This U.S. industry comprises establishments primarily engaged in (1) milling flour or meal from grains (except rice) or vegetables and/or (2) milling flour and preparing flour mixes or doughs. Cross-References. Establishments primarily engaged in-- ? Preparing breakfast cereals from flour milled in the same establishment--are classified in Industry 311230, Breakfast Cereal Manufacturing; ? Manufacturing prepared flour mixes or doughs from flour ground elsewhere--are classified in U.S. Industry 311822, Flour Mixes and Dough Manufacturing from Purchased Flour; ? Milling rice or cleaning and polishing rice--are classified in U.S. Industry 311212, Rice Milling; ? Wet milling corn and vegetables--are classified in U.S. Industry 311221, Wet Corn Milling; and ? Crushing soybean and extracting soybean oil--are classified in U.S. Industry 311222, Soybean Processing.