Distribution of Marbling Throughout the M. Longissimus Thoracis et Lumborum of Beef Carcasses Using an Instrument-Grading System

Abstract

Beef Loin, Strip Loins (IMPS #180; n = 20) with marbling scores between Modest00 and Modest30 at the 12th and 13th rib interface of the M. longissimus thoracis et lumborum (LL) were collected. Each strip loin was fabricated into 6 samples taken perpendicular to the long axis of the LL from the 13th thoracic vertebra to the fifth lumbar vertebra with the cut made on the anterior side of the respective vertebra. A Computer Vision System Cold Camera measured the LL cross-section of each sample location for USDA marbling score, marbling distribution, average marbling fleck size, LL area, LL length (distance medial to lateral), and LL width (distance dorsal to ventral). In the present study, mean LL marbling score decreased (P < 0.05) from the second lumbar vertebrae location to the fifth lumbar vertebrae location. Marbling size and marbling distance were the smallest (P < 0.05) in samples from the 13th thoracic vertebrae location. The LL area and width was largest (P < 0.05) for the samples from the most anterior location and thus decreased (P < 0.05) as the samples became more posterior. Samples from the most posterior end of the strip loin were the longest (P < 0.05) in length. It was observed that marbling score, distribution, and size, as well as, LL area, length, and width vary from anterior to posterior in the strip loin which can have potential marketing implications for food service distributors and retailers.