Potassium Metabisulphite
The short version
A potassium metabisulfite preservative — common in winemaking as a low-sodium sulfite source.
A sulfite preservative (common in wine and pickles). Sulfites can trigger breathing problems in people with asthma and reactions in other sensitive people, so labels must declare them. That's why we flag it.
Safety profile
JECFA's group ADI for sulfur dioxide and sulfites is 0–0.7 mg/kg body weight, expressed as SO2 (1998). In 2022 EFSA withdrew its temporary group ADI of 0.7 mg SO2/kg body weight per day, finding the toxicity data inadequate to derive an ADI, and concluded that estimated dietary exposure raises a safety concern. Same allergen profile as all sulfite forms. The potassium content is generally beneficial vs. sodium but the SO2 exposure and asthma trigger risk are identical.
Sources
- EFSA FAF Panel — Follow-up of the re-evaluation of sulfur dioxide (E 220) and sulfites including potassium metabisulfite (E 224), EFSA Journal 20(11):e07594 (2022), doi:10.2903/j.efsa.2022.7594 — European Food Safety Authority (EFSA), 2022. ADI status; safety concern at current exposure
- JECFA evaluation summary — Potassium metabisulfite (INS 224), group ADI 0–0.7 mg/kg bw (1998) — WHO/IPCS INCHEM (JECFA), 1998. JECFA group ADI 0–0.7 mg/kg bw as SO2
- 21 CFR 182.3637 — Potassium metabisulfite (GRAS, with use restrictions) — US eCFR (Office of the Federal Register / FDA), 2026. US status and restrictions
- Regulation (EU) No 1169/2011 on food information to consumers — Annex II (substances causing allergies or intolerances) — EUR-Lex (European Union), 2011. Mandatory declaration as SO2 in the EU
Checked against these sources on .
Educational information only. Not medical, dietary or veterinary advice. Spotted an error? Tell us.