Sodium nitrite

Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. It is a useful precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best known as a food additive used in processed meats and (in some countries) in fish products. Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. It is a useful precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best known as a food additive used in processed meats and (in some countries) in fish products. Nitrate or nitrite (ingested) under conditions that result in endogenous nitrosation has been classified as 'probably carcinogenic to humans' by International Agency for Research on Cancer (IARC). Nitrite is an easy way to give a pink shade to processed meats. Nitrite reacts with the meat myoglobin to cause color changes, first converting to nitrosomyoglobin (bright red), then, on heating, to nitrosohemochrome (a pink pigment). According to the meat industry, nitrite is used to prevent botulism. Yet several large meat processors produce safe processed meats without relying on nitrite or nitrate. The main use of sodium nitrite is for the industrial production of organonitrogen compounds. It is a reagent for conversion of amines into diazo compounds, which are key precursors to many dyes, such as diazo dyes. Nitroso compounds are produced from nitrites. These are used in the rubber industry. It is used in a variety of metallurgical applications, for phosphatizing and detinning. Sodium nitrite is an effective corrosion inhibitor and is used as an additive in industrial greases, as an aqueous solution in closed loop cooling systems, and in a molten state as a heat transfer medium. Sodium nitrite is on the World Health Organization's List of Essential Medicines as it is an efficient drug in case of cyanide poisoning. It is used together with sodium thiosulfate. Historically, salt has been used for the preservation of meat. The salt-preserved meatproduct was usually brownish-gray in color. When sodium nitrite is added with the salt, the meat develops a red, then pink color, which is associated with cured meats such as ham, bacon, hot dogs, and bologna.