National Beef Market Basket Survey - 2006: External fat thickness measurements and separable component determinations for beef from US retail establishments.

A market basket survey for beef retail cut composition at the retail level (four stores each from two chains in each city) was conducted in 11 US cities from January to March 2006. Beef cuts (n=17,495) were measured for external fat thickness with cuts from the chuck (0.05cm), round (0.05cm), and miscellaneous (0.04cm) having less (P<0.05) fat than cuts from the loin (0.11cm) and rib (0.11cm). Beef cuts (n=1327) were separated physically into separable components with round cuts having more (P<0.05) separable lean (96.63%) than chuck cuts (86.81%) and miscellaneous cuts (86.18%), which had more (P<0.05) separable lean than loin cuts (84.53%) with rib cuts (69.34%) having the lowest (P<0.05) separable lean. Chemical fat from the separable lean differed (P<0.05) between each cut category: round cuts (3.71%), miscellaneous cuts (4.99%), loin cuts (5.60%), chuck cuts (6.90%), and rib cuts (8.61%). Ground beef samples (n=235), with declared lean/fat percentages ranging from 73/27 to 96/4, had overall chemical fat values of 13.41% and moisture values of 67.42%. This survey documents the current beef retail cut and ground beef composition, which is helpful to those who need this information for various dietary and marketing purposes.

Chemical properties of cow and beef muscles: benchmarking the differences and similarities.

The objective of this study was to identify muscles from cow populations that are equivalent or may possibly be made equivalent to muscles from A-maturity, Select-grade cattle in terms of chemical, compositional, and color characteristics. Objective color, expressible moisture, proximate composition, pH, heme iron concentration, and total collagen content were determined for 9 muscles (M. gluteus medius, M. infraspinatus, M. longissimus dorsi, M. psoas major, M. rectus femoris, M. tensor fascia latae, M. teres major, M. triceps brachii lateral-head, and M. triceps brachii long-head) from 15 cattle from each of 5 commercially identified populations [fed beef cows (B-F), non-fed beef cows (B-NF), fed dairy cows (D-F), non-fed dairy cows (D-NF), and A-maturity, Select-grade cattle (SEL)]. Muscles from B-F and B-NF populations were more similar to the SEL than were the D-F and D-NF. There were 2 muscles, the M. infraspinatus and M. teres major, from the population of B-F that were similar, physically and chemically, to SEL in most traits. The majority of the 9 muscles from the cows did not differ (P < 0.05) from SEL for percentage expressible moisture, proximate composition, and total collagen content. However, notable differences in pH, objective color L*, total pigment content, and heme iron content existed between cow populations and SEL. The muscles from SEL had significantly (P < 0.05) lower total pigment and heme iron concentrations. These differences likely relate to the visual appearance of muscles from the different populations of cattle. Two of the 9 muscles studied were similar among cow populations and A-maturity, Select-grade beef.

Benchmarking carcass characteristics and muscles from commercially identified beef and dairy cull cow carcasses for Warner-Bratzler shear force and sensory attributes.

The objective of this study was to benchmark carcasses and muscles from commercially identified fed (animals that were perceived to have been fed an increased plane of nutrition before slaughter) and nonfed cull beef and dairy cows and A-maturity, USDA Select steers, so that the muscles could be identified from cull cow carcasses that may be used to fill a void of intermediately priced beef steaks. Carcass characteristics were measured at 24 h postmortem for 75 carcasses from 5 populations consisting of cull beef cows commercially identified as fed (B-F, n = 15); cull beef cows commercially identified as nonfed (B-NF, n = 15); cull dairy cows commercially identified as fed (D-F, n = 15); cull dairy cows commercially identified as nonfed (D-NF, n = 15); and A-maturity, USDA Select grade steers (SEL, n = 15). Nine muscles were excised from each carcass [m. infraspinatus, m. triceps brachii (lateral and long heads), m. teres major, m. longissimus dorsi (also termed LM), m. psoas major, m. gluteus medius, m. rectus femoris, and m. tensor fasciae latae] and subjected to Warner-Bratzler shear force testing and objective sensory panel evaluation after 14 d of postmortem aging. Carcass characteristics differed (P < 0.05) among the 5 commercially identified slaughter groups for the traits of lean maturity, bone maturity, muscle score, HCW, fat color, subjective lean color, marbling, ribeye area, 12th-rib fat thickness, and preliminary yield grade. Carcasses from commercially identified, fed cull cows exhibited more (P < 0.01) weight in carcass lean than did commercially identified, nonfed cull cows. There was a group x muscle interaction (P = 0.02) for Warner-Bratzler shear force. Warner-Bratzler shear force and sensory overall tenderness values demonstrates that muscles from the SEL group were the most tender (P < 0.01), whereas muscles from the B-NF group were the least tender (P < 0.01). Sensory, beef flavor intensity was similar (P > 0.20) among cull cow carcass groups and more intense (P < 0.01) than the SEL carcass group. Muscles from the SEL group exhibited less (P < 0.01) detectable off-flavor than the cull cow carcass groups, whereas the B-NF group exhibited the most (P < 0.01) detectable off-flavor. Although carcass and muscle quality from commercially identified, fed, cull beef and dairy cows was not similar to A-maturity, USDA Select beef, they did show improvements when compared with nonfed, cull, beef and dairy cow carcasses and muscles.

National beef tenderness survey - 2006: Assessment of Warner-Bratzler shear and sensory panel ratings for beef from US retail and foodservice establishments.

Beef from retail and foodservice establishments in 11 US cities was evaluated using Warner-Bratzler shear (WBS) and consumer evaluation panels. Postmortem aging times ranged from 3 to 83d for retail and 7 to 136d for foodservice with mean aging times of 22.6d and 30.1d, respectively. For retail, the three cuts from the round - top round, bottom round, and eye of round - had the highest (P<0.05) WBS values compared to cuts from the chuck, rib, and loin. Top loin steaks had the lowest (P<0.05) WBS value compared to ribeye and top sirloin foodservice steaks. Retail bone-in top loin, top loin, ribeye, T-bone, and porterhouse received the highest (P<0.05) ratings by consumers for overall like and like tenderness. Quality grade had little or no effect on foodservice sensory evaluations. Improvements in round tenderness are needed to increase consumer acceptability.

Fecal prevalence of Escherichia coli O157, Salmonella, Listeria, and Bacteriophage Infecting E. coli O157:H7 in feedlot cattle in the Southern Plains region of the United States.

Escherichia coli O157:H7, Salmonella, and Listeria are foodborne pathogens of critical importance that often colonize cattle. E. coli O157:H7 can be specifically killed by lytic bacteriophage, and lytic bacteriophage treatment has been suggested as a pre-harvest intervention strategy to reduce foodborne pathogens in cattle. To date, no systematic approach to determine the incidence of E. coli O157:H7-infecting lytic bacteriophage has been published. Therefore, the current study was designed to determine (1) the incidence of E. coli O157, Salmonella spp., and Listeria and (2) the incidence of E. coli O157:H7-infecting bacteriophage in the feces of feedlot steers in commercial feedlots in the United States. Fecal samples (n=60) were collected from four feedlots in two Southern Great Plains states (total (n=240 fecal samples). Salmonella and E. coli O157:H7 were found in 3.8% and 11.7% of the fecal samples, respectively. Bacteriophage targeting E. coli O157:H7 were found in all four feedlots, in 15% of the individual fecal samples, and in 55% of the cattle pens. Our results indicate that such bacteriophage are widespread in feedlot cattle, suggesting that further research into the ecological role of bacteriophage in the gastrointestinal tract is needed.

Beef customer satisfaction: factors affecting consumer evaluations of calcium chloride-injected top sirloin steaks when given instructions for preparation.

The objectives of this study were to evaluate whether instructions can help consumers properly prepare top sirloin steaks and to evaluate the use of calcium chloride injection to decrease the sensitivity of top sirloin steaks to degree of doneness, thereby improving customer satisfaction ratings. An in-home study evaluated top sirloin steaks (gluteus medius) as influenced by calcium chloride injection (injected vs. noninjected), consumer segment (beef loyalists = heavy consumers of beef, budget rotators = cost-driven and split meat consumption between beef and chicken, and variety rotators = higher incomes and education and split meat consumption among beef, poultry, and other foods), degree of doneness, cooking method, and instructions (given vs. not given). Consumers evaluated overall like, tenderness, juiciness, flavor like, and flavor amount using 10-point scales. Beef loyalists consistently rated steaks higher for overall like, juiciness, and flavor when instructions were provided (P < 0.05) and rated top sirloin steaks higher for overall like and tenderness when given instructions for grilling (P < 0.05). Budget rotators and variety rotators rated steaks differently among cooking methods (P < 0.05). Correlation and stepwise regression analyses indicated that flavor like was the most highly correlated with overall like, followed by tenderness, flavor amount, and juiciness. Calcium chloride injection had no effect on consumers' likes or dislikes or on tenderness (P < 0.05). For top sirloin steaks, it was likely that preparation played a major role in consumer satisfaction, and beef loyalists benefited the most from providing cooking instructions.

Beef customer satisfaction: USDA quality grade and marination effects on consumer evaluations of top round steaks.

An in-home beef study evaluated consumer ratings of top round steaks (semimembranosus) as influenced by USDA quality grade (top Choice or high Select), city (Chicago or Philadelphia), consumer segment (beef loyalists = heavy consumers of beef; budget rotators = cost-driven and split meat consumption between beef and chicken; and variety rotators = higher incomes and education and split meat consumption among beef, poultry, and other foods), degree of doneness, cooking method, and marination. Consumers evaluated each steak for overall like, tenderness, juiciness, flavor like, and flavor amount using 10-point scales (1 = dislike extremely, not at all tender, not at all juicy, dislike extremely, and none at all to 10 = like extremely, extremely tender, extremely juicy, like extremely, and an extreme amount of flavor, respectively). Quality grade affected several consumer sensory traits, with top Choice receiving higher (P < or = 0.004) tenderness, juiciness, and flavor like scores than high Select. Consumers in Chicago rated steaks cooked "medium and less" higher for overall like, tenderness, juiciness, flavor like, and flavor amount than those in Philadelphia (city x degree of doneness; P < or = 0.020). Steaks braised by customers in Philadelphia received among the highest scores for overall like, tenderness, juiciness, flavor like, and flavor amount compared with any cooking method used by customers in Chicago (cooking method x city; P < or = 0.026). Overall like and flavor amount ratings were least (P < 0.05) for steaks that were marinated and cooked to "medium and less" degree of doneness (marination x degree of doneness; P < or = 0.014). Braised steaks received among the highest values for overall like, tenderness, juiciness, flavor like, and flavor amount when cooked to "medium and less" or "medium well and more" (cooking method x degree of doneness; P < or = 0.008). Correlation and stepwise regression analysis indicated that flavor like was pivotal in customers' satisfaction with top round steaks, and was the sensory trait most highly correlated to overall like, followed by tenderness, flavor amount, and juiciness. Preparation of top round steaks was crucial in consumers' likes and dislikes, and by improving flavor, higher consumer satisfaction may be achieved.

The effects of quality grade, aging, and location within muscle on Warner-Bratzler shear force in beef muscles of locomotion.

Aging patterns of nine muscles from the chuck and round from two quality classifications of beef: USDA Select and upper 2/3 of USDA Choice grade were determined. The following muscles were evaluated: infraspinatus, triceps brachii - lateral head, triceps brachii - long head, serratus ventralis, complexus, splenius, rhomboideus, vastus lateralis and rectus femoris. Muscles were divided into four portions, progressing from anterior to posterior or dorsal to ventral orientation to the carcass depending on muscle fiber orientation. One steak was removed from each portion and aged for 7, 14, 21, or 28 d postmortem, then Warner-Bratzler shear force (WBSF) analysis was conducted. Consistent aging recommendations can be given for all muscles studied, as there was no aging by muscle interaction. An aging by USDA grade interaction was noted (P<0.05). The upper 2/3 of USDA Choice need not be aged beyond 7 d. USDA Select should be aged at least 14 d. Steak location within muscle had an effect (P<0.05) on WBSF values in four muscles. These data indicate that fabrication and merchandizing decisions should be made on an individual muscle basis.

Muscle profiling: Characterizing the muscles of the beef chuck and round.

To fully characterize properties of the muscles of the beef chuck and round, and to reveal potential opportunities to upgrade the value, 39 different muscles were dissected from 142 beef carcasses differing in carcass weight, yield grade, and quality grade. Numerous physical and chemical properties of the muscles were determined. Muscle effects were observed for all traits (objective color, expressible moisture, proximate composition, emulsion capacity, pH, total collagen content, total heme-iron concentration, and Warner-Bratzler shear force). USDA quality grade generally had the most effect on muscle traits, with carcass weight and yield grade having lesser effects. These muscle profile data will allow for more informed decisions to be made in the selection of individual muscles from the beef chuck and round for the production of value-added products.

Enhancing palatability traits in beef chuck muscles.

Thirty-six USDA Select complexus, latissimus dorsi, rhomboideus, serratus ventralis (SEV), splenius, subscapularis, supraspinatus (SUS), and triceps brachii (TRB) muscles were studied. Muscles were assigned to one of four treatments: control, marinated, needle-pumped, and vacuum-tumbled to reach 10% brine pick-up after treatment. The solution was formulated to have 0.5% of sodium chloride and 0.4% of sodium tripolyphosphate in the end product. Steaks from the SEV, SUS, and TRB muscles were cooked on a grill and the other five muscles were oven-roasted whole, all of them cooked to an internal temperature of 71°C. Sensory evaluations and Warner-Bratzler shear force (WBSF) determinations were conducted immediately after cooking (Day-1), and after being cooked and stored frozen for 60 days (Day-60). For the Day-60 evaluation, samples were reheated using a microwave oven. The needle-pumped treatment reduced WBSF values compared to the control in 3 out of 8 muscles (P<0.05). The marinated treatment appeared to have the greatest influence on juiciness and was different from the control in 7 of 8 muscles (P<0.05). Comparing treated muscles to the control, tenderness was increased in 4 out of 8 muscles when needle pumped (P<0.05). Brine treatment reduced sensory detected connective tissue only in 2 of 8 muscles. More off-flavors were detected by the panel for marinated samples from six of eight muscles. All muscles had lower values for WBSF, less connective tissue and off-flavors, and higher juiciness, overall tenderness, and beef flavor intensity on Day-1 than Day-60. The needle-pumped method was slightly superior to the marinated and vacuum-tumbled treatments even though the differences were not always consistent. But, regardless of the application method, palatability traits were generally enhanced by brine treatments.

Fiber-type composition of muscles of the beef chuck and round.

Thirty-eight muscles of the beef chuck and round were histochemically stained to characterize fiber-type composition in order to facilitate optimal muscle use in value-added products. Select-grade chucks and rounds (n = 4 each) were chosen to represent two carcass weight classes (250 to 295 kg and 363 to 410 kg) and two yield grades (1 and 3). Muscles were sectioned and stained with a procedure that included a succinate dehydrogenase and an adenosine triphosphatase staining technique. Number and diameter of beta-red, alpha-red, and alpha-white muscle fibers were used to determine muscle fiber percentage, muscle fiber area, and percent area in each muscle. Weight did not significantly (P > 0.05) affect these muscle fiber-type characteristics, probably because of limited sample numbers. Muscles containing greater than 40% beta-red fibers were classified as red; greater than 40% alpha-white fibers were classified as white. All other muscles were classified as intermediate. Nine of 12 round muscles were white, including semitendinosus, biceps femoris, rectus femoris, adductor, and semimembranosus. The chuck muscles were red (10 of 26), intermediate (9 of 26), and white (7 of 26). These data indicate variable fiber-type composition of most of the muscles of the beef chuck and round. Functional and biochemical traits of each muscle fiber class would be expected to create different processing characteristics, which would influence optimal muscle use in value-added products.

Beef customer satisfaction: factors affecting consumer evaluations of clod steaks.

An in-home beef study evaluated consumer ratings of clod steaks (n = 1,264) as influenced by USDA quality grade (Top Choice, Low Choice, High Select, and Low Select), city (Chicago and Philadelphia), consumer segment (Beef Loyals, who are heavy consumers of beef; Budget Rotators, who are cost-driven and split meat consumption between beef and chicken; and Variety Rotators, who have higher incomes and education and split their meat consumption among beef, poultry, and other foods), degree of doneness, and cooking method. Consumers evaluated each steak for Overall Like, Tenderness, Juiciness, Flavor Like, and Flavor Amount using 10-point scales. Grilling was the predominant cooking method used, and steaks were cooked to medium-well and greater degrees of doneness. Interactions existed involving the consumer-controlled factors of degree of doneness and(or) cooking method for all consumer-evaluated traits for the clod steak (P < 0.05). USDA grade did not affect any consumer evaluation traits or Warner-Bratzler shear force values (P > 0.05). One significant main effect, segment (P = 0.006), and one significant interaction, cooking method x city (P = 0.0407), existed for Overall Like ratings. Consumers in the Beef Loyals segment rated clod steaks higher in Overall Like than the other segments. Consumers in Chicago tended to give more uniform Overall Like ratings to clod steaks cooked by various methods; however, consumers in Philadelphia gave among the highest ratings to clod steaks that were fried and among the lowest to those that were grilled. Additionally, although clod steaks that were fried were given generally high ratings by consumers in Philadelphia, consumers in Chicago rated clod steaks cooked in this manner significantly lower than those in Philadelphia. Conversely, consumers in Chicago rated clod steaks that were grilled significantly higher than consumers in Philadelphia. Correlation and stepwise regression analyses indicated that Flavor Like was driving customer satisfaction of the clod steak. Flavor Like was the sensory trait most highly correlated to Overall Like, followed by Tenderness, Flavor Amount, and Juiciness. Flavor Like was the first variable to enter into the stepwise regression equation for predicting Overall Like, followed by Tenderness and Flavor Amount. For the clod steak, it is likely that preparation techniques that improve flavor without reducing tenderness positively affect customer satisfaction.

The efficacy of three objective systems for identifying beef cuts that can be guaranteed tender.

The objective of this study was to determine the accuracy of three objective systems (prototype BeefCam, colorimeter, and slice shear force) for identifying guaranteed tender beef. In Phase I, 308 carcasses (105 Top Choice, 101 Low Choice, and 102 Select) from two commercial plants were tested. In Phase II, 400 carcasses (200 rolled USDA Select and 200 rolled USDA Choice) from one commercial plant were tested. The three systems were evaluated based on progressive certification of the longissimus as "tender" in 10% increments (the best 10, 20, 30%, etc., certified as "tender" by each technology; 100% certification would mean no sorting for tenderness). In Phase I, the error (percentage of carcasses certified as tender that had Warner-Bratzler shear force of > or = 5 kg at 14 d postmortem) for 100% certification using all carcasses was 14.1%. All certification levels up to 80% (slice shear force) and up to 70% (colorimeter) had less error (P < 0.05) than 100% certification. Errors in all levels of certification by prototype BeefCam (13.8 to 9.7%) were not different (P > 0.05) from 100% certification. In Phase I, the error for 100% certification for USDA Select carcasses was 30.7%. For Select carcasses, all slice shear force certification levels up to 60% (0 to 14.8%) had less error (P < 0.05) than 100% certification. For Select carcasses, errors in all levels of certification by colorimeter (20.0 to 29.6%) and by BeefCam (27.5 to 31.4%) were not different (P > 0.05) from 100% certification. In Phase II, the error for 100% certification for all carcasses was 9.3%. For all levels of slice shear force certification less than 90% (for all carcasses) or less than 80% (Select carcasses), errors in tenderness certification were less than (P < 0.05) for 100% certification. In Phase II, for all carcasses or Select carcasses, colorimeter and prototype BeefCam certifications did not significantly reduce errors (P > 0.05) compared to 100% certification. Thus, the direct measure of tenderness provided by slice shear force results in more accurate identification of "tender" beef carcasses than either of the indirect technologies, prototype BeefCam, or colorimeter, particularly for USDA Select carcasses. As tested in this study, slice shear force, but not the prototype BeefCam or colorimeter systems, accurately identified "tender" beef.

National Beef Tenderness Survey-1998.

Fifty-six retail stores representing 15 retail chains and 14 foodservice facilities in eight U.S. cities were sampled to determine the tenderness of beef steaks at retail and foodservice levels based on Warner-Bratzler shear (WBS) values and consumer evaluation panels. Retail consumer panels were conducted at five universities. Each retail and foodservice steak was evaluated using 10-point scales. Steaks were divided into the following quality groups for statistical analysis: Prime, Top Choice, Choice, Select, and Lean or No Roll. Quality group had no effect on WBS values of retail clod, chuck roll, top round, bottom round, eye of round, top loin, top sirloin, or ribeye steaks but did (P < .05) affect values for the T-bone/porterhouse. The percentages of retail top round, eye of round, and bottom round steaks with a WBS force > 3.9 kg were 39.6, 55.9, and 68.0, respectively. Foodservice ribeye, top loin, and top sirloin steaks had WBS values less than 3.4 kg for all quality groups, with Prime ribeye steaks having lower (P < .05) WBS values than ribeyes from the other quality groups. With the exception of the retail ribeye steak, quality group did not affect consumer sensory ratings of retail and foodservice steaks. Average postfabrication aging times were 32 d for foodservice subprimals and 19 d for retail cut subprimals. These data indicate that improvements in the tenderness of retail cuts from the round are needed. Finally, quality group had little or no effect on consumer sensory evaluations and WBS values of retail and foodservice steaks used in this study.

Influence of sample orientation on prediction of fresh ham lean content by electromagnetic scanning.

To evaluate the effect of orientation of hams during electromagnetic scanning on the estimation of dissected lean content, hams were scanned horizontally, posterior first (POS) or dorsal first (DOR), and vertically, medial side (aitchbone) first (MED; standing on the butt face). Weight and percentage of dissected lean were estimated using scan peak for each orientation, ham weight, and fat thickness. The mean scan peak for the MED orientation was approximately twice as great as peaks for the POS and DOR orientations, which suggests that this orientation may offer greater predictive accuracy by reducing the signal to noise ratio. Results, however, indicated that all orientations were equally effective at predicting lean weight and percentage, with R2 values of .95 and .75 and root mean square errors of .21 kg and 2.6%, respectively.

Use of expected progeny differences for marbling in beef: I. Production traits.

Six Angus bulls with HIGH ( > .4) and six bulls with LOW ( < -.16) expected progeny differences (EPD) for marbling were used to evaluate the impact of marbling on progeny production and carcass traits. Bulls were randomly bred to MARC II (1/4 Hereford, 1/4 Simmental, 1/4 Angus, 1/4 Gelbvieh) composite cows in each of 2 yr to calve in the spring. At weaning, steers and heifers were separated and managed in different production systems. Steers (n = 131) were fed a growing diet (1.1 Mcal of NEg/kg) for 48 d followed by adaptation to a 93% concentrate finishing diet. Heifers (n = 125) were fed a growing diet (.79 Mcal of NEg/kg) for 191 d followed by adaptation to the same 93% concentrate diet. Steers and heifers from each treatment were slaughtered at two times spaced about 60 d apart within both years. Marbling EPD class had no effect on fat thickness, USDA yield grade, carcass weight, finishing daily gain, finishing DMI, or finishing efficiency (P > .18). More (P < .05) carcasses of calves from sires with HIGH EPD for marbling graded USDA Choice than from LOW EPD sires, 74% vs 47%, respectively. Angus sires can be selected to produce progeny that have increased ability to grade Choice without increasing yield grade or decreasing animal growth or feed efficiency.

Use of expected progeny differences for marbling in beef: II. Carcass and palatability traits.

A 2-yr study was conducted to determine the effect of EPD for marbling on marbling score, palatability traits, and carcass fatness in beef. Steer (n = 122) and heifer (n = 123) carcasses were obtained by mating Angus bulls having a high ( > .4) or low ( < -.16) EPD for marbling to MARC II cows (1/4 Angus, 1/4 Hereford, 1/4 Simmental, and 1/4 Gelbvieh). Carcass traits, composition of primals, quarters, and sides, palatability, and shear force data were obtained and adjusted to the mean number of days on feed, equal marbling score (Small50), fat thickness (1.0 cm), and carcass weight (318 kg) end points. Steer carcasses from the high marbling EPD group, adjusted to the mean number of days on feed, had significantly more marbling (P < .01) and less subcutaneous fat in the side and the hindquarter (P < .10) than their low marbling EPD counterparts. Adjusting steers to Small50 marbling produced smaller longissimus muscle area (by 5 cm2), less fat thickness (1.15 vs 1.28 cm), and lighter side weights (306 vs 333 kg) for high marbling vs low marbling EPD groups, indicating a faster rate of marbling deposition. Similar relationships of a greater magnitude were found for heifers, perhaps because the heifers were older than the steers at slaughter. No differences in taste panel ratings or shear force values were noted among steer carcasses. Heifer carcasses from the high marbling EPD group had better (P < .05) ratings for juiciness, muscle fiber tenderness, and overall tenderness than the low marbling EPD group heifers. These results indicate that it is possible, using existing genetic resources, to maintain marbling score and decrease fat in other depots of the carcass without compromising palatability.

The effects of orientation and storage time on the prediction of beef rib composition using electromagnetic scanning.

To investigate the effects of orientation of beef ribs in an electromagnetic field and storage time on the prediction of rib composition, 64 ribs (IMPS 103) were scanned (2.5 MHz) in three different orientations: posterior end first (POS), dorsal end first (DOR), and fat side first, blade end down (BLD). Scans were obtained after 1 and 5 d of storage. Scan peak, rib weight, 3/4 fat depth, length, and temperature were used to predict percentage and weight of dissectable and fat-free lean. The mean peak for the BLD scans was four to six times higher than the POS or DOR scans. Ribs scanned in the BLD orientation on d 5 had the highest coefficient of determination (CD; 94.0) and the lowest residual standard deviation (RSD; .22 kg) for prediction of lean weight. The POS and DOR scans were similar at d 5 (CD = 91.4 and 90.3, respectively) with RSD of .30 and .31 kg, respectively. Prediction of lean percentage resulted in lower CD than predicting lean weight. For percentage of lean, BLD scans at d 5 once again resulted in the best CD (81.6) and lowest RSD (1.5%). Prediction of percentage lean using POS or DOR orientation resulted in CD of 71.2 and 67.1 and RSD of 2.0 and 2.1%, respectively. The CD were similar for POS and DOR scans at d 1 and d 5. Predicting fat-free lean weight resulted in equal or lower CD than dissected lean and higher CD for lean percentage. It seems that orientation during scanning, when consistent, is not a major concern.(ABSTRACT TRUNCATED AT 250 WORDS)

Electromagnetic scanning of beef quarters to predict carcass and primal lean content.

To study the use of electromagnetic scanning in prediction of lean content in beef carcasses and cuts, 100 beef cattle (60 steers and 40 heifers), representing a broad range in external fat thickness (.1 to 2.9 cm) and live weight (414 to 742 kg), were selected. Chilled right sides were divided into streamlined (foreshank, brisket, and ventral plate removed) forequarters (FQ) and full hindquarters (HQ) and scanned. Primal rounds, loins, ribs, and chucks were fabricated from the right side, scanned, and physically separated into lean, fat, and bone. Prediction equations for dissected lean content and percentage of lean included the peak of the electromagnetic scan response curve (obtained from scanning the HQ or FQ), length, temperature and weight of the scanned cut, and fat thickness at the 12th rib. Using the coefficient of determination, root mean square error, and Mallows' Cp statistic, the best model for each dependent variable (weight and percentage of lean) that included up to five independent variables was selected. Prediction equations for the HQ or FQ of steers accounted for 84 to 93% of the variation in lean weight of beef sides and quarters and 71 to 93% of primals. Sixty-one to 75% of the variation in percentage of lean in sides and quarters and 48 to 65% of primals was also explained. Similar results were obtained for heifer carcasses. Predicting percentage of lean in any scanned cut, rather than weight of lean, accounted for less of the variation. Weight and fat thickness contributed significantly when predicting percentage of lean.(ABSTRACT TRUNCATED AT 250 WORDS)

Foodservice industry market profile study: in-plant beef fat trim level survey and cutting yields.

Fifty foodservice purveying companies were sampled in 12 U.S. cities evenly distributed across six geographical regions. Beef whole muscle cuts (WMC) and portion control items (PCI) from the primal rib and loin were evaluated for surface fat levels. Fat thicknesses were measured on WMC before and after fabrication, whereas additional PCI were measured for fat trim levels before distribution. The average initial fat thickness was 11.9 mm (174 Short Loin and 180A Strip Loin) and 15.6 mm (184 Top Sirloin Butt); maximum fat thicknesses ranged from 16.2 mm (strip loin) to 22.2 mm (top sirloin butt). After fabrication, average fat thicknesses were 6.2, 5.1, and 4.0 mm for resulting products from the short loin, strip loin, and top sirloin butt, respectively. The average initial fat thickness for the strip loin was greater (P < .05) in Southeast and Northeast regions than in Mountain/Desert, Midwest, and Southwest regions. In contrast, average trimmed fat thicknesses for products from the strip loin and top sirloin butt were lower (P < .05) in the Southeast and Northeast than in all other regions. Average fat trim levels for PCI were 3.0 (1112A Ribeye Roll steak, Lip-On), 5.3 (1173B/1174B T-Bone/Porterhouse steak), 5.0 (1180A Strip Loin steak), and 4.0 mm (1184B Top Sirloin steak). Maximum fat trim levels were 4.4 (IMPS 1112A), 7.4 (IMPS 1173B/1174B), 6.9 (IMPS 1180A), and 5.5 mm (IMPS 1184B). The PCI had average and maximum fat trim levels in compliance with USDA (1988) recommendations for fat trim specifications.(ABSTRACT TRUNCATED AT 250 WORDS)