Spoilage characteristics of ground beef with added lactic acid bacteria at abusive and refrigerated temperatures packaged in modified atmosphere and traditional packaging
Lactic acid bacteria (LAB) can reduce Escherichia coli O157:H7 and Salmonella spp. in ground beef during storage. Two packaging studies evaluated if LAB masked changes typically associated with the spoilage of ground beef displayed under refrigerated (0°C) or abusive (10°C) temperatures. Packaging consisted of traditional (foam trays wrapped with permeable film) and MAP packaging (80% O2 and 20% CO2). To mimic industry practice, one-half of MAP samples contained 1000 ppm added rosemary oleoresin. Microbial and sensory analyses were conducted to determine spoilage endpoints. At 0°C, traditionally packaged LAB samples had significantly lower yeast and mold (YM) counts than controls throughout display. Among traditional packages, there were no significant differences in coliform, Brochothrix thermosphacta, and Pseudomonas spp. counts between LAB treatments. At abusive display temperatures, there were no significant differences in coliform, YM, B. thermosphacta, and Pseudomonas spp. counts between traditionally packaged LAB treatments. At 0°C and 10°C, total plate counts and LAB populations in both traditional and MAP packaged LAB inoculated samples were significantly higher than the control. In MAP packaging, no significant differences existed between LAB treatments for YM, coliform, B. thermosphacta, and Pseudomonas spp. No significant differences in trained or consumer sensory color and odor scores existed between LAB and controls for traditional and MAP packaging indicating spoilage was not masked. Therefore, LAB can be added to ground beef as an antimicrobial agent in traditional and MAP packaing. In addition, LAB may slow lipid oxidation in traditionally packaged ground beef.