Sodium metabisulphite (SMBS) — one of the most commonly labelled sulphite preservatives in wine, dried fruit and processed foods, assessed with the E220–E228 group.
Sodium metabisulphite (E223), often abbreviated SMBS or written sodium metabisulfite, is a sulphite used as a preservative and antioxidant in wine, dried fruit, potato products and other foods. It is assessed with the wider sulphite group (E220–E228). It is permitted in Australia/NZ, the EU and the US within set limits, and must usually be declared when present at 10 milligrams per kilogram or more. EFSA's 2022 follow-up withdrew the temporary group Acceptable Daily Intake for sulphur dioxide–sulphites because toxicity data remained inadequate, and instead used a margin-of-exposure approach that raised a safety concern for high consumers in most population groups. Regulators and allergy bodies have long noted that sulphites may be associated with asthma-like symptoms in some sensitive individuals. Goodnessly rates it Avoid.
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Read the FAQ →Sodium metabisulphite (E223) is an inorganic sulphite salt (also called sodium pyrosulphite). In solution it releases sulphur dioxide, which provides the preservative and antioxidant effect. It belongs to the wider sulphite group that also includes sulphur dioxide (220), sodium sulphite (221), sodium bisulphite (222), potassium metabisulphite (224) and related salts (226–228). On labels you may see "sodium metabisulphite", "sodium metabisulfite" (US spelling), "SMBS", "223", or the class name "preservative" / "antioxidant" with the number.
Sodium metabisulphite is one of the sulphites you are most likely to see named on wine, dried fruit and processed-food labels.
Sodium metabisulphite is regulated as part of the sulphur dioxide–sulphites group. It remains widely permitted, carries mandatory declaration rules in major markets, and sits under EFSA's 2022 group assessment that withdrew the temporary ADI and flagged a safety concern for high consumers. Sulphites have long been associated in clinical and regulatory literature with adverse reactions in some people with asthma.
| Region | Status | What this means |
|---|---|---|
| AU/NZ Australia & New Zealand (FSANZ) | Permitted; declare ≥10 mg/kg | Permitted under the Food Standards Code for specified foods at maximum levels (often expressed as sulphur dioxide equivalents). Added sulphites must be declared when present at 10 milligrams per kilogram (10 mg/kg) or more. FSANZ and Australian allergy guidance note that sulphite sensitivity is more common among people with asthma. |
| EU European Union (EFSA) | Permitted; ADI withdrawn 2022 | Authorised as E223 within the E220–E228 group. EFSA's 2016 re-evaluation set a temporary group ADI of 0.7 milligrams of SO₂ equivalents per kilogram of body weight per day. The 2022 follow-up withdrew that temporary ADI because the toxicity database remained inadequate, applied a margin-of-exposure approach (reference point 38 mg SO₂ equivalents/kg bw/day; assessment factor 80), and concluded this raises a safety concern for estimated dietary exposures in both refined and maximum-permitted-level scenarios for most population groups. EFSA also restated the need to further investigate hypersensitivity among some sensitive consumers. |
| US United States (FDA) | GRAS; declare ≥10 ppm | Sodium metabisulfite is listed as generally recognized as safe under 21 CFR 182.3766 when used in accordance with good manufacturing practice, with carve-outs including meats, foods recognised as a source of vitamin B1, and fruits or vegetables intended to be served or sold raw/fresh. Sulfiting agents must generally be declared when present at 10 parts per million (10 mg/kg) or more; functional sulfites must be declared regardless of level. |
Wording matters here: regulators describe sulphite-related breathing difficulties in some sensitive people — particularly some people with asthma — as a recognised hypersensitivity concern, not as proof that sodium metabisulphite will cause asthma in the general population. Prevalence estimates vary; ASCIA and similar bodies advise sulphite-sensitive individuals to read labels carefully.
This section is checked periodically rather than continuously — if you're reading this well after the date above, it's worth confirming nothing has changed before citing it.
Goodnessly rates E223 Avoid. Sodium metabisulphite remains permitted within set limits in Australia/NZ, the EU and the US, but EFSA's 2022 withdrawal of the temporary group ADI for E220–E228, the margin-of-exposure concern for high consumers, and the well-recognised association between sulphites and adverse reactions in some sensitive people — including some people with asthma — place it in our highest-caution category.
E223 and related sulphites must usually be declared when at or above 10 mg/kg. Look out for:
Especially common on wine, dried fruit and some potato-product or seafood labels.
Sodium metabisulphite is an inorganic sulphite salt manufactured for use as a food preservative and antioxidant. In solution it releases sulphur dioxide. It belongs to the sulphite group (E220–E228). Small amounts of sulphites can also occur naturally in some foods.
Winemakers use sulphites, including sodium metabisulphite, to help control unwanted microbes and limit oxidation. Residual sulphite must usually be declared when at or above 10 mg/kg. That technological use is why E223 appears so often on wine labels — it is not evidence of a unique hazard beyond the wider sulphite group assessment.
Sulphites have long been associated in clinical and regulatory literature with adverse reactions — including asthma-like symptoms such as wheezing — in some sensitive individuals, and sensitivity appears more common among people who already have asthma. That is an association for a sensitive subgroup, not evidence that sodium metabisulphite causes asthma in the general population. If you have asthma or a known sulphite sensitivity, check labels and follow clinical advice.
Goodnessly rates E223 (Sodium metabisulphite) as Avoid. It remains permitted within set limits, but EFSA's 2022 group ADI withdrawal and high-consumer concern, plus the recognised association with reactions in some sulphite-sensitive people, place it in our highest-caution category.
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