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How to Tell When Mushrooms Go Bad

Kathryn studies and writes about health, nutrition, and food safety.

Are your fungi fresh or foul? Eat safe and learn the signs of spoiled mushrooms.

Are your fungi fresh or foul? Eat safe and learn the signs of spoiled mushrooms.

Mushrooms are an iffy food for a lot of people. After all, they're one of the only things we eat that isn't a plant or an animal. Over the years, however, more and more people have become interested in cooking and consuming mushrooms. They're healthy and low on calories, and their unique textures and flavors incorporate well into a wide variety of dishes.

Some people are hesitant to try them due to the fact that certain species are inedible, poisonous, or have hallucinogenic effects. You might think that if your store-bought mushrooms go bad, you'll end up going on a bad trip. Luckily, this is not so. Bad mushrooms can, however, make you very sick. The risk of this happening is low if the mushrooms you eat are store-bought or farm-fresh. They pose even less risk if you eat them cooked. Nevertheless, it's still a good idea to take steps to avoid eating spoiled or rotten food. You don't want to take any chances.

This article discusses tell-tale signs to look for to determine whether your mushrooms have turned and provides tips on how to properly store them to prevent (or at least delay) spoilage.

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

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

How to Tell If Your Mushrooms Have Gone Bad

Here are some obvious and not-so-obvious signs that your mushrooms need to go in the trash. Use your best judgment, but err on the side of caution when deciding whether to keep, cook, or toss your fungi.

  • They're slimy. The number one rule-of-thumb when it comes to detecting freshness is that when mushrooms are slimy, they're no longer fit for eating. Sliminess often occurs on mushrooms that have been 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, older mushrooms don't get slimy and instead 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. If they look pretty shriveled, it's a safer bet to toss them than consume them.
  • They're becoming darker or have dark spots. Dark spots are a sign that your fungi are starting to go bad. The best thing that you can do is to keep an eye on your mushrooms throughout the entire time they're in the fridge. If you notice 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 that about two weeks in the fridge is the outer limit. Of course, you should use your common sense and best judgment. If it's been just over two weeks but they still look, smell, and feel fine, they're probably 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 notice a mushroom 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. Get rid of them!

Signs of Spoiled/Rotten Mushrooms

Use your best judgment. Sniff, eyeball, and poke at your mushrooms to determine whether they're still fresh or not. Use this cheat sheet if you need help, but always err on the side of caution.

They smell bad

They're wrinkly

They're getting darker

They're slimy

They're older than two weeks

They've developed dark spots

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 to Properly Store Mushrooms

How can you properly store mushrooms to optimize their shelf life? Here are a few storage tips to help you get the most out of your fungi before they spoil.

  • Let them breathe. Store mushrooms in a way that allows them some air without drying them out too much. Keeping them in a paper bag with the top loosely rolled up inside the refrigerator is popular storage method.
  • Use plastic bags and paper towels. Another way to keep mushrooms relatively fresh is to store them in plastic bags lined with paper towels to help capture moisture. Make sure you change the towels regularly if you don't plan to use your mushrooms right away. It's a good idea to experiment with including them in a variety of dishes so that you use them up 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. If they are packaged in a cardboard tub wrapped with plastic, there's no need to transfer them to an alternate container when you bring them home. Make sure you don't open or tamper with them until you're ready to use them.
  • Freeze them. It is possible to freeze mushrooms for later use. Because mushrooms retain so much water, however, 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 them to an air-tight bag with as much of the air pressed out as possible. The best way to freeze them is to cook them first, then pack them into airtight containers or freezer bags (use whichever holds less air when sealed).

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 the texture and nutrition that these flavorful fungi can add to your recipes!

Comments

greeneryday from Some tropical country on May 25, 2020:

very useful tips

ogunsemore olasimbo esther from akure on March 10, 2020:

thanks for the information

Kari Poulsen from Ohio on November 07, 2019:

I have thought that these signs mean mushrooms are bad, but it is very good to see it in print. Thanks for the info!

penderlu on January 17, 2019:

Wow, thread goes back ten years, but great information about something I've been wondering about for years, having consumed some suspicious mushrooms on few occasions. Never got noticeably sick, but I will definitely be more careful from now on.

Also, thoughts and prayers for JJ, who ate the slimy, spotted mushrooms nine years ago and never reported back.

Muditha Kumburegama on January 11, 2019:

Many thanks all.Rei si I have gone through yours.Highly appriciated for the information.Now i know always need to take care..Prevention is better than cure..!Again many thanks everyone here.

Mrs Heidi on September 17, 2018:

WTF happened to JJ?

JoeMayo on August 28, 2018:

I've just finished a meal my wonderful mother made for us this afternoon, here in the beautiful state of Illinois, and being the humble, caring son that I am, I ate her delicious homemade food no questions asked.

Immediately my stomach turned. It twisted 360 degrees and my butt hole winked. I'm sweating and I'm on the way to work.

Portabella mushrooms the size of your head, fried lightly on the skillet. Lightly.

Mama. How could you?

peachy from Home Sweet Home on June 12, 2018:

Mushroom would turn blackish or moldy and fleas will grow

Lena Durante from San Francisco Bay Area on May 02, 2017:

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.

Karen flynn on September 10, 2016:

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

Jane on September 03, 2016:

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

perg on August 30, 2016:

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

Eh on June 13, 2016:

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 on April 20, 2016:

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 on March 31, 2016:

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?

Janis Leslie Evans from Washington, DC on May 21, 2015:

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 on May 18, 2015:

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 on March 27, 2015:

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 on February 23, 2015:

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. on March 23, 2014:

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 on March 05, 2014:

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

shroomgobbler on November 16, 2013:

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

Rei shi on November 14, 2013:

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 on November 13, 2013:

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

Tina on April 12, 2013:

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

anonymous on December 16, 2012:

Helpful info.

jazz on October 23, 2012:

i think jj died...lol

tebeth on August 04, 2012:

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

Jenna Ditsch from Illinois on July 31, 2012:

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

R on May 27, 2012:

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 on May 26, 2012:

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 in..lol

Lavender on May 22, 2012:

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 on April 29, 2012:

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 on February 18, 2012:

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 on January 27, 2012:

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 from London. on January 23, 2012:

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 on November 20, 2011:

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 on November 12, 2011:

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 on November 06, 2011:

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 on October 23, 2011:

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

Jackie on September 24, 2011:

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 on September 22, 2011:

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 on August 20, 2011:

Smazette popped out me, a mushroom baby!!!

aleesya hanee on April 18, 2011:

white mushroom will take time 3 day to changes..

Barbara Radisavljevic from Templeton, CA on April 10, 2011:

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 on April 06, 2011:

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 on January 28, 2011:

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

billy on December 10, 2010:

i like um oh yes i do

eilander1542011 from Everywhere on October 26, 2010:

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 on October 07, 2010:

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 on September 22, 2010:

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 from Chennai on September 21, 2010:

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

jar-one on September 04, 2010:

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

RoseGardenAdvice from San Francisco on August 08, 2010:

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

India Arnold from Northern, California on June 17, 2010:

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

Blake on June 13, 2010:

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.

WHAT HAPPENED?

smazette on March 10, 2010:

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 on February 25, 2010:

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

Brian on February 20, 2010:

I sure do hope JJ is alright.

JJ on December 12, 2009:

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 from Pretoria, South Africa on November 11, 2009:

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 on November 09, 2009:

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

GerryG on March 22, 2009:

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 from London on January 28, 2009:

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 from Oregon, USA on December 02, 2008:

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.