E225 - Calcium Disulphite

At a glance

• What it is: A calcium salt of disulphite in the sulfites family, intended to keep foods fresh and protect color.
• What it does: Preserves foods and prevents browning by reacting with oxygen and inhibiting enzymes and microbes.
• Where it shows up: Historically in the same spaces as other sulfites (wine, dried fruit, some pickled or processed foods), but today it is uncommon as a named ingredient.
• Regulatory note: In the EU specifications list, sulfites are defined for E220–E224 and E226–E228; E225 is not included as a separate authorised entry. In the U.S., FDA’s sulfiting agents list does not include calcium disulphite.
• Who should avoid it: People with sulfite sensitivity or certain asthma should avoid sulfites.

Why is Calcium Disulphite added to food?

Manufacturers use sulfites to keep foods from turning brown and to extend shelf life. They work in two main ways: as antioxidants (limiting oxidation) and as preservatives (inhibiting microbes). Calcium Disulphite fits this profile, but in practice producers more often choose closely related additives such as sulphur dioxide, sodium metabisulphite, or potassium metabisulphite. The current EU specifications list covers sulfites E220–E224 and E226–E228 and does not include E225 as an authorised specification, which helps explain its rarity on labels.¹

What foods contain Calcium Disulphite?

You are unlikely to find “Calcium Disulphite (E225)” named on today’s ingredient lists. Where older references mention it, the intended uses are similar to those for other sulfites:

• Fermented drinks, especially wine and cider
• Dried fruit and some pickled products
• Certain crustaceans (like shrimp) during processing

In practice, these foods are usually preserved with sulphur dioxide, sodium metabisulphite, potassium metabisulphite, calcium sulphite, calcium bisulphite, or potassium bisulphite. In the U.S., when sulfites are present at 10 parts per million (ppm) or more, they must be declared on the label.² Wine that contains at least 10 ppm sulfites must also state “Contains sulfites.”³

What can replace Calcium Disulphite?

If a recipe or product calls for E225, common swaps are:

• Other sulfites where permitted: sulphur dioxide, sodium metabisulphite, potassium metabisulphite
• Antioxidants that limit browning: ascorbic acid, sodium ascorbate, citric acid, extracts of rosemary
• Preservatives for microbial control (where suitable): sorbic acid, potassium sorbate, sodium benzoate
• Non-additive options: pH control (more acidity), lower oxygen exposure, refrigeration, or shorter shelf life

How is Calcium Disulphite made?

Sulfites are typically produced by absorbing sulphur dioxide gas into an aqueous solution of a base (such as a carbonate or hydroxide) of the desired cation. For calcium-based sulfites, producers start with calcium hydroxide or carbonate and control conditions to form the target sulfite species. EU specifications describe this general manufacturing approach for the authorised sulfites group (E220–E224, E226–E228).¹

Is Calcium Disulphite safe to eat?

Safety for sulfites has been evaluated as a group. The European Food Safety Authority (EFSA) set a group acceptable daily intake (ADI) of 0.7 mg per kilogram of body weight per day, expressed as sulphur dioxide equivalents. EFSA also noted that some consumers—especially children—may exceed this intake from high-sulfite foods.⁴ In the U.S., sulfites must be declared on labels when present at 10 ppm or more, which helps sensitive consumers avoid them.² For wine, a “Contains sulfites” statement is required at the same threshold.³

Because E225 is not widely authorised on its own, most safety and compliance questions in real products relate to the specific sulfite that is permitted and used (for example, potassium metabisulphite or sodium metabisulphite).

Does Calcium Disulphite have any benefits?

• Helps retain color and freshness by preventing enzymatic browning.
• Extends shelf life by slowing microbial growth in suitable foods.
• Can protect flavor by limiting oxidation during storage.

These benefits are shared across the sulfites group and are the reason related additives remain common in foods and beverages.

Who should avoid Calcium Disulphite?

People with sulfite sensitivity—including some individuals with asthma—should avoid foods containing sulfites or seek medical guidance. Reactions can include wheezing, chest tightness, hives, and flushing; severe reactions are uncommon but possible in highly sensitive individuals.⁵ If you are sensitive, check labels for “sulphites,” “sulphur dioxide,” or named sulfite salts, and look for the “Contains sulfites” statement on wine.³

Myths & facts

• Myth: “Sulfites are only in wine.” Fact: They can appear in dried fruit, some pickled foods, and certain crustaceans, though specific additives vary by country and product.
• Myth: “Sulfites cause hangovers.” Fact: Hangovers have many causes; sulfites are preservatives and are not proven to cause hangovers.
• Myth: “If a product is ‘natural,’ it can’t have sulfites.” Fact: Natural products can still contain added sulfites, and labels must disclose them at required levels.
• Myth: “All sulfites are banned.” Fact: Many sulfites are authorised with conditions; E225 specifically is uncommon and not broadly authorised as its own entry in the EU specifications.

Calcium Disulphite in branded foods

Modern brands seldom list “Calcium Disulphite (E225).” Instead, you’ll typically see “sulphites,” “sulphur dioxide,” or specific salts like potassium metabisulphite on wines and ciders, or sodium metabisulphite on shelf-stable products. If you avoid sulfites, scan ingredient lists and look for the mandatory sulfite declaration where required.

References

Footnotes

1. Commission Regulation (EU) No 231/2012 — EU specifications for food additives (sulphur dioxide and sulphites E220–E224, E226–E228). https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩²

2. 21 CFR 101.100(a)(4) — U.S. food labeling; declaration of sulfiting agents at ≥10 ppm. https://www.ecfr.gov/current/title-21/section-101.100 ↩ ↩²

3. 27 CFR 4.32(e) — Wine labeling; mandatory “Contains sulfites” statement (≥10 ppm). https://www.ecfr.gov/current/title-27/section-4.32 ↩ ↩² ↩³

4. Re-evaluation of sulphur dioxide (E 220) and sulphites (E 221–228) as food additives — EFSA Journal (2016). https://efsa.europa.eu/en/efsajournal/pub/4438 ↩

5. Sulfite sensitivity — MedlinePlus, National Institutes of Health (NIH). https://medlineplus.gov/ency/article/001431.htm ↩