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E252 · Preservatives

Potassium nitrate

High risk carcinogenpreservative

Converts to nitrite; same nitrosamine concern.

Category
Preservatives
Acceptable daily intake
3.7 mg/kg body weight/day (EFSA)
Vegan
Yes
Vegetarian
Yes

What it is

Potassium nitrate (E252), famous historically as "saltpeter", is a curing salt. It functions exactly like Sodium nitrate (E251) acting as a slow-release source of nitrites for long-aged meats.

How it is used in food

Used to cure meat since the Middle Ages.

Commonly found in
  • Aged and dry-cured meats (salami, prosciutto)
  • Hard cheeses (to prevent bacterial blowing)

Health and safety

Bacteria convert it to nitrite in the meat, where the nitrosamine chemistry starts.

Like E251, it breaks down into nitrites over time. It carries the identical risk profile regarding the formation of carcinogenic nitrosamines.

Forms carcinogenic nitrosamines

general population · evidence: established

Converts to nitrite, which then reacts with amino acids to form cancer-causing nitrosamines.

EFSA re-evaluation of nitrates

Shares the IARC processed-meat concerns.

Regulatory status

RegionStatusNotes
Australia & New Zealand
FSANZ		 Restricted Permitted.
European Union
EFSA / European Commission		 Restricted Authorised under Regulation (EC) No 1333/2008 with maximum added amounts, tightened in 2023 over nitrosamine formation in cured meat.
United States
FDA (Food and Drug Administration)		 Restricted Approved.

Identification on labels

E-number
E252

Also printed asSaltpeter

How it is made

Produced by reacting nitric acid with potassium chloride or potassium carbonate.

  1. Synthesis — Synthesized chemically using nitric acid and a potassium source.

Worth knowing

Also known as Saltpetre, which is a key ingredient in gunpowder.

Conclusion

It is a hazard-class ingredient due to its link to bowel cancer through processed meat consumption. It is tightly regulated, and its use is being steadily reduced across the industry.

References

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Entry last reviewed 2026-07-28.

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