Why does a cheese contain sodium chloride?

Answer 1

Salt (sodium chloride) serves as a catalyst and/or a speeder-upper for many reactions, including the ones that turn milk or cream into cheese. There are cheeses that can be made with little or no salt, but they are almost all soft cheeses, ones that are made in a short period of time (such as mozzarella). Aged cheeses pretty much need salt to keep things going until they turn into something that's recognizable as cheddar or gruyere or whatever.