If I buy them in big cans, they are so cheap and I can afford Wellness... but I only have one cat. She refuses to eat any dry food I offer so I give her a little dry mixed in her canned. She would be able to finish a 12.5 oz can in 3 days...... is that too long in the fridge? What can I do to keep it fresher? Or should I stick to brands I can afford like Fancy Feast?