E303 - Potassium ascorbate

At a glance

• What it is: the potassium salt of vitamin C (L‑ascorbic acid) with antioxidant properties.
• What it does: helps prevent oxidation, slows browning, and can stabilize color in foods.
• Where it’s used: permitted in certain meat products in the United States; authorization differs elsewhere.
• Regulatory note: the European Union sets specifications for E300–E302 but does not list E303 on its current Union list of food additives.
• Diet notes: adds small amounts of potassium and vitamin C; the amounts used as an additive are usually low.

Why is Potassium ascorbate added to food?

Food makers use potassium ascorbate as an antioxidant. Antioxidants slow chemical reactions with oxygen that cause rancidity, loss of flavor, or browning. This helps keep foods tasting and looking fresh for longer.¹

In meat processing, ascorbates can also act as “curing accelerators,” helping nitrite curing reactions go faster, which supports stable color and consistency when allowed by local rules.²

What foods contain Potassium ascorbate?

• Cured and processed meats and poultry: in the United States, potassium ascorbate is listed by the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA‑FSIS) as a safe and suitable ingredient for certain meat, poultry, and egg products when used as specified.²
• Other categories: use in non‑meat foods depends on the country. Always check the ingredient list for “potassium ascorbate” or “E303.”

If you’re in the European Union, you are unlikely to see E303 on labels because it is not on the current Union list of authorized food additives.³

What can replace Potassium ascorbate?

Depending on the recipe and local laws, formulators may choose:

• Other vitamin C forms: ascorbic acid, sodium ascorbate, or calcium ascorbate.
• Related antioxidants: erythorbic acid or sodium erythorbate.
• Plant extracts and acidulants (to support color/oxidation control): extracts of rosemary or citric acid.

The best substitute depends on taste, pH, processing conditions, labeling needs, and local regulations.

How is Potassium ascorbate made?

Potassium ascorbate is the potassium salt of L‑ascorbic acid (vitamin C). In practice, such salts are produced by neutralizing L‑ascorbic acid with a suitable potassium base to form a stable, water‑soluble compound.⁴¹

Is Potassium ascorbate safe to eat?

Safety assessments of vitamin C and its salts by international and national bodies have found low toxicity at permitted uses. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) assigned an Acceptable Daily Intake (ADI) of “not specified” for L‑ascorbic acid and its sodium, potassium, and calcium salts, a category reserved for very low‑toxicity additives used at levels needed for technology.¹ The European Food Safety Authority (EFSA) likewise found no safety concern for the authorized ascorbates E300–E302 at reported use levels.⁵

Regulatory status varies:

• United States: USDA‑FSIS lists potassium ascorbate as safe and suitable in certain meat and poultry applications when used as specified.²
• European Union: potassium ascorbate (E303) is not listed in the EU specifications covering food additives included in the Union list (Regulation 231/2012), whereas E300–E302 are listed.³

Does Potassium ascorbate have any benefits?

Functionally, it helps protect flavor and color by slowing oxidation.¹ Nutritionally, potassium ascorbate is a source of vitamin C, which the body uses for collagen formation, immune function, and as an antioxidant. However, the amounts added to foods for technological purposes are usually small and may not significantly boost your daily intake.⁶

Who should avoid Potassium ascorbate?

• People on potassium‑restricted diets: those with chronic kidney disease or a risk of high blood potassium (hyperkalemia) may need to monitor all potassium sources in consultation with a clinician.⁷
• Individuals advised to limit specific additives for medical or dietary reasons should review labels and seek personalized advice.

Myths & facts

• Myth: “E303 is the same as vitamin C.” Fact: it is the potassium salt of vitamin C. It behaves like vitamin C in many ways but is a distinct compound.⁴
• Myth: “E303 is approved everywhere.” Fact: authorization is country‑specific; it is not on the EU’s current Union list of food additives.³
• Myth: “It adds a lot of potassium.” Fact: typical use levels are low; it contributes potassium, but usually in small amounts relative to daily intake from foods.

Potassium ascorbate in branded foods

Ingredient lists may show it as “potassium ascorbate” or “E303.” In the U.S., you may find it in some cured or processed meats where allowed. In other regions, availability depends on local regulations. If you are avoiding potassium additives, scan labels and consider contacting the manufacturer for details about use levels.

References

Footnotes

1. Ascorbic acid and its sodium, potassium and calcium salts: toxicological evaluation — WHO/FAO JECFA. http://www.inchem.org/documents/jecfa/jecmono/v05je01.htm ↩ ↩² ↩³ ↩⁴

2. Safe and Suitable Ingredients Used in the Production of Meat, Poultry, and Egg Products (Directive 7120.1) — USDA FSIS. https://www.fsis.usda.gov/policy/fsis-directives/7120.1 ↩ ↩² ↩³

3. Commission Regulation (EU) No 231/2012: specifications for food additives — EUR-Lex. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩² ↩³

4. Potassium ascorbate — PubChem, National Institutes of Health. https://pubchem.ncbi.nlm.nih.gov/compound/Potassium-ascorbate ↩ ↩²

5. Re-evaluation of ascorbic acid (E 300), sodium ascorbate (E 301) and calcium ascorbate (E 302) as food additives — EFSA Journal. https://www.efsa.europa.eu/en/efsajournal/pub/4087 ↩

6. Vitamin C Fact Sheet for Health Professionals — NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/ ↩

7. Potassium and Your CKD Diet — National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/kidney-disease/ckd-healthy-eating-nutrition/potassium ↩