My 4 year old GSD bit me when I tried to take garbage away from him. I ran away. What should I do now?

Hi,

My 4 yr. old German Shepherd and constant loving companion, bit me. I had placed a bag of garbage containing a turkey bone on the floor. I heard him chewing the bone from the garbage and went over to him. He growled at me, which surprised me greatly. I then spoke firmly to him and reached for his collar to pull him away from the bone. He growled again and bit my wrist. It was one quick bite and I pulled away and ran. He has been quite humble ever since. I was shocked. I thought I trained him to not pick up food on my command. As a puppy I took food from him, and at times I will test him and put a piece of food in front of him and say "No" and he would not touch it until I commanded him to do so.

He is very lovable and friendly and excitable. I am very concerned with regard to his repeating this as children do visit.

He had asked me to take him for a walk this a.m., but I was not ready. He is quite aggressive when he wants his walk.

He is healthy, has all his needles, is well fed, and should not have been hungry at the time. I am so disappointed and hurt, more than the bite.

Thanks for your reply,
Dona