MEATPACKERS STRIKE MORRELL SIOUX CITY PLANT About 800 members of the United Food and Commercial Workers Union, UFCWU, struck John Morrell's Sioux City, Iowa, pork processing plant at midnight Sunday, a spokesman for the UFCWU national said. Meatpackers at the plant have been working without a contract since the old pact expired January 31, UFCWU spokesman John Mancuso said. The plant can slaughter and process about 13,000 to 14,000 hogs a day, he estimated. The UFCWU bargaining committee and full membership rejected in late January a contract proposal by John Morrell, a subsidiary of United Brands Inc, he said.