What is E252?
Potassium nitrate — a curing salt permitted with limits in AU/NZ, the EU and the US, related to nitrite and often discussed alongside processed-meat risk assessments.
Potassium nitrate (E252) is a curing agent and preservative used mainly in some cured meats, and in other permitted categories such as certain cheeses in some markets. It is permitted in Australia/NZ, the EU and the US within set maximum levels. EFSA's 2017 re-evaluation kept an Acceptable Daily Intake of 3.7 milligrams of nitrate ion per kilogram of body weight per day; exposure from the additive alone was below the ADI, but total dietary nitrate from all sources (including vegetables and environmental nitrate) could exceed the ADI. Nitrate can convert to nitrite in the body; Goodnessly rates E252 Avoid alongside the related nitrites and sodium nitrate.
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What is potassium nitrate?
Potassium nitrate is the potassium salt of nitric acid (INS/E 252). In food it is used as a curing agent and antimicrobial preservative, most often in slower-cured or dried meat products where nitrate can gradually convert to nitrite. It is evaluated together with sodium nitrate (E251). Related nitrite salts (E249/E250) are authorised separately and are the more direct curing agents in many cooked products. Nitrate also occurs naturally at high levels in some vegetables; the additive form is added deliberately for curing or preservation. Historically it was also known as saltpetre in curing.
What's it used for?
- Curing agent in some dried, slow-cured or fermented meat products
- Helping retain cured colour and flavour where nitrate-to-nitrite conversion is part of the process
- Antimicrobial preservative role in authorised meat (and related) categories
- Used in some cheese and other specified categories where regional rules allow nitrates
Where you'll find E252 on the shelf
It shows up mainly in cured and dried meats — often alongside or as an alternative to sodium nitrate (E251) in the same product families.
Is potassium nitrate safe? What the research says
Potassium nitrate remains authorised for specified uses, with Acceptable Daily Intakes set by EFSA/JECFA. The scientific debate focuses less on banning the additive and more on total dietary nitrate, conversion to nitrite, formation of N-nitroso compounds, and the separate classification of processed-meat consumption by IARC.
| Region | Status | What this means |
|---|---|---|
| AU/NZ Australia & New Zealand (FSANZ) | Permitted | Permitted as 252 under the Food Standards Code (Schedule 15) for specified meat and related categories at maximum permitted levels. Unless a contrary intention appears, references to nitrates or nitrites in the Code relate to the total of nitrates and nitrites calculated as sodium nitrite. FSANZ has surveyed nitrates and nitrites in Australian foods in the context of dietary exposure and methaemoglobin risk framing. |
| EU European Union (EFSA) | Permitted; ADI 3.7 mg/kg | Authorised as E252 under Regulation (EC) No 1333/2008 for specified categories. EFSA's 2017 re-evaluation of E251/E252 concluded there was insufficient evidence to withdraw the existing ADI of 3.7 milligrams of nitrate ion per kilogram of body weight per day. Exposure from nitrate used solely as a food additive was estimated below the ADI (and a small share of total dietary nitrate); when natural presence, contamination and additive use were combined, the ADI could be exceeded for all age groups at mean and high exposure. Commission Regulation (EU) 2023/2108 later tightened several maximum levels for nitrates (and nitrites) in meat products (applicable from October 2025). |
| US United States (FDA) | Permitted (specified uses) | Potassium nitrate is permitted as a food additive under 21 CFR 172.160 for specified cured fish and meat-curing uses, with finished-product limits alongside related nitrite limits. It is also prior-sanctioned with sodium nitrite for curing of red meat and poultry under 21 CFR 181.33. Commercial cured-meat practice is further constrained by USDA FSIS rules. |
IARC has classified consumption of processed meat as Group 1 (carcinogenic to humans) based on epidemiological evidence for colorectal cancer. That classification applies to the food category (meats transformed by salting, curing, fermentation, smoking or similar processes), not uniquely to potassium nitrate as a stand-alone additive. EFSA discusses nitrate-to-nitrite conversion and theoretical endogenous N-nitroso compound formation with careful uncertainty language — not as proof that E252 alone causes cancer.
- EFSA 2017 re-evaluation: retained the ADI of 3.7 mg nitrate ion/kg bw/day for E251/E252; additive-only exposure below ADI; total dietary nitrate from all sources could exceed the ADI; discussed methaemoglobin via nitrite conversion and endogenous N-nitroso compounds with uncertainty notes.
- EU 2023/2108: Commission Regulation tightened several maximum levels for nitrites (E249–250) and nitrates (E251–252) in meat products, applicable from October 2025 — still permitted, at lower caps in several categories.
- IARC processed-meat context: consumption of processed meat remains classified Group 1; that is a food-category finding used carefully here, not a chemical-unique verdict on potassium nitrate alone.
This section is checked periodically rather than continuously — if you're reading this well after the date above, it's worth confirming nothing has changed before citing it.
Who might want to limit or avoid it
- People who already limit processed meat for health or dietary reasons, given IARC's classification of processed-meat consumption (food category, not uniquely E252)
- Parents of children who eat cured meats frequently, given EFSA's notes that total dietary nitrate from all sources can exceed the ADI
- Anyone who prefers to minimise curing salts (nitrates and nitrites) and chooses uncured or nitrate/nitrite-free labelled alternatives where available
- People who have been advised by a clinician to limit nitrates, nitrites or nitrosamine-related exposures
Goodnessly rates E252 Avoid. Regulators in Australia/NZ, the EU and the US still permit potassium nitrate within set limits for technological and antimicrobial reasons, but EFSA's total-diet nitrate exceedance notes, nitrate-to-nitrite conversion, N-nitroso compound discussions, and the separate IARC classification of processed-meat consumption place it in our highest-caution category.
How to spot it on a label
E252 must be declared clearly on packaged foods. Look out for:
- Potassium nitrate / saltpetre (historical curing name)
- 252 or E252
- Preservative (252)
- Related curing agents: 249, 250, 251 (nitrites and sodium nitrate)
Most common in cured, dried or fermented meats; sometimes paired with ascorbate/erythorbate curing accelerators (301/316).
Related additives
Frequently asked questions
What is Potassium nitrate (E252) made from?
Potassium nitrate is an inorganic salt (the potassium salt of nitric acid) manufactured for use as a food curing agent and preservative. Nitrate also occurs naturally in many vegetables; the additive form is added deliberately for curing or preservation. It was historically known as saltpetre in curing.
Is potassium nitrate the same as sodium nitrate?
They are closely related curing salts. Potassium nitrate is E252; sodium nitrate is E251. Both supply nitrate ion and are assessed together by EFSA. Nitrate can convert to nitrite in the body and during some curing processes. Check the number or full name on the label.
Did IARC ban potassium nitrate?
No. IARC classified consumption of processed meat as Group 1 (carcinogenic to humans) based on evidence for colorectal cancer. That applies to the food category of processed meat, not uniquely to potassium nitrate as a chemical. Potassium nitrate remains permitted as a food additive within limits in AU/NZ, the EU and the US.
Does Goodnessly rate E252 as safe, caution or avoid?
Goodnessly rates E252 (Potassium nitrate) as Avoid. It remains permitted within set limits, but total-diet nitrate exposure notes, conversion to nitrite, N-nitroso compound discussions, and the separate IARC classification of processed-meat consumption place it in our highest-caution category.
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