Ground meat samples were formulated which contained: (a) beef from grass-fed steers, (b) beef from grain-fed steers, (c) fat beef trim from grain-fed steers and beef from grass-fed steers, (d) fat pork trim and beef from grass-fed steers. The samples were packaged and stored in retail over-wrap, freezer wrap or a vacuum-type film. Mixing of fat from different sources generally caused no increase in numbers of microorganisms in newly formed products compared to beef from grass-fed steers. In one instance, however, the psychrotrophic count (as measured on CVT agar) of mixtures of grain-fed beef trim or pork trim and grass-fed beef was increased compared to that of grass-fed beef alone. Lipid deterioration, as measured by the 2-thiobarbituric acid test (TBA), was significantly higher for the pork trim/grass-fed beef mixture than for beef from grass-fed steers. Based upon mean scores, a consumer panel ranked the meat patties in the following order (most preferred to least preferred): all grain, grass-fed lean and grain-fed beef trim, all grass, grass-fed lean and pork trim. Results from the present investigation showed that addition of fat beef trim from grain-fed steers to beef from grass-fed steers potentially improved its palatability and may be an acceptable alternative for increasing the utilization of beef from grass-fed animals.