Irradiated beef (whole ‐muscle and ground product with identical fat, protein, and moisture composition) was exposed to a Salmonella‐ inoculated marinade and heated in brass tubes in a water bath at 55 °C, 60 °C, and 62.5 °C. The bacterial load and thermal lag time were similar (α= 0.05) for both whole and ground muscle; therefore, all samples had equivalent composition, inoculation levels, and thermal histories. Assuming 1st‐order kinetics, the inactivation rate constants (k values) in whole muscle were 50% lower than those in ground product at each temperature (P = 0.0001), and Arrhenius‐type models described the temperature dependency of k (R² > 0.95). Because thermal processing regulations are generally based on ground product studies, thermal process validations for meat and poultry products may need to consider the physical state (whole ‐muscle versus ground) of the product being manufactured.