Shelf Life of m. longissimus lumborum from Beef Fed Antioxidants and Wet Distillers Grains

de Mello Jr. et al. (2008 Nebraska Beef Cattle Report, pp. 116-117) and Senaratne et al. (2009 Nebraska Beef Cattle Report, pp. 110-111) have shown that WDGS increase polyunsaturated fatty acids (PUFA) in beef. Elevated levels of PUFA in beef may affect color and flavor of beef, eventually affecting consumer appeal at retail. Feeding vitamin E, an antioxidant, with WDGS has shown to be a promising strategy to mitigate detrimental effects on beef due to feeding WDGS (Senaratne et al. 2009 Nebraska Beef Cattle Report, pp. 113-115), but it may increase the feeding cost. Feedlot studies with a mixture of synthetic antioxidant, ethoxyquin, and tertiary butyl hydroquinone (AG; AGRADO®PLUS) have shown improvement in average daily gain and a decrease in morbidity and mortality of cattle by improving the antioxidant capacity at the ruminal and postruminal stages of digestion (Han et al. 2002 Journal of Animal Science, 80, pp. 1117-1123). Others (Moore et days retail display shear force analysis under OW and HiO 2 -MAP packaging systems, respectively. Surface discoloration ratings were determined on steaks assigned for seven days retail display shear force analysis. All steaks assigned for OW retail display were packaged (oxidation as four pieces per tray, shear force as two steaks per tray) on Styrofoam trays and overwrapped with oxygen permeable polyvinyl chloride film. All steaks assigned for HiO 2 -MAP retail display were packaged (steaks arrangement was similar to OW packaging system) on high foam-barrier polypropylene trays with a gas mixture (80% O 2 : 20% CO 2 ) and mechanically sealed with oxygen impermeable film. Overwrapped and HiO 2 -MAP packaged 8 and 29 days aged steaks, placed on a table in a cooler (at 0 ± 36oF) were exposed to continuous 1,000-1,800 lux warm white fluorescence lighting to provide simulated retail display conditions. Steaks (8 and 29 days aged) assigned for four and seven days of retail display were removed from tables accordingly for oxidation and shear force analysis, and immediately vacuum-packaged and stored at -4oF. A six-person trained panel subjectively evaluated the percentage surface discoloration. Discoloration ratings were made on each steak from 0 to 7 days of retail display at 24-hour intervals. The 2-thiobarbuteric acid reactive substance (TBARS) assay was used to measure the oxidation status of 8and 29-day aged steaks in both packaging systems displayed for 0, 4 and 7 days in simulated retail display. Tenderness evaluations were performed by Warner-Bratzler shear force testing (WBSF). Data were analyzed by ANOVA in the GLIMMIX procedure of SAS (version 9.2, Cary, N.C., 2009) as a splitsplit-split-plot design with dietary treatments as the whole-plot treatment, aging period as the first splital. 2010 Proceedings 43rd Midwestern Sectional Animal Science Meetings, pp. 86) have reported AGRADO®PLUS supplementation affects neither performance nor carcass characteristics of feedlot cattle. Feeding AGRADO®PLUS may increase the antioxidant level of muscles. Our study evaluated the antioxidant effects of feeding AGRADO®PLUS with WDGS diets on color and lipid stability, and tenderness of beef m. longissimus lumborum during its shelf life.