Sodium nitrite (food additive Е250) is used in food industry as color fixing agent and preservative in meat and fish products. Chemical formula of sodium nitrite: NaNO2. Pure additive Е250 is white hygroscopic crystalline powder, slightly yellowish. Sodium nitrite is very soluble in water. In air, additive Е250 is slowly oxidized forming sodium nitrate (NaNO3).
Sodium nitrite is extremely toxic. Human lethal dose is 2 to 6 g depending on body morphology. Incorrect use of food additive Е250 in production of meat or fish food products can lead to serious poisonings; therefore, sodium nitrite is used in mixture with edible salt.
This does not mean that it is necessary to completely exclude nitrite- and nitrate-containing products from consumption (these substances are contained in trace quantities in tomatoes, potatoes and many other vegetables and fruit), though it is not recommended to eat a lot of foodstuffs containing nitrates and nitrites. Doctors recommend increasing consumption of natural products containing substances slowing down the process of nitrosation (e.g., vitamins С and Е).
Nitrites are well absorbed from gastrointestinal tract. They cause reduction of muscle tonus, vasodilation and reduction of blood pressure. However, all negative properties of nitrites cannot manifest in concentrations used in food industry. The report of the Scientific Council published in the edition of the American Medical Association states that sodium nitrite when used in food products as preservative Е250 in recommended doses is harmless. This conclusion was reached by scientists after the analysis of all available research and publications on usage of preservative Е250, as well as more than a hundred years’ experience of using sodium nitrite in food industry.
Sodium nitrite is an important food additive for meat industry. Adding Е250 to products grants them richer red color and protects products from oxidation and bacterial spoilage. Specifically, sodium nitrite as food additive Е250 hinders development of dangerous bacteria Clostridium botulinum in products that cause botulism, i.e. a serious food intoxication leading to nervous system damage. Antimicrobic action of preservative Е250 is demonstrated in concentrations of 50–160 mg per 1 kg of the finished product.
The legislation of many countries provides for the maximum limit of additive Е250 of 50 mg per 1 kg of the finished product. In European Union, sodium nitrite is allowed for use as a 0.6% additive to salt only. In facilities, using preservative Е250 strict rules of storage and handling this food additive shall be implemented in accordance with the legislation.
Besides usage as food additive Е250, sodium nitrite has found use in various industries:
- in medicine as vasodilator, antidote in poisoning with cyanides, medicine for bronchial diseases treatment;
- in construction as concrete additive for its frost resistance;
- in chemical industry for production of dyes and nitrocompounds;
- in textile industry in cloth dying processes;
- in traditional photography as photograph-treating chemical.
Additive Е250 is included into the list of additives allowed for use in food industry both in the Ukraine, and in the Russian Federation.