Do Mushrooms Go Bad & How Long Do They Last?

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Mushrooms are a fungus that thrive in a naturally dark and moist environment. Because they’re so unique among food types, you may be wondering, do mushrooms go bad, and how long do they last for?

Mushrooms are just as susceptible as any other edible item to rot and bacterial growth, so yes, they can and do go bad – and more rapidly than you may anticipate. While larger mushrooms have a longer shelf life than smaller ones, you have a week – give or take – before you’re facing slimy and rotting mushrooms.

Mushroom Shelf Life

Whole mushrooms last a great deal longer than sliced ones, and larger mushrooms will stay good for at least a few more days than smaller varieties. This is because there is less exposed surface to become contaminated.

box of mushrooms

Cooking mushrooms can extend their life by two or three days, and they can be frozen once cooked to last at least six months.

  • Whole Shiitake, Portobello, Oyster, Chanterelles – stored correctly in the fridge, these varieties will last between seven and ten days.
  • Whole Morels – With many small crevices, these smaller mushrooms are more prone to spoilage and are best eaten within four days.
  • Sliced mushrooms, uncooked – once sliced, mushrooms will go bad much more quickly, lasting up to five days in the fridge.
  • Cooked mushrooms – between seven and ten days in the refrigerator.
  • Dried mushrooms – dried mushrooms can potentially last for years, but we recommend using them within one year.

SEE ALSO: Best Way To Store Mushrooms

How To Tell If Mushrooms Are Bad

​Fortunately, it’s easy to identify a mushroom that is starting to go bad or has already turned. If you catch them early enough, you can cook them and store again, but if the spoiling has progressed, it’s safer to dispose of them altogether.

bad moldy slimy mushrooms

Here are the signs that indicate a bad mushroom:

  1. Sliminess – a mushroom that is starting to develop a slimy surface is beginning to spoil. If they’re only slightly slippery, cook them up straight away. However, advanced sliminess or stickiness means they’re no longer good to eat.
  2. Color changes – some varieties of mushroom – such as button mushrooms – will start to turn dark brown or black when rotting. If there are only a small number of brown or dark spots, cook them up and use them (or freeze), but advanced color change throughout the mushroom indicates they are bad.
  3. Bad smells – fresh mushrooms will have little to no odor, while spoiled mushrooms may develop an unpleasant, ammonia-like smell. If your mushrooms have any strange aromas, throw them out.
  4. Wrinkles – while it’s normal for some slight wrinkling to develop as the mushrooms dry out, any major wrinkled or shriveled mushrooms should be discarded. Fresh mushrooms are plump and smooth.

What Happens If You Eat Bad Mushrooms

As with any food that has been contaminated with bacteria or mold, eating bad mushrooms can make you sick.

Although mushrooms don’t naturally contain bacteria, they are often grown in compost, which may not have been sterilized sufficiently.

Mushrooms can also become infected with bacteria during handling, storage, and transportation.

Eating bad mushrooms may cause food poisoning, with associated symptoms of nausea, vomiting, and diarrhea.

However, mushrooms have also been known to grow the botulism bacteria, which is a very serious and often fatal illness with a high chance of causing paralysis and death.

Early signs of botulism include nausea, vomiting, diarrhea and a swollen abdomen, along with weakness and difficulty breathing. Signs of paralysis follow. Contraction of botulism is a medical emergency and should be taken very seriously.

To reduce the risks of illness, be sure to clean mushrooms well before eating and always store them in the refrigerator.

Related | How To Clean Mushrooms

How Long Do Mushrooms Last In The Fridge?

Oddly enough, the greatest threat to mushrooms in the refrigerator is moisture.

While mushrooms need a consistent source of moisture to thrive in the wild, refrigerated mushrooms will grow an appalling crop of slime if left in a moist environment.

If you buy pre-packaged mushrooms, keep them in their original packaging in the fridge. Avoid storing them in the crisper drawer, as it is more humid.

do mushrooms go bad

The paper bag storage method is the best and simplest way to protect your mushrooms from sliming.

You should give your mushrooms a quick wipe down with a damp paper towel to clean away any dirt on your capped mushrooms before transferring them to a paper bag and refrigerating.

Perforated plastic wrap will work on grocery store mushrooms, or you can poke a few holes in the store container and consider it perforated.

When working out how to keep mushrooms fresh, airflow is the key. Fresh mushrooms that are stored correctly may last up to two weeks in the fridge, but for safety’s sake, try to eat them within 10 days and monitor them for signs of spoilage.

How Long Do Mushrooms Last In The Freezer?

Because mushrooms contain so much water, it can be difficult to freeze them raw. Many mushrooms, such as shiitakes, won’t survive the freezing process and will turn into sludgy lumps upon thawing.

However, if you sauté or blanch your mushrooms before freezing, they can easily be added into soups and sauces for lush flavor.

Sauté your mushrooms until they’re an even gold and all the fluid is evaporated from the pan. Once the mushrooms cool, freeze them in an airtight container.

Cooked mushrooms will last indefinitely in the freezer, but for best quality should be thawed and used within six to eight months.

Written By Tara Williams

Tara is a food writer that has been editing and authoring articles for KitchenSanity since its founding. Her writing offers personal experience from experimentation with food and recipe creation. If you’re looking for simple tips, she will make your journey in the kitchen straightforward with a dash of fun.