Sulfur Dioxide

CAS 7446-09-5 · E220 · sulphur dioxide · SO2

A sulfite preservative and antioxidant used to stop browning and spoilage in dried fruit, wine and juices. Safe for most people, but it triggers reactions in sulfite-sensitive individuals — especially asthmatics — which is why FDA mandates labeling at 10 ppm or more.

high confidence

Researched July 7, 2026

Specimen 0214Sulfur Dioxide

Concerns

Sulfites including sulfur dioxide can provoke adverse reactions in sensitive individuals, especially asthmatics: reviews report roughly 3-10% of asthmatic patients react to ingested sulfites, with effects ranging from dermatitis, flushing, hypotension, abdominal pain and diarrhea to, rarely, life-threatening asthmatic and anaphylactic reactions (Vally & Misso; Vally et al.)
Because of these sensitivity reactions, FDA requires sulfiting agents present at 10 ppm or more in a finished food to be declared on the label (21 CFR 101.100), and prohibits their use on fruits and vegetables intended to be sold or served raw
EFSA's 2016 re-evaluation set only a temporary group ADI of 0.7 mg SO2 equivalents/kg body weight per day; in 2022 EFSA withdrew even that temporary ADI, concluding the available toxicity database was inadequate to establish a safe intake level

Regulatory flags

⚑IARC Class: NL
⚑EDC Status: None
⚑Regulatory: US: GRAS w/ mandatory labeling >=10 ppm (21 CFR 101.100), banned on raw produce (1986); EU: E220, temporary group ADI 0.7 mg SO2/kg withdrawn (EFSA 2022)
⚑Evidence Grade: A

Commonly found in

Dried fruitWineFruit juicesFrozen/processed shrimpPickled foods

Sources & references

Last researched: July 7, 2026

Research disclaimer: This rating is based on available peer-reviewed research and regulatory assessments at the time of publication. It is not medical advice. Consult a qualified professional for personal health or skin concerns.

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