If you buy shrimp in the morning and they die at noon, it is recommended that you first observe the shrimp for signs of spoilage and deterioration. If shrimp are kept at room temperature and have been dead for more than two hours or even longer, they are susceptible to spoilage by contaminating bacteria and are not recommended for consumption. It is usually recommended that after purchasing live shrimp, they should be promptly soaked in water, but live shrimp stored for a longer period of time can also die due to lack of oxygen, so it is recommended that they be cooked as early as possible. As live shrimp itself will host more bacteria and microorganisms, bacteria will decompose the histidine in the shrimp after it dies, thus producing histamine components that are harmful to humans. With the passage of time, the harmful substances produced in the dead shrimp will gradually increase, even through steaming, boiling and other cooking means, but also can not remove the toxins. And already dead shrimp will gradually appear rotten smell, taste will become worse, and nutrition will be damaged. Therefore, some people may experience abdominal pain, diarrhea and other symptoms after consumption, especially for the elderly and children with poor gastrointestinal function, as well as allergic people, the symptoms may be more pronounced, so it is not recommended. In addition, live shrimp cooked, should also be consumed in a timely manner, try to avoid eating leftover shrimp, and shrimp after cooking if stored for too long, but also easy to breed certain bacteria on the surface, after consumption may be harmful to humans, and even cause food poisoning. Shrimp is suitable for simple cooking, stir-fry in time for consumption, in the purchase and selection of live shrimp should also pay attention to, try to avoid choosing the abdomen darkened, or the emergence of shrimp whiskers off the live shrimp.