Aquatic products such as oysters, clams, clams and snails that grow in shallows cannot be eaten raw. Because these shellfish and meretrix meretrix belong to bivalves, they are infected with germs to varying degrees. Oyster, Meretrix meretrix, crab and razor clam all have many pathogens, especially Escherichia coli and Vibrio parahaemolyticus, among which the detection rate of pathogens is the highest in summer. In recent years, the outbreak of such gastrointestinal diseases has lasted for many years. The frequent outbreaks, long duration and wide spread of the disease make people pay attention to the risk of gastrointestinal diseases, especially Norwalk virus enteritis.

People in coastal areas of Jiangsu and Zhejiang often eat conch and swollen turtle with a small amount of salt, but they don't know that low concentration of salt can't kill pathogenic bacteria in clam and crab.