Enhancement technology improves palatability of normal and callipyge lambs.

The objective of this research was to determine if BPI Processing Technology (BPT) improved palatability of normal (NN) and callipyge (CN) lamb meat and to determine the mechanism by which palatability was improved. Ten ewe and 10 wether lambs of each phenotype were slaughtered, and carcass traits were assessed by a trained evaluator. The LM was removed at 2 d postmortem. Alternating sides served as controls (CON) or were treated with BPT. Muscles designated BPT were injected to a target 120% by weight with a patented solution containing water, ammonium hydroxide, carbon monoxide, and salt. Muscle pH, cooking loss, Warner-Bratzler shear force (WBS), sarcomere length, cooked moisture retention, and desmin degradation were measured. A trained sensory panel and a take-home consumer panel evaluated LM chops. Callipyge had a heavier BW and HCW, less adjusted fat thickness, reduced yield grades, and greater conformation scores than NN (P < 0.05). For LM, NN had shorter sarcomeres, smaller WBS values, greater juiciness ratings, more off-flavors, reduced consumer ratings for raw characteristics (like of portion size, like of color, like of leanness, overall like of appearance) and greater consumer ratings for eating characteristics (like of juiciness, like of flavor) than CN (P < 0.05). For LM, BPT had greater cooked moisture retention, smaller WBS values, greater juiciness ratings, less off-flavors, and greater consumer ratings for raw characteristics (like of portion size, like of color, overall like of appearance) and eating characteristics (like of juiciness, like of flavor) than CON (P < 0.05). Significant phenotype × treatment interactions occurred for LM muscle pH, desmin degradation, tenderness, consumer like of texture/tenderness, and consumer overall like of eating quality (P < 0.05). For LM, BPT increased muscle pH more for NN than CN (P < 0.01) and increased desmin degradation for NN but decreased desmin degradation for CN (P < 0.01). The BPT enhancement improved LM tenderness ratings for CN more than NN (P < 0.05). For consumer like of texture/tenderness, BPT improved ratings for CN more than NN (P < 0.01). For consumer overall like of eating quality, BPT improved ratings for CN more than NN (P < 0.05). In summary, BPT had little to no effect on sarcomere length and desmin degradation, but improved palatability of NN and CN lamb by increasing cooked moisture retention, improving consumer acceptability of CN to near-normal levels.

Influence of feeding various quantities of wet and dry distillers grains to finishing steers on carcass characteristics, meat quality, retail-case life of ground beef, and fatty acid profile of longissimus muscle.

Two hundred forty Angus crossbred steers were used to determine the influence of feeding various quantities of wet and dry distillers grains to finishing steers on carcass characteristics, meat quality, retail-case life of ground beef, and fatty acid profile of LM. Three replications of 5 dietary treatments were randomly applied to 15 pens in each of 2 yr. A finishing diet containing dry-rolled corn, soybean meal, and alfalfa hay was fed as the control diet. Wet distillers grains with solubles (DGS) or dry DGS was added to the finishing diets at either 20.0 or 40.0% of the dietary DM to replace all soybean meal and part of the cracked corn in treatment diets. Carcasses of steers fed DGS had greater (P < 0.05) fat thickness (1.47 vs. 1.28 cm), greater (P < 0.05) USDA yield grades (3.23 vs. 2.94), and smaller (P < 0.05) percentage of yield grades 1 and 2 (41.1 vs. 60.4%) than carcasses of steers fed the control diet. Longissimus muscle from steers fed dry DGS had greater (P < 0.05) ultimate pH values (5.52 vs. 5.49) than LM from steers fed wet DGS. Ground beef from steers fed DGS had greater (P < 0.05) concentrations of α-tocopherol (1.77 vs. 1.43 µg/g) than ground beef from steers fed the control diet. Ground beef from steers fed 40% DGS had greater (P < 0.05) thiobarbituric acid-reactive substances (2.84 vs. 2.13 mg/kg) on d 2 of retail display than ground beef from steers fed 20% DGS. Longissimus muscle of steers fed DGS had less (P < 0.05) C17:0 and more (P < 0.05) C18:0, C18:1t, C16:1c9, C18:2c9c12 (where t is trans and c is cis), and total PUFA than LM of steers fed the control diet. Feedlot steers fed DGS may need to be marketed earlier than normal to avoid excess external fat and carcasses with a greater numerical yield grade. These data suggest feeding DGS to finishing steers will have no adverse or beneficial effects on glycolytic variables (dark cutters), retail display life of ground beef, or meat tenderness. However, beef from cattle finished on diets containing DGS will likely have a greater proportion of PUFA and therefore may be more susceptible to oxidative rancidity.

Quality characteristics of chunked and formed hams from pale, average and dark muscles were improved using an ammonium hydroxide curing solution.

Cooking yield, cooked pH, purge loss, moisture, lipid oxidation, external and internal color, break strength and elongation distance were assessed for pale (PALE), average (AVG) and dark (DARK) inside hams injected with either a control cure solution (CON) or BPI-processing technology cure solution (BPT). Following enhancement, muscles were chunked, vacuum tumbled, smoked and cooked to 66 degrees C. Cooked ham pH was 6.49 for DARK, 6.40 for AVG, and 6.30 for PALE, respectively (P<0.0001). Cooked pH was higher (P<.0001) for BPT than CON. Cooked ham moisture content was higher (P<0.0001) for BPT hams than CON hams (74.83 vs. 74.11%) but BPT did not significantly influence cooking yield or lipid oxidation. Consumers (n=150) of diverse demographics rated hams for appearance and taste. Results indicated that BPI-processing technology improved visual appearance of hams made from pale, average, and dark muscles and improved the eating quality of hams made from pale muscles.

Evaluation of corn grain with the genetically modified input trait DAS-59122-7 fed to growing-finishing pigs.

A growth performance experiment was conducted to assess the feeding value of a double-stacked transgenic corn grain for growing-finishing pigs. The genetically modified corn grain contained event DAS-59122-7, which expresses the Cry34/35Ab1 binary insecticidal protein for the control of corn rootworm. This modified transgenic grain is resistant to western corn rootworm and is also tolerant to herbicides containing the active ingredient glufosinate-ammonium. The modified grain (59122), a nontransgenic near-isoline grain (control corn), and a commercial corn (Pioneer brand hybrid 35P12) were grown in a 2005 production trial in individually isolated plots that were located 201 m apart. A total of 108 pigs were allotted to corn-soybean meal diets containing 1 of the 3 grains as the sole source of corn. There were 3 pigs per pen and 12 replicate pens per treatment. Pigs were fed grower diets from 37 to 60 kg, early finisher diets from 60 to 90 kg, and late finisher diets from 90 to 127 kg. Within each phase, data for ADG, ADFI, and G:F were calculated. At the conclusion of the experiment, pigs were slaughtered and data for carcass quality were collected. Differences between 59122 and the control corn were evaluated, with statistical significance at P<0.05. No differences in ADG, ADFI, or G:F between pigs fed the control corn and pigs fed the modified corn were observed during the grower, early finisher, or late finisher phases. For the entire experimental period, no difference between pigs fed the control and the 59122 corn were observed for final BW (128.9 vs. 127.1 kg), ADG (1.02 vs. 1.00 kg), ADFI (2.88 vs. 2.80 kg), or G:F (0.356 vs. 0.345 kg/kg). Likewise, no differences in dressing percentage (76.48 vs. 76.30%), LM area (49.8 vs. 50.4 cm(2)), 10th-rib back fat (2.20 vs. 2.12 cm), and carcass lean content (52.9 vs. 53.4%) were observed between pigs fed the control and the 59122 corn grain. It was concluded that the nutritional value of the modified transgenic corn grain containing event DAS-59122-7 was similar to that of the nontransgenic near-isoline control.

Effects of feeding distillers dried grains with solubles, high-protein distillers dried grains, and corn germ to growing-finishing pigs on pig performance, carcass quality, and the palatability of pork.

An experiment was conducted to investigate pig performance, carcass quality, and palatability of pork from pigs fed distillers dried grains with solubles (DDGS), high-protein distillers dried grains (HPDDG), and corn germ. Eighty-four pigs (initial BW, 22 +/- 1.7 kg) were allotted to 7 dietary treatments with 6 replicates per treatment and 2 pigs per pen. Diets were fed for 114 d in a 3-phase program. The control treatment was based on corn and soybean meal. Two treatments were formulated using 10 or 20% DDGS in each phase. Two additional treatments contained HP-DDG in amounts sufficient to substitute for either 50 or 100% of the soybean meal used in the control treatment. An additional 2 treatments contained 5 or 10% corn germ, which was calculated to provide the same amount of fat as 10 or 20% DDGS. Results showed that for the entire experiment, pig performance was not affected by DDGS or HP-DDG, but final BW increased (linear, P < 0.05) as corn germ was included in the diets. Carcass composition and muscle quality were not affected by DDGS, but LM area and LM depth decreased (linear, P < 0.05) as HP-DDG was added to the diets. Lean meat percentage increased and drip loss decreased as corn germ was included in the diets (quadratic, P < 0.05). There was no effect of DDGS on fat quality except that belly firmness decreased (linear, P < 0.05) as dietary DDGS concentration increased. Including HP-DDG or corn germ in the diets did not affect fat quality, except that the iodine value increased (linear, P < 0.05) in pigs fed HP-DDG diets and decreased (linear, P < 0.05) in pigs fed corn germ diets. Cooking loss, shear force, and bacon distortion score were not affected by the inclusion of DDGS, HP-DDG, or corn germ in the diets, and the overall palatability of the bacon and pork chops was not affected by dietary treatment. In conclusion, feeding 20% DDGS or high levels of HP-DDG to growing-finishing pigs did not negatively affect overall pig performance, carcass composition, muscle quality, or palatability but may decrease fat quality. Feeding up to 10% corn germ did not negatively affect pig performance, carcass composition, carcass quality, or pork palatability but increased final BW of the pigs and reduced the iodine value of belly fat.

Effects of potential antimicrobial ingredients used to control Listeriamonocytogenes on quality of natural casing frankfurters.

Listeriosis concerns have led to increased antimicrobial use; reformulation may affect quality. The objective was to determine the effects of potential antimicrobials on quality of natural casing frankfurters. Eleven treatments were used: no antimicrobials (control); 3.0% sodium lactate and sodium diacetate blend (SL+SD); 1.0%, 2.5%, and 3.5% buffered sodium citrate (SC); 1.0%, 2.5%, and 3.5% buffered sodium citrate and sodium diacetate blend (SC+SD); and 1.0%, 2.5%, and 5.0% whey protein peptides (WP). Trained and consumer panelists analyzed sensory characteristics. Cooking yield was unaffected by treatment (P>0.05). Addition of SC and SC+SD decreased pH (P<0.05). Texture profile analysis was conducted. Hunter color values and growth of aerobic bacteria and lactic acid bacteria were monitored over 15 weeks of storage. No samples reached spoilage. SL+SD 3% caused few changes; WP caused changes perceived as negative; and SC and SC+SD caused changes often perceived as positive.

Growth performance and carcass characteristics of grower-finisher pigs fed high-quality corn distillers dried grain with solubles originating from a modern Midwestern ethanol plant.

A growth performance and carcass evaluation study was conducted to determine the maximal inclusion rate of corn distillers dried grain with solubles (DDGS) in grower-finisher pig diets when formulated on a total AA basis. A total of 240 (28.4 +/- 0.8 kg of BW) crossbred pigs [(Yorkshire x Landrace) x Duroc] were allotted randomly within sex and weight outcome groups to 1 of 24 pens. Pens were assigned randomly within the initial BW groups to 1 of 4 dietary treatment sequences in a 5-phase grower-finisher feeding program in a 4 x 3 factorial arrangement of treatments. The inclusion level of DDGS (0, 10, 20, or 30%) in the diet and the initial BW class [low (23.2 kg), medium (28.1 kg), or high (33.8 kg)] served as the main factors for the grower-finisher performance study. All diets were formulated to contain similar concentrations of total Lys, ME, calcium, and phosphorus within each phase. Pigs were slaughtered and carcass data were collected when the average BW of pigs in a pen reached 114 +/- 2.25 kg. Dietary treatment and initial weight groups did not interact for any response variables, and only the main effects of dietary treatment are presented. Pigs fed the 20 or 30% DDGS diets had reduced ADG (P < 0.05) compared with that of the 0 or 10% DDGS groups, but ADFI was unaffected by dietary treatment. Gain:feed decreased when pigs were fed 30% DDGS (P < 0.05) compared with the 0, 10, and 20% DDGS dietary inclusion levels. Loin depth was lower in pigs fed the 30% DDGS diets (P < 0.05), but backfat depth and percentage of carcass lean did not differ among treatments. Iodine number of carcass fat increased linearly (P < 0.01) with increasing dietary DDGS concentration, and belly firmness adjusted for belly thickness was reduced (P < 0.05) for pigs fed the 30% DDGS diets compared with pigs fed the 0 or 20% DDGS diets. Color measurements, ultimate pH, and visual evaluations (color, firmness, and marbling scores) of the LM did not differ among treatments. Cooking loss, 24-h drip loss, and total moisture loss were not affected by DDGS in the diets. However, differences were detected between 0 and 20% DDGS treatments for 11-d purge loss (P < 0.05). Dietary treatment did not affect Warner-Bratzler shear force of cooked loin chops. Results from this study indicate that when diets for grower-finisher pigs are formulated on a total AA basis, less than 20% DDGS should be included in the diet for optimal performance and carcass composition. Feeding DDGS in swine finishing diets did not have any detrimental effects on pork muscle quality.

The influence of dietary field peas (Pisum sativum L.) on pig performance, carcass quality, and the palatability of pork.

An experiment was conducted to test the hypothesis that field peas may replace soybean meal in diets fed to growing and finishing pigs without negatively influencing pig performance, carcass quality, or pork palatability. Forty-eight pigs (initial average BW 22.7 +/- 1.21 kg) were allotted to 1 of 3 treatments with 2 pigs per pen. There were 8 replications per treatment, 4 with barrows and 4 with gilts. The treatments were control, medium field peas, and maximum field peas. Pigs were fed grower diets for 35 d, early finisher diets for 35 d, and late finisher diets for 45 d. Pigs receiving the control treatment were fed corn-soybean meal diets. All diets fed to pigs receiving the medium field peas treatment contained 36% field peas and varying amounts of corn; soybean meal was also included in the grower and the early finisher diets fed to pigs on this treatment. In contrast, no soybean meal was included in diets fed to pigs on the maximum field peas treatment, and field peas were included at concentrations of 66, 48, and 36% in the grower, early finisher, and late finisher diets, respectively. Pig performance was monitored within each phase and for the entire experimental period. At the conclusion of the experiment, carcass composition, carcass quality, and the palatability of pork chops and pork patties were measured. Results showed that there were no effects of dietary treatments on ADFI, ADG, or G:F. Likewise, there were no differences in carcass composition among the treatment groups, but gilts had larger (P = 0.001) and deeper (P = 0.003) LM, less backfat (P = 0.007), and a greater (P = 0.002) lean meat percentage than barrows. The pH and marbling of the LM, and the 10th rib backfat were not influenced by treatment, but there was a trend (P = 0.10) for more marbling in barrows than in gilts. The subjective color scores (P = 0.003) and the objective color score (P = 0.06) indicated that dietary field peas made the LM darker and more desirable. Pork chops from pigs fed field peas also had less (P = 0.02) moisture loss compared with chops from pigs fed the control diet. Treatment or sex did not influence palatability of pork chops or pork patties. In conclusion, field peas may replace all of the soybean meal in diets fed to growing and finishing pigs without negatively influencing pig performance, carcass composition, carcass quality, or pork palatability.

Intramuscular tenderness variation within four muscles of the beef chuck.

The i.m. tenderness variation was examined within four beef chuck muscles, the infraspinatus (IF), supraspinatus (SS), triceps brachii (TB), and serratus ventralis (SV). The IF, SS, TB, and SV muscles were cut into 2.5 cm thick steaks perpendicular to the long axis of the muscle. An identification tag was placed on each steak, consisting of a muscle identification number, steak number, and orientation of the steak. Steaks were vacuum-packaged and stored at -22 degrees C until subsequent analysis. Steaks were thawed at 1 degrees C and cooked on electric broilers to an internal temperature of 71 degrees C. One core was removed from each 2.5-cm x 2.5-cm section parallel to the muscle fiber and sheared once to determine Warner-Bratzler shear force (WBSF). The SS had an overall WBSF mean of 5.43 kg (SD = 2.20 kg) with no tenderness difference (P = 0.43) among steak locations. The IF had an overall WBSF mean of 3.16 kg (SD = 1.01 kg) with no tenderness difference (P = 0.51) among steak locations. The SV had a mean WBSF value of 4.37 kg (SD = 1.27 kg) with tenderness variation (P < 0.05) among steak locations; however, tenderness variations were not dispersed in a discernible pattern. The TB had a mean WBSF value of 4.12 kg (SD = 1.26 kg) with lower (P < 0.05) shear force in the middle region of the TB, and the distal and proximal ends were tougher (P < 0.05). Results of this study provided a reasonably detailed mapping of the tenderness regions within the IF, SS, TB, and SV muscles, and this information could be used to add value to the beef chuck by cutting and marketing consistently tender regions.

Determining the optimum beef longissimus muscle size for retail consumers.

Research was conducted in two phases to determine the optimum beef LM size for retail consumers. In Phase I, 50 USDA Choice beef carcass sides were selected at a commercial packing plant and assigned to five different categories (10 sides per category) based on LM size: 61 to 68 cm2 (A), 70 to 78 cm2 (B), 80 to 90 cm2 (C), 92 to 103 cm2 (D), and 105 to 119 cm2 (E). Ribeye rolls were retrieved from all carcass sides. Steaks (2.5-cm thick; 14 per ribeye roll) were cut as needed and transported in groups of 35 steaks (seven per LM size category) to a retail grocery store in Brookings, SD, where they were placed into a designated section of the retail meat case. Steaks were tallied every 4 h on weekdays and every 2 h on weekends and holidays to determine the number of monitoring periods that each steak remained in the retail case. Steaks that did not sell within an allotted time were removed from the case and termed "pulled." Time in case and percentage of steaks pulled from the case did not differ among LM size categories (P > 0.16). Quadratic regression indicated that larger LM steaks sold faster (P < 0.05) than average and small LM steaks. Steaks from rib locations 6 and 7 spent more (P < 0.05) time in the case than steaks from rib locations 8 through 12. Steaks from the 7th rib location were more (P < 0.05) likely to be pulled than steaks from the 8th through 12th rib locations. In Phase II, 15 USDA Choice ribeye rolls were selected from a commercial packing plant to represent two LM size categories: 80 to 90 cm2 (AVG; n = 5); and 105 to 119 cm2 (LARGE; n = 10) and cut into 2.5-cm-thick steaks. A portion of the LARGE steaks was subsequently cut in half (HALF). Four display steaks represented each treatment group in each of five random nth price auctions. Seventy-five people were recruited from the Brookings, SD area to participate in the auctions to determine their willingness to pay for the three different types of ribeye steak. Consumers were willing to pay a premium of 1.50 dollars/kg for LARGE ribeye steaks over AVG ribeye steaks (P < 0.05). Consumers discounted HALF ribeye steaks by 1.01 dollars/kg compared with AVG ribeye steaks (P < 0.05). In conclusion, no optimum LM size existed for beef retail consumers; however, a trend existed toward greater demand for larger LM sizes over smaller LM sizes.

Evaluating consumer acceptability and willingness to pay for various beef chuck muscles.

In-home consumer steak evaluations, followed by centralized laboratory-setting auctions, were used to determine consumer (n = 74 consumers) acceptability and willingness to pay for various beef chuck muscles. The infraspinatus (IF), serratus ventralis (SV), supraspinatus (SS), and triceps brachii (TB) from the beef chuck were evaluated against LM steaks from the rib to determine price and trait differentials. Muscles from USDA Choice, boneless, boxed-beef sub-primals were aged 14 d, frozen, and cut into 2.5-cm-thick steaks. Consumers received two steaks from each muscle for in-home evaluations of uncooked steak appearance and cooked steak palatability. After in-home evaluation of steaks, consumers participated in a random nth price auction session to determine willingness to pay for those steaks. Muscles differed (P < 0.05) for overall like of appearance, like of size, like of shape, and like of leanness; LM generally rated the highest. Steaks from the LM rated highest (P < 0.05) for overall like, and steaks from the SS and SV were lowest (P < 0.05) for overall like. Juiciness and beef flavor intensity scores were highest (P < 0.05) for steaks from the LM and IF, whereas SS steaks received the lowest (P < 0.05) juiciness scores, and SS and SV steaks were rated lowest (P < 0.05) for beef flavor intensity. Average auction price differentials differed (P < 0.05) from the LM, and were -0.71 dollars, -0.79 dollars, -1.75 dollars, and -2.44 dollars/0.45 kg for the TB, IF, SS, and SV, respectively. Average appearance trait differentials and average palatability trait differentials were correlated significantly with average price differentials. Results indicate the IF and TB were acceptable to consumers as steaks but only at prices lower than the LM.

Characteristics of lambs fed concentrates or grazed on ryegrass to traditional or heavy slaughter weights. II. Wholesale cuts and tissue accretion.

Targhee x Hampshire lambs (average BW 24 +/- 1 kg) were used to determine the effect of finishing on concentrate or by grazing ryegrass forage on slaughter weights of 52 kg (N) or 77 kg (H) on tissue accretion and lamb wholesale cutout. When fed to similar slaughter weights, the wholesale cuts of concentrate-fed lambs were heavier (P < 0.05) than the same cuts from forage-fed lambs; however, when expressed as a percentage of side weight, carcasses of forage-fed lambs had a higher (P < 0.001) percentage of leg than concentrate-fed lambs. Increasing slaughter weight from 52 to 77 kg resulted in a 1-kg increase in loin weight for lambs finished on concentrate and a 0.60-kg increase for lambs finished on forage (diet x slaughter weight, P < 0.03); however, the increased loin weight for lambs finished on concentrate was due largely to increased fat deposition. For lambs slaughtered at 77 kg, those finished on forage had more lean mass in the leg, loin, rack, and shoulder than those finished on concentrate, but lean mass in these cuts did not differ between diets for lambs slaughtered at 52 kg (diet x slaughter weight, P < 0.01). At the normal slaughter weight (52 kg), concentrate-fed lambs had 50% more dissectible fat than forage-fed lambs, whereas at the heavy slaughter weight, a 79% greater amount of dissectible fat was observed for concentrate- vs. forage-fed lambs (diet x slaughter weight, P < 0.001). Lean and fat accretion rates were higher (P < 0.001) for concentrate-fed lambs than for forage-fed lambs. The lean-to-fat ratio of forage-fed lambs was higher (P < 0.001) than that of concentrate-fed lambs; however, forage finishing decreased accretion rates of all tissues compared with concentrate feeding, and these differences between forage and concentrate feeding were magnified at heavier slaughter weights.

Comparison of characteristics of lambs fed concentrate or grazed on ryegrass to traditional or heavy slaughter weights. I. Production, carcass, and organoleptic characteristics.

The objectives of this study were to determine the effects of finishing lambs on concentrate (C) or by grazing ryegrass forage (F) to slaughter end weights of 52 (N) or 77 kg (H) on carcass characteristics and organoleptic properties. This experiment included 64 Targhee x Hampshire lambs (average BW = 24 +/- 1 kg) in a 2 x 2 x 2 factorial arrangement of treatments to compare wethers vs. ewes, C vs. F, and N vs. H slaughter weights. No interactions (P > 0.10) were observed between gender and other main effects. Hot carcass weight and dressing percent were greater (P < 0.001) for C- than for F-fed lambs. Backfat thickness also was greater (P < 0.001) for lambs fed C than for those fed F. Moreover, USDA lean quality score and USDA yield grades were higher (P < 0.001) for C- than for F-fed lambs, as well as for lambs slaughtered at H vs. N market weights. There was a higher (P < 0.005) incidence of off odors and off flavors in cooked muscle from F- vs. C-fed lambs, and also from H vs. N slaughter-weight lambs. The heavy C-fed lambs had juicier (P < 0.001) meat than other treatment combinations. Cooked meat from C-fed lambs received higher (P < 0.001) overall acceptability scores. Concentrate-finished lambs produced fatter carcasses and more palatable meat than forage-finished lambs; however, forage finishing allowed for slaughter at heavier weights without excessive fat deposition.

Evaluating consumer acceptability of various muscles from the beef chuck and rib.

One hundred thirty-eight consumers evaluated steaks from the complexus (CX), infraspinatus (IF), serratus ventralis (SV), supraspinatus (SS), and triceps brachii (TB) from the wholesale beef chuck; the deep pectoral (DP) from the wholesale brisket; and the longissimus thoracis (LT) from the wholesale rib. The LT was used as a reference for comparison to the other muscles. Ten USDA Choice and ten USDA Select boneless boxed beef subprimals were used for each muscle. Subprimals were aged 14 d from box date, frozen, and cut into 2.5-cm-thick steaks. Consumers rated the IF highest (P < 0.05) for overall like, tenderness, juiciness, and flavor, and assigned it the highest (P < 0.05) price/0.45 kg. The TB also was rated higher (P < 0.05) than the LT for overall like, tenderness, juiciness, flavor, and price/0.45 kg. The SV and CX were rated as being similar (P < 0.05) to the LT for overall like, tenderness, juiciness, flavor, and price/0.45 kg. Consumers rated the SS lower (P < 0.05) than the LT for tenderness, juiciness, flavor, and price. The DP was rated as the toughest, driest, and blandest (P < 0.05), resulting in assignment of the lowest (P < 0.05) price/0.45 kg. Differences in palatability ratings due to quality grade were found for several muscles; USDA Choice SV and SS were rated higher (P < 0.05) for overall like, tenderness, and juiciness than USDA Select SV and SS. For the IF, USDA Choice was rated higher (P < 0.05) for tenderness and juiciness than USDA Select. The USDA Choice TB was rated higher (P < 0.05) for juiciness, and the USDA Choice DP was rated higher (P < 0.05) for overall like, than their USDA Select counterparts. Tenderness, juiciness, and flavor ratings were correlated with overall like ratings (r = 0.84, 0.77, and 0.76, respectively) and with price (r = 0.73, 0.70, and 0.68, respectively). These results indicate the IF, TB, SV, and CX were acceptable, whereas and the SS and DP were unacceptable as steaks.

Factors associated with surface iridescence in fresh beef.

The objective of this study was to investigate factors associated with surface iridescence in fresh beef. Eight muscles were evaluated for occurrence of surface iridescence: Biceps femoris (BF), Gluteus medius (GM), Longissimus lumborum (LD), Psoas major (PM), Rectus femoris (RF), Semimembranosus (SM), Semitendinosus (ST), and Tensor fasciae latae (TF). Incidence of surface iridescence was 91% for ST, 34% for SM, 27% for LD, 20% for GM, 12% for RF, 9% for BF, 8% for TF, and 6% for PM (P<0.05). Factors associated with surface iridescence in the ST were further examined because iridescence was observed to a much higher degree in the ST as compared with other muscles evaluated. Greater ST surface iridescence was associated with larger ribeye areas, more youthful lean maturity scores, higher L(∗), a(∗) and b(∗) colorimeter values, lower ultimate pH values, and faster cooking (P<0.05).

Mapping intramuscular tenderness variation in four major muscles of the beef round.

The objective of this study was to quantify intramuscular tenderness variation within four muscles from the beef round: biceps femoris (BF), semitendinosus (ST), semimembranosus (SM), and adductor (AD). At 48 h postmortem, the BF, ST, SM, and AD were dissected from either the left or right side of ten carcasses, vacuum packaged, and aged for an additional 8 d. Each muscle was then frozen and cut into 2.54-cm-thick steaks perpendicular to the long axis of the muscle. Steaks were broiled on electric broilers to an internal temperature of 71 degrees C. Location-specific cores were obtained from each cooked steak, and Warner-Bratzler shear force was evaluated. Definable intramuscular shear force variation (SD = 0.56 kg) was almost twice as large as between-animal shear force variation (SD = 0.29 kg) and 2.8 times as large as between-muscle variation (SD = 0.20 kg). The ranking of muscles from greatest to least definable intramuscular shear force variation was BF, SM, ST, and AD (SD = 1.09, 0.72, 0.29, and 0.15 kg, respectively). The BF had its lowest shear force values at the origin (sirloin end), intermediate shear force values at the insertion, and its highest shear force values in a middle region 7 to 10 cm posterior to the sirloin-round break point (P < 0.05). The BF had lower shear force values toward the ST side than toward the vastus lateralis side (P < 0.05). The ST had its lowest shear force values in a 10-cm region in the middle, and its highest shear force values toward each end (P < 0.05). The SM had its lowest shear force values in the first 10-cm from the ischial end (origin), and its highest shear force values in a 13-cm region at the insertion end (P < 0.05). Generally, shear force was lower toward the superficial (medial) side than toward the deep side of the SM (P < 0.05). There were no intramuscular differences in shear force values within the AD (P > 0.05). These data indicate that definable intramuscular tenderness variation is substantial and could be used to develop alternative fabrication and(or) merchandising methods for beef round muscles.

Technical note: the effect of freezing on Warner-Bratzler shear force values of beef longissimus steaks across several postmortem aging periods.

The objective of this study was to compare fresh and frozen protocol procedures for Warner-Bratzler shear force (WBSF) determination on steaks aged for different periods of time. The fresh protocol consisted of measuring WBSF on steaks cooked on the exact day the aging period ended. The frozen protocol consisted of measuring WBSF on steaks that were aged, frozen (-16 degrees C) for approximately 2 mo, thawed for 24 h, and then cooked. Twenty-two strip loin steaks from each of 20 crossbred heifers and steers were individually vacuum-packaged and assigned to either the fresh or frozen protocol and one of 11 aging periods (1, 2, 3, 4, 5, 6, 7, 10, 14, 21, or 35 d). The frozen protocol resulted in lower (P < 0.05) WBSF values than the fresh protocol for beef longissimus steaks that were aged for 1, 2, 3, 4, 6, 7, 10, 14, or 35 d postmortem. An interaction (P < 0.05) between protocol and postmortem aging resulted from larger differences between protocols at shorter aging periods than at longer aging periods. Correlations and mean differences revealed that frozen protocol WBSF values were not highly indicative of fresh protocol WBSF values at the same period of postmortem aging, but rather suggested that frozen protocol WBSF values at shorter aging times were useful in estimating WBSF values from fresh protocols at longer aging times. Cooking loss was higher (P < 0.05) for frozen vs fresh protocol steaks at all aging periods except for 14, 21, or 35 d. These findings suggest that if research constraints warrant the freezing of samples, shorter aging periods before freezing (6 and 7 d) should be used to estimate WBSF of fresh aged beef (14 to 21 d). In trials in which several postmortem aging periods or very short aging periods are of interest, we recommend that WBSF be assessed using the fresh protocol.

Relationships among glycolytic potential, dark cutting (dark, firm, and dry) beef, and cooked beef palatability.

One hundred beef carcasses were selected at three packing plants and were used to determine the relationship between glycolytic potential (GP) and dark, firm, and dry (DFD) beef and to determine the effects of DFD status and GP on cooked beef palatability. Eight individual muscles were excised from one hindquarter of each carcass at d 7 postmortem: longissimus lumborum, psoas major, gluteus medius, tensor fasciae latae, rectus femoris, semimembranosus, biceps femoris, and semitendinosus. Ultimate pH, colorimeter readings, and Warner-Bratzler shear force were determined for all eight muscles at d 7 postmortem. A nine-member trained sensory panel evaluated cooked longissimus lumborum, gluteus medius, and semimembranosus steaks. Traits determined solely for the longissimus lumborum were GP (2 x [glycogen + glucose + glucose-6-phosphate] + lactate) and ether-extractable fat. A curvilinear relationship existed between GP and ultimate pH within the longissimus muscle. There appeared to be a GP threshold at approximately 100 micromol/g, below which lower GP was associated with higher ultimate pH and above which GP had no effect on ultimate pH. The greatest pH and muscle color differences between normal and DFD carcasses were observed in the longissimus lumborum, gluteus medius, semimembranosus, and semitendinosus muscles. Cooked longissimus from DFD carcasses had higher shear force values (46% greater) and more shear force variation (2.3 times greater variation) than those from normal carcasses. Dark cutting carcasses also had higher shear force values for gluteus medius (33% greater) and semimembranosus (36% greater) than normal carcasses. Sensory panel tenderness of longissimus, gluteus medius, and semimembranosus was lower for DFD carcasses than for normal carcasses. Longissimus and gluteus medius flavor desirability scores were lower for DFD than for normal carcasses. Steaks from DFD carcasses had more off-flavor comments than steaks from normal carcasses, specifically more "peanutty," "sour," and "bitter" flavors. The DFD effect of higher shear force values was approximately five times greater (+3.11 kg vs +0.63 kg) for carcasses with "slight" marbling scores than for carcasses with "small" marbling scores. In general, higher GP was associated with increased tenderness, even among normal carcasses. In conclusion, low GP was associated with DFD beef and resulted in substantially less-palatable cooked steaks.

Effect of an accelerated finishing program on performance, carcass characteristics, and circulating insulin-like growth factor I concentration of early-weaned bulls and steers.

Sixty-three Angus x Simmental calves were allotted to a bull or a steer group based on sire, birth date, and birth weight to determine effects of castration status on performance, carcass characteristics, and circulating insulin-like growth factor I (IGF-I) concentrations in early-weaned cattle. At 75 d of age, calves in the steer group were castrated. Calves were not creep-fed prior to weaning. All calves were weaned and weighed at an average age of 115 d and transported by truck to the OARDC feedlot in Wooster, OH. Performance and carcass characteristics were measured in three phases. Phase 1 was from 115 to 200 d of age, phase 2 was from 201 to 277 d of age, and phase 3 was from 278 d of age to slaughter. Before implantation, four bulls and four steers were selected for serial slaughter and carcass evaluation. Steers were implanted with Synovex-C at 130 d of age and with Revalor-S at 200 and 277 d of age. Serum samples were collected from all calves on the day of implantation, 28 and 42 d after implantation, and at slaughter and analyzed for circulating IGF-I concentration. Bulls gained 9.7% faster (1.75 vs 1.60 kg/d; P < 0.01), consumed 25 kg more DM (521 vs 496 kg; P = 0.11), and were 3.3% more efficient (282 vs 273 g/kg, P < 0.10) than steers in phase 1. However, steers gained 10.5% faster (1.62 vs 1.46 kg/d; P < 0.02), consumed similar amounts of DM, and were 6.5% more efficient than bulls (214 vs 201 g/kg; P < 0.06) in phase 2. Overall gains and efficiency were similar between bulls and steers; however, bulls consumed 140 kg more DM (P < 0.05), were 27 kg heavier (P < 0.05), and had to stay in the feedlot 18 more days (P < 0.05) than steers to achieve a similar amount of fat thickness. Implanted steers had greater concentrations of circulating IGF-I than bulls (P < 0.01), and the pattern of IGF-I concentration over time was affected by castration status (castration status x time interaction; P < 0.01). Synovex-C had a lower impact on circulating IGF-I concentration (implant effect, P < 0.01) than either Revalor-S implant. Eighty-five percent of both bulls and steers had marbling scores sufficient to grade low Choice or better. Bulls achieved their target fat thickness later, increased muscle growth, and deposited fat more favorably than steers, possibly due to a gradual increase in IGF-I concentration as the testicles grew rather than the large fluctuations in IGF-I concentration observed in steers following implantation.

Evaluating the point of separation, during carcass fabrication, between the beef wholesale rib and the beef wholesale chuck.

This study determined whether there is a logical point of value change, related to either tenderness or consumer acceptance, at which to separate the beef carcass within the rib/chuck region. Rib/chuck rolls (RCR); (n = 30) consisting of the ribeye roll and chuck eye roll subprimals (2nd through 12th rib locations) were cut into 22 steaks each (two steaks per rib location), and Warner-Bratzler shear force and consumer purchase preference were evaluated for steaks at each rib location. Steaks from different locations of the RCR were composed of differing proportions of several muscles: longissimus muscle (LM), spinalis dorsi and multifidus dorsi (SM), and complexus (CO). The LM (4th to 12th rib) contained three tenderness regions: 7th through 12th rib, 5th and 6th ribs, and 4th rib regions (lowest, intermediate, and highest shear force values, respectively; P < 0.01). Shear force differed (P < 0.05) among rib locations for the SM (2nd to 9th rib), but no logical pattern was evident. The CO (2nd to 7th rib) was more tender toward the anterior end (P < 0.05). The region of the RCR represented by the 4th through 6th rib locations had steaks with higher weighted-average shear force (average shear force of each steak, weighted for surface area of each muscle) values than the remainder of the RCR (P < 0.05). Animal-to-animal variation in shear force was 36% greater than rib-to-rib variation in shear force; thus, statistically significant differences in tenderness among rib locations may be undetectable by consumers. Steaks (n = 330) were offered for sale at a retail supermarket and case time was monitored on each steak to determine consumer purchase preference. Steaks from the 2nd through 4th rib locations required more time to sell (P < 0.01) than steaks from the 5th through 12th rib locations. Two alternative locations for the rib/chuck separation point could be between the 6th and 7th ribs, yielding a ribeye subprimal useful in marketing a "premium quality" product, or between the 4th and 5th ribs, which would yield four more 2.5-cm ribeye steaks per carcass.