Shiitake mushrooms are a popular ingredient used in cooking, especially in Asian dishes. In addition, many Asian cultures believe that the shiitake mushroom has powerful medicinal properties and therefore these cultures use them in natural healing remedies. In recent years, shiitake mushrooms have become widely available in the produce section of most grocery stores. Many shoppers are intimidated by mushrooms because they do not know how to identify the ones that are spoiled.
Look for wrinkles and puckering on the skin of the shiitake mushroom. This indicates that the mushroom is past its prime and the internal moisture has begun to evaporate.
Press a finger into the top of the shiitake mushroom and then release it. If the skin bounces back, then the mushroom is fresh. If the skin remains pushed in, it indicates that the mushroom is going bad.
Examine the entire mushroom for signs of slime. Slime is actually the decomposition of the mushroom, so these mushrooms should be avoided.
Look for a stem that is dried or cracked. This sometimes occurs prior to the development of slime and is also an indication of a bad mushroom.