Effect of feeding distillers grains during different phases of production and addition of postmortem antioxidants on shelf life of ground beef1

Feeding distillers grains (DGS) to cattle can increase PUFA concentration, increase lipid oxidation, and de- crease color stability of beef. The objective of this study was to evaluate the effects of feeding DGS and the post- mortem addition of antioxidants on the shelf life of ground beef products. Crossbred heifers (n = 64; initial BW = 225 kg) were supplemented with different amounts of modi- fied DGS (MDGS; 0.91 or 2.27 kg daily, DM basis) dur- ing backgrounding and finished on diets containing corn gluten feed or MDGS. Four beef shoulder clods from each dietary group were ground independently. Fatty acid com- position was analyzed in lean tissue, s.c. fat, and compos- ite samples. Raw patties in retail display were analyzed for lipid oxidation, percent discoloration, and objective color. Cooked beef links were manufactured with salt, phosphate, and varying quantities of an antioxidant (rose- mary and green tea extract), and lipid oxidation was mea- sured throughout storage. Finishing cattle fed MDGS had greater C18:2 and PUFA (P ≤ 0.028) content in all loca- tions, whereas cattle supplemented with greater amounts of MDGS during backgrounding had more C18:0 (P = 0.005) and less C16:1 (P = 0.020) in s.c. fat. Raw ground beef from heifers finished with MDGS discolored at a greater rate (P \u3c 0.001), but lipid oxidation was not dif- ferent (P = 0.47). Greater lipid oxidation in cooked beef links occurred when cattle were fed greater amounts of MDGS during backgrounding or MDGS during finishing, but adding the rosemary and green tea extract decreased lipid oxidation regardless of dietary treatment