seeking information about chemical rxn used in MRE's

Hello-

I'm trying to develop an idea for heating foods, based similar to the
concept of an MRE.  does any one out there know much about the chemical
reaction used by the army in their MRE's, and if so, what chemicals are
used, how hot does it get, how long does the reaction last, what kind of
materials can/cannot be used to package the chemicals containing the
reaction, etc...?  any information that you could provide me would be really
appreciated.  thank you.

-brian jaffe
food science major
university of maryland - college park