December 18, 2011 How The Army Made A Sandwich That Stays Fresh For Two Years Edit Delete Tags Autopost Army food scientists have figured out how to control pH, moisture, and oxygen inside the packaging of a pocket sandwich so that it can last for up to two years.Source: http://www.npr.org/blogs/thesalt/2011/12/14/143722936/how-the-army-made-a-sandwich-that-stays-fresh-for-two-years?ft=1&f=1007hillary clinton