A judge has blocked Iowa State University from releasing documents about food safety research conducted for the beef-processing company that makes the product dubbed "pink slime" by critics.

District Judge Dale Ruigh ruled last month that releasing the records would damage Beef Products, Inc. by revealing information about its proprietary food-processing techniques. Releasing them also would eliminate revenue that Iowa State laboratories receive from companies, who would go elsewhere for testing if they feared results were public records, he said.