1 Transfer the mixture to a 5x9 inch loaf pan. 2  Bake uncovered in the preheated oven 40 minutes. 3  Increase oven temperature to 400 degrees F (200 degrees C), and continue baking 15 minutes, to an internal temperature of 160 degrees F (70 degrees C). 4  In a small bowl, mix the remaining tomato sauce and ketchup. Bake uncovered in the preheated oven 40 minutes. 2  Increase oven temperature to 400 degrees F (200 degrees C), and continue baking 15 minutes, to an internal temperature of 160 degrees F (70 degrees C). 3  In a small bowl, mix the remaining tomato sauce and ketchup.