WannaB Writer 5 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.

Helltd351 5 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!

Afd 5 years ago

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

billy  5 years ago

i like um oh yes i do

eilander1542011 profile image

eilander1542011 6 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. :)

Iain 6 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?

jstlistnin 6 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 6 years ago from Chennai

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

jar-one 6 years ago

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

RoseGardenAdvice profile image

RoseGardenAdvice 6 years ago from San Francisco

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

K9keystrokes profile image

K9keystrokes 6 years ago from Northern, California

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

Blake 6 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.


smazette 6 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?

Si Lossibin 6 years ago

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

Brian 6 years ago

I sure do hope JJ is alright.

JJ 6 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 6 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 6 years ago

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

GerryG 7 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 7 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.

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hot dorkage 7 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.

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