In a large kettle or Dutch oven, brown meat loaf mixture; drain. Add 3 cups water, onion and celery. Cook until vegetables are crisp-tender (5-10 minutes). Stir in soy sauce, sugar, salt and brown sauce. Stir in bean sprouts. Bring to a boil. Combine cornstarch and 1/3 cup cold water until smooth; gradually stir into chow mein mixture. Bring to a boil, stirring constantly; boil and stir 1 minute. Serve over hot cooked rice, top with chow mein noodles.