If a live crab has been left to die overnight and has not spoiled, it can be eaten.

If the crab has been dead for a few hours, the crab will be properly preserved, placed in the refrigerator or lower temperature, the crab body has not been deteriorated, this time can be eaten, but its food value as well as the nutritional value may be relatively reduced. If the crab has been dead for a few hours and not properly preserved, deterioration and decay may occur in the crab's body.

And there are all kinds of bacteria and viruses in the body of the crab, which will continue to reproduce even after the crab is dead, so it is not edible at this time. In daily life, if the crab before eating, you need to thoroughly clean the crab before eating, but also pay attention not to eat too much, the crab must be cooked at high temperatures before eating, usually about fifteen minutes can be.

Precautions for eating crabs:

The gills, sandbags, and internal organs of crabs contain a lot of bacteria and toxins, and must be cleaned before eating, drunken crabs or pickled crabs, such as undercooked crabs should not be eaten, and should be steamed and boiled through and then eaten, and stored for a long time of cooked crabs should not be eaten, fat crabs is the persimmon ripe season, and should pay attention to the avoidance of crab and Persimmon mixed, family consumption of crab to steam-based, to eat that is steamed, eat how much steamed, do not eat leftover crab.

Lift up the crab, backlit look at the jagged top of the crab shell, if it is completely opaque, that is more fat, and vice versa, is not full, the bottom of the crab is white or even transparent, on behalf of the crab has just finished changing the shell. The crab consumes most of its energy when it changes its shell, so it usually has little meat as well. Those with dirtier bottoms tend to be more plump, and it is important to eat crabs in the right way.

Refer to Baidu Encyclopedia-Crab for the above