Be careful when microwaving though! Always stick your finger in various areas of the food to ensure it didn't get too hot. The first time I microwaved my kitties food, I did it for 10 seconds and was suprised to feel that it was VERY hot in some parts when I took it out!
I've heard various things about how long food can last when refridgerated. I usually toss it if it's been in there for more than 4 days. Rarely does a can of food ever last that long with my kitties though! haha