Sorting through ingredients in foods can be complicated because names of some chemicals are very similar. Sodium nitrite is also known as nitrous acid sodium salt and diazotizing salt. You shouldn't confuse sodium nitrite with its chemical cousin sodium nitrate, because these two have very different properties. The properties of sodium nitrite are responsible for the beneficial uses of this chemical.
Chemical Properties
Sodium nitrite has one sodium atom, one nitrogen atom and two oxygen atoms. This white to off-white powder has a melting point of 281 degrees Celsius, or 537 degrees Fahrenheit, and a boiling point of 320 degrees C, or 608 degrees F. It will self-ignite if the temperature is raised to 490 degrees Celsius. This is equivalent to 914 degrees Fahrenheit. Since it is very soluble in water, this chemical is useful in food chemistry.
Nitrosoamine Concerns
Sodium nitrite is hygroscopic. This means that it can pull water vapor out of the air. Slowly, this causes the sodium nitrite to oxidize and become sodium nitrate. Sodium nitrate reacts with the amine groups found in protein to form nitrosoamines. The presence of nitrosoamines in food was a significant concern because they cause cancer. In the 1970's, the USDA addressed this concern by requiring meat manufacturers to add 550 ppm of ascorbic acid to cured meat, to prevent the formation of nitrosoamines. The Linus Pauling Institute explains that most manufacturers add an isomer of ascorbic acid called erythorbic acid. Erythorbic acid is equally safe and effective as ascorbic acid.
Benefits
Sodium nitrite is widely used to cure meat. It prevents cured meat from becoming rancid and stabilizes taste. Cured meat retains its red color because sodium nitrite reacts with the myoglobin in the meat. Most important, sodium nitrite prevents the formation of the botulism toxin. These benefits need to be balanced against the relatively small risks posed by this chemical.
Safety
If sodium nitrite is "defanged" by preventing it from becoming a nitrosoamine, the risks associated with it are minimal. Although it is toxic, the FDA has classified it as "generally recognized as safe." The fatal dose of this chemical is between 22 to 23 mg per kilogram of body weight. The University of Minnesota Extension estimates that a 154-pound person would have to eat 18.57 lbs. of cured meat product containing 200 ppm sodium nitrite in one sitting to consume this much sodium nitrite.
References
- Oxford University; Material Safety Data Sheet -- Sodium Nitrite; Dec. 17, 2010
- University of Minnesota Extension: Nitrite in Meat; Richard J. Epley, et al.
- Linus Pauling Institute; Nitrosoamines and Cancer; Richard A. Scanlan, Ph.D.; Nov. 2000
- World Journal of Gastroenterology; Nitrosamine and Related Food Intake and Gastric and Oesophageal Cancer Risk; Paula Jakszyn; July 2006
Member Comments