Acetic acid (ethanoic acid)

  • Our verdict: 2 - with reservations, otherwise relatively ok
  • Latest update & fact check: 2.7.2024 - Rebecca Taylor, CNP
  • Origin: It is produced from natural sources that are not further chemically treated.

Acetic acid, also known as ethanoic acid, is a colorless liquid organic compound with a pungent smell and a sour taste. It is a simple carboxylic acid and has the chemical formula CH₃COOH. Acetic acid is a major component of vinegar, which contains about 4‑8% acetic acid by volume, and it is responsible for the characteristic smell and taste of vinegar.


Acetic acid can be found both in natural and artificial forms. Naturally, it is produced by the fermentation of ethanol by acetic acid bacteria. This process is commonly seen in the production of vinegar. Industrially, acetic acid is synthesized using methods such as methanol carbonylation and the oxidation of acetaldehyde. These industrial processes ensure a high purity and large‑scale production of acetic acid.


Acetic acid is widely used in various applications due to its versatile properties:

  • Preservative: Acetic acid inhibits the growth of bacteria and fungi, making it effective as a food preservative.
  • Flavouring Agent: It provides a sour taste to foods, enhancing flavours.
  • pH Regulator: Acetic acid can adjust and maintain the pH of foods, which is crucial in many food processing techniques.
  • Solvent: It is used as a solvent in the production of certain food additives and flavourings.

Uses in Ultra‑Processed Foods

In ultra‑processed foods, acetic acid serves several key functions:

  • Preservation: Acetic acid helps extend the shelf life of ultra‑processed foods by preventing microbial growth. This is particularly useful in products like pickles, sauces, and condiments.
  • Flavour Enhancement: The sourness of acetic acid is used to enhance and balance the flavours of many processed foods. It is commonly found in salad dressings, marinades, and some snack foods.
  • Acidulant: Acetic acid is used to control the acidity level in foods. This is important in maintaining the desired taste, texture, and stability of various products, including baked goods and dairy products.
  • Antimicrobial Agent: In ready‑to‑eat meals and pre‑packaged foods, acetic acid acts as an antimicrobial agent, ensuring the safety and quality of the food during storage and distribution.

Health Considerations

While acetic acid is generally recognized as safe (GRAS) for consumption in moderate amounts, there are several health considerations to keep in mind:

  • Irritation: Concentrated acetic acid can cause irritation to the skin, eyes, and mucous membranes. It should be handled with care in its pure form.
  • Dental Health: Excessive consumption of acetic acid‑containing foods can erode tooth enamel over time due to its acidic nature.
  • Digestive Issues: Some individuals may experience digestive discomfort, such as heartburn or stomach upset, when consuming high levels of acetic acid.
  • Allergic Reactions: Rarely, some people may experience allergic reactions to acetic acid, which can manifest as skin rashes or respiratory issues.


  1. National Center for Biotechnology Information. PubChem Compound Summary for CID 176, Acetic acid. Retrieved from‑acid.
  2. McGee, Harold. "On Food and Cooking: The Science and Lore of the Kitchen." Scribner, 2004. This book provides a detailed understanding of the chemical properties and culinary uses of acetic acid.
  3. U.S. Food and Drug Administration (FDA). Code of Federal Regulations Title 21, Part 184 - Direct Food Substances Affirmed as Generally Recognized as Safe. Retrieved from‑21/chapter‑I/subchapter‑B/part‑184.
  4. European Food Safety Authority (EFSA). Scientific Opinion on the safety and efficacy of acetic acid, sodium diacetate, and calcium acetate when used as feed additives for all animal species. EFSA Journal, 2012.