Oysters are oysters. Oysters, like other shellfish, can be poisoned by parasites and other pollution. It can be eaten raw, but in order to meet the requirements of raw eating, the growth and breeding environment of oysters is high, and they must be cultured in the first-class sea area, and oysters that need strict monitoring and testing can be eaten raw.

Oysters cultured in secondary sea areas can only be cooked.

Grade III and IV water is inedible.