To tell if mushrooms are bad, check the following signs:

• Texture: Fresh mushrooms should be firm, plump, and dry. If they feel slimy, sticky, soggy, soft, or spongy, they are starting to rot and should be discarded

. Sliminess is a clear indication of bacterial breakdown.

• Appearance: Look for bruises, dark spots, or discoloration. Mushrooms that have developed dark spots or have become darker overall are past their prime. Wrinkled or shriveled mushrooms are dehydrated and old; if very shriveled, they are unsafe to eat

• Smell: Fresh mushrooms have a mild, earthy scent or almost no smell. A foul, sour, ammonia-like, or rotten odor indicates spoilage and they should be thrown out

• Mold: Any fuzzy mold growth or unusual colors (white, green patches) on the surface means the mushrooms are spoiled and unsafe

• Other signs: For specific types like portabella, the gills should be dry and pinkish; wet or blackened gills mean they are going bad

In summary, mushrooms that are slimy, soft, discolored, shriveled, moldy, or smell bad are no longer safe to eat and should be discarded

. Always trust your senses—if in doubt, throw them out.