Mushrooms are a great addition to a variety of dishes, but they do spoil quickly. If mushrooms are allowed to go bad, they can lose their texture and flavor and pose a risk for foodborne illness. Mushrooms are a delicate vegetable that can be difficult to tell if they are bad, but regular visual and touch inspections can help you avoid throwing away spoiled mushrooms.
One of the most common signs that mushrooms are going bad is a gradual color change. The mushroom gills located under the cap can begin to darken, which is the first sign that the mushrooms are starting to rot. Dark spots may also appear on the cap or stems of the mushroom. These dark areas are a sign that the mushrooms have gone past their prime and should be discarded.
When mushrooms become slimy, they are no longer safe to eat and should be discarded immediately. Mushrooms can develop a slimy texture when they are stored incorrectly or if they have been left in the refrigerator too long.
A foul smell is another sign that mushrooms are spoiled and should be discarded. Mushrooms can emit a strong ammonia or fishy odor when they are rotting.