Food-grade copper sulfate can be used as chelating agent and clarifying agent in the production of preserved eggs and wine, but the dosage should be paid attention to. Excessive dosage will lead to excessive heavy metal content in food.

Preserved eggs, also called preserved eggs or preserved eggs, can not only increase appetite and promote digestion and absorption of nutrients, but also have the effects of cooling and lowering blood pressure. They are made of lime, salt and edible alkali.