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Potassium Nitrate (E252) — What You Need to Know

Questionable(4/10)Synthetic

The score is an eNumbers.org editorial summary, not an official agency rating or medical advice. Start with the regulatory status and primary sources below.

What Is Potassium Nitrate?

Potassium nitrate, historically known as saltpeter, is a preservative used in cured meats and certain cheeses. It is either mined from natural deposits or synthetically produced. Like sodium nitrate, it serves as a slow-release source of nitrite during curing, and is particularly important in traditional European cheese-making to prevent defects caused by gas-producing bacteria.

What Is It Used For?

Used in cured meats for long-term preservation and in hard cheeses such as Gouda and Edam to prevent late blowing caused by Clostridium tyrobutyricum. Also traditionally used in dry-cured sausages and salami.

Function: Preservative, curing agent, antimicrobial in meat and cheese

Regulatory & Editorial Context

📊
Acceptable Daily Intake (ADI)
3.7 mg/kg bw/day
🏛️
Regulatory Status
🇺🇸 USA (FDA): Approved. Limited use in cured meat products.
🇪🇺 EU (EFSA): Re-evaluated 2017. Group ADI of 3.7 mg/kg bw/day as nitrate ion (shared with E251). Concerns over nitrate-to-nitrite conversion.
⚠️ Key Concerns

Known historically as saltpeter. Same concerns as sodium nitrate — converts to nitrite and potentially to nitrosamines. Traditionally used in cheese production (especially Gouda-type cheeses) to prevent late blowing caused by Clostridium tyrobutyricum. EFSA 2017 group re-evaluation. The conversion pathway: nitrate to nitrite to nitrosamines means all nitrate/nitrite additives share similar carcinogenicity concerns.

Editorial context score

eNumbers.org currently assigns Potassium Nitrate an editorial context label of Questionable with a score of 4/10. This is 1.7 points below the database average for preservatives (5.7/10). Dataset reference year: 2017.

This score is not issued by EFSA, FDA, WHO or another regulator.

Commonly Found In

Cured meatsHard cheeses (Gouda, Edam)SalamiPepperoni
Example brands:
BeemsterReypenaerLevoni

Always check the label for E252 or 'Potassium Nitrate'

▶Chemical Information
Formula: KNO3
Molecular Weight: 101.1 g/mol
CAS Number: 7757-79-1
INS Number: 252
Also known as: E252, INS 252, Saltpeter, Saltpetre, Niter

Frequently Asked Questions about Potassium Nitrate

Current dataset status: FDA — Approved. Limited use in cured meat products.; EFSA/EU — Re-evaluated 2017. Group ADI of 3.7 mg/kg bw/day as nitrate ion (shared with E251). Concerns over nitrate-to-nitrite conversion.. Reported concerns: Known historically as saltpeter. Same concerns as sodium nitrate — converts to nitrite and potentially to nitrosamines. Traditionally used in cheese production (especially Gouda-type cheeses) to prevent late blowing caused by Clostridium tyrobutyricum. EFSA 2017 group re-evaluation. The conversion pathway: nitrate to nitrite to nitrosamines means all nitrate/nitrite additives share similar carcinogenicity concerns. Regulatory status and individual risk are not the same; check the primary sources and permitted conditions of use.

Quick Facts

E-Number
E252
INS Number
252
Category
Preservatives
Origin
Synthetic
FDA Status
Approved. Limited use in cured meat products.
EFSA Status
Re-evaluated 2017. Group ADI of 3.7 mg/kg bw/day as nitrate ion (shared with E251). Concerns over nitrate-to-nitrite conversion.
ADI
3.7 mg/kg bw/day
Dataset Review
2017
Ingredient-level Dietary Notes
Vegan: ✅ YesHalal: ✅ YesKosher: ✅ YesGluten-Free: ✅ Yes

Carriers, processing aids and product certification can change suitability. Verify the final label and certifier.

Quick Links

Disclaimer: This information is for educational purposes only and is not medical advice. Always consult a healthcare professional for health-related decisions.

Related Additives

Other preservatives in the same family

Sodium Nitrate (E251)Sodium Nitrite (E250)Potassium Nitrite (E249)