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E270AcidulantLow concern
Lactic Acid
In plain words
The short version
The natural acid of sour milk — a mild, ubiquitous acidulant and preservative.
Why it's green
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Safety profile
No ADI required — naturally occurring central intermediate in human metabolism. GRAS in the US. Infants under 3 months should not receive D-lactic acid due to limited metabolic capacity; food-grade is typically L- or DL-isomer.
The detail
First isolated by Carl Scheele in 1780 from sour milk — hence the name. Produced industrially today primarily by bacterial fermentation of sugars (Lactobacillus species), as well as by chemical synthesis from lactonitrile.
Used in yogurts, pickles, salad dressings, cured meats, and infant formula. Provides tartness, controls pH, and acts as a mild preservative. Commercially important as a building block for biodegradable plastics.
Colorless to pale yellow syrupy liquid (commercial 80–88% solution). Miscible with water. Weak acid (pKa 3.86). Hygroscopic. Optically active in pure isomers.
In the US it is affirmed as GRAS for use at levels not exceeding good manufacturing practice, but that GRAS listing excludes infant foods and infant formulas. Specific guidance restricts D-lactic acid in infant foods.
Sources
- WHO JECFA database — Lactic acid (INS 270), ADI 'not limited' (1973) — Joint FAO/WHO Expert Committee on Food Additives (JECFA), WHO, 1973. No ADI required
- 21 CFR 184.1061 — Lactic acid, affirmed as GRAS (CFR, 2025 edition) — U.S. Government Publishing Office / FDA, 2025. GRAS in the US; excluded from infant foods and infant formulas
- Commission Regulation (EU) No 1129/2011 establishing the Union list of food additives — category 13.1.1 infant formulae — European Union, Official Journal L 295, 12.11.2011, 2011. EU restricts lactic acid in infant formulae to the L(+)-form
Checked against these sources on .
Educational information only. Not medical, dietary or veterinary advice. Spotted an error? Tell us.