Food additives database

E223 – Sodium metabisulfite

Orange grain dots symbol for food additive with some concerns (E number classification – ORANGE level).

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Safety grading ORANGE – SOME CONCERNS

The current group ADI (Acceptable Daily Intake) for sulfur dioxide and sulfites, including E223 sodium metabisulfite, is 0–0.7 mg/kg body weight/day expressed as sulfur dioxide equivalents. EFSA retained this temporary group ADI from JECFA, using a default uncertainty factor of 100 and long-term rat data, including a three-generation reproductive study in which a NOEL (No Observed Effect Level) of 0.25% sodium metabisulfite in the diet, equivalent to about 70 mg/kg bw/day as SO2, was identified the key concern was site-of-contact irritation rather than clear systemic toxicity (EFSA ANS Panel, 2016; DOI 10.2903/j.efsa.2016.4438).

E223 is best graded ORANGE – SOME CONCERNS rather than GREEN – SAFE because it is still legally permitted, but there is a well-established subset of sensitive people who can react to sulfites, especially those with asthma. In a challenge study of 203 asthmatic patients, the best estimate of sulfite sensitivity was 3.9%, with steroid-dependent patients at greatest risk (Bush et al., 1986; PMID 3535492). In another oral challenge study of steroid-dependent asthmatics, the estimated prevalence was 4.5% (Prieto et al., 1988; PMID 3266541). Wright et al. exposed 30 asthmatic and 16 non-asthmatic subjects to inhaled sodium metabisulfite and found that all asthmatic subjects responded, while only one atopic non-asthmatic subject did (Wright et al., 1990; PMID 2161625). Reviews have consistently concluded that sulfite reactions are uncommon in the general population but clinically important in susceptible asthmatics and occasionally severe (Vally et al., 2009; PMID 19775253; Vally and Misso, 2012; PMID 24834193). EFSA’s 2022 follow-up also noted that high consumers can still exceed the temporary ADI and that some toxicology gaps remain (EFSA FAF Panel, 2022; DOI 10.2903/j.efsa.2022.7594).

That does not make E223 broadly dangerous for everyone. For most consumers it functions as a low-dose preservative and antioxidant without obvious harm. The downgrade to ORANGE is mainly driven by reproducible respiratory sensitivity in a vulnerable minority, plus the fact that exposure can be high in products such as wine, dried fruit, shrimp, and some potato products.

Side effects

  • Wheezing or bronchospasm: the most important known risk is sulfite-triggered breathing difficulty in sensitive asthmatic individuals.
  • Flushing, hives, or itching: some sensitive people report skin symptoms after sulfite-containing foods or drinks.
  • Stomach upset: nausea, abdominal pain, or diarrhoea are reported in some intolerance cases.
  • Rare severe reactions: anaphylactoid reactions have been described, although they are much less common than asthma-related reactions.
  • Thiamine loss in foods: sulfites can destroy vitamin B1, which is why their use is restricted in foods recognized as important thiamine sources.

Should You Avoid This Additive?

Most people do not need to avoid E223 completely. Extra caution makes sense for people with asthma, a known sulfite sensitivity, or a history of unexplained reactions to wine, dried fruit, shrimp, or sulfite-preserved restaurant foods. It may also be sensible to limit exposure when the diet already relies heavily on sulfited foods. For the general population, occasional intake is usually not a major concern, but it is not one of the additives that deserves a fully reassuring GREEN rating.

Common Uses

  • Dried fruit: helps prevent browning and microbial spoilage.
  • Wine, cider, and some fruit drinks: acts as an antioxidant and antimicrobial preservative.
  • Shrimp and some crustaceans: helps prevent black spot formation during storage.
  • Potato products: reduces browning after cutting or processing.
  • Juices and concentrates: helps stabilize colour and shelf life.
  • Dough and some bakery applications: can act as a reducing agent during processing.

Common names / Synonyms

  • Sodium metabisulfite
  • Sodium metabisulphite
  • Sodium disulfite
  • Disodium disulfite
  • Sodium pyrosulfite
  • Disodium pyrosulfite
  • E223
  • INS 223

What is it?

E223 is the food-additive code for sodium metabisulfite, an inorganic sulfite salt with the formula Na2S2O5. In water and acidic foods it can release sulfur dioxide, which explains both its preservative effect and many of its practical uses. Food manufacturers use it because it slows enzymatic browning, limits the growth of bacteria and fungi, and helps protect colour and flavour in products that would otherwise deteriorate more quickly.

It is usually made by reacting sulfur dioxide with a sodium base and then removing water to form a dry crystalline powder. On labels, it is most often found in dried fruit, wine, seafood preparations, fruit-based products, and some processed potato foods. Chemically, it is mainly an antioxidant, antimicrobial agent, and reducing agent rather than a nutrient. One practical drawback is that sulfites can break down thiamine (vitamin B1), which is why regulators restrict their use in certain foods. Laboratory research has also suggested that sulfites can inhibit some beneficial gut bacteria at concentrations regarded as safe for food use, but the real-world relevance of that finding in humans is still uncertain (Irwin et al., 2017; PMID 29045472).

Where it’s allowed (EU vs US)

E223 is authorised in the EU as sodium metabisulphite within defined food categories and limits. In the United States, sodium metabisulfite remains permitted and generally recognized as safe when used according to good manufacturing practice, but not in meats, foods recognized as sources of vitamin B1, or fruits and vegetables intended to be sold or served raw. In the US, sulfites must also be declared on the label when present at 10 ppm or more.

Further reading