What do mushrooms look like when they're not fresh anymore

When mushrooms are not fresh, they usually appear darker in color, softer in texture, sticky on the surface, or have a strange odor. Fresh mushrooms should have a uniform color, compact texture, and fresh aroma. If the edges of the mushroom cap turn black, the gills change color, water seeps out, or mold spots appear, it indicates that they have spoiled. Eating spoiled mushrooms by mistake may cause gastrointestinal discomfort and even food poisoning. It is recommended to dispose of them. The color change of mushrooms is the most intuitive signal of spoilage. The white mushrooms show yellow brown spots, the mushroom cap changes from brown to dark black, and the tip of the golden needle mushroom turns yellow or sticky, all of which are typical characteristics of decay. Some varieties, such as shiitake mushrooms, will produce dark green mold spots when they spoil, while shiitake mushrooms will shrink and curl from the edges. These pigment changes are caused by the oxidative polymerization of polyphenolic substances through the action of polyphenol oxidase.

Texture change is an important basis for judging the freshness of mushrooms. Fresh mushrooms have elasticity and are not easy to leave marks when lightly pressed. After spoilage, the cell wall will decompose and become noticeably softer, making it difficult to rebound or even exuding juice when pressed. Especially for varieties with high water content such as shiitake mushrooms and shiitake mushrooms, the stem is easily separated from the cap after decay, and the internal tissue is sponge like. If a slippery or brushed surface is found on the mushroom, it indicates that microorganisms have proliferated in large numbers.

For daily storage of mushrooms, it is recommended to wrap them in kraft paper bags and refrigerate them to avoid sealing the plastic bags and accelerating the decay of condensed water. Before cooking, carefully check the condition of the mushrooms. If they are slightly dehydrated, they can be removed and consumed as soon as possible. However, if there is a noticeable odor or mold, they must be discarded. For wild mushrooms, even if they look normal, it is not recommended to consume them. Ingesting poisonous mushrooms by mistake may cause liver and kidney damage, and vomiting and diarrhea symptoms require immediate medical attention.