Shear gradient in longissimus steaks.

Boneless top loin subprimals (n = 320) from Slight and Small marbled carcasses were fabricated into 2.54-cm thick steaks to determine core location effects on tenderness. In Exp. 1, top loins were aged to 7 d before steaks were cut and cooked to an internal temperature of 71 degrees C. After cooking, a maximum of 15 1.27-cm diameter cores were removed and sheared with a Warner-Bratzler shear force (WBSF) device. There was not a marbling score x core location interaction (P = 0.36). However, there was a main effect of core location (P < 0.01). Cores from the medial, middle, and lateral portion of the longissimus muscle (LM) aged for 7 d differed, with less resistance (P < 0.05) in the medial than the lateral end. Also, there was an effect of marbling score on WBSF, with Small-marbled steaks having lower (P < 0.02) WBSF values than Slight-marbled steaks. In a second experiment, steaks were removed from the middle of the top loin subprimals and aged an additional 7 d to produce 14-d aged steaks. Shear values decreased (P < 0.05) from Exp. 1 to 2 for all core locations. Neither the main effect of marbling score nor the core location x marbling score interaction was significant (P > 0.40); however, the same lateral to medial gradient in WBSF values was discovered again in Exp. 2. Both experiments indicated there were regions of WBSF values that differed (P < 0.05) across the cross section of the LM producing a shear-force/tenderness gradient, with the most medial cores having the lowest WBSF values in both experiments independent of marbling score. Regression analyses indicated the middle and center portions of LM steaks tended to have the most predictive capacity of average WBSF. Because of the variability in tenderness caused by location within the LM, care should be exercised when selecting sampling areas for the measurements of tenderness using the WBSF measure.

Accuracy of application of USDA beef quality and yield grades using the traditional system and the proposed seven-grade yield grade system.

Beef carcasses (n = 5,542) were evaluated by three USDA on-line graders and compared with the computed expert USDA quality (QG) and yield grades (YG) during 8-h shifts at a major beef-processing facility for a 2-wk period to evaluate the accuracy of applying USDA QG and YG within the traditional five-grade and the proposed seven-grade (segregating YG 2 and 3 into YG 2A, 2B, 3A, and 3B) YG systems. Quality grade distribution of the carcasses was 1.1% Prime, 50.0% Choice, 43.8% Select, and 5.1% No-Roll. Accuracy of applying QG was not affected (P>.05) by changing from the five-grade (91.5%) to either the seven-grade system, when determining only QG (94.3%), or the seven-grade system, when determining QG and YG (95.0%). Calculated expert YG successfully segregated carcasses into their respective YG, but on-line graders could not differentiate between YG 4 and 5 in the seven-grade systems. The application of YG in the five-grade system was more accurate (P<.05) than either of the seven-grade systems. A trend existed for on-line graders to undergrade carcasses as the numerical YG increased. Total accuracy of applying YG decreased by 19.4 to 21.8% when switching from the five-grade to the seven-grade system. The segmentation of USDA YG 2 and 3 into YG 2A, 2B, 3A, and 3B resulted in a decrease in the ability of on-line graders to accurately apply the YG.

Slaughter plant location, USDA quality grade, external fat thickness, and aging time effects on sensory characteristics of beef loin strip steak.

A boneless beef strip loin (IMPS #180) was fabricated from each of 320 carcasses to study the effects of slaughter plant location, quality grade, fat thickness, and aging time on beef tenderness and palatability. Carcasses were selected for fat thickness (< .5 cm or > or = .5 cm fat thickness) and USDA quality grade (Select or Low Choice) from two slaughter facilities (IBP, Inc., Garden City, KS or Excel Inc., Plainview, TX), and the strips were aged for either 7 or 14 d. Aging steaks 14 d improved all sensory traits and Warner-Bratzler shear (WBS) values regardless of all other main effects (P < .05). Steaks from Choice carcasses that were processed in Kansas had higher initial and sustained tenderness ratings than steaks from carcasses that were processed in Texas or Select steaks from Kansas after 7 d of aging (P < .05). However, aging for 14 d removed differences from all sensory characteristics of steaks from Kansas and Texas. All sensory scores for steaks from carcasses that graded Choice were higher than those from carcasses that graded Select (P < .05). The USDA quality grade did not affect WBS values, and fat thickness did not affect sensory characteristics or WBS values (P > .05). Therefore, aging beef strip loin steaks for 14 compared with 7 d improved sensory score and decreased WBS values, but fat thickness had no effect on the palatability of loin strip steaks processed under these conditions.

Restaurant consumer acceptance of beef loin strip steaks tenderized with calcium chloride.

Beef strip loins from either the right or left side of 22 carcasses of Bos indicus-type steers were injected with 200 mM calcium chloride (CaCl2) solution at 5% (wt/wt) to determine its effect on tenderness and other selected quality traits of steaks. Loins from opposite sides of the carcasses were untreated and served as the control. The steaks were evaluated for tenderness, juiciness, flavor intensity, tenderness acceptability, and overall acceptability by 62 restaurant consumers over a 6-wk period. The CaCl2 injection improved (P < .05) tenderness and flavor intensity ratings by the restaurant consumers. Tenderness acceptability and overall acceptability were improved 23 and 17%, respectively, by the CaCl2 injection. Flavor was not compromised by the CaCl2 injection. The CaCl2-treated steaks were rated superior(P < .05) for flavor compared to the control steaks. Restaurant consumers preferred the beef loin strip steaks injected with 200 mM CaCl2 at 5% (wt/wt). The results of this study are interpreted to indicate that, from a restaurant consumer perspective, CaCl2 injection is an acceptable means of making beef a more consistently tender product.

Postmortem injection of calcium chloride effects on beef quality traits.

Twenty-two Bos indicus type steers were commercially slaughtered, and their carcasses were chilled and processed to determine the effects of injecting calcium chloride (CaCl2) on beef steak palatability and quality traits. Top loin and inside round subprimals were removed from each carcass using industry fabrication procedures. No injection (control) or injection of 200 mM CaCl2 at 5% (wt/wt) was applied at 30 h postmortem to subprimals from alternating right and left sides. After vacuum storage for 7 d postmortem at 2 degrees C, 2.54-cm thick steaks were cut from each subprimal. Eighty-six percent of the control longissimus lumborum (LL) steaks and 78% of the semimembranosus (SM) control steaks had Warner-Bratzler (WBS) values > 4.5 kg, and the injection of CaCl2 reduced this percentage to 43 and 24%, respectively. The injection of CaCl2 improved (P < .05) trained sensory tenderness ratings for both LL and SM, while not affecting (P > .05) flavor intensity or causing any off-flavor problems (P > .05), compared with the controls. Lean color scores for the LL were not affected (P > .05) by the injection of CaCl2, but SM lean color was lighter red (P < .05) than controls. Therefore, a 5% (wt/wt) injection of 200 mM CaCl2 solution can be applied under commercial conditions to improve beef steak tenderness and reduce tenderness variation without detrimental effects on other palatability or quality traits.

Effects of postmortem injection time, injection level, and concentration of calcium chloride on beef quality traits.

Two experiments were conducted to determine the optimum protocol for maximizing meat quality with CaCl2 injection. Experiment 1 compared the effects of 30 min or 24 h postmortem injection of 175 mM CaCl2 or water at 10% (wt/wt) to controls on various measures of meat quality. An injection of CaCl2 reduced (P < .05) shear force values in all three beef muscles evaluated (longissimus, semimembranosus, and triceps brachii). Retail lean color was not affected (P > .05) by a CaCl2 injection at 24 h postmortem, but was slightly darker (P < .05) for an injection at 30 min postmortem. Psychrophilic and total aerobic microbial counts were higher (P < .05) in 30-min than in 24-h treatments and were higher (P < .05) in CaCl2- or water-injected semimembranosus muscle than in the control, but the treatment differences were minimal in 24-h injected meat. Experiment 2 compared the effects of 24-h postmortem injection of 200 mM or 250 mM CaCl2 at either 5 or 10% (wt/wt) to controls on meat quality traits. Both 200 and 250 mM CaCl2 reduced (P < .05) shear force values compared with the control. In addition, variation in shear force was decreased (P < .05) with CaCl2 injection. Beef flavor intensity was slightly lower (P < .05) and off-flavor ratings were slightly higher (P < .05) in CaCl2-injected meat, but the small differences were of no practical significance. Retail lean color was not affected (P > .05) by injection of the CaCl2 at 24 h. Injecting 200 mM CaCl2 at 5% (wt/wt) into 24 h postmortem meat can produce consistently tender meat without compromising other palatability or lean quality traits.