E260: Acetic Acid (Vinegar Acidulant / Preservative)

Direct Answer

E260 (Acetic Acid / Ethanoic acid) is a natural carboxylic acid produced via aerobic Acetobacter fermentation of ethanol. INS 260, ADI is Not Limited (Quantum Satis), giving vinegar its characteristic pungent sour flavor and pickling preservative action.

Source: Codex Alimentarius / EFSA · Last reviewed Aug 28, 2026

Specs

E-Number Code	E260
INS / Codex Number	INS 260
Functional Class	Acidity Regulator, Preservative, Flavoring Tastant
Acceptable Daily Intake (ADI)	Not Limited (Quantum Satis)
Chemical Formula	CH3COOH (pKa 4.76)
Primary Mechanism	Lowers pH below 4.2, destroying bacterial cell membrane proton motive force
Common Target Foods	Table vinegars (4–8%), pickled cucumbers, mustard, mayonnaise, tomato ketchup
Dietary Compliance	100% Vegan (Biological vinegar fermentation), Halal, Kosher
Safety Approval	EFSA Authorized / FDA GRAS (21 CFR 184.1005)

Food Preservation via Cytoplasmic Acidification

Undissociated acetic acid freely crosses bacterial cell walls. Inside the neutral cytoplasm (pH ~7), it dissociates, releasing protons that exhaust the bacterial ATPase pump and prevent pathogen outgrowth.