Propionic acid

E number E280INS 280CAS 79-09-4

Used as a preservative.

Propionic acid is the mould inhibitor of bread. It is what keeps a supermarket loaf from going mouldy for a week, and occurs naturally in Swiss cheese as a product of the bacteria that make the holes.

Where it is and isn’t permitted

Status of Propionic acid by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
United StatesFood and Drug AdministrationPermitted21 CFR 184.1081retrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFAPermitted, with conditions

2 food categories

highest permitted level 3,000 mg/kg

Show every food category
  • 01.6.2.1 Ripened cheese, includes rind — GMP
  • 01.6.6 Whey protein cheese — 3,000 mg/kg
CXS 192-1995 Table Three, INS 280and 2 further provisionsretrieved 2026-09-07

What it is made from

Produced industrially from petroleum-derived ethylene, and by fermentation where a natural label is wanted.

  • Vegan
  • Vegetarian
CAS registry number
79-09-4
InChIKey
XBDQKXXYIPTUBI-UHFFFAOYSA-N
PubChem
CID 1032

Every name it appears under

65 recorded names. A label may use any of them.

E number

  • E280

INS number

  • 280

CAS registry number

  • 79-09-4

As it appears in regulation

  • Propionic acid

Other names

  • 1-propanoic acid
  • 2-methylacetic acid
  • Acid C3
  • acide propanoique
  • Acide propionique
  • Adofeed
  • Antischim B
  • BRN 0506071
  • C2H5COOH
  • C3 acid
  • Carboxyethane
  • Caswell No. 707
  • CCRIS 6096
  • CH3-CH2-COOH
  • E 280
  • EPA Pesticide Chemical Code 077702
  • Epitope ID:139981
  • EtCO2H
  • Ethanecarboxylic acid
  • ethylformic acid
  • FEMA No. 2924
  • FEMA Number 2924
  • HSDB 1192
  • INS NO.280
  • INS-280
  • JHU490RVYR
  • Kyselina propionova
  • Luprisol
  • Luprosil
  • Metacetonic acid
  • Methyl acetic acid
  • methylacetic acid
  • Monoprop
  • n-propionic acid
  • Propanoic acid
  • Propanoic acid (9CI)
  • Propanyl acid
  • Propcorn
  • Propioic acid
  • Propionic acid
  • Propionic acid (6CI,8CI)
  • Propionic acid (natural)
  • Propionic acid (NF)
  • Propionic acid grain preserver
  • Propionic acid, 99%
  • Propionic acid, 99.5%
  • Propionic acid, >=99%
  • Propionic acid, >=99.5%
  • Propionoic acid
  • Propionsaeure
  • Propkorn
  • propoic acid
  • proponic acid
  • proprionic acid
  • Prozoin
  • Pseudoacetic acid
  • Sentry grain preserver
  • Tenox P grain preservative
  • Toxi-Check
  • ultra-long-chain fatty acid

Systematic names

  • Propanoic acid

Hazard reference values

No reference value for this substance in the sources we hold.

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.

Sources for this page

  • ecfr retrieved 2026-09-07
  • gsfa retrieved 2026-09-07

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable:/api/v1/additives/propionic-acid.json