LAUSR

This research was conducted to evaluate the effects of feeding different types of processed corn, with or without distiller grains, on shelf life of beef steaks. Steers (n = 240) were finished on Dry Rolled Corn (DRC), DRC + 30% Dried Distillers Grains (DDGS), Steam Flaked Corn (SFC), or SFC + 30% DDGS. Cattle were fed 10 per pen. Only pens with upper 2/3 Choice and Select-grade carcasses were sampled, with a goal of two (and a minimum of one) of each grade per pen. Three pens per treatment met the selection criterion and 36 carcasses were chosen (21 upper 2/3 Choice and 15 Select). Pen was considered the experimental unit. Both strip loins were collected from each carcass, halved, and aged for 2, 9, 16, or 23 d. After aging, steaks were placed under retail display for 7 d. Discoloration and objective color (L*, a*, and b*) were determined daily and lipid oxidation (thiobarbituric acid reactive substances; TBARS) was measured after 0 and 7 d of retail display. Fatty acid profile of the lean was obtained. Minimal to no impacts of grade on color and lipid oxidation were found (P > 0.05). Steaks from cattle fed DRC were statistically or numerically lowest for discoloration and C18:2 (linoleic acid) and highest for redness compared to the other treatments (P < 0.05). Conversely, steaks from cattle fed SFC+DDGS had the most C18:2 and the worst (least desirable) values for discoloration and redness toward the end of retail display (P < 0.05). Steaks from cattle fed DRC had the lowest TBARS values, while steaks from cattle fed SFC+DDGS had the highest TBARS values (P < 0.05). These data suggest that steaks from cattle fed SFC+DDGS oxidize, discolor, and lose redness more quickly under retail display than steaks from cattle fed DRC, likely due to changes in fatty acid content.