Nitrite and Nitrate Curing Salt

Nitrite / Nitrate Curing Agents

Nitrate came into use as naturally occurring contaminant of salt. Meat containing nitrates was found to have improved flavor, color, and shelf life. When nitrate/nitrite was identified as the compound that improved the quality of the meat, they were then added as ingredients by design.

In addition to the color role these products perform, nitrates and nitrites have a pronounced effect on flavor. Without them cured meats would simply be salty cooked meat with no color and enhanced shelf life. Acting as a powerful antioxidant nitrates and nitrites also enhance flavor and reduce oxidative rancidity. Antioxidants (sodium ascorbate vitamin C, sodium erythorbate vitamin C salt, alpha-tocopherols vitamin E, BHA/BHT, phenolic compounds) are compounds that prevent the development of oxidative rancidity and help avoid pigment oxidation. However, nitrates/nitrites have a stronger effect when compared to these compounds.

Rapid curing using nitrites is today's preferred processing method, and nitrite is added directly into cured sausage, hams, bacon, etc. Nitrites are the primary chemicals that are responsible for the inhibition of pathogen growth when curing meats, and nitrite is a very effective inhibitor of the growth of Clostridium botulinum, the bacteria that causes botulism poisoning.

Nitrate in itself is not successful in producing the curing reaction. Nitrate must be reduced by lactic acid bacteria (Micrococcaceae species) or other natural means including microorganisms present in meat to nitrite to cause color change. Inevitable, this means that the color forming process will be more dependent on the activity of the Micrococcaceae species and that color formation will take longer than in sausages using nitrite. Since Micrococcaceae species are inhibited at low pH, sausages relying on nitrate reduction must be fermented by a traditional process. Nitrate is still used by many dry sausage manufacturers because nitrate serves as a long time reservoir of nitrite, but it has also been reported that sausages cured with nitrate have a better flavor than when cured with nitrite.

Nitrates and nitrites must be used with caution during curing. Both can be considered toxic and for that reason, strict limits on their use have been established. Usually, the amount of added sodium nitrite lies in the range of 50-200 mg/kg and nitrate in the range of 200 to 600 mg /kg. Excessive use of nitrate (too much) and/or nitrites can cause severe oxidation of the meat pigment producing a green pigment. This form of greening of cured meats is referred to as nitrite burn.