End-point temperature and tenderness variability in pork and beef cooked to varying degrees of doneness using sous-vide style immersion heaters and grills

Abstract

The objective was to determine endpoint temperature and Warner-Bratzler shear force (WBSF) variability (range, coefficient of variation) differences in both pork and beef cooked using grilling and sous vide. Four 2.54-cm steaks were cut from 10 beef eye-of-round (<i>semitendinosus</i>) Choice-grade muscles (<i>n</i> = 40) and aged for 21 d. Four 2.54-cm chops were cut from 51 pork loins (<i>n</i> = 204) sourced from standard commercial pigs and aged for 7 d. Steaks and chops were randomly allotted within whole muscle to 4 treatments: grilled to 63°C, sous vide to 63°C, grilled to 71°C, and sous vide to 71°C. Four cores measuring 1.25 cm in diameter were excised parallel to the muscle fibers of each chop and steak respectively, and analyzed for WBSF. Temperature accuracy was defined as how close thermometer readings were to the targeted cooked temperature. Temperature precision was defined as how similar 2 thermometer readings within a single cut were to each other. WBSF accuracy was defined as how close individual core values were to the cut average. WBSF precision was defined as how similar individual core values were to each other. In both pork and beef, sous vide was more accurate (<i>P</i> &lt; 0.01) and precise (<i>P</i> &lt; 0.01) in achieving target endpoint temperature at both 63°C and 71°C. At 63°C, chops cooked using sous vide were more tender than grilled (<i>P</i> &lt; 0.01), but at 71°C, chops cooked using sous vide were less tender than grilled (<i>P</i> &lt; 0.01). Steaks cooked to 71°C using sous vide had the lowest core coefficient of variation, whereas other treatments were not different. Cooking method had no effect on average WBSF within target endpoint temperature. Overall, these data indicate that sous vide is more precise and accurate in reaching target temperature but may decrease tenderness when used at 71°C in pork.