E262ii - Sodium diacetate
What it is and how it is used
Sodium diacetate is a curious little compound: not a simple salt but a molecular complex of sodium acetate and acetic acid, locked together in a stable crystal. Practically, it is dry vinegar.
That is exactly why it is used. Acetic acid inhibits moulds and Listeria, but liquid vinegar cannot be added to a dry seasoning or a crisp coating. Sodium diacetate delivers the same acid as a free-flowing powder that releases it on contact with moisture — which is what makes salt-and-vinegar crisps taste of vinegar without going soggy, and what extends the shelf life of packaged bread and sliced deli meat.
Foods commonly containing it
Salt-and-vinegar crisps and snack seasonings, packaged bread and baked goods (as a mould inhibitor), sliced cooked and cured meats, sauces and marinade mixes, and pickled products.
Safety summary
Sodium acetates are authorised in Great Britain as E 262 and sit in Group I, permitted at quantum satis. Sodium diacetate is specified as E 262(ii).
No numerical ADI has been assigned. Acetic acid and acetate are ordinary dietary constituents and normal products of human metabolism, which is the basis for the quantum satis permission.