1. Used as chromatographic analysis reagent, preservative and reducing agent, used in dye and pharmaceutical industry

2. Sodium metabisulfite has stronger reducing properties than sulfate, and its effect is similar to that of sodium sulfite. Our country stipulates that it can be used for candied fruit, biscuits, sugar, rock sugar, caramel, candies, glucose, liquid glucose, bamboo shoots, mushrooms and canned mushrooms. The maximum use amount is 0.45g/kg. The residual amount of candied fruit, bamboo shoots, mushrooms and canned mushrooms, grape and blackcurrant concentrated juice (calculated as SO2) is less than 0.05g/kg; the residual amount of biscuits, sugar, vermicelli and other varieties is less than 0.1g/kg; the residual amount of liquid glucose The amount shall not exceed 0.2g/kg.

3. Used in food industry as bleaching agent, preservative, bulking agent, antioxidant, color protectant and preservative.

4. In the pharmaceutical industry, it is used to produce chloroform, benzaldehyde and benzaldehyde. Used as a coagulant in the rubber industry. In printing and dyeing industry, it is used as a dechlorinating agent after bleaching of cotton cloth, and as a scouring aid for cotton cloth. The leather industry is used in leather processing to make leather soft, plump, tough, waterproof, flexural, and wear-resistant. In the chemical industry, it is used in the production of hydroxyvanilaldehyde and hydroxylamine hydrochloride. The photosensitive industry is used as a developer and so on.

Sodium metabisulfite is also a carcinogen. Therefore, strict control of the residual amount of sulfur dioxide in agricultural products is important to control table pollution and protect consumers' health rights. Sodium metabisulfite is produced in industrial grade and food grade, and its quality indicators are different.