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The objective of this study was to characterize flavor, fatty acid composition, and volatile compounds of beef treated with common antimicrobial interventions in beef processing facilities. The effect of 3 prechilling antimicrobial interventions (4.5% lactic acid [LA]; 400 ppm peroxyacetic acid acidified to pH 1.2 with a sulfuric acid and sodium sulfate blend [aPAA]; or untreated control [CON]) and 4 postchilling treatments (CON; LA; aPAA; or a 2.5% solution of a commercial blend of lactic and citric acid [LAC]) were analyzed. Briskets (n = 30/treatment) were treated before and after chilling using a custom-built pilot-sized spray cabinet, ground twice, and formed into patties. Cooked patties were analyzed by a trained sensory panel, and a subset of raw samples (n = 6) were analyzed for fatty acid composition and volatile compounds. Samples treated with LA before and after chilling were more intense in sourness than the CON (P < 0.05). Fatty acid analysis showed no differences (P > 0.05) due to the use of chemical interventions. Only postchilling treatments had an effect on volatile compounds. The relative abundances of pentanal and pentanol were greater (P < 0.05) in LA-treated postchilling intervention samples than CON and LAC, hexanoic acid was greater (P < 0.05) in aPAA than CON and LAC, and acetic acid was greater (P < 0.05) in aPAA than LAC. Overall, these results demonstrated that LA pre- and postchilling antimicrobial interventions only impact the sourness of ground beef but did not affect the fatty acid composition, while postchilling antimicrobial treatments had a minimal impact on volatile compounds.

ObjectivesDue to developing meat trade issues associated with use of the β-agonist ractopamine hydrochloride (RH) as a growth-promoting agent in livestock production, this project was developed to provide recommendations of best practices to beef cattle producers in the United States who intend to export to China. This study is critically important in better understanding the bioaccumulation and depletion of RH in live animals, and how this may relate to depletion in differing tissues on animal harvest.This study was designed to determine dose response and depletion curves in the lower gastrointestinal (GI) tract of fistulated (i.e., cannulated- both rumen and duodenal) steers either receiving or not receiving ractopamine hydrochloride as part of the daily ration. There were originally five steers in this study, but due to performance challenges and scarring issues, one animal was removed from the study for a total of four test subjects.Materials and MethodsIn the dose and depletion study, four steers (n = 2 not receiving RH and n = 2 receiving RH at the approved dosage) were assessed from –3 d (still receiving RH if on the RH treatment) to 13 d post-withdrawal to determine the amount of RH present and length of time required for RH to clear the GI tract should a contamination event of low levels occur. Residues were quantified using liquid chromatography mass spectrometry (LC-MS).ResultsFor the dose and depletion study, RH residues were quantified in rumen fluids, rumen solids, fecal material, and duodenal fluids. Overall, the RH present in the two control steers (which did not receive RH) declined from approximately 30 ppb in all matrices 3 d before withdrawal to below the limit of quantitation at the end of withdrawal. Furthermore, samples tended to be below the limit of quantitation by Day 4 post-withdrawal. The steers that received RH also exhibited a decline of RH throughout the withdrawal period for all matrices (e.g., 5800 ppb in rumen fluids at day –3 versus 1.81 ppb 13 d post-withdrawal).ConclusionThe dose and depletion study results suggest that RH declines rapidly in the lower GI of beef cattle, with levels below detection by day four. There are events in which RH declines and then spikes, so further research may be necessary to determine why this rapid increase occurs.

Descriptive trained sensory attributes, fatty acids, and volatile compounds were determined to characterize the effects of dry-aging on ground beef. Beef shoulder clods were ground to include 100% fresh beef, 100% dry-aged beef, and a 50% fresh and 50% dry-aged ground beef blend. Samples comprised of 100% dry-aged beef were rated greatest (P < 0.001) for browned/grilled, earthy/mushroom, and nutty/roasted-nut flavors; however, panelists also detected greater (P ≤ 0.011) incidences of sour/acidic and bitter flavors. The addition of dry-aged beef increased (P < 0.001) hardness and reduced (P < 0.001) tenderness. Dry-aging also caused a shift in saturated fatty acids, where shorter chain saturated fatty acids (≤ 16:0) were reduced (P ≤ 0.034) compared to stearic acid (18:0). Meanwhile, increases of trans-octadecenoic acid (18:1 trans) and decreases of cis monounsaturated fatty acids were present in dry-aged beef. Concentrations of 18:2 conjugated linoleic isomers were greatest (P < 0.001) in fresh beef and decreased with the incorporation of dry-aged beef. Several lipid-derived volatile compounds were greater (P < 0.05) in dry-aged beef compared with fresh beef, implying a greater degree of lipid degradation among dry-aged beef. Increases (P ≤ 0.031) were determined for 3- and 2-methyl butanal with the addition of dry-aged beef. Intermediates of the Maillard reaction, 2,3-butanedione and acetoin, were determined to be greatest (P ≤ 0.046) from dry-aged beef. Alterations of fatty acids and volatile compounds with dry-aging were determined to be related with intensity of individual flavor attributes. Overall, it may be concluded that inclusion of dry-aged beef impacts flavor profile through altered fatty acid profiles and flavor related compounds. These results support the idea that dry-aging may be utilized to impart an altered ground beef flavor experience.