Comparing E221 - Sodium sulphite vs E222 - Sodium bisulphite

Overview

E221 - Sodium sulphite

Sodium sulphite (E221) is a preservative and antioxidant used to slow browning and keep foods stable and fresh-tasting. It belongs to the “sulphites” group, which also includes sulphur dioxide and several sulphite salts used for similar purposes. While widely permitted with limits and labeling rules, a small number of people—especially some with asthma—are sensitive to sulphites.

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E222 - Sodium bisulphite

Sodium bisulphite (E222) is a sulfiting agent used as a preservative and antioxidant to keep foods and drinks stable and fresh. It helps slow browning and oxidation in products like wine, dried fruit, and some seafood, but a small number of people are sensitive to sulfites, especially some with asthma. It is also spelled sodium bisulfite; both names refer to the same ingredient.

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Synonyms
E221
Sodium sulphite
Sodium sulfite
E222
Sodium bisulphite
Sodium bisulfite
Functions
antioxidantpreservative
antioxidantpreservative
Origins
Synthetic
Synthetic
Products

Found in 595 products

Found in 1,804 products

Search rank & volume
#2093.4K / mo🇺🇸U.S.
#2024K / mo🇺🇸U.S.
Awareness score

×0.84
normal

×0.33
under-aware

Search volume over time

Interest over time for 3 keywords in U.S. during the last 10 years.

Interest over time for 3 keywords in U.S. during the last 10 years.

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Popular questions

  1. What is the formula for sodium sulfite?

    Na2SO3; it’s also commonly available as the heptahydrate Na2SO3·7H2O.

  2. What is the chemical formula for sodium sulfite?

    Na2SO3 (sodium sulfite), sometimes encountered as the heptahydrate Na2SO3·7H2O.

  3. Is sodium phosphate a sulfite?

    No—sodium phosphate contains the phosphate anion (PO4^3-), not the sulfite anion (SO3^2-).

  4. What is sodium sulfite used for?

    It’s an antioxidant/preservative that prevents browning and oxidation and helps stabilize color and flavor in foods like dried fruits and potatoes; in wine it also helps control unwanted microbes.

  5. "sodium sulfite as a preservative is not allowed on what foods"?

    In the U.S., sulfiting agents like sodium sulfite are not allowed on fresh fruits and vegetables intended to be served or sold raw to consumers (e.g., salad bars, fresh-cut produce).

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  1. Is sodium bisulfite bad for you?

    At approved food-use levels, sodium bisulfite (E222) is considered safe; regulators set a group ADI of 0–0.7 mg/kg body weight expressed as SO2. However, sulfite‑sensitive people—especially some asthmatics—may experience reactions like wheezing, hives, or headaches and should avoid it.

  2. What is sodium bisulfite used for?

    It’s an antioxidant and preservative that prevents browning and oxidation and helps control microbes, commonly used in products like wines, dried fruits, shrimp, and cut potatoes.

  3. What is sodium bisulfite in food?

    It’s a sulfiting agent (E222) that releases sulfur dioxide to protect color and flavor and extend shelf life; it must be declared on labels when present above about 10 ppm (as SO2).

  4. How much sodium bisulfite to neutralize chlorine?

    Approximately 1.5 mg of sodium bisulfite (NaHSO3) is needed per 1 mg of free chlorine (as Cl2) per liter, stoichiometrically. In practice use a slight excess and confirm with a chlorine test; the reaction releases heat and SO2, so handle carefully.

  5. Is sodium bisulfite gluten free?

    Yes—sodium bisulfite is a synthetic mineral salt and contains no gluten; any gluten risk would come from other ingredients, not the additive itself.

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