Location: Meat Safety and Quality
Project Number: 3040-31430-006-04-T
Project Type: Trust Fund Cooperative Agreement
Start Date: May 1, 2019
End Date: Nov 30, 2020
1) Determine the appropriate specifications for tenderness claims of beef top sirloin by comparing top sirloin and strip loin as impacted by packing plant, quality grade program, and grading camera predicted slice shear force class, and postmortem aging time.
Carcasses will be sampled from four large-scale fed-beef packing plants. During the routine grading process, carcasses will be evaluated with the VBG2000 grading camera and predicted slice shear force will be determined. For each plant and for each of 3 quality grade programs (Premium (upper 2/3) Choice, Choice, and Select), 14 carcasses will be randomly selected for inclusion in the experiment. It is anticipated that approximately 98%, 75%, and 60% of the Premium Choice, Choice, and Select carcasses, respectively, will be predicted tender by the grading camera. To ensure that we obtain a broad sample for the comparison of "predicted tender" with "not predicted tender," additional carcasses will be selected for Choice and Select in such a manner that the total number of "predicted tender" and the total number of "not predicted tender" for each of those quality grade programs will be 14 for each plant. So, across the four packing plants, we will be able to make an unbiased comparison of quality grade programs using 56 Premium Choice, 56 Choice, and 56 Select carcasses. Additionally, we will be able to make an unbiased comparison of tenderness classes using 56 Choice carcasses "predicted tender", 56 Choice carcasses "not predicted tender", 56 Select carcasses "predicted tender", 56 Select carcasses "not predicted tender." For each carcass included in the experiment, we will obtain the strip loin and the top sirloin butt from the left side of the carcass. Cuts will be collected and transported (-1°C) to the U.S. Meat Animal Research Center (USMARC) and aged (-1°C). At 13 d postmortem, center-cut top sirloins will be obtained by removing the top sirloin cap and all minor muscles (gluteus accessorius and gluteus profundus) and strip loins will be trimmed of s.c. fat and minor muscles. Each strip loin section and center-cut top sirloin will be sliced into 28-mm thick steaks using a Grasselli NSL 400 portion meat slicer. Steaks for trained sensory panel will be vacuum-packaged and frozen (-20°C) for subsequent evaluation of tenderness, juiciness, flavor profile using the beef flavor lexicon (Adhikari et al., 2011). Steaks for d 14 slice shear force evaluation will be held overnight (5°C) and fresh (never frozen) steaks will be cooked and slice shear force will be determined. Additional steaks will be obtained from each cut for slice shear force evaluation at 28 and 42 d postmortem. Those steaks will be placed on trays and packaged with gas flushing (25% CO2, 75% N) to prevent deformation of the steaks and aged an additional 14 d before cooking and slice shear force measurement. Use of SSF at 14, 28, and 42 d postmortem will allow us to impute SSF distributions at intermediate aging periods (e.g., 21 and 35 d postmortem).