Quality evaluation of beef carcasses produced under tropical conditions of México

Twenty-three thousand four hundred eighty-four beef carcasses were classifi ed according to the Mexican norm NMX-FF-078-SCFI-2002 at the No. 51 Federal Inspected Type abattoir located in the State of Tabasco, Mexico, owned by the Beef Cattle Union of Tabasco State. Tabasco State has a Tropical humid (Am) and subhumid (Aw) climate with rains in summer. The study took place between November 2009 and February 2010. The objective of this study was to evaluate inde- pendently the infl uence of each of the grading criteria used for classifi cation on the fi nal quality grade and determine areas for improvement to enhance the qual- ity of Mexican beef carcasses. The beef carcass norm implementation followed a mechanistic approach of the 5 basic evaluation criteria applied in the sequential order: 1) maturity (age), 2) conformation (muscularity), 3) color of the meat, 4) fat color, and 5) distribution of the subcutaneous fat. The quality grades possible were Supreme, Select, Standard, Commercial, Out of Grade, and Veal. The proportion of carcasses classifi ed as Select, Standard, Commercial, Out of Grade, and Veal were 13.4, 45.8, 27.4, 10.6, and 2.7%, respectively. No carcasses had a fi nal quality grade of Supreme. Based on maturity, 79.2% of the carcasses met the specifi ca- tions for Supreme; however, when the next criterion, conformation, was evaluated only 0.5% of the carcass- es met the specifi cations for Supreme. When carcasses with a criterion grade of Supreme are not included in the analysis, the γ and κ statistics indicated that matu- rity and conformation have the greatest association and agreement, respectively, with fi nal quality grade. When carcasses with a criterion grade of Supreme are included in the analysis, the κ statistic for the assess- ment of agreement between fi nal quality grade and cri- terion indicated a descending order of conformation, subcutaneous fat distribution, maturity, meat color, and fat color. Thus, based on the degree of association and agreement, conformation was identifi ed as the criterion with the greatest infl uence on fi nal quality grade and the primary reason for the absence of Supreme grading among the carcasses studied. It is concluded that the application of the Mexican beef carcass classifi cation norm NMX-FF-078-SCFI-2002 into a sample popula- tion of beef cattle coming out of a tropical beef produc- tion environment highlights a system capable of send- ing animals to slaughter at an early age with adequate meat and fat color and subcutaneous fat distribution although requiring improvement in conformation.