Some dogs are just born optimistic, and even though they have never received food from the table, they plant themselves at the table, hoping something will fall their way. Dropped food is a good beggar reinforcement, especially if you have a child who likes to make a game of dropping food on purpose. You may choose to train the dog to settle or down-stay in another room or at a distance from the table.
The dog must never bite the hand that feeds. To make sure that he doesnt, teach him the command "easy." Offer him a treat by holding the treat in your thumb and index finger keeping your palm toward your body and your knuckles facing the dog. If the dog grabs for the treat, give him a very loud and firm command by saying "Easy". After a few rounds of this practice, he will generally take the food from your hand gently.
-- Dick Colman