What is the difference between sodium bisulfite and sodium metabisulfite

What does sodium metabisulfite become in water?

First: Sodium metabisulfite is a toxic chemical that has a significant stimulating effect on the skin and mucous membranes and can cause conjunctival and bronchitis symptoms.

Second: Sodium metabisulfite is mainly used as a bleaching agent, preservative, loosening agent, antioxidant, color retention agent and preservative in the food industry.

Third: There are strict standards for the amount of sodium metabisulfite used in the food industry. When used as a bleaching agent, it can only be used for fumigation, and cannot be directly soaked and contacted with objects.

Fourth: Long-term consumption of foods containing sodium metabisulfite can damage the liver and kidneys of the human body.

Sodium metabisulfite is mainly used to prevent the blackening and deterioration of shrimp caught in the sea, and the chemical reducing agent commonly used in chilled aquatic products. After fishing, fishers often add it directly on fishing vessels or fishing vessels. Generally, they are used in summer, but are used in spring and autumn, but not in winter. use. In aquatic products, sodium metabisulfite is decomposed into sulfur dioxide. Sulfur dioxide meets water to produce sulfurous acid. Sulfurous acid has reducibility. It can effectively control the browning of aquatic products, block the physiological oxidation process of microorganisms, inhibit reproduction, and inhibit the activity and development of food oxidase. Chromophore, while showing its bleaching, decolorization, antiseptic and antioxidant effects. The residual substance is sulfur dioxide (SO2). Sodium metabisulfite is prescribed for use in dried fruits, fruits and vegetables, fruit juice drinks, candied fruit, wine, etc. in China's "Sanitation Standards for the Use of Additives". The scope of use does not include aquatic products. Therefore, in theory, water Sodium metabisulfite cannot be used in products, but it is actually used by fishing vessels. However, the substance is recommended by the United Nations for freshwater shrimp preservatives, and is also recommended by the United States, Japan and Taiwan Provinces and other countries and regions. The local standard "Quality Requirements for Prawned Sea Prawns" in our province also mentions the use limit of sodium metabisulfite, so it is neither necessary nor feasible to ban the use. The key is to prevent excessive use and endanger health. For the use method, please refer to "Technical Requirements for Preservation of Freshwater Shrimp" The excessive use of sodium metabisulfite is a common problem. Its use is mostly in the production link (fishing boats and fishing vessels), rather than in processing plants and market links. The residual limit of the residual substance sulfur dioxide is 100 mg/k.