Yes, it is okay to reheat food that contains sour cream. However, you should be aware that heat will cause the proteins in the cream to break down and form curds. This is not ideal for recipes that call for sour cream, but it's a good option for making a large batch of sour cream ahead of time or for using in baking recipes that don't require the cream to be whipped. Just make sure to thaw it completely before using it and stir well to recombine the curds.