Glacial Acetic Acid (E260) earns its name from its ability to form ice-like crystals at temperatures below 16.7°C. Commercially produced by carbonylation of methanol (Monsanto/Cativa process), food grade material is held to strict purity specifications to eliminate process-related contaminants.
As a preservative, acetic acid functions by lowering pH and inhibiting microbial growth; the undissociated form penetrates microbial cell membranes, acidifies the cytoplasm, and inhibits metabolic enzymes. It is one of the most effective antimicrobials against rope-forming Bacillus species in bakery products. Approved globally as E260 (EU), GRAS (FDA 21 CFR 184.1005), and Codex INS 260 with no numerical ADI ('not limited') given its natural occurrence as a metabolite in mammals.