Preheat oven to 350°F. Arrange opened Roasting Bag in 13x9-inch baking pan. Add flour to bag; shake to coat well. Mix Seasoning Mix with bread, egg and 1/4 cup of the ketchup in large bowl. Add meat; mix well. Shape into 8x4-inch loaf.
Place meat loaf in bag. Pour remaining 1/2 cup ketchup over top. Close bag loosely with nylon tie. Cut 4 small holes in top of bag to allow steam to escape.
Bake in lower half of oven 1 hour or until meat loaf is cooked through. Let stand 5 minutes before serving.