2. The blue crab is an aquatic crustacean with a high content of protein. When it is alive, it can excrete bacteria through metabolism in the body. Once it dies, a large amount of protein in its body will be rapidly decomposed by bacteria, and gradually produce harmful substances such as cadaverine and histamine, which cannot be well eliminated by high temperature. If you continue to eat it, it will be harmful to your health. Therefore, the dead blue crabs should be thrown away in time to avoid eating by mistake.