They drop their nutritional value greatly after 10 years, but as long as the packaging is still intact, I have had MREs from the mid 80's with no ill effect. Some of the items turn bland and tasteless. Nothing was putrid. Some of the stuff at least still had taste to it. Doubt it would sustain me. More of a parlor trick.
Like was mentioned. Sniff and small taste test as you go. I don't think you should have any problems.
NOTE: I am not a lawyer, nor do I play a lawyer on this program.