eating from strangers

Question
I would like to find out a method to train my dog not to eat from other people like neighbors or people who pass by our yard, especially when he is left alone.

Answer
You have to be careful. You can teach him this by practicing with people you know that your dog doesn't know. They can give him unpalatable "treats" (those sprayed with bitter apple or hot sauce) and/or you can give him leash corrections if he tries to take treats from them, thereby making negative associations with taking treats from strangers - or with the presence of strangers, and therein is the danger of negative teaching. He could learn to hate all strangers. Better to teach your dog never to take a treat unless YOU give him permission.

To do this, teach him "leave it" first and then "take it". Tell him "take it" whenever he gets a treat and let him know that taking food (including his meal) is not allowed until you say "take it".

You can adapt the tips here http://www.examiner.com/x-7644-Detroit-Pet-Training-Examiner~y2009m10d5-Games-Go... to your purposes.

You will need to get someone you know who won't be spending any time with the dog in the future (like a coworker who needs a favor perhaps, or your the neighbor's teenager's disposable boyfriend?) to help you out. You may need to do some hiding and sneaking around to train the behavior to stick when you aren't around to supervise.