When I bought the bags, I immediately divided the medallions into tiny zip lock bags when I got home (3.5 per bag ~ for Ariel's age, weight, & activity level, the NV website recommends 3.4 medallions a day). I then put all of bags into a larger zip lock bag and put it in the freezer.
Every night, I take out one of the prepared zip lock bags, place it in tupperware, and thaw it overnight in the fridge. When I feed her, I cut them up into pieces. She loves it!