The Trick To Keeping Mushrooms Fresh
Nothing's worse than buying a package of beautiful mushrooms at the grocery store or farmers' market, only to find that they've gotten slimy and fishy-smelling when you reach for them a few days later. Thankfully, there are a few different tricks to keeping mushrooms fresh, so when you go to saute them in butter for a frittata, or grill them as a topping for your favorite red meat, they're still just as good as the day you bought them.
The first method applies to mushrooms you buy at the grocery store that come in a shrink-wrapped container. According to The Kitchn, the best way to keep these mushrooms fresh is to keep them in their original packaging. If you need to use a few mushrooms take them out of the package and then re-wrap it in plastic wrap, or put the whole container in a plastic bag.
If you buy mushrooms that come in a plastic produce bag, you can keep the mushrooms fresher by taking them out of the bag, wrapping them in paper towels, and then putting them back in the bag (ensuring the bag isn't sealed tight). The paper towel will absorb any excess moisture, so no mushrooms are sitting in drops of water, but also helps keep the mushrooms in a humid environment so they don't dry up (via Food Network).
If you've tried these methods and still find yourself with slimy mushrooms on a regular basis, or are dealing with wild mushrooms from the farmers' market, there's one other option. Try storing your mushrooms in a partially opened paper bag. This will allow more airflow around the mushrooms which helps control humidity, and the porous nature of the brown paper bag allows naturally occurring gasses that come off of maturing mushrooms to escape the bag so they don't ripen too quickly (via Southern Living).