How To Tell If Mushrooms Have Gone Bad: Are Your Fungi Finished?

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Ever taken a bag of your favorite fungi from the fridge and wondered whether or not they’re still good to eat? If you have, you’ve probably also wondered how to tell if mushrooms have gone bad, and that, dear reader, is what we’re going to be exploring today.

First, though, let’s take a look at why we should all be eating fabulous fungi in the first place.

Why mushrooms are So good for you

mushrooms in a basket

As they’re a distinctly weird type of food anyway, many of us are more than just a little dubious about eating these odd little morsels. However, you’re missing out if don’t have them in your diet.

As one of the only veggie foods to contain vitamin D, mushrooms are a great way to boost your daily requirements of this vital compound. They’re also packed with other goodies too, such as selenium, copper, iron, potassium, niacin, and vitamin C, to name but a few. (1)

They’re also a decent way to get a little more calcium into your diet as well. This works symbiotically with the aforementioned vitamin D, as it helps your body absorb calcium. Furthermore, mushrooms are packed with antioxidants and are considered to have a greater capacity than many veggies, making them brilliant immune system boosters. (2)

So, despite the numerous tales of poisonous fungi and psychedelic trips found in literature through the ages, the truth is that you really should be eating these little suckers.

NOTE: Picking wild mushrooms can be hazardous. Only do so if you know what you’re doing and in a region that allows you to harvest wild mushrooms. Sticking to store bought mushrooms is much safer. (3)

various wild mushrooms in a plastic container

How to tell if mushrooms have gone bad

Being able to spot when your fungi has taken a turn for the worse is essential if you’re going to make them a regular part of your diet, but how do you tell if a mushroom has gone bad? Here’s how.

As with almost every type of fresh food, your senses are your best friend when it comes to detecting a spoiled mushroom. Sight, smell, and even touch will all help you determine whether or not you should be eating your fungi or not. The key things to look our for are:

  • Sliminess
  • Stickiness
  • Ammonia-like odor
  • Wrinkles
  • Spots on the cap (head)
  • Darkened gills

Let’s take a look at each in a little more detail:


The cap, or head, of the mushroom is where this is most likely to occur. If you run a finger across the top of your fungi and it feels in any way slippery or slimy, it’s probably on its way out.


Similar to the slimy feel above, a viscous residue is a bad sign and it’ll likely manifest on the cap as well. Mushrooms should be relatively dry to the touch, so anything other than that should be treated with caution. Better safe than sorry, throw them away.


Probably one of the best ways to tell if your mushrooms have gone bad is to smell them. Mushrooms give off a rather pungent, ammonia-like odor when they are past their best. They can also smell somewhat fishy, too. Anything other than a regular earthy smell is not a good sign.


Oddly, mushrooms that have gone off can shrivel up and wrinkle as well as get a slimy coating to them. If the cap of your mushroom isn’t smooth and shows signs of dehydration, it’s time to get yourself some fresh ones. These are no good.


To the cap again, but this time we’re looking for spots. If you can see dark spots on your fungi, it’s likely they’re starting to spoil. In some instances, these may not be as obvious as out and out spots, but rather stains. It’s a good idea to check your mushrooms before refrigerating so you’ll notice any changes more easily.


Flip your fungi over and look at its gills. Any darkening of these “vents” is a sure sign of decay beginning to happen. As with all of the above, if you spot this on your mushrooms, it’s time to throw them out.

And finally…

Another good way to find out if your mushrooms are still good to eat is to just exercise common sense. Have you had your mushrooms for over a week? If you have, then there’s a good chance that they’ll be close to turning bad, even if they haven’t already.

Mushrooms are pretty delicate and they really should be eaten as soon as you possibly can, so buy them on the day you intend to use them. Any left over should be used quickly to avoid the chance of falling foul of food-borne illness.

Eating mushrooms fresh on the day you buy them is by far the best advice. However, sometimes you’ll want to keep them in good shape for as long as you possibly can, so…

How to store mushrooms

brown paper bag is how to store mushrooms

If they are so susceptible to going bad, how on earth do you store mushrooms? Well, there are differing opinions over the best way to store mushrooms, but I’ve always found the brown paper bag method to work well.

Some claim that wrapping them in plastic is best, but I don’t agree. These little guys are prone to sliminess, so why would you want to keep them under wraps where they’re likely to get damp? Dry is best, and you won’t be using any unnecessary plastic wrap, either.

So, if you want to give your fresh mushrooms the very best chance of lasting more than just a couple of days, here’s what you need to do (don’t worry, it’s easy!).

If you’ve bought your mushrooms in a plastic wrapped punnet, open that up and check through your mushrooms to see what condition they’re in. Looking them over now will give you an idea of their coloration, enable you to spot any bad mushrooms, and give you a benchmark when you come to check them later.

Take a brown paper bag and pop your checked over fresh mushrooms inside. Now, here’s the tip. Instead of scrunching your bag shut, roll the edges over so that it resembles a mini open coffee sack. The picture above will give you an idea, but you don’t want yours to be so full!

This will do two things. Firstly, having the bag open will give your mushies a chance to breathe. Second, the brown paper bag will absorb any moisture rather than let it gather on your fungi. This is a good thing.

Place your newly fashioned bag of fungi into the main part of your fridge and make sure they don’t get cluttered in amongst other foodstuffs. Give your ‘shrooms room! Storing them in this way will help prolong their life and give you a chance of keeping them for up to a week.

If you’ve bought yours loose (instead of in a pre-wrapped carton), but they’re in a plastic bag, take them out and switch them over to a paper bag instead. They’ll thank you for it…in a way ?

Remember, although storing mushrooms correctly can extend their shelf life a little, it’s still best practice to eat them as soon as you possibly can. Oh, and don’t forget to give them a thorough checking before you start cooking.

Storing Fresh sliced mushrooms vs. fresh whole mushrooms

You can probably already guess what I’m going to say here…fresh sliced mushrooms will deteriorate a lot quicker than fresh whole mushrooms, so you’d think storing those bad boys brings another level of complexity.

Not so.

Simply follow the above paper bag advice and you’ll likely have three days before you’re confronted with spoiled mushrooms.

That’s about it, friends. If you have any other mushroomy tips and tricks, let me know in the comments section below! Oh, and be sure to check out some of the amazing vegan pie recipes in our roundup that call for fabulous fungi to make them delicious.

About The Author:
Lisa Williams
Happy Happy Vegan editor

Lisa Williams is a committed vegan, passionate animal welfare advocate, and keen follower of too many v-friendly food blogs to mention. She started back in 2016 because she felt there was a need for more straightforward information on plant-based living.

Back then, too many sites seem to either concentrate solely on recipes or be too intimidating or inaccessible for the v-curious, and she wanted to change that. The landscape is certainly a whole lot different now!

  1. Glenn Cardwell, Janet F. Bornman, Anthony P. James, and Lucinda J. Black | A Review of Mushrooms as a Potential Source of Dietary Vitamin D |
  2. Alena G. Guggenheim, ND, Kirsten M. Wright, BS, and Heather L. Zwickey, PhD | Immune Modulation From Five Major Mushrooms: Application to Integrative Oncology |
  3. Steve Brill | Wild Mushrooms |

13 thoughts on “How To Tell If Mushrooms Have Gone Bad: Are Your Fungi Finished?”

  1. “it’s probably on its way out” doesn’t mean “it’s on its way out” or for that matter “it’s unsafe to eat”. A tiny bit of slip is much different than the whole top has a “glide” to it. When you’re talking about if “aged” food is safe to eat, don’t use ambiguous qualifiers/phrases like “probably” or “on its way out”. People should safely expect an article about food “gone bad” to be unequivocal with its advice—something past a certain age is “suspect”, past another certain age is “unsafe”.

    Regarding a mushroom’s odor: if there’s no ammonia scent whatsoever, but a little fishiness, are the mushrooms “safe” or “suspect”?

    • Thanks for the tips, I’ll bear them in mind for future posts.

      Regarding the fishy smell, as stated in the article, anything other than an neutral, earthy odor means your mushrooms are better off in the trash than in your stomach.

      Enjoy the rest of your weekend!

  2. Thanks 4 your helpful hints. I unknowingly bought some bad mushrooms and they made my sister’s stomach sick.

  3. Great information!
    Thanks for posting this!
    I can now eat mushrooms that I used to toss and know when ti should toss them ?.

  4. Very amazing tips Lisa. Thanks a lot for such pleasing information. I guess it’s time for me toss my mushrooms. Was very helpful.

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