Try scouting some cheddar cheeses on grocery shelf. Read the ingredient listing and count each. You will find out that most of them have five or more raw materials. Guess what? Majority of the ingredients are not really needed.
Cheese manufacture starts from cow. The cow produce good quality milk for cheese production. Then a rennet is added to initiate coagulation. Rennet are bacteria naturally living in cow’s stomach. Coagulated milk are gathered, salted, dried and press to form cheddar cheese. Aging process follows, usually done in cave. Then package and sold.
The manufacturing process has a lot of technical details from the view of food technologist. I just wrote a brief summary.
Analyzing the second paragraph, there are only three materials needed for cheddar cheese making. The rennet, milk and salt. Microbial rennet is a processing aid, a bacteria responsible for milk coagulation and not a part of the finished product. The ingredients are now trimmed down to two, the milk and salt. Other written ingredients are not necessary. It could be preservatives, flavorings or fillers.
Cheddar cheese could last for years depending on moisture content, packaging and environmental conditions.