Spoilage characteristics of ground beef with added lactic acid bacteria and rosemary oleoresin packaged in a modified-atmosphere package and displayed at abusive temperatures

Lactic acid bacteria (LAB) can reduce Escherichia coli O157:H7 and Salmonella spp. in ground beef during storage. Furthermore, the addition of rosemary oleoresin (RO), a natural antioxidant, to ground beef has been shown to increase shelf life and is commonly used in modified-atmosphere packaged (MAP) ground beef. This study evaluated the effects of LAB and RO treatment on the shelf life and stability of MAP ground beef displayed at abusive (10°C) temperatures for 36 h. Subjective and objective sensory analyses were conducted to determine spoilage endpoints. Trained and consumer panel responses and Hunter lightness (L*), redness (a*), and yellowness (b*) values were not affected (P = 0.62, 0.66, 0.45) by LAB addition, although RO inclusion improved (P < 0.05) lean color. Ground beef with LAB and RO had significantly less (P < 0.0001) thiobarbituric acid reactive substance values than control ground beef, indicating decreased lipid oxidation. Additionally, RO inclusion reduced (P < 0.0001) off odors, as determined by trained and consumer odor panelists. Overall, the addition of LAB did not negatively affect beef color, odor, or oxidative rancidity, suggesting that LAB can be added to ground beef in MAP packaging as a processing intervention without detrimentally affecting shelf life or stability.