you have to teach him that it is bad what he is doing and he is not allowed to go in the cuboards. you can do this through training. Make it seem like that is the end of the world when he does it so he learns that is a really bad thing to do. Then reward him for being in the kitchen without him doing that.
I would bring the crate back!...sorry

But he should not be allowed to get away with that and he is so if you cannot watch him he should be in his crate; you don't want to do any more damage than he already has or hurt himself by eating somehting he shouldn't.
Another suggestion is baby gates or anything that will stop him from going in the kitchen. Then he will not have access to the kitchen. also, he should not be allowed in there without your supervision because you have to catch him in the act of doing it to punish him. if you punish after the fact he won't learn because dogs have a differnt way of learning/thinking than humans.
you are in charge not him and if your dog doesn't listen then you need to control him. Also, obedience classes might help so he will learn to respect and obey what you say.
hope that helps!
