I didn't read all the answers to this topic but I would say that in an an emergency it would be good to eat . I remember tasting some of the dogs food when I was a kid and it was awfull . But when you're REALLY hungry I'm sure just about anything would taste good .
There are some good quality pet foods around that are supposed to be " human grade " food .
I'm pretty sure that dry pet food has a long shelf life .