The purpose of this study was to evaluate the effect of porcine somatotropin (pST) treatment on the lipid content and fatty acid profile of cooked pork roasts and to determine if differences were exacerbated by extended frozen storage. Pigs were injected with 3 mg porcine somatotropin (pST) or a placebo daily. At slaughter, roasts were cut from the second to tenth ribs, frozen (−20°C) for 2.5 weeks or 4 months, then cooked and evaluated. Roasts from pST-treated pigs had a lower content of lipids than did the placebo-treated pigs, with the saturated fatty acids decreasing about 40%. They also demonstrated greater Warner-Bratzler shear values. Cholesterol content of the roasts stored frozen for 4 months decreased slightly. Four-month storage slightly decreased cooking time, cooking losses, and expressible moisture index and increased moisture, typical flavor, and juiciness of the roasts. These data suggest that pST treatment altered fat favorably when viewed in light of current dietary recommendations but had less effect on meat quality than did extended frozen storage.Copyright 1993, 1999 Academic Press