Silver ear fungus contains a relatively high level of nitrates. If it is left to stand for too long after being cooked, the nitrates will be converted into nitrites by bacteria within 1-2 days. Consuming this soup can lead to poisoning.
In addition, fresh wood ear mushrooms should be avoided. Fresh wood ear mushrooms contain porphyrin, a photosensitive substance. This substance is sensitive to light, and after consumption, exposure to the sun can easily cause solar dermatitis. Exposed areas may experience edema, pain, intense itching, and in severe cases, necrosis. In rare and severe instances, laryngeal edema can lead to difficulty breathing.