Did a little more digging and found this article on cures. Very helpful explaining the why and types of cures. The paragraph below is from this article.
http://www.susanminor.org/forums/showthread.php?736-Curing-Salts"Though salt has properties that can cure meat, when one talks about curing salts or cures they are referring to the use of sodium nitrite, potassium nitrite, sodium nitrate or potassium nitrate (saltpeter) which are used in the processing of their meat. The main reasons to use curing salts in smoked sausages are to prevent botulism poisoning, as well as impede the development of many food spoiling bacteria that can thrive in low temperature environment of a smoker. But that is not all that cures do. These curing ingredients also retard rancidity, provide the characteristic flavor, color and extend the self life of the meat."
