Not true. Real American cheese is a “natural” cheese as referred to in the following excerpt. It is a very mild cheddar cheese. Processed cheese food iis franken cheese:
Processed Cheese: What is that Stuff Anyway?
Zey Ustunol
Dept. of Food Science and Human Nutrition
Processed cheese is made from natural cheeses that may vary in degree of sharpness of flavor. Natural cheeses are shredded and heated to a molten mass. The molten mass of protein, water and oil is emulsified during heating with suitable emulsifying salts to produce a stable oil-in-water emulsion. Depending on the desired end use, the melted mixture is then
reformed and packaged into blocks, or as slices, or into tubs or jars. Processed cheeses typically cost less than natural cheeses; they have longer shelf-life, and provide for unlimited variety of products.
Right, the FDA has specific rules about wording when it comes to American cheese. If the word “cheese” is followed by artful terms like “product” or “food” then all bets are off as to the amount of non-cheese ingredients you’re getting. If it just says “processed cheese” then it’s real cheese plus a small amount of emulsifier so it melts smoothly and is more shelf stable.
If in doubt you can always check the ingredients. And the price is another indicator. The truly fake stuff tends to be much cheaper.
Here’s a how-to on making your own processed cheese at home using sodium citrate:
https://www.cheeseprofessor.com/blog/sodium-citrate-cheese-sauce
You might ask why would anyone want to do this? The answer is to make smooth melted cheese for nachos and that kind of thing.