nitrites

Nitrite refers to the nitrite ion (NO2−) and salts such as sodium nitrite. It is the conjugate base of nitrous acid and nitrogen is in the +3 oxidation state. Nitrite salts are widely used in food processing, agriculture, and industry.

In nature, nitrite is produced primarily by the microbial reduction of nitrate (NO3−) and serves as an intermediate in nitrification and denitrification. It can accumulate transiently in water and soils and may form from the partial oxidation of ammonia. Nitrite can react with amines and under acidic conditions form nitrosating agents, including nitrosamines.

In food processing, nitrite salts are used as curing agents to preserve color, inhibit the growth of Clostridium botulinum, and act as antioxidants. They are also used in various chemical syntheses as reducing agents and intermediates.

Health and safety: Elevated nitrite levels can cause methemoglobinemia, a condition in which hemoglobin cannot effectively carry oxygen. This risk is particularly noted in infants and in cases of ingestion of large amounts. Nitrite can also participate in nitrosation reactions to form nitrosamines, which are suspected carcinogens; as a result, regulatory limits are placed on nitrite concentrations in drinking water and foods.

Measurement and regulation: Nitrite is routinely detected by colorimetric assays such as the Griess reaction in water testing and food analysis. Environmental and health agencies monitor nitrite levels to manage exposure and prevent adverse effects.