Variability in color, cooking times, and internal temperature of beef patties under controlled cooking conditions

Four studies were performed to document the variability in cooking properties of beef patties when considerable control was exerted on several cooking procedures. Two replications of beef patties produced from the same facility, to the same fat content (10%), and with similar raw materials were panfried to internal temperatures of 68, 71 or 74 degrees C. The second replication required longer (P < 0.05) cooking times to reach designated internal temperatures, appeared less well done and had higher Hunter a* color values than the first replication. Beef patties containing either 10 or 20% fat were used to compare two endpoints of cooking (constant internal temperature, constant cooking time) for two temperatures, 68 and 71 degrees C. Considerable variability was found in degree of doneness for both endpoints of cooking and internal temperatures when constant cooking times were used. Eighteen different formulations of beef patties made with various ingredients were used for evaluating the variability of internal temperatures when cooked for constant times that would reach 71 degrees C or slightly higher. Wide variability in internal temperatures was found for all 18 formulations. Some patties (9.0%) did not reach an internal temperature of 68 degrees C and 1.3% did not reach an internal temperature of 60 degrees C. In evaluating postcooking changes in internal temperature of beef patties cooked by convection oven or panfrying, a 40-s period is available to accurately assess endpoint temperature. The substantial variability in cooking properties observed in these studies clearly demonstrates that mechanisms for controlling cooking properties of patties must be determined.