How to Choose Mushrooms
Look for button mushrooms that are light in color, since the mushrooms darken when they get older.
Make sure button mushrooms are clean and that the area where the cap meets the stem is closed.
Choose specialty mushrooms, such as oysters and porcini that are open where the cap meets the stem. The gills under the cap should be light in color, not dark brown or black.
Make sure mushrooms are firm, meaty and dry, and not withered.
Smell all types to make sure they smell pleasant and earthy.
Avoid mushrooms with bruises or pits or mushrooms that feel slimy.
How to Store Mushrooms
If the mushrooms are prepackaged, leave them in the packaging
If the mushrooms are loose, place them in a paper bag and loosely fold the top of the bag over, or place them in a glass container and cover it with a dishtowel or moist paper towel. Be sure to allow air circulation.
Store the mushrooms in the refrigerator, but not in the crisper.
Use the mushrooms within a few days, or within a week if they are packaged and unopened.