I asked just to aid the conversation. Desiccation has a long history in successful food preservation. As to the original question, once opened, the package has a dramatically reduced life span. Moisture and oxygen will work with the nutrients as a viable growth medium for many organisms. Storage conditions are important.

While I do like cans, even they do not last forever. All food stocks must be rotated, the time interval depending on the food, how it was preserved, and how it was sealed and stored.