caverdude.. although this is an old thread, i just came across it today.. even joined so i could reply to this thread… you are correct.. MRE’s (IMP’s in canada) are done in retort bags.. some, usually in the case of military rations, the food is pre-prepared and cooked before packaging.. this isnt “always ” the case, but it is for the most part, and as u stated, reheated viz a heater pack or water and boiled.. usually 5.3mil thickness bags.. they come generally in silver and/or white for commercial usage, olive drab/green exclusively for military usage, and then for general use.. it is in gold..
the bonus is that you “CAN” cook in these bags.. as opposed to mylar which isnt safe.. the retort bags essentially become the can… or in the case of canning, the mason jar.. just…easier to pack, easier to store, easier to ship… but they have the increased protection because of their (depending on specific model) 3 and 4 layers of materials.. it increases protection from gas’s…oxygen and light (which is the killer for food storage)
and elnav.. this is the same process used for canadian rations.. the process is the same completly
