Modeling Techniques for Prediction of Safe Cooking Times of Mechanically Tenderized Beef Steaks

Abstract

Microbial safety issues related to mechanically tenderized beef have become prevalent, resulting in new labeling regulations for mechanically tenderized raw or partially cooked beef products. These products must bear labels to include validated cooking instructions, with specifications for minimum internal temperatures, to ensure that they are fully cooked. However, validation of cooking instructions for individual steak cuts of different sizes and weights is costly and time consuming. The objective of this study was to utilize predictive modeling techniques to determine safe cooking times for various mechanically tenderized steaks, cooked to an internal temperature of 70 to 71°C. A total of 162 steaks of various types (top round, knuckle, strip loin, top sirloin, sirloin cap, tri-tip, ribeye, flap, and flank), thicknesses (1.27, 2.54, and 3.81 cm), and weights (113 to 567 g) were used. Prior to cooking, samples were needle-tenderized, cut, vacuum-packaged, and refrigerated. Steak dimensions (width, thickness, and length) were measured prior to each cooking experiment. Samples were cooked on a flat-top-grill until they reached an internal temperature of 70 to 71°C, and the time taken to reach that temperature was defined as the Experimental Safe Cooking Time (ESCT). A thermocouple, attached to a data logger, recorded the steak-center temperature every 10 s. The time-temperature profiles obtained were used to determine the rate of temperature increase (RTI). Data generated through the experiments was used for model development and determination of predicted safe cooking time (PSCT) for steaks. The thickness, weight, and RTI of the steaks were identified as factors that had a 60% or higher correlation with the ESCT. Prediction accuracy of the regression model was 79%, with no significant differences (P < 0.01) between the ESCT and PSCT. This approach could help the meat industry formulate safe cooking times of various steak cuts, without repeating costly validation studies.