A NOVEL TECHNOLOGY, RAPID EVAPORATIVE IONIZATION MASS SPECTROMETRY (REIMS), UTILIZESMETABOLOMICS TO IDENTIFY COMPOSITIONAL DIFFERENCES IN BEEF TO PREDICT BEEF SENSORY PERFORMANCE.AGING OF BEEF IS A WIDELY ACCEPTED PROCESS TO ENHANCE EATING CHARACTERISTICS OF BEEF BY INCREASINGTHE TENDERNESS OF BEEF. RECENT RESEARCH HAS DEMONSTRATED THAT OVER-AGING BEEF RESULTS IN THEDEVELOPMENT OF OFF-FLAVORS RELATED TO COMPOSITIONAL CHANGES. USING TIME-OF-FLIGHT (TOF) MASSSPECTROMETRY, REIMS PROFILING PROVIDES IN SITU, REAL-TIME MOLECULARLY-RESOLVED INFORMATION BYIONIZING BIOLOGICAL SAMPLES IN REAL-TIME WITHOUT ANY SAMPLE PREPARATION. THIS STUDY WILL UTILIZEBEEF SAMPLES THAT HAVE BEEN AGED OVER A WIDE RANGE OF DAYS POSTMORTEM AND ARE INDICATIVE OFDOMESTIC AND EXPORTED BEEF PRODUCTS. SHEAR FORCE MEASUREMENTS, SENSORY PANEL RATINGS OF FLAVOR,TENDERNESS, AND JUICINESS AND REIMS ANALYSIS WILL BE REPEATED MEASUREMENTS WITHIN AN ANIMAL.PREDICTION MODELS, INCLUDING MULTIPLE MACHINE LEARNING APPROACHES, WILL BE DEVELOPED AND TESTEDTO UNDERSTAND THE ABILITY OF REIMS TO MEASURE AND PREDICT CHANGES IN TENDERNESS, FLAVOR, ANDJUICINESS. WITH RESPECT TO THE BEEF INDUSTRY, FOR THE FIRST TIME, THIS TECHNOLOGY WOULD ALLOW FORMEAT QUALITY ATTRIBUTES SUCH AS FLAVOR, TENDERNESS, AND FRESHNESS TO BE MEASURED AND CHARACTERIZEDIN REAL TIME. THE OVERALL PROJECT GOAL IS TO DEVELOP REIMS AS A REAL TIME METHOD FOR CLASSIFYINGTHE QUALITY OF BEEF PRODUCTS BY EVALUATING THE ABILITY OF REIMS TO PREDICT BEEF SENSORY ANDTENDERNESS IN REAL TIME, IDENTIFY CHANGES IN BEEF FLAVOR AND TENDERNESS AS AGING TIME INCREASES,AND CHARACTERIZE THE EFFECT OF EXTENDED AGING ON PALATABILITY.