E223 - Natriummetabisulfit

Origin

Sodium metabisulphite is an inorganic compound composed of sodium, sulfur, and oxygen. It is a disulfite and typically exists as a white or yellowish crystalline powder. It is a sulfur-based antioxidant and preservative. It is synthetically produced by reacting sulfur dioxide with sodium carbonate solution.

Usage

Sodium metabisulphite is widely used as a preservative, antioxidant, and bleaching agent in the food industry. It inhibits microbial growth, prevents enzymatic browning, and maintains the color and texture of various food products. Common applications include preserving dried fruits, fruit juices, sausages, and wine. It is also used in the brewing industry to prevent oxidation and bacterial growth. Furthermore, it finds application in photography, water treatment, and as a laboratory reagent.

Side Effects

While generally recognized as safe (GRAS) at permitted levels, sodium metabisulphite can cause adverse reactions in sensitive individuals, particularly those with sulfite allergies or asthma. Reactions may include hives, itching, angioedema, bronchospasm, and gastrointestinal distress. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established an Acceptable Daily Intake (ADI) of 0-0.7 mg/kg body weight for sulfites, including sodium metabisulphite. Exceeding this ADI, especially in sensitive individuals, may increase the risk of adverse effects. It can also destroy thiamine (Vitamin B1) in food.

Regulatory Status

Sodium metabisulphite is approved for use as a food additive in many countries, including the United States, the European Union, and Canada. Regulations specify maximum permitted levels in various food categories. In the EU, it is designated as E223. Food products containing sodium metabisulphite above a certain threshold (typically 10 mg/kg or 10 ppm) must be labeled to inform consumers about its presence. The FDA also requires declaration when it is used.