E228 · Potassium hydrogen sulfite
- WHO
- Safe in moderation
- FDA
- Safe in moderation
- EFSA
- Safe
- FSANZ
- Safe
- Japan
- Safe
- UK FSA
- Safe
- Health Canada
- Safe
What is E228?
Potassium hydrogen sulfite (chemical formula KHSO3) is a sulfite preservative and antioxidant used mainly in winemaking and brewing to prevent oxidation and microbial spoilage. It works by releasing sulfur dioxide (SO2), which inhibits spoilage bacteria and yeast. Food use is approved within regulated limits by the FDA and EFSA. Like other sulfites, it can cause allergic-type reactions or respiratory symptoms in sensitive individuals, including some people with asthma.
Also appears on labels as: Potassium hydrogen sulfite, Potassium bisulfite, Potassium metabisulfite (in solution), KHSO3, E228, E 228, E-228, Sulfur dioxide potassium salt, Potassium bisulphite, Food preservative potassium hydrogen sulfite, Potassium metabisulphite, INS 228.
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 E228 safe?
Our overall verdict for E228 (Potassium hydrogen sulfite) is “Safe in moderation”, based on the most cautious of the major regulators’ positions — FDA: safe in moderation; WHO: safe in moderation; EFSA: safe; FSANZ: safe; Japan: safe; UK FSA: safe; Health Canada: safe.
Is E228 vegan, halal or gluten-free?
According to our ingredient data for Potassium 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 E228 and why is it used?
Potassium hydrogen sulfite (chemical formula KHSO3) is a sulfite preservative and antioxidant used mainly in winemaking and brewing to prevent oxidation and microbial spoilage. It works by releasing sulfur dioxide (SO2), which inhibits spoilage bacteria and yeast. Food use is approved within regulated limits by the FDA and EFSA. Like other sulfites, it can cause allergic-type reactions or respiratory symptoms in sensitive individuals, including some people with asthma.
Does E228 contain allergens?
No known allergens are recorded for Potassium 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.