Shrimp head black is not necessarily because of heavy metals. Shrimp head black for many reasons, shrimp head protein contains amino acids, under certain effects will produce melanin, if the shrimp before being caught, just eat a lot of brown algae and other dark-colored algae, there may also be shrimp head black.

Eating shrimp notes

Just bought back the shrimp if not immediately boiled, it should first be sealed in a plastic bag, put in the refrigerator to save, so as to avoid the loss of nutrients.

Shrimp head black is edible, this is due to the amino acids contained in the protein in the head of the shrimp, under certain effects will produce melanin.

General shrimp should be cooked before eating, dead shrimp will breed a lot of bacteria and harmful substances, should not be eaten again.