South Dakota has about 580 manufacturing and processing plants, but only about 40 of them employ 50 or more persons. Food products earn about seven-tenths of the manufacturing income. Meat processing and packing ranks as the most important industry, with the largest plant at Sioux Falls. Other plants are in Huron, Mitchell, and Watertown. The centers for the dressing and packing of poultry at Madison, Sisseton, Watertown, and other eastern cities. Creameries and dairy-processing plants operate at Rapid City, Sioux Falls, Madison, and many other towns. Belle Fouche has a sugar refinery, and flour and feed mills operate in Rapid City and Sioux Falls.