To ensure high eating quality of pork, the industry has relied on “enhancing” the product by pumping it with a solution of phosphates, salt and sometimes flavorings.  This approach has been relatively successful, however, there are growing indications that the demand for non-enhanced pork products is increasing and would be considered a premium product.  Thus, the ability to select pork that is “naturally” tender for use in a non-enhanced product line would increase the marketing opportunities for pork and the profitability of pork production.  A system for noninvasive prediction of pork loin tenderness has been developed and tested under some laboratory and commercial conditions.  The present experiments were conducted to provide a broad-scale test of the efficacy of this system across multiple packing plants representing a diversity of carcass chilling methods, including both conventional spray chilling and blast chilling.  Twelve hundred eight boneless pork loins were evaluated on the loin boning and trimming line of four large-scale commercial plants and tenderness was predicted with a noninvasive technology.  Vacuum-packaged loins were aged and tenderness was measured objectively with slice shear force at 15 days after harvest, which is approximately the average time between harvest and retail consumption of loin chops.  The prediction system allowed for identification of a group  of loins that were more consistently tender.  The system was efficacious both among and within packing plants.  This technology could both facilitate tenderness-based pork merchandising systems and serve as a research tool to facilitate improvement of pork tenderness.  Consequently, use this technology should help the industry to improve consumer satisfaction and demand for pork.