What ingredient causes cured meats to turn pink?

The pink coloration in cured meats is primarily attributed to the presence of nitrites. When nitrites are added to meat, they react with myoglobin, the protein responsible for storing oxygen in muscle tissue, to form a stable pink pigment called nitrosomyoglobin. This process not only gives cured meats, such as bacon and ham, their characteristic pink hue but also helps in preserving the meat and preventing the growth of harmful bacteria.

While salt is an essential ingredient in curing, its primary role is to enhance flavor and inhibit the growth of spoilage bacteria, rather than contributing to color change. Monosodium glutamate is a flavor enhancer and does not play a role in developing the pink color of meats. Liquid smoke is a flavoring agent used to impart a smoky taste and aroma but does not affect the color of the meat in the same way that nitrites do. Thus, nitrites are the key ingredient responsible for causing cured meats to turn pink.