I agree fully agree with Blueduck answer. You should not rely on those ready made foods. You never know what they have done with them before packing them and selling them to you.
If we (my family) go camping and we plan to set fire, we buy clean medium size potatoes, some fish (fillet or whole), beef fillet (no fat on it)everything is fresh, Sea Salt and roll of baking foil, the thicker the foil is the better.
You cut meat and fish in portion pieces, salt it and wrap it thoroughly in foil. Salt and wrap whole potatoes too.
When you get nice coals you just put those wrapped things on the coals. Potatos take longer time and it is good to check if they are done by piercing them right through the foil with some wooden pick. Fish of cource takes less time than meat.
It is simple, it tastes great, and you are always aware of what you ate.