Allervibe
E221
Sodium sulphite
A soluble sodium salt of sulphurous acid used as a preservative and antioxidant.
i Additive Details
| Is E221 Sodium sulphite safe?
Sulphites are one of the 14 allergens that must be declared under EU Regulation 1169/2011 whenever they are present above 10 mg/kg or 10 mg/litre expressed as SO2. Sulphite sensitivity is well documented in people with asthma, who may react with wheezing, chest tightness or bronchospasm. Most sulphite reactions are intolerance rather than classical IgE-mediated allergy, although rare IgE-mediated cases have been reported. Sodium sulphite belongs to this group, so anyone who reacts to sulphites in wine or dried fruit should treat E220 to E228 as a single set of ingredients to avoid.
| Uses
Acts as a preservative and antioxidant, preventing enzymatic browning, oxidation and microbial spoilage. Used in dried fruit and vegetables, processed potato products, fruit juices and concentrates, and in winemaking and brewing. Because its solutions are alkaline rather than acidic, it is chosen where an acidic sulphite would disturb the product.
| Interactions
In water it forms an equilibrium of sulphite and bisulphite ions, and the bisulphite ion is what binds aldehydes and ketones. That binding is why sulphites block browning, but it is also why they slowly destroy thiamine (vitamin B1) and can bleach anthocyanin pigments. Sodium sulphite oxidises to sodium sulphate on contact with air, so it loses strength during storage.
| Origin
Manufactured by absorbing sulphur dioxide into a solution of sodium carbonate or sodium hydroxide and then crystallising the salt. It is not a natural food ingredient, although yeasts produce small amounts of sulphite during fermentation.
| Daily Intake
A group ADI of 0.7 mg per kg of body weight per day, expressed as SO2, applies jointly to E220 to E228 rather than to each salt individually. EFSA's 2022 follow-up to its re-evaluation of the group concluded that the available data are not sufficient to confirm the ADI and that estimated intake can exceed it in some consumer groups.
Information is sourced from public regulatory bodies (EFSA, FDA, WHO) and is for reference only. Always read the package and consult a healthcare professional for medical advice.
Related additives
- E1105 Lysozyme An enzyme isolated from hen egg white that breaks down the cell walls of Gram-positive bacteria.
- E222 Sodium bisulphite The sodium salt of hydrogen sulphite, supplied as an aqueous solution and used as a preservative and antioxidant.
- E223 Sodium metabisulphite A white crystalline salt that releases sulphur dioxide in water and is the most widely used sulphite preservative.
- E224 Potassium metabisulphite The potassium form of metabisulphite, used mainly as a preservative and antioxidant in wine and cider.
- E226 Calcium sulphite A calcium salt of sulphurous acid with low water solubility, used as a preservative and antioxidant.
- E227 Calcium bisulphite A calcium sulphite that exists only in solution, used as a preservative and antioxidant.
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