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E252 Potassium nitrate

E252PreservativesOrigin: Mineral
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The short answer
Potassium nitrate (E252), traditionally called saltpeter, cures some meats and cheeses. It is legal only within tight limits because nitrate turns into nitrite, and nitrite can form nitrosamines.
Best to avoid

Controversial, restricted or banned somewhere.

E-numberE252
Comes fromMineral
What it doesPreservatives
Glycemic index—
Daily limit3.7 mg/kg
Also calledPotassium nitrate, Saltpetre

Rules by country

🇺🇸 US FDAApproved with limits
🇪🇺 European UnionApproved with limits
🇨🇦 Health CanadaApproved with limits
CaliforniaNo extra rules

Potassium nitrate is allowed only in specific cured meats and cheeses, with strict residual limits, in the US, the EU and Canada. EFSA's limit for nitrate from all sources is 3.7 mg per kg of body weight a day. It is a slower cousin of sodium nitrite, not a harmless salt.

How much is too much? (Acceptable Daily Intake)

259 mgper day is the safe upper limit

Based on 3.7 mg per kg of body weight (EFSA / JECFA). A 20 kg (44 lb) child: 74 mg a day.

What is it?

Old curing recipes used saltpeter to keep ham and salami pink and safe from botulism. Modern plants more often add nitrite directly. Nitrate is still used where a long, slow cure is the point, and in some cheeses to stop late blowing from unwanted bacteria.

Where it comes from: Food-grade potassium nitrate is a purified mineral salt. In meat it slowly converts to nitrite, which is the form that preserves color and slows dangerous bacteria.

Why it’s in food

  • Cures slow-aged meats
  • Keeps cured color
  • Slows cheese spoilage
  • Controls Clostridium

Often found in

Dry-cured hamSalamiSome hard cheesesTraditional corned beefBacon in older recipes

Also listed as: Potassium nitrate, Saltpetre, Saltpeter, Nitre, Niter

Health & gut impact

NitrosaminesConcern

Nitrate converts to nitrite, and nitrite can form nitrosamines, which is part of why the WHO treats processed meat as a cause of colorectal cancer.

IARC Monograph 114, processed meat (2015)

Legal limitsUnder study

Residual nitrate and nitrite in cured meat are capped, and the EU tightened those caps in 2023.

EU Regulation 2023/2108 on nitrites and nitrates

What can I use instead?

Fresh uncured meat

Ratio: Skip the cure

Best for: When shelf life is not the goal

Celery powder

Ratio: Follow a tested cure

Best for: Still supplies nitrate

Related

More preservatives:

Benzoic acid E210Benzoic acid (E210) is the parent of sodium benzoate. It keeps acidic foods from molding. It is allowed within a daily limit, and in soft drinks with vitamin C it can form a little benzene.Use in moderationCalcium disodium EDTA (EDTA) E385Calcium disodium EDTA (E385) grabs stray metals so dressings, sodas and canned beans keep their color and flavor. Very little is absorbed, and it's safe in the small amounts allowed.Use in moderationCalcium Propionate E282Calcium propionate (E282) is the mold inhibitor in most packaged bread. It's considered safe, vegan and gluten-free, though a few small studies have raised questions about behavior in children and blood sugar.Use in moderationCelery powderCelery powder is how "uncured" bacon and hot dogs are cured. It's a natural source of nitrite, the same chemical as sodium nitrite, so "no nitrites added" meats aren't nitrite-free.Use in moderation

Common questions

Is saltpeter the same as curing salt?

Saltpeter is potassium nitrate. Modern pink curing salt is mostly table salt plus sodium nitrite. They are related and they are not interchangeable in a recipe.

Is Potassium nitrate safe?

Best to avoid (43/100). Potassium nitrate is allowed only in specific cured meats and cheeses, with strict residual limits, in the US, the EU and Canada. EFSA's limit for nitrate from all sources is 3.7 mg per kg of body weight a day. It is a slower cousin of sodium nitrite, not a harmless salt.

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Scientific sources & regulatory citations
  • 21 CFR 172.160 (US FDA)
  • EFSA OpenFoodTox: E252
  • IARC Monograph 114, processed meat (2015)
  • EU Regulation 2023/2108 on nitrites and nitrates

INS 252 · CAS 7757-79-1