Seashell Casserole Serves 100. 6 pounds medium shell macaroni 14 pounds lean ground beef 6 (50 ounce) cans condensed tomato soup Cook macaroni; rinse and drain. In large saucepot cook beef. Cook until internal temperature is 160 degrees F or higher for 15 seconds and beef is browned, stirring to separate meat. Drain fat. Add macaroni and soup. Heat until internal temperature is 140 degrees F or higher for 15 seconds, stirring often. Hold at 140 degrees F or higher. Portion using a 3 3/4 cup scoop.