You can't eat it. When the crab is dying or dying, the oxygen acid in the crab will decompose to produce histamine. Histamine is a toxic substance. With the extension of death time, more and more histamine is accumulated in crabs, and more and more toxic gases are produced. Even if the crab is cooked, this toxin is not easy to be destroyed.

Buy fresh river crabs, and choose crabs to do "five looks": look at the color; Second, look at the individual; Third, look at the navel; Fourth, look at crab hair; Fifth, look at the action. The color of crab should be green back and white belly; Golden claw yellow hair; Individuals should be big, old and healthy; The navel should protrude outward; Crab feet should be hairy; Stay agile and active. Only those who meet these five conditions can buy it. The estimate in the sea is similar.