The effect of the physical structure of turkey meat (ground and whole muscle) on the thermal resistance of Salmonella was evaluated. Irradiated whole and ground turkey breasts were exposed to a marinade containing eight serovars of Salmonella at approximately 10(8) CFU/ml for 20 min. Inoculated samples then were subjected to isothermal heating at 55, 60, or 62.5 degrees C, for varying times. Salmonella counts before and after the thermal lag time (time to reach the target temperature) were not significantly different (alpha = 0.05). The first-order inactivation rate constants in whole muscle were approximately 50% lower than those in ground muscle of the same composition, at each temperature, indicating that the Salmonella inactivation rate was greater (P < 0.05) in ground samples than in whole-muscle samples. These results suggest that internalization of Salmonella in whole-muscle product leads to enhanced thermal resistance.