There's a theoretical risk of contamination of the food from the metal in the can (or the metal that's used to seal the can together) but many cans now have a thin plastic lining anyway, making that risk minimal.
If you were running a restaurant, and the local food hygiene inspector found an open can in your fridge, you'd be marked down for it. However plenty of people are happy to leave food in opened cans (including me, and I haven't even got a fridge!) and nobody seems to come to any harm through doing so.