Peel and finely chop the garlic (or use a garlic press).
Place the beef into a large bowl. Add the milk, bread crumbs, Wocestershire sauce, onion powder, sage, salt, mustard, pepper and egg to the beef mixture. Mix with a fork or your hands until the ingredients are well mixed.
Place the beef mixture in an ungreased loaf pan, and spread ketchup over the top.
Bake uncovered 50 to 60 minutes or until beef in center of loaf is no longer pink. Let stand 5 minutes, so it will be easier to remove from the pan. Cut the loaf into slices.