All you have to do is take a look at American cheese singles to know that they can't be good for you. They don't even melt properly when they're heated and they're an unnatural color. There's a reason for that and it's because they're dyed in order to get that yellow-orange tinge. As you can probably guess, some of these food dyes are carcinogenic, which means they could cause cancer.
Cheese singles like this are also packed with sodium and other chemicals that are not good for you. The one piece of good news in all this is that you now have a great excuse to buy fresh, healthy cheese for your sandwiches. Don't risk it on this fake food. Pick up some nice parmesan, brie, or cheddar at the store and watch your food and life improve.