Crab stomach black is belong to the dirt, the existence of toxicity and its growth environment has a great impact.

Crab stomach black is crab intestine: that is, from the crab stomach to the crab umbilicus of a black line, should be discarded.

In addition to this, there are three other places that should not be eaten:

1. Crab stomach: it is the triangular-shaped bone package in the crab's lid. Eat the crab cover first, use a small spoon to pull out the middle part of the crab stomach, and gently suck the crab yolk wrapped around the outside clean. Be careful not to suck through the triangular cone-shaped stomach in the center, which is full of dirt and sand and should be discarded.

2. Crab heart: After eating the crab cover, use a pair of scissors to cut off the excess crab legs and crab mouth. Use the handle of a spoon to pick out a hexagonal piece in the center of the crab body, which is the heart of the crab and should be discarded.

Crab gills: Two rows of floppy things that grow like eyebrows on the crab's abdomen should be removed.

The crab is an omnivore, feeding on aquatic plants, benthic animals, organic debris and animal carcasses. Feeding relies on the chelicerae to catch and then deliver the food to the mouth. Its favorite food is snails. It likes snails, small shrimps, mussels, small fish and pumpkins, boiled potatoes, rice crumbs, bread crumbs and so on. All these, are harmless to the human body and to the crab.

There are very many types of crabs, pike crabs, green crabs, frog crabs, Guan Gong crabs, etc. Because of the distribution of different geographic locations, so there are grades, first-class lake crabs, such as Yangcheng Lake, Jiaxing Lake; second-class is the river crabs, such as Jiujiang, Wuhu; third-class is the river crabs; fourth-class is the stream crabs; fifth-class is the ditch crabs; sixth-class is the sea crabs.