How to tell if mushrooms are bad. Discolored, shriveled mushrooms

How to Tell if Mushrooms are Bad: The Telltale Signs

If you regularly use fresh mushrooms to add flavor and nutrients to your meals, you may occasionally collect or buy more mushrooms than you need. 

And, the extra mushrooms often land up in the back of the fridge for future use.

You can store excess mushrooms in the fridge for a short while before they go bad. 

But, like other fresh foods you should use them as soon as possible.

When you remember the mushrooms in the fridge and want to use them, you may wonder, “How do I know when my mushrooms have gone bad?”

Good news, some easy telltale signs will help you to know whether your mushrooms are bad or not.

In this article, you’ll learn how to tell if mushrooms are bad and find some ideas for using extra mushrooms before they go bad.

How to Tell if Mushrooms Are Bad

Since the beginning of time, humans have used their senses to tell if something is good to eat or potentially dangerous. 

Checking mushrooms to tell if they are safe to eat is no different. So if you are wondering, “How do you test a mushroom?” trust your senses to guide you. 

To test a mushroom for freshness, you need to look at it carefully, touch it to check it’s still firm and smell it.

Here are seven telltale signs that mushrooms are bad:

1. They Feel Slimy or Sticky

How to tell if mushrooms are bad. Dark, slimy mushrooms that are not longer edible.

The first thing to check and one of the easiest ways to tell if mushrooms are bad is to check if they’re slimy.

Mushrooms should look dry, crisp and fresh. If your mushrooms look wet, have developed a slimy film and feel slimy or sticky, they’re not edible anymore.

Slimy skin is an indication that the mushrooms are beginning to rot, and bacteria are breaking them down.

Slimy mushrooms are often the result of keeping mushrooms in the fridge for too long.

2. They’re Wrinkled or Shrivelled

How to tell if mushrooms are bad. Wrinkled and shriveled mushrooms that have passed their prime

Mushrooms have a high water content and, when fresh, are smooth and plump.

If your mushrooms are starting to wrinkle, it means they’re getting old and dehydrated.

If they have just started to wrinkle and aren’t slimy, smelly or discolored, it’s a sign that they will go bad soon, so use them immediately.

But, if your mushrooms have lots of wrinkles and look very shriveled, they’re too far gone, and it’s safer not to eat them.

3. They Have Developed Dark Spots

Button or white mushrooms with dark spots

As mushrooms begin to go bad, they start to develop dark spots. Being exposed to air for too long causes mushrooms to oxidize and discolor.

Keep an eye on those mushrooms in your fridge, and if you notice dark spots beginning to form, your fresh mushrooms are past their prime.

If the spots are minor, the mushrooms are usually not too spoiled to eat. But they’re not going to last much longer.

Mushrooms completely covered with dark spots are too far gone, and it’s probably not safe to eat them.

4. They’re Darker in Color

Dark, wet looking mushrooms that have gone bad.

Besides getting dark spots, mushrooms may also darken as a whole when they’re past their prime.

Dark spots often appear on mushroom caps, while stems and gills get darker as mushrooms go bad.

Mushrooms that are a darker color have a few days left before they go bad. So try to pick lighter-colored mushrooms when you’re at the store.

5. They Feel Soft And Spongy

Fresh mushrooms should feel firm, springy, plump, and light. Never soft or spongy. 

If your mushrooms feel soft, soggy or spongy and they’re floppy, then they have begun to decompose, and you should not eat them.

6. They Have a Strong Smell

Mushrooms have a subtle, light scent that is often sweet and earthy, and you can usually only smell them when they’re close to your face.

If your mushrooms have a strong smell, evident from a distance, then they are bad.

What Do Mushrooms Smell Like When They’re Bad?

Bad mushrooms may give off various strange smells, ranging from ammonia-like odors to sour or fishy smells. 

When the mushroom ferments and breaks down, it causes the smell. Different bacteria on the mushrooms cause different odors.

7. They’re Moldy 

Moldy mushrooms

When you store mushrooms in a moist environment for a long time, they may get moldy. 

Moisture is the enemy of mushrooms. Keeping them as dry as possible will help to prevent the growth of mildew, bacteria and mold. 

If there’s only one moldy mushroom in a container, take it out right away to prevent the mold from spreading. 

If the other mushrooms aren’t moldy, they should be okay to use if cooked within a day or two.

But, if your mushrooms show any of the other telltale signs of being bad, it’s best to throw them out.

Do Store-Bought Mushrooms Last Longer?

Store-bought mushrooms don’t necessarily last longer than mushrooms collected in the wild.

How long a mushroom lasts often depends on how they were harvested, handled, cleaned and packaged before storing. 

In fact, store-bought mushrooms, although packed well, may have been on the shelf in the store for several days and will not last long once you get them home.

Let’s have a look at some of the most common store-bought mushrooms and how to tell if they’re bad:

How to Tell if Sliced Mushrooms are Bad

Moldy sliced mushrooms

Sliced mushrooms only last around three to five days in the fridge and will usually become soft, slimy and discolored when they’re bad.

Sliced mushrooms don’t last as long as whole mushrooms as they have a much greater surface area exposed to the conditions around them.

Try to buy whole mushrooms and only slice them right before use. Or, buy sliced mushrooms the day you plan on using them.

How to Tell if White Mushrooms are Bad

White mushrooms should be smooth, plump, firm and evenly colored. 

If they have bruises or dark spots, look slimy and wet or are slightly darker in color than usual, they’re going bad.

And, if they feel soggy or soft and are floppy, they’re definitely not edible.

How to Tell if Cremini Mushrooms are Bad

How to tell if mushrooms have gone bad. Moldy cremini mushrooms.

Cremini mushrooms, also known as brown mushrooms, are actually baby portabella mushrooms. 

Cremini mushrooms are darker than white mushrooms with a brownish tan cap, but they’re similar in size and shape.

Fresh cremini mushrooms should be plump, solid, smooth, firm and dry with an earthy smell.

Avoid bruised, slippery or shriveled cremini mushrooms, especially if they have a strong smell.

How to Tell if Portabella Mushrooms are Bad

Portabella mushrooms should have a firm cap and stem, and the gills should be dry with a pinkish hue in the light.

If the portabella mushroom cap is soft or shriveled and the gills are dark black or wet looking, then it’s past its prime and won’t last long before going bad.

How Long Do Mushrooms Last? 

Fresh cremini mushrooms

Most mushrooms will only stay fresh for about a day at room temperature before they start to turn brown and shrivel or become slimy.

Whether you collected your mushrooms in the wild or purchased them pre-packed or loose, how you store them will impact how long they last.

If you store mushrooms correctly in the fridge, they will last much longer.

How long do mushrooms last in the fridge?

Whole, fresh mushrooms can last for up to seven days in the fridge if you store them properly. 

Our article, “How Long Do Mushrooms Last? Everything You Need To Know” has more information on how to store mushrooms so that they’ll last longer.

Can you freeze fresh mushrooms? 

Yes, you can freeze mushrooms, and they will last for up to 12 months in the freezer.

If you freeze raw mushrooms, they don’t retain their texture and end up a bit mushy when thawed. 

The best way to freeze mushrooms is to cook them first, then pack them into freezer bags or airtight containers.

Freezing is not the only way to preserve mushrooms; you can also try drying or dehydrating them. Like freezing, drying preserves their original flavor.

Some people also like to preserve mushrooms by pickling, confiting or smoking them. These methods create tasty preserved mushrooms but do change the flavor of the mushrooms.

Discover nine ways to preserve your mushrooms so they don’t go bad.

How to Use Extra Mushrooms Before They go Bad

Mushrooms are so tasty and nutritious it’s a shame to throw any part of them away. 

A quick and easy way to use leftover mushrooms, as well as mushroom stems, is to dice and saute them. Then freeze small portions in freezer bags.

You can use the extra mushrooms and stems, frozen or fresh, to add flavor to many dishes, including:

  • Pasta dishes
  • Soups and broths
  • Omelets and frittatas
  • Savory tarts
  • Quiches
  • Pies
  • Blended burgers
  • Pizzas
Sauteed mushrooms

Can You Cook Spoiled Mushrooms? 

If your mushrooms are showing telltale signs of being bad, or even if in doubt, don’t cook spoiled mushrooms.

You may get lucky and be fine, or you could experience unpleasant symptoms ranging from an upset stomach to being very ill with food poisoning.

Final Thoughts

When you collect or buy mushrooms, always check to make sure they are not past their prime.

Fresh mushrooms should be plump, firm, evenly colored and dry with a light earthy smell.

If you store fresh mushrooms properly, they can last for up to seven days in the fridge before they show telltale signs and start to go bad. 

But mushrooms are so delicious and versatile you can easily find a way to use them long before they go bad.

Visit our Mushroom Education Hub to discover our 30 favorite mushroom recipes and much more.

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