Sodium metabisulfite is used in many fields. In the food industry, it is often used as a color-protecting and preservative agent. It can prevent browning and preserve the fresh color of fruits and vegetables by soaking them. When added to wine, it can remove oxygen and prevent oxidation, inhibit bacteria to help fermentation, and protect the purity of the wine. In dry goods, it is used to prevent mold and protect the quality, extending the storage period. In flour products, it is used as a leavening agent to improve the dough and make the cakes crispy and delicious. This is the "magic of food seasoning". In industry, it can be used as a deoxidizer in printing and dyeing to help dyes color evenly; in the papermaking industry, it is used as a bleaching agent to remove impurities and make it white; in wastewater treatment, it can reduce heavy metal ions and purify water quality. However, this substance is corrosive, and when used in food, the dosage must be strictly followed. Excessive use is harmful to the human body. Therefore, users should understand its advantages and disadvantages and act in accordance with the regulations, so as to promote its strengths and avoid its weaknesses and make the best use of it.

Sodium metabisulfite is a versatile agent in the food industry. When processing fruits and vegetables, it is an important agent for color protection and preservation. It can prevent oxidation and browning when soaking fresh fruits and seasonal vegetables, keep their colors bright, and inhibit the growth of microorganisms to prolong their freshness. This is the effect of "locking freshness and color". When brewing wine, it often acts as an antioxidant pioneer, which can remove residual oxygen in the wine, protect the wine from oxidation and rancidity, and curb the reproduction of miscellaneous bacteria, help yeast ferment smoothly, and keep the wine fragrant and mellow. In the production of dried goods, such as mushrooms and seafood, adding it can prevent mold and change and protect its quality. In the baking field, it is used in biscuits and pastries as a leavening agent to improve the toughness and ductility of the dough, making the finished product crispy and delicious. However, it is strong in nature, and its use must strictly abide by the national standards and accurately control the amount. Excessive use is harmful to health. Therefore, users should carefully weigh and use it according to regulations to promote its benefits and avoid its disadvantages, and ensure food safety.

When using sodium metabisulfite, you need to pay attention to dosage control, storage conditions, incompatibility, regulatory compliance, etc. National standards (such as GB 2760) must be followed. The maximum usage in different foods is different (for example, the limit in dried fruits is 0.2g/kg). Excessive use can easily lead to excessive sulfur dioxide residues and irritate the respiratory tract or gastrointestinal mucosa. It needs to be dissolved and added evenly during food processing to avoid excessive local concentration; when used for color protection or preservation, it needs to be added during the raw material pretreatment stage or the initial processing stage to ensure the effect. Store sealed in a cool, dry, well-ventilated place, away from heat sources and direct sunlight to prevent moisture decomposition; avoid mixing with oxidants and acids to avoid chemical reactions. Because it has strong reducing properties, it should not be mixed with oxidants such as sodium nitrite, otherwise it will weaken the efficacy of each other; it may react with additives containing aldehydes, ketones, and proteins, and the order of addition needs to be reasonably planned. If it comes into contact with metal ions such as copper and iron during production, it is easy to accelerate the oxidation of sulfurous acid or cause the reduction pigment to change color. If necessary, it should be used with metal chelators (such as EDTA). Food-grade sodium metabisulfite must have relevant certification, and when used, it must be marked with "sodium metabisulfite" or "sulfur dioxide" on the food label to ensure compliance with food safety regulations. It is recommended to wear protective gloves and masks during operation to avoid powder contact with skin or inhalation. If accidentally contacted, it must be rinsed with clean water in time to ensure the safety of the operator.

The impact of sodium metabisulfite on human health is closely related to its intake and contact mode, and the risk is low when used reasonably. Intake of high doses of sodium metabisulfite in a short period of time (usually due to excessive residues in food) may cause gastrointestinal irritation symptoms such as nausea, vomiting, abdominal pain, diarrhea, and severe cases may cause gastric mucosal damage. After its powder or released sulfur dioxide gas is inhaled, it may irritate the respiratory mucosa, causing coughing and throat discomfort, and the impact is more significant for asthma patients or people with respiratory sensitivity. Direct contact with its crystals or solutions may cause skin allergies and redness. If it accidentally enters the eyes, it may cause eye stinging, conjunctival congestion and other injuries. Sodium metabisulfite will decompose into sulfur dioxide in the body. Long-term intake of a small amount of residues may affect the body's antioxidant system and increase the metabolic burden on the liver and kidneys. People who are allergic to sulfites (about 0.5% of the population) may experience allergic reactions such as urticaria, difficulty breathing, and decreased blood pressure even if they are exposed to trace amounts of sodium metabisulfite, which may be life-threatening in severe cases. Animal experiments show that high doses of sulfites may inhibit the absorption of vitamin B₁. Whether long-term high-dose intake is associated with digestive tract diseases (such as gastritis and esophagitis) still needs more epidemiological studies to confirm. The Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) stipulate that the ADI value of sodium metabisulfite is 0-0.7 mg/kg body weight (in terms of sulfur dioxide). Intake according to this standard is generally considered to pose no significant health risk. Countries have strict regulations on the residues of sodium metabisulfite in food (such as China's GB 2760 requirement that the residue of sulfur dioxide in dried fruits and vegetables is ≤0.2g/kg), and foods from regular channels must meet this standard before they can be put on the market. Choose foods from regular channels and avoid buying processed products with abnormally white colors (such as over-bleached yuba and bamboo shoots) or pungent odors. People who are allergic to sulfites need to read food labels carefully and avoid eating foods containing sodium metabisulfite (such as some dried fruits, pickles, and wine). Food processing companies need to strictly control the amount of sodium metabisulfite used to ensure that the residual amount meets national standards and reduce consumer exposure risks.

Sodium metabisulfite needs to be sealed and stored in a cool, dry, well-ventilated warehouse, away from fire and heat sources, and avoid direct sunlight. The warehouse temperature should not exceed 30°C, and the relative humidity should be kept below 75%. It needs to be stored separately from oxidants, acids, and edible chemicals, and must not be mixed to prevent chemical reactions. The storage area should be equipped with appropriate materials to contain leaks, and the packaging should be checked regularly to prevent moisture decomposition or moisture absorption and agglomeration. At the same time, fire and moisture prevention management should be done to ensure that the storage environment meets safety regulations.