Sodium nitrite (molecular formula: NaNO2); CAS No: 7632-00-0.
Sodium salt of nitrous acid (see nitrites below). Approved as preservative food additive (E 250). When mixed with common salt, as a nitrite curing salt (the sodium nitrite content of curing salt must not exceed 0,5 %) it gives the meat a red colour. The red-coloured nitrosomyoglobin is formed. The growth of bacteria (curing) is also prevented.