Nitrite in Meat
Richard J. Epley, Paul B. Addis and Joseph J. Warthesen
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Copyright © 2012 Regents of the University of Minnesota. All rights reserved.
Background
For centuries, meat has been preserved with salt. At certain levels, salt prevents growth of some types of bacteria that are responsible for meat spoilage. Salt prevents bacterial growth either because of its direct inhibitory effect or because of the drying effect it has on meat (most bacteria require substantial amounts of moisture to live and grow).
As use of salt as a meat preservative spread, a preference developed for certain salts that produced a pink color and special flavor in meat. This is the effect we see in cured meats today. Near the turn of the century it was determined that nitrate, present in some salt, was responsible for this special color and flavor. Still later it was determined that nitrate actually is changed to nitrite by bacterial action during processing and storage and that nitrate itself has no effect on meat color. Today the nitrite used in meat curing is produced commercially as sodium nitrite.
What Nitrite Does in Meat
Nitrite in meat greatly delays development of botulinal toxin (botulism), develops cured meat flavor and color, retards development of rancidity and off-odors and off-flavors during storage, inhibits development of warmed-over flavor, and preserves flavors of spices, smoke, etc.
Adding nitrite to meat is only part of the curing process. Ordinary table salt (sodium chloride) is added because of its effect on flavor. Sugar is added to reduce the harshness of salt. Spices and other flavorings often are added to achieve a characteristic "brand" flavor. Most, but not all, cured meat products are smoked after the curing process to impart a smoked meat flavor.
Sodium nitrite, rather than sodium nitrate, is most commonly used for curing (although in some products, such as country ham, sodium nitrate is used because of the long aging period). In a series of normal reactions, nitrite is converted to nitric oxide. Nitric oxide combines with myoglobin, the pigment responsible for the natural red color of uncured meat. They form nitric oxide myoglobin, which is a deep red color (as in uncooked dry sausage) that changes to the characteristic bright pink normally associated with cured and smoked meat (such as wieners and ham) when heated during the smoking process.
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