WASHINGTON (Reuters) -
                        The Texas hamburger plant at
                        the  center of a landmark
                        lawsuit challenging the U.S.
                        Agriculture  Department's food
                        safety testing has flunked
                        another set of  salmonella tests,
                        the USDA said on Wednesday.
               
              Supreme Beef Processors Inc. won a key
              victory last month  when a federal judge
              ruled that the USDA tests to detect
               salmonella contamination at meat
              processing plants were not a  fair way to
              determine if a plant is clean.  
              The Clinton administration, which plants to
              appeal the court  ruling, contends that the
              food safety tests have dramatically  cut
              salmonella contamination on raw meat and
              poultry by up to 50  percent in the past two
              years.  
              Tom Billy, administrator of the USDA's
              Food Safety and  Inspection Service, said
              new results show Supreme Beef failed  its
              fourth consecutive set of tests for
              salmonella. The latest  set of tests were
              performed by regulators to determine if the
               plant had changed procedures to make its
              hamburger safer.  
              "If this were any other plant, FSIS would
              immediately  suspend inspection upon
              learning that the corrective changes  were
              inadequate," Billy said in a statement.  
              "However, because of a federal district
              court decision in  Texas, we are precluded
              from suspending inspection, which shuts
               down the ground beef operations, even
              though Supreme Beef has  failed to meet a
              food safety standard that other plants around
               the country are required to meet," he said.  
              The government is asking Supreme Beef to
              voluntarily shut  its plant until it can pass
              food safety tests, Billy said.  
              Supreme Beef, which grinds about 500,000
              pounds of hamburger  daily, has repeatedly
              said that its plant produces safe food.  The
              company challenged the USDA, saying its
              salmonella tests are  arbitrary and an unfair
              way to measure food safety.  
              The USDA salmonella tests allow a 7.5
              percent rate of  salmonella contamination in
              ground beef, and higher levels in  raw
              chicken and turkey.