Shrimp head black can eat should depend on the specific circumstances, generally if it is live or frozen shrimp after thawing shrimp head black, but not spoiled, you can eat. But if it is thawed shrimp, or cooking shrimp not eaten in time, shrimp head black accompanied by odor, touch and other abnormal changes, suggesting that has deteriorated, this time can not be eaten.
Live shrimp head blackened shrimp may be considered shrimp ate some brown algae food, generally does not affect the nutritional value of shrimp, so you can eat. If the frozen dead shrimp, before thawing shrimp head color is normal, thawed shrimp head black, but the body of the shrimp did not turn black, shrimp meat did not deteriorate, may be due to the shrimp head of polyphenol oxidase converted to melanin, but also the normal situation, you can eat.
If the thawed shrimp, or cooking shrimp not eaten in time, etc., not only black shrimp head, and shrimp surface is not smooth, but also accompanied by putrid odor, can no longer eat. May be a long time to place the process of pathogenic bacteria attack and deterioration, blindly eat may cause gastrointestinal discomfort, stomach pain, abdominal pain, diarrhea and other symptoms, and even induce food poisoning.
It is generally recommended to purchase fresh live shrimp, when purchasing not only to observe the head of the shrimp, but also pay attention to observe the shrimp overall touch, taste, etc.. Shrimp need to be preserved is recommended to be placed in the refrigerator freezer to keep fresh, can extend the preservation time, reduce the risk of deterioration. People who are allergic to shrimp should not eat shrimp.