E228 - Potassium bisulphite

At a glance

• What it is: the potassium salt of bisulphite, part of the sulphite group (E220–E228).
• What it does: preservative and antioxidant; helps stop browning and off-flavours.
• Where it’s found: wines and ciders, some fruit products, pickled foods, and a few seafood items.
• Also called: potassium bisulfite, potassium hydrogen sulfite, E228.
• Safety notes: approved with limits; must be declared on labels above set levels; some people are sensitive to sulphites.

Why is Potassium bisulphite added to food?

Food makers use potassium bisulphite to keep foods and drinks fresh for longer. As a preservative and antioxidant, it slows the growth of unwanted microbes and prevents oxidation that can lead to browning and off-flavours, especially in grape products and cut or processed fruits.¹

It belongs to the wider sulphite family alongside additives like sulphur dioxide, sodium bisulphite, sodium metabisulphite, and potassium metabisulphite. In the European Union (EU), E228 has a defined identity and purity specification as a food additive.²

What foods contain Potassium bisulphite?

You are most likely to see potassium bisulphite in:

• Wine and cider
• Fruit juices, concentrates, and nectars
• Dried or semi-dried fruits
• Pickled or acidified vegetables
• Some seafood products (for example, prepared shrimp)

These uses reflect the need to prevent browning, keep colour, and reduce spoilage in high-sugar or fruit-based foods and drinks.¹

What can replace Potassium bisulphite?

Possible alternatives depend on the food and the problem you are trying to solve:

• For preservation: potassium sorbate, sorbic acid, sodium benzoate, or benzoic acid.
• For antioxidant effect and colour control: ascorbic acid, citric acid, or extracts of rosemary.
• For certain microbial targets in specific foods: nisin.
• Non-additive steps (good hygiene, oxygen control, heat treatment) can also help.

No single swap fits all foods, so formulators often test a combination.

How is Potassium bisulphite made?

Potassium bisulphite is the potassium “acid” salt of sulphite (often written as potassium hydrogen sulphite). In practice, manufacturers produce a food-grade solution that meets the EU specification for identity and purity (for example, defined content and limits on impurities).²

A common industrial approach is to react sulphur dioxide with a potassium base to form the bisulphite solution, then filter and standardise it for use in foods and beverages.²

Is Potassium bisulphite safe to eat?

Regulators evaluate sulphites as a group. In its most recent review, 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 high consumers, including children, could exceed this intake from diet alone.³

Labelling rules help consumers manage intake. In the United States, sulphiting agents present at 10 parts per million (ppm) or more must be declared on the ingredient label.⁴ For wine, U.S. labels must state “Contains sulfites” when total sulphites are 10 ppm or higher.⁵

Does Potassium bisulphite have any benefits?

Yes. In foods and drinks where it is permitted, potassium bisulphite:

• Helps keep fresh colour and flavour by slowing oxidation
• Controls microbial spoilage in sensitive products
• Limits enzymatic browning in fruit-based items

These functions can reduce waste and improve shelf life, especially in grape products and fruit preparations.¹

Who should avoid Potassium bisulphite?

Most people can consume foods with permitted levels of sulphites without issues. However, a small portion of the population—especially some people with asthma—may experience sensitivity to sulphites and should avoid or limit them based on medical advice.⁶ If you are sensitive, check labels for “sulphites,” “sulfites,” or “E228.”

Myths & facts

• Myth: “Labels don’t need to list tiny amounts.” Fact: In the U.S., sulphites at 10 ppm or more must be declared on food labels, and wine must state “Contains sulfites” at the same threshold.⁴⁵
• Myth: “E228 is unrelated to other sulphites.” Fact: Potassium bisulphite is part of the sulphite group of additives (E220–E228), which share similar functions and are regulated together in the EU.²
• Myth: “Sulphites are unsafe for everyone.” Fact: Regulators set strict limits. EFSA set a group ADI and considers permitted uses acceptable for the general population, though sensitive individuals should take care.³

Potassium bisulphite in branded foods

On ingredient lists, it may appear as “potassium bisulphite,” “potassium bisulfite,” “potassium hydrogen sulfite,” or “E228.” In the U.S., products with 10 ppm or more total sulphites must list them on the label, and wines at or above this level must state “Contains sulfites.”⁴⁵

You may also see related sulphites such as sulphur dioxide, sodium bisulphite, sodium metabisulphite, or potassium metabisulphite on labels for similar purposes.

References

Footnotes

1. Re-evaluation of sulphur dioxide (E 220) and sulphites (E 221–E 228) as food additives — European Food Safety Authority (EFSA). https://www.efsa.europa.eu/en/efsajournal/pub/4438 ↩ ↩² ↩³

2. Commission Regulation (EU) No 231/2012 — Specifications for food additives. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0231 ↩ ↩² ↩³ ↩⁴

3. EFSA group ADI for sulphites and exposure considerations — European Food Safety Authority. https://www.efsa.europa.eu/en/efsajournal/pub/4438 ↩ ↩²

4. 21 CFR 101.100(a)(4): Food labeling; exemptions; sulfiting agents at ≥10 ppm must be declared — U.S. FDA (eCFR). https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-101/section-101.100 ↩ ↩² ↩³

5. 27 CFR 4.32(e): Wine labels; “Contains sulfites” statement — U.S. TTB (eCFR). https://www.ecfr.gov/current/title-27/chapter-I/subchapter-A/part-4/section-4.32 ↩ ↩² ↩³

6. Sulfiting Agents — U.S. Food and Drug Administration. https://www.fda.gov/food/food-additives-petitions/sulfiting-agents ↩