Cats are curious and love to explore things – boxes, cabinets, spaces between walls and rafters – it is part of what makes a cat a cat. I would try enriching her home environment with things she can crwal and creep into (boxes, paper bags, cat tunnels, etc) and see if that help distract her from crawling in the fridge. When she comes to the fridge, just shoo her away and redirect her to something better. I also have five cats. One is very fixated by the fridge but ONLY when she hears the cold cut drawer open and a bag come out. My kitten (about 16 weeks old) was very intrigued with the fridge until we gave her more things to quell her need to explore. Now she ignores it totally. Enrich the environment and redirect her activities to something better and safer to explore in.