How can I stop my dog from scavenging in my home?

You need to set your dog up for success. That means absolutely everything needs to be put away. You also need to set up exercises. Put out food and practice a "leave it" command. He gets a treat from you when he leaves food alone. He'll begin to understand that you are the source of food, not anything he can get his mouth on. Also you need to double his exercise and mental stimulation.