Sodium nitrate is a white crystalline salt used as a fertiliser and in curing meat. In the curing cellar it is the slow-release source of nitrite: bacteria convert nitrate to nitrite, which fixes the pink colour of cured meats, builds their characteristic flavour, and crucially inhibits Clostridium botulinum. Traditional long cures for hams and salamis rely on it, while modern rapid curing uses nitrite directly for precision. As a fertiliser it supplies nitrogen to crops. The compound demands respect: in the body excess nitrate can convert to nitrite and form nitrosamines, so its food use is strictly limited, and it is an oxidiser that must be stored away from combustibles. It is a chemical of two trades, field and curing room.