Crab steamed, meat sour is steamed is dying or already dead crabs, will produce toxic substances after steaming a histamine, is not eaten.

Crab body contains more histidine, histidine is easy to decompose, can be produced under the action of decarboxylase enzyme histamine and histamine-like substances. When the crabs die, histidine decomposition is more rapid, the longer the crabs die, the more histamine accumulates in the body, and when the histamine accumulates to a certain amount, eating it will cause poisoning.

If you eat such crabs, it is easy to cause food poisoning, common manifestations of nausea, vomiting, abdominal pain, diarrhea, severe dehydration, electrolyte disorders, convulsions, and even shock, coma, sepsis and so on. This is the reason why river crabs can only be eaten fresh.

Extended information:

How to select live crabs

1. You can use your finger to gently press the shell surface by the crab's eye, if the crab's eye moves right away, then it means that its vitality is abundant, or you can put your finger between the crab's claws, such as the crab's claws are powerful, then it means that the crab's vitality is very strong. There is also the fact that the crab that leaves the water and spits out foam is a live crab and can be purchased with confidence.

2, the crab to distinguish between male and female is very easy, we put the crab in turn, the crab belly was triangular for male, round for female.

3, however, the masters can tell by looking at the legs, female crabs have a gray and black mass of fluff on the two chelae, and no other place. And the male eight legs there are arranged as a brush of fine hairs.

Expert Opinion

Dead crabs contain high levels of toxic substances, so you can't buy and eat dead crabs because of their price or for other reasons. When buying crabs, try to buy live crabs as much as possible. In addition, you should also pay attention to the people who avoid eating crabs, not everyone is suitable for eating crabs.

Reference:

People's Daily Online: Can you eat dead crabs? The first thing you need to do is to get your hands dirty.