What is E260? Acetic Acid Explained

Vinegar on the label, E260 on the ingredients list — what's actually different

Vinegar and E260 are the same active compound — acetic acid — but they usually get there by different routes, and food labelling rules care about the difference even though your body doesn't. Vinegar is legally defined in the EU, UK and most other food standards as the product of fermenting ethanol with acetic-acid bacteria, the same slow biological process used for centuries, typically yielding a 4–8% acetic acid solution plus the trace flavour compounds of whatever was fermented (wine, cider, malt). E260 on an ingredients list, by contrast, is typically manufactured industrially, most commonly via methanol carbonylation — reacting methanol with carbon monoxide under a catalyst to produce acetic acid directly, without any fermentation step at all. Both routes produce food-grade acetic acid that meets the same purity specifications, and the molecule itself is identical either way — there's no chemical test that can tell a fermented acetic acid molecule from a synthetic one. The practical difference is really about process and label wording, not about safety: a product calling itself ‘vinegar’ has to be fermented, while one simply listing ‘acetic acid’ or ‘E260’ in its ingredients is very likely using the synthetic, non-fermented version, usually for cost and consistency reasons in large-scale manufacturing.

Why E260 gets one of the most relaxed safety ratings on this site

Acetic acid holds a JECFA group Acceptable Daily Intake (ADI) of ‘not specified’ — the designation given to a small number of additives considered safe at the levels realistically consumed in food, with no numerical daily limit considered necessary. It's also affirmed GRAS (Generally Recognized As Safe) by the US FDA. This isn't a case of an additive being grandfathered in without scrutiny: acetic acid is one of the most extensively studied substances in food chemistry, partly because humans have eaten it in vinegar for thousands of years, and partly because the body already produces and processes small amounts of it naturally as part of normal metabolism — it's an intermediate in several core metabolic pathways, broken down the same way whether it arrived via food or was made by your own cells.

Where E260 actually turns up

Beyond the obvious — pickles, chutneys and salad dressings — E260 is a workhorse acidity regulator and preservative used in sauces and condiments (ketchup, mayonnaise, mustard), bread and baked goods (where it helps control dough pH and extend shelf life), processed cheese and dairy analogues, canned vegetables, and ready meals. It's also the active ingredient behind a product most people don't think of as a food additive at all: descaling kettles and cleaning surfaces with diluted white vinegar is the exact same compound doing a non-food job, which is part of why acetic acid's safety profile is so well characterised — it's been studied from both the food-safety and industrial-chemistry sides for well over a century.

Common myths about E260, checked against the evidence

Further reading

• EFSA: Safety evaluation of buffered vinegar as a food additive (2022)