How to Tell If Mushrooms Are Bad

Here's how to tell if your mushrooms have gone bad, plus learn how to choose the freshest mushrooms, how to properly store them and whether or not you should freeze fungi.

How to Select the Freshest Mushrooms

Having good mushrooms to cook with all begins at the grocery store or farmers market, where shoppers should select the freshest mushrooms available. Your shrooms should feel dry and firm to the touch with a smooth outer appearance.

If you see dirt on your mushrooms, don't worry! Grab a dry paper towel or cloth and wipe off any grime before storing. If you see what looks like a little too much dirt, wait to rinse the mushrooms until you are ready to use them. Then give them a quick rinse in water, drain, dry and get to cooking! Even if you thoroughly drain and pat dry the shrooms or even take them for a ride in a salad spinner, there could still be residual moisture that will cause your fungi to deteriorate while they're in storage waiting to become dinner.

How to Properly Store Mushrooms

Mushrooms are primarily made of water, and they need air to survive and thrive before being cooked. Even though many commercially sold mushrooms are in containers with a top layer of plastic wrap, sometimes perforated with tiny holes, your best chance at keeping them fresh at home is to store them elsewhere.

"The best way to store fresh mushrooms is to wrap [them] up in a paper towel and [place them] in a brown paper bag. Avoid keeping them in plastic wrap or a plastic container that [will hold and not absorb any] moisture," says World Mushroom Society founder Jason Vergara. The trapped moisture may cause the mushrooms to become moldy, slimy and discolored, and there will be a loss of texture and taste, according to Vergara.

The paper towel inside the brown bag will absorb any excess moisture, keeping it from sitting on the surface of the mushrooms and causing slime. Similarly, the open paper bag allows air to flow freely and keeps your shrooms feeling and looking fresh. Place the bag in the crisper drawer of your refrigerator with the vents open to lower the humidity.

How Long Do Mushrooms Last?

If they're properly stored, your mushrooms can last longer than you might think.

Brian Jupiter, Chopped champion and executive chef of Frontier Chicago and Ina Mae Tavern, explains, "Raw mushrooms can last up to 10 days in the fridge. However, they are best within the first week. After that, their quality decreases. Mushrooms left out of a refrigerator will last up to a day, depending on the temperature."

However, the 10-day rule does not apply to all mushrooms. If you are purchasing presliced mushrooms, their shelf life may only be five to seven days when stored correctly. Some delicate varieties, like maitake or oyster, may only last for a few days before you should check for signs of spoilage.

How to Tell If Mushrooms Are Bad

It usually won't take a taste test to know whether or not your mushrooms have gone bad.

One of the easiest giveaways that your mushrooms are bad is if their texture has changed from firm and plump to sticky and slimy. Similarly, if they are drying out or downright shriveled, it's time to say goodbye.

If the color has noticeably changed on your mushrooms, or if they have begun growing any dark spots or fuzzy mold, they should be headed for the compost heap. Most mushrooms are barely, if at all, scented, so a foul odor can be another telltale sign that your mushrooms have gone bad.

"Some of the more delicate varieties of mushrooms, like enoki, may spoil more quickly. It's best to have a meal planned for any mushrooms you purchase," says Ashley Petrie, RDN, at Everyday Nutrition and Wellness.

Because there are so many mushroom varieties available, all with different flavors and textures, some may exhibit signs of turning bad sooner or slower. So, have a meal plan ready for your shrooms, and if you're storing them because you're not cooking with them immediately, keep an eye on them.

Can You Freeze Mushrooms?

Technically, mushrooms can be frozen, but freezing them raw may not yield the most ideal results.

"Mushrooms are best cooked and consumed when they are fresh. Freezing mushrooms will still preserve the delicious taste, but you will lose a lot of the nutritional value and texture of the mushroom after thawing," says Vergara. "If you choose to freeze mushrooms, wipe them down first with a paper towel and store them in an airtight bag. Do not wash the mushrooms! Mushrooms have a high water content and can act like a sponge when more water is added. Freezing mushrooms after washing them will leave you with very poor-quality and -textured mushrooms when you cook them."

If you really want to prolong the life of your mushrooms, try making dried mushrooms, which pack a savory umami punch when added to recipes. And don't forget to hold off on washing or rinsing your mushrooms until it's time to cook with them, as the added moisture could cause them to spoil more quickly.

The Bottom Line

Fresh mushrooms are dry, firm and smooth and have a pleasant earthy smell. Bad mushrooms are softer (possibly mushy), sticky, slimy, shriveled, maybe moldy and discolored, and may smell unpleasant.

To use up your good mushrooms, try them in this tangy and flavorful recipe for Balsamic-Roasted Mushrooms with Parmesan or in this quick and easy recipe for Spinach & Mushroom Quiche.