Sodium Metabisulfite E223
sulfite — Primarily synthetic.
Disodium disulfite
CAS: 7681-57-4
Factual Regulatory Reference
This database provides factual regulatory information compiled from official government sources. It does not constitute medical, nutritional, or safety advice. Regulatory status varies by country and is subject to change. Always refer to your local regulatory authority for the most current information.
? Did You Know?
Beyond food, Sodium Metabisulfite is also used in cosmetics, medicine, industrial applications, household products. Its versatility makes it one of the most multi-purpose chemical compounds in everyday life.
To reach the Acceptable Daily Intake limit, a 60kg adult would need to consume approximately ~0.1 tablet Campden tablets (standard dose for 20L wine) in a single day. (This is a mathematical illustration, not a safety recommendation.)
Regulatory Analysis
Sodium metabisulfite occupies the intersection of food regulation and amateur food production, as the primary ingredient in Campden tablets used by millions of home wine-makers and brewers who operate entirely outside regulatory oversight of additive use levels. The clinical literature on sulfite-induced anaphylaxis in asthmatics provides an unusually direct evidence base linking this preservative class to severe adverse events, yet regulatory agencies have maintained approval while shifting responsibility to allergen labeling. The fundamental policy tension is whether mandatory disclosure adequately protects a sensitive subpopulation that may comprise 5-10% of asthmatics, or whether the ubiquity of sulfites across food categories makes meaningful avoidance impractical even for informed consumers.
Detailed Regulatory Assessment
European Union (EFSA)
MANDATORY allergen declaration 'contains sulfites' required when total SO₂ ≥ 10 mg/kg or 10 mg/L. Temporary group ADI established with concerns for high consumers.
United States (FDA)
MANDATORY allergen declaration 'contains sulfites' when ≥10 ppm SO₂. Banned from fresh produce intended to be eaten raw (since 1986).
Japan (MHLW)
Part of sulfite group; allergen labeling mandatory
Acceptable Daily Intake (ADI)
International Standard (JECFA)
mg/kg body weight per day
European Standard (EFSA)
Everyday Perspective
For a 60kg adult, this limit is roughly equivalent to consuming:
Natural Occurrence
This additive is not known to occur naturally in significant quantities.
Manufacturing
Produced by treating a solution of sodium carbonate or sodium hydroxide with excess sulfur dioxide (SO₂) gas. The resulting solution is concentrated and crystallized to yield sodium metabisulfite. Can also be made by dehydrating sodium bisulfite. The compound exists as Na₂S₂O₅ but dissociates to form sulfur dioxide in aqueous solution.
Applications Beyond Food
Used in some cosmetic formulations as an antioxidant
Used in pharmaceutical formulations as an antioxidant and stabilizer
Used in water treatment, textile bleaching, paper manufacturing, photography, and mining
Main ingredient in Campden tablets for home wine-making and brewing