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Sodium Sulphite (E221) — What You Need to Know

Caution(5/10)Synthetic

The score is an eNumbers.org editorial summary, not an official agency rating or medical advice. Start with the regulatory status and primary sources below.

What Is Sodium Sulphite?

Sodium sulphite is an inorganic compound used as a preservative and antioxidant in the food industry. It releases sulphur dioxide (SO2) in solution, which is the active antimicrobial and antioxidant agent. It is part of the sulphite group of preservatives (E220–E228) that have been used in food preservation for centuries.

What Is It Used For?

Used to prevent browning and microbial spoilage in dried fruits, wines, and dehydrated vegetables. Acts as both an antioxidant and antimicrobial agent, and is also used as a bleaching agent in some food processing applications.

Function: Preservative, antioxidant, bleaching agent

Regulatory & Editorial Context

📊
Acceptable Daily Intake (ADI)
0.7 mg/kg bw/day
🏛️
Regulatory Status
🇺🇸 USA (FDA): GRAS (with mandatory labeling above 10 ppm)
🇪🇺 EU (EFSA): Authorized — group ADI as SO2 for all sulphites (E220–E228)
⚠️ Key Concerns

Part of the sulphite group (E220–E228). Sulphites can trigger severe asthmatic reactions in sulphite-sensitive individuals (estimated 3-10% of asthmatic patients). FDA mandates labeling when sulphites exceed 10 ppm. Sulphites destroy vitamin B1 (thiamine). EFSA lowered the group ADI from 0.7 to 0.7 mg SO2/kg bw/day in 2016 after finding exposure frequently exceeded ADI.

Editorial context score

eNumbers.org currently assigns Sodium Sulphite an editorial context label of Caution with a score of 5/10. This is 0.7 points below the database average for preservatives (5.7/10). Dataset reference year: 2016.

This score is not issued by EFSA, FDA, WHO or another regulator.

Commonly Found In

Dried fruitsWineShrimpDehydrated vegetablesFruit juices
Example brands:
Sun-MaidOcean Spray

Always check the label for E221 or 'Sodium Sulphite'

▶Chemical Information
Formula: Na2SO3
Molecular Weight: 126.04 g/mol
CAS Number: 7757-83-7
INS Number: 221
Also known as: E221, INS 221, Sodium sulfite

Frequently Asked Questions about Sodium Sulphite

Current dataset status: FDA — GRAS (with mandatory labeling above 10 ppm); EFSA/EU — Authorized — group ADI as SO2 for all sulphites (E220–E228). Reported concerns: Part of the sulphite group (E220–E228). Sulphites can trigger severe asthmatic reactions in sulphite-sensitive individuals (estimated 3-10% of asthmatic patients). FDA mandates labeling when sulphites exceed 10 ppm. Sulphites destroy vitamin B1 (thiamine). EFSA lowered the group ADI from 0.7 to 0.7 mg SO2/kg bw/day in 2016 after finding exposure frequently exceeded ADI. Regulatory status and individual risk are not the same; check the primary sources and permitted conditions of use.

Quick Facts

E-Number
E221
INS Number
221
Category
Preservatives
Origin
Synthetic
FDA Status
GRAS (with mandatory labeling above 10 ppm)
EFSA Status
Authorized — group ADI as SO2 for all sulphites (E220–E228)
ADI
0.7 mg/kg bw/day
Dataset Review
2016
Ingredient-level Dietary Notes
Vegan: ✅ YesHalal: ✅ YesKosher: ✅ YesGluten-Free: ✅ Yes

Carriers, processing aids and product certification can change suitability. Verify the final label and certifier.

Quick Links

Disclaimer: This information is for educational purposes only and is not medical advice. Always consult a healthcare professional for health-related decisions.

Related Additives

Other preservatives in the same family

Sulfur Dioxide (E220)Sodium Metabisulphite (E223)Potassium Metabisulphite (E224)