How Long Do Mushrooms Last Before They’ve Gone Bad?

There’s nothing like the delicious aroma of savory sauteed mushrooms filling your kitchen— not to mention the savory taste of them paired with your steak or roasted vegetables.

But anyone who’s bought fresh mushrooms knows what it’s like to open the fridge and see your caps shriveled and spotty. You were so excited to add them to your dish, but they’re a little slimy. Are these mushrooms still good to cook with? you wonder. 

Let’s look at the tell-tale signs that your mushrooms are going bad. Our mushroom experts at Monterey know exactly what to look out for, as well as the best tips for keeping your mushrooms as fresh as possible.

What Does an Expired/Bad Mushroom Look Like?

Mushrooms aren’t exactly shy about letting you know when they’re reaching their expiration date! Here are some warning signs that your mushrooms are, or are getting very close, to their expected shelf life: 

1. The mushrooms are slimy. 

This is always a sign that your fresh fungi is reaching a point of no return. A film of slime means the mushroom is getting ready to decompose. We always like to say, “if a mushroom is completely covered in slime, it’s past its prime!” Do not eat.  

2. The mushrooms have dark spots. 

Spots aren’t necessarily a sign your mushrooms are bad unless it’s paired with slime or if the spots are very dark. Some mushrooms can develop natural blotches, light bruises or mild discoloration on the caps from handling during packaging. If the spots are deep in color and noticeable and present with other warning signs above, those mushrooms aren’t fresh anymore. If the spots look at all like decay, throw them away.

3. The mushrooms are smelly.

Fresh raw White or Brown mushrooms have a very subtle, natural smell that’s nearly unnoticeable. You’d have to stick them right against your nose to smell that earthy scent. Mushrooms that are spoiled will likely have a distinct bad odor. If you open the packaging or bag and catch a nasty whiff, those mushrooms are starting to decompose and are expired.

4. The mushrooms are wrinkled or shrunken. 

Wrinkles are typically not a sign of expiration. It means your mushroom is starting to dry out from being in the fridge for too long and is often seen with diminished scale of the cap itself— AKA shrinkage in size! Mushrooms are 95% water, so they show signs of dehydration more distinctly than other produce items. If they are a little dry, consider immediately eating them and adding them to a wet dish like a soup to rehydrate and improve their texture. 

5. The mushrooms are deformed or cracked.

No two mushrooms grow into the exact same shape, but a mushroom that is noticeably deformed can be a sign of shriveling from dehydrating in the fridge. Cracking of the cap can also indicate the mushroom is drying out. Follow the same advice for wrinkled or shrunken mushrooms and eat immediately, or else throw them away.

FUN-GI FACT: Did you know decomposing mushrooms are a great food to add to your compost?
Their rich nutrient profile can be passed along to your plants in the garden.

The Average Shelf Life of Mushrooms

One of the best ways to know how long your mushrooms are good for is to know where to find the expiration date on the packaging. 

The average shelf life of mushrooms is 10 days from the day they were harvested. While growers like us at Monterey have made significant improvements in packing and shipping mushrooms, you must realize that the ‘shrooms had to travel from the farm to a distribution center and then a grocery store. With this in mind, the average mushroom package has 7 days from the time it hits the grocery shelves to when they need to be eaten.

Finding Your Mushroom’s Packaging Date

In order to pick the freshest mushrooms in the produce section, be sure to read the coded information on its packaging. Here at Monterey, our coding is on the right-hand side of most packages: as depicted below.

All mushroom tills, bags and bulk cases will be coded with the following: Location code(s) / Julian date / Line number / Military time.

What you care about is the Julian date, or the second number of the code.

How to Keep Mushrooms Fresher Longer

While your mushrooms will have their expected shelf life, there are many things you can do to keep your ‘shrooms fresher, longer. 

• Store your mushrooms in their original container until open; then, paper bag them. The best place for mushrooms is in their original container since they are specifically designed by the experts to keep your food fresh. But after opening the package, you can move your mushrooms to a paper bag. Not plastic! This will allow the moisture they naturally retain to be slowly released, whereas, in a sealed plastic bag, the trapped wetness will cause your mushrooms to age quickly.

• Know when and how to wash your mushrooms. Many think that after opening a package of mushrooms, the next step is to wash them like you would other produce before eating. The texture and shelf life of mushrooms, however, can be affected by rinsing them directly under a running faucet. Instead, only clean your mushrooms prior to eating them by lightly brushing off any dirt using your hands or a damp paper towel.

• Freeze, marinate or dehydrate your mushrooms to save for later! While fresh mushrooms are typically best eaten within 10 days of being harvested, you can extend the lifespan of your mushrooms by freezing or dehydrating them. From there, they can be added to soups, sauces or other popular dishes. Dehydrated mushrooms can even be ground into a powder and added to smoothies and more. Lastly, marinated mushrooms can be sealed in mason jars and stored for up to a year.

Discover more ways to keep your mushrooms firm and flavorful by reading Tips for Serving the Freshest Mushrooms.

Let’s Get Cookin’

With a few exciting recipes to whip up, you’re sure to use your mushrooms well before they expire. 

In our More Flavor, Less Guilt Cookbook, we have over a dozen delicious recipes that are both fresh and low calorie! Download your free ebook, today.