Palatability of New Zealand grass-finished and American grain-finished beef strip steaks of varying USDA quality grades and wet-aging treatments

Authors: LUCHERK, LONI - Texas A&M University; O'QUINN, TRAVIS - Kansas State University; LEGAKO, JERRAD - Texas Tech University; Shackelford, Steven; BROOKS, J.C. - Texas Tech University; MILLER, MARK - Texas Tech University

Submitted to: Meat and Muscle Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2021
Publication Date: 10/6/2022
Citation: Lucherk, L.W., O'Quinn, T.G., Legako, J.F., Shackelford, S.D., Brooks, J.C., Miller, M.F. 2022. Palatability of New Zealand grass-finished and American grain-finished beef strip steaks of varying USDA quality grades and wet-aging treatments. Meat and Muscle Biology. 6(1). Article 12601, p. 1-15. http://doi.org/10.22175/mmb.12601.
DOI: https://doi.org/10.22175/mmb.12601

Interpretive Summary: Only 4% of U.S. beef sales are from grass-fed beef, but demand is increasing every year. The availability of grass in the U.S. limits the supply of grass-fed beef, so about 75% is imported from other countries that can grow grass year around such as New Zealand. Because of the lower nutritional value of grass compared to grain in the U.S., grass feeding requires longer feeding times and the beef still never reaches the higher fat levels in the ribeye to qualify for the higher quality grades such as Prime. Thus, most grain versus grass feeding studies have inherent bias in animal age and quality grade levels. In addition, shipping times for imported beef mean longer chilled aging time which improves tenderness but can be detrimental to flavor of grass-fed beef. Thus, this study compared the consumer satisfaction of a wide range in quality grades and aging times of U.S. grain-fed and New Zealand grass-fed beef. Results indicate New Zealand grass feeding programs for cattle result in beef with similar eating quality when compared to beef of the same quality grade from U.S. grain-fed cattle, even at extended chilled beef aging times. Thus, higher quality grades are more important for ensuring high eating satisfaction for beef than whether the cattle were fed grass or grain during finishing.

Technical Abstract: The objective of this study was to evaluate palatability of strip loin steaks from grass- and grain-fed beef across5 United States Department of Agriculture (USDA) quality grades and 3 wet-aging periods. Beef strip loins (N=200; 20/USDA quality grade×fed cattle type) representing 5 USDA quality grades (USDA Prime, Top Choice [Average and High Choice], Low Choice, Select, and Standard) and 2 fed cattle types (New Zealand grass-finished and U.S. grain-finished)were used in the study. Each strip loin was equally portioned into thirds and randomly assigned to one of 3 wet-aging periods (7 d, 21 d, or 42 d). Consumer panelists (N=600; 120/location: Texas, California, Florida, Kansas, and Pennsylvania) evaluated 8 grilled beef steak samples for palatability traits, acceptability, and eating quality. All palatability traits were impacted by the interaction of diet×quality grade (P<0.05). Although similar (P>0.05) to grass-fed Prime steaks for juiciness, tenderness, and overall liking, grain-fed Prime steaks rated higher (P<0.05) than all other grass- and grain-finished treatments for all palatability attributes. Grass-finished Top Choice, Low Choice, and Standard steaks rated higher (P<0.05) than the respective grain-finished quality grades for juiciness and tenderness. Grain-finished Standard steaks rated lower (P<0.05) than all other grass- and grain-finished treatments for juiciness, tenderness, and overall liking but were similar (P>0.05) to grass-finished Standard steaks for flavor liking. Our results indicate that beef strip loin steaks of similar quality grades from grass-finished New Zealand cattle produce similar eating experiences when compared with those from U.S. grain-finished beef, even following extended postmortem aging. This indicates improved palatability for consumers based on marbling without respect to grass- or grain-finishing diets.