Sensory and microbiological characteristics of grass-fed beef formulated with fat beef or pork trim

Microbiological and sensory quality of grass-fed ground beef formulated with fat beef or pork trim was assessed. Samples were packaged in retail over-wrap, freezer wrap and a vacuum type film and stored under different conditions. Nine tests were conducted to detect potential spoilage and pathogenic microorganisms in the raw meat. Similar initial and final microbial plate counts were found for retail over-wrap samples analyzed during storage (4°C) on days 0, 2, 4, 6 and 8, and freezer wrap samples evaluated after 4 weeks in the frozen state (-29°C) and thawed (4°C) for 0, 1, 3, 5 and 7 days. However, the all grass-fed beef formulation in the retail over-wrap packaging had reduced psychrotrophic growth compared to the meat formulations containing grass-fed beef and fat grain-fed beef trim, grass-fed beef and fat pork trim, and all grain-fed beef. This did not occur with other packaging methods. Lipid deterioration was measured by the 2-thiobarbituric acid test (TBA). Difference in degree of oxidation of the various meat types during storage could be attributed to variation in the fatty acid composition from different muscle and fat sources. TBA values for the beef-pork mixes were significantly higher than the 3 other meat types, but were comparable or lower than the figures reported by previous investigators. Sensory evaluation of the meat patties indicated average scores in the acceptable range with beef-pork mixes possessing the lowest sensory attributes. Results from the present study show that the addition of fat beef to grass-fed beef potentially Improves its palatability. Microbiological data suggest that grass-fed beef mixes may be used safely as ground meat products.