The black things in oysters are the internal organs and some metabolites of oysters. The environment of oysters is usually relatively clean. Oysters feed on natural algae and phytoplankton in the ocean every day. The black and green lump in the stomach is actually the digestive organs and undigested food of oysters.

The black stuff in oysters is non-toxic and nutritious, which is harmless to human body after eating. If you don't feel like eating, you can also pick it out and throw it away. When eating oysters, you can eat anything except the shell.

Tips for selecting oysters

1. The bigger the shell, the fatter the oyster. You know, the bigger the shell, the heavier the scale. If the meat is not fat, it is really a waste of money. Choose a head with a uniform shape, not grotesque, round is better than long.

2. Look at the thickness of oyster shells. The thicker and deeper the shell, the fatter the meat. Don't buy it if it's thin and small. Most of them are not fat.

3. Break oysters by hand. If they can be easily broken, they are not fresh, otherwise the gap between the upper and lower shells is very tight. According to these three points, you can buy fresh and fat oysters.