E227 · Calcium hydrogen sulfite
- WHO
- Safe
- FDA
- Safe
- EFSA
- Safe
- FSANZ
- Safe
- Japan
- Safe
- UK FSA
- Safe
- Health Canada
- Safe
What is E227?
Calcium hydrogen sulfite (chemical formula Ca(HSO3)2) is a sulfite preservative used in winemaking, fruit juices, and pickled vegetables to slow oxidation and microbial spoilage. It releases sulfur dioxide (SO2), which acts as the active antimicrobial and antioxidant component. It's separately used in the paper industry to help break down wood pulp, but that is not a food application. Food use is regulated, and sulfite-sensitive individuals, including some people with asthma, may experience allergic-type reactions.
Also appears on labels as: Calcium hydrogen sulfite, Calcium bisulfite, Calcium metabisulfite (in solution), Ca(HSO3)2, E227, E 227, E-227, Sulfur dioxide calcium salt, Calcium bisulphite, Food preservative calcium hydrogen sulfite, Calcium metabisulphite, INS 227.
What the evidence says
- Can trigger reactions (flushing, hives, wheezing, or in rare severe cases anaphylactoid symptoms) in sulfite-sensitive individuals, especially some people with asthma.
- EU/EFSA and FDA require allergen labelling when total sulfur dioxide residues are 10 mg/kg or more.
Frequently asked questions
Is E227 safe?
Our overall verdict for E227 (Calcium hydrogen sulfite) is “Safe”, based on the most cautious of the major regulators’ positions — FDA: safe; WHO: safe; EFSA: safe; FSANZ: safe; Japan: safe; UK FSA: safe; Health Canada: safe.
Is E227 vegan, halal or gluten-free?
According to our ingredient data for Calcium hydrogen sulfite — vegan: yes, vegetarian: yes, halal: yes, kosher: yes, gluten-free: yes, dairy-free: yes. Manufacturing sources can vary between products; check the label if it matters to you.
What is E227 and why is it used?
Calcium hydrogen sulfite (chemical formula Ca(HSO3)2) is a sulfite preservative used in winemaking, fruit juices, and pickled vegetables to slow oxidation and microbial spoilage. It releases sulfur dioxide (SO2), which acts as the active antimicrobial and antioxidant component. It's separately used in the paper industry to help break down wood pulp, but that is not a food application. Food use is regulated, and sulfite-sensitive individuals, including some people with asthma, may experience allergic-type reactions.
Does E227 contain allergens?
No known allergens are recorded for Calcium hydrogen sulfite, though some people report sensitivity (sulfites).
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This page summarises publicly available regulatory assessments and research. It is general information, not medical advice. Sources: EFSA, FDA, WHO and the studies linked above.