SLAUGHTER PLANT LOCATION, USDA QUALITY GRADE, EXTERNAL FAT THICKNESS,AND AGING TIME EFFECTS ON SENSORY CHARACTERISTICS OF BEEF LOIN STRIP STEAK

A boneless beef strip loin (IMPS #180) was fabricated from each of 320 carcasses to study the effects of slaughter plant location, quality g rade, fat thickness, and aging time on beef tenderness and palatabilit y. Carcasses were selected for fat thickness (< .5 cm or greater than or equal to .5 cm fat thickness) and USDA quality grade (Select or Low Choice) from two slaughter facilities (IBP, Inc., Garden City, KS or Excel Inc., Plainview, TX), and the strips were aged for either 7 or 1 4 d. Aging steaks 14 d improved all sensory traits and Warner-Bratzler shear (WBS) values regardless of all other main effects (P < .05). St eaks from Choice carcasses that were processed in Kansas had higher in itial and sustained tenderness ratings than steaks from carcasses that were processed in Texas or Select steaks from Kansas after 7 d of agi ng (P < .05). However, aging for 14 d removed differences from all sen sory characteristics of steaks from Kansas and Texas. All sensory scor es for steaks from carcasses that graded Choice were higher than those from carcasses that graded Select (P < .05). The USDA quality grade d id not affect WBS values, and fat thickness did not affect sensory cha racteristics or WBS values (P > .05). Therefore, aging beef strip loin steaks for 14 compared with 7 d improved sensory score and decreased WBS values, but fat thickness had no effect on the palatability of loi n strip steaks processed under these conditions.