Implementation of chemometrics for quality control and authentication of meat and meat products

Multivariate analysis has been established as a very powerful and effective tool in classifying and grouping individual products. Principal Component Analysis, Canonical analysis, Cluster and Partial Least Squares were found to be indispensable for classifying food products according to variety and/or geographical origin. Meat and meat products were correctly classified for authentication purposes to various groups following instrumental and/or sensory analyses.

Mechanical measures of uncooked beef longissimus muscle can predict sensory panel tenderness and Warner-Bratzler shear force of cooked steaks

Two experiments were conducted to investigate mechanical measures of tenderness on uncooked USDA Select longissimus muscle as a means to predict Warner-Bratzler shear force (WBSF) and trained sensory panel tenderness (SPT) of cooked steaks. In Exp. 1, strip loins (n = 24) were aged 14 d postmortem and fabricated into steaks (2.54 cm). Medial, center, and lateral locations within uncooked steaks were evaluated by a plumb bob device and correlated with WBSF and SPT of cooked steaks. In Exp. 2, 24 strip loins were used to evaluate how well plumb bob and needle probe devices used on uncooked steaks predicted WBSF and SPT of cooked steaks. At 2 d postmortem, two steaks were fabricated from the anterior end. One uncooked steak (2.54 cm) was assigned to the plumb bob treatment and the other uncooked steak (5.08 cm) was assigned to needle probe treatment. At 14 d postmortem, one uncooked steak (5.08 cm) was assigned to needle probe treatment, a second uncooked steak (2.54 cm) was assigned to plumb bob treatment, whereas the remaining steaks (2.54 cm) were cooked and evaluated by a trained sensory panel and WBSF device. In Exp. 1, average plumb bob values were negatively correlated (P < 0.05) to average SPT scores (r = -0.48). However, correlations between WBSF and plumb bob values for medial, lateral, and average of all sections were not significant (P > 0.05). In Exp. 2, regression models to predict SPT from needle probe and plumb bob measurements individually taken at 2 d postmortem had R2 of 0.54 and 0.51, respectively. Combining needle probe and plumb bob measurements resulted in an R2 of 0.76; when quadratic terms for both variables were in the model, the R2 was 0.80. Regressing needle probe and plumb bob measurements at 2 d postmortem with WBSF produced R2 values of 0.51 and 0.45, respectively. If linear terms of both probes were combined to predict WBSF, the R2 increased to 0.77. An equation to predict WBSF, including both the linear and quadratic terms of needle probe and plumb bob measurements, resulted in an R2 of 0.84. Using plumb bob and needle probe devices on uncooked longissimus muscle at 2 d postmortem can predict cooked WBSF and SPT of USDA Select Grade steaks at 14 d postmortem.

Prediction of retail product weight and percentage using ultrasound and carcass measurements in beef cattle

Data from 534 steers representing six sire breed groups were used to develop live animal ultrasound prediction equations for weight and percentage of retail product. Steers were ultrasonically measured for 12th-rib fat thickness (UFAT), rump fat thickness (URPFAT), longissimus muscle area (ULMA), and body wall thickness (UBDWALL) within 5 d before slaughter. Carcass measurements included in USDA yield grade (YG) and quality grade calculations were obtained. Carcasses were fabricated into boneless, totally trimmed retail products. Regression equations to predict weight and percentage of retail product were developed using either live animal or carcass traits as independent variables. Most of the variation in weight of retail product was accounted for by live weight (FWT) and carcass weight with R2 values of 0.66 and 0.69, respectively. Fat measurements accounted for the largest portion of the variation in percentage of retail product when used as single predictors (R2 = 0.54, 0.44, 0.23, and 0.54 for UFAT, URPFAT, UBDWALL, and carcass fat, respectively). Final models (P < 0.10) using live animal variables included FWT, UFAT, ULMA, and URPFAT for retail product weight (R2 = 0.84) and UFAT, URPFAT, ULMA, UBDWALL, and FWT for retail product percentage (R2 = 0.61). Comparatively, equations using YG variables resulted in R2 values of 0.86 and 0.65 for weight and percentage of retail product, respectively. Results indicate that live animal equations using ultrasound measurements are similar in accuracy to carcass measurements for predicting beef carcass composition, and alternative ultrasound measurements of rump fat and body wall thickness enhance the predictive capability of live animal-based equations for retail yield.

An evaluation of the lamb vision system as a predictor of lamb carcass red meat yield percentage

An objective method for predicting red meat yield in lamb carcasses is needed to accurately assess true carcass value. This study was performed to evaluate the ability of the lamb vision system (LVS; Research Management Systems USA, Fort Collins, CO) to predict fabrication yields of lamb carcasses. Lamb carcasses (n = 246) were evaluated using LVS and hot carcass weight (HCW), as well as by USDA expert and on-line graders, before fabrication of carcass sides to either bone-in or boneless cuts. On-line whole number, expert whole-number, and expert nearest-tenth USDA yield grades and LVS + HCW estimates accounted for 53, 52, 58, and 60%, respectively, of the observed variability in boneless, saleable meat yields, and accounted for 56, 57, 62, and 62%, respectively, of the variation in bone-in, saleable meat yields. The LVS + HCW system predicted 77, 65, 70, and 87% of the variation in weights of boneless shoulders, racks, loins, and legs, respectively, and 85, 72, 75, and 86% of the variation in weights of bone-in shoulders, racks, loins, and legs, respectively. Addition of longissimus muscle area (REA), adjusted fat thickness (AFT), or both REA and AFT to LVS + HCW models resulted in improved prediction of boneless saleable meat yields by 5, 3, and 5 percentage points, respectively. Bone-in, saleable meat yield estimations were improved in predictive accuracy by 7.7, 6.6, and 10.1 percentage points, and in precision, when REA alone, AFT alone, or both REA and AFT, respectively, were added to the LVS + HCW output models. Use of LVS + HCW to predict boneless red meat yields of lamb carcasses was more accurate than use of current on-line whole-number, expert whole-number, or expert nearest-tenth USDA yield grades. Thus, LVS + HCW output, when used alone or in combination with AFT and/or REA, improved on-line estimation of boneless cut yields from lamb carcasses. The ability of LVS + HCW to predict yields of wholesale cuts suggests that LVS could be used as an objective means for pricing carcasses in a value-based marketing system.

Retail yields from beef chuck and round subprimals from two grade groups when merchandised as single muscle cuts

Beef subprimals from two different grade groups were obtained from two beef processors to assist in updating the Beef Computer Assisted Retail Decision Support (CARDS) program with new fabrication styles. The grade groups consisted of Top Choice (containing subprimals from carcasses with a Modest or Moderate degree of marbling) and Select (containing subprimals from carcasses with a Slight degree of marbling). Subprimals (shoulder clod; top blade, roast; arm roast; knuckle, peeled; outside round, flat) were separated into individual muscles and fabricated into retail cuts by professional retail meat cutters. Mean retail cutting yields and labor requirements were calculated from observed weights (kilograms) and processing times (seconds). Data were analyzed to determine means and standard errors of percentage yield and processing times for subprimals in each grade group, and comparisons were made between grade groups. Generally, there were few differences in processing times between Top Choice and Select subprimals, and the trimming phase required the most time to complete for each subprimal. Differences (P < 0.05) were observed in saleable yield between Top Choice and Select subprimals for the shoulder clod (Top Choice = 73.89%; Select = 78.49%), top blade, roast (Top Choice = 84.36%; Select = 86.70%), and outside round, flat (Top Choice = 85.99%; Select = 91.34%). Trimmable fat differed (P < 0.05) between Top Choice and Select subprimals: shoulder clod (Top Choice = 25.30%; Select = 20.85%), top blade, roast (Top Choice = 14.88%; Select = 12.59%), arm roast (Top Choice = 8.35%; Select = 7.47%), knuckle (Top Choice = 5.72%; Select = 2.73%), and outside round, flat (Top Choice = 13.82%; Select = 7.26%). Most of the differences in saleable yields were related to less trimmable fat for Select subprimals, which also required less trimming time than Top Choice subprimals. These data will serve to update the Beef CARDS program and will provide retailers and foodservice operators with third-party cutting yield and time allocation information.

Comparison of different methods to assess the composition of pig bellies in progeny testing

The objective of the study was to validate methods that assess the belly composition of stationary tested progenies of Piétrain boars. In German performance test stations, there are currently three methods of determining belly compositon in use: 1) a regression equation that contains different carcass characteristics, such as fat thickness and muscle area; 2) planimetric analysis of video or digital images acquired at the cut between the 13th and 14th ribs; and 3) estimation of the belly composition using ultrasound data from a three-dimensional ultrasound image produced an online carcass-grading system. Validation of these techniques was performed on 400 carcasses of stationary-tested Piétrain and Piétrain-sired crossbred pigs, which were slaughtered at a mean carcass weight of 85 and 97 kg. Magnetic resonance imaging (MRI) served as a reference to determine the lean content of the bellies. The correlation to MRI lean content ranged from 0.71 to 0.81, and corresponding correlation values were 0.62 to 0.64 for the digital imaging technique, and 0.53 to 0.59 for the AutoFOM online carcass-grading system. An increase in precision was achieved when information from digital imaging and linear carcass measures were included in the regression equation. Accuracy of the AutoFOM system does not seem to be sufficient to assess the belly composition for the special breeds in performance testing. However, extracting and combining 127 AutoFOM-base recordings into modified equations using partial least squares techniques yielded an improvement in the prediction accuracy for all tested breed and/or weight groups.

Establishment and application of a fluorescent polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for identifying porcine, caprine, and bovine meats

A method of fluorescent Polymerase Chain Reaction-restriction fragment length polymorphism (PCR-RFLP) was applied as an analytical and quantitative tool for meat identification. Following alignments of the nucleotide sequences, an oligonucleotide primer pair was designed to amplify the partial sequences within the 12S ribosomal RNA (12S rRNA) gene of mitochondrial DNA from porcine, caprine, and bovine meats. No fragment can be amplified from dog, cat, fish, duck, goose, turkey, and chicken DNA with the primer pair. Using fluorescence sensor capillary electrophoresis, the species-specific DNA fingerprints of pork, goat, and beef were generated by restriction enzyme digestion following a fluorescence-labeling PCR amplification. Species identification was conducted on the meat mixtures. The reliably semiquantitative levels were below 1% for binary mixtures of pork, goat, and beef. Cooking and autoclaving of meats did not influence the generation of the PCR-RFLP profiles or the analytical accuracy.

Identification of grouper (Epinephelus guaza), wreck fish (Polyprion americanus), and Nile perch (Lates niloticus) fillets by polyclonal antibody-based enzyme-linked immunosorbent assay

An indirect enzyme-linked immunosorbent assay (ELISA) has been developed for the species identification of grouper (Epinephelus guaza), wreck fish (Polyprion americanus), and Nile perch (Lates niloticus) fillets. The assay was performed in two different formats, microtiter plates and immunostick tubes, and uses polyclonal antibodies raised in rabbits against muscle-soluble proteins of grouper (anti-GSP), wreck fish (anti-WSP), and Nile perch (anti-PSP). The antibodies were made species-specific by blocking them with the heterologous soluble muscle proteins. Immunorecognition of polyclonal antibodies adsorbed to their specific fish samples was made with swine antirabbit immunoglobulins conjugated to the enzyme horseradish peroxidase. Subsequent enzymatic conversion of the substrate allowed unequivocal identification of the species studied.

Online prediction of beef tenderness using a computer vision system equipped with a BeefCam module

Four experiments were conducted in two commercial packing plants to evaluate the effectiveness of a commercial online video image analysis (VIA) system (the Computer Vision System equipped with a BeefCam module [CVS BeefCam]) to predict tenderness of beef steaks using online measurements obtained at chain speeds. Longissimus muscle (LM) samples from the rib (Exp. 1, 2, and 4) or strip loin (Exp. 3) were obtained from each carcass and Warner-Bratzler shear force (WBSF) was measured after 14 d of aging. The CVS BeefCam output variable for LM area, adjusted for carcass weight (cm2/kg), was correlated (P < 0.05) with WBSF values in all experiments. The CVS BeefCam lean color measurements, a* and b*, were effective (P < 0.05) in all experiments for segregating carcasses into groups that produced LM steaks differing in WBSF values. Fat color measurements by CVS BeefCam were usually ineffective for segregating carcasses into groups differing in WBSF values; however, in Exp. 4, fat b* identified a group of carcasses that produced tough LM steaks. Quality grade factors accounted for 3, 18, 21, and 0% of the variation in WBSF among steaks in Exp. 1 (n = 399), 2 (n = 195), 3 (n = 304), and 4 (n = 184), respectively, whereas CVS BeefCam output variables accounted for 17, 30, 19, and 6% of the variation in WBSF among steaks in Exp. 1, 2, 3, and 4, respectively. A multiple linear regression equation developed with data from Exp. 2 accurately classified carcasses in Exp. 1 and 4 and thereby may be useful for decreasing the likelihood that a consumer would encounter a tough (WBSF > 4.5 kg) LM steak in a group classified as "tender" by CVS BeefCam compared with an unsorted population. Online measurements of beef carcasses by use of CVS BeefCam were useful for predicting the tenderness of beef LM steaks, and sorting carcasses using these measurements could aid in producing groups of beef carcasses with more uniform LM steak tenderness.

Effectiveness of the SmartMV prototype BeefCam System to sort beef carcasses into expected palatability groups

This study was conducted to determine the effectiveness of the SmartMV prototype BeefCam Video Imaging System (prototype BeefCam) for classifying beef carcasses into palatability ("certified" or "not certified" as palatable) groups. Carcasses (n = 769) were selected from four beef-packing plants to represent three USDA quality grade groups (Top Choice, TC; Low Choice, LC; and Select, SE). Following chilling, a prototype BeefCam image of the longissimus muscle was obtained for each carcass. Strip loins were collected from the left side of each carcass and aged for 10 d; Warner-Bratzler shear force (WBSF; n = 769) values and consumer panel ratings (hedonic, end-anchored, 9-point ratings for overall like/dislike; n = 500 carcasses) were obtained for cooked steaks. Using information from the images, two regression models were developed to predict the first principal component of WBSF and consumer panel ratings for sorting carcasses based on expected eating quality. Model I used only prototype BeefCam output, whereas Model II used prototype BeefCam output and a coded value for quality grade group. For both models, carcasses with a predicted value of less than 0.0 were certified as producing palatable beef Additional carcasses (n = 292) were evaluated at a fifth and separate packing plant by prototype BeefCam to validate Models I and II. A strip loin was collected from each carcass and WBSF was measured after 14 d of aging. The percentages of validation carcasses that generated tough (WBSF > or = 4.5 kg) steaks were 6.5,5.8,10.7, and 7.9% for, TC, LC, SE, and all carcasses, respectively. Use of Model I certified 51.9, 47.6, 43.8, and 47.3% of TC, LC, SE, and all carcasses, respectively. Of the carcasses certified by use of Model I, 0.0,0.0, 4.1, and 1.4% of TC, LC, SE, and all carcasses, respectively, generated tough steaks. Use of Model II certified 59.7, 47.6, 25.0, and 42.1% of TC, LC, SE, and all carcasses, respectively. Of the carcasses certified by use of Model II, 2.2, 0.0, 3.6, and 1.6% of TC, LC, SE, and all carcasses, respectively, generated tough steaks. For both models, the frequency of carcasses that produced tough steaks in the certified group was lower (P < 0.05) for all validation carcasses sampled compared with that of the original carcass population. Based on the decrease in the frequency of carcasses that produced tough steaks, further development of a commercial BeefCam system is warranted.

Accuracy of predicting weight and percentage of beef carcass retail product using ultrasound and live animal measures

Five hundred thirty-four steers were evaluated over a 2-yr period to develop and validate prediction equations for estimating carcass composition from live animal ultrasound measurements and to compare these equations with those developed from carcass measurements. Within 5 d before slaughter, steers were ultrasonically measured for 12th-rib fat thickness (UFAT), longissimus area (ULMA), rump fat thickness (URPFAT), and body wall thickness (UBDWALL). Carcasses were fabricated to determine weight (KGRPRD) and percentage (PRPRD) of boneless, totally trimmed retail product. Data from steers born in Year 1 (n = 282) were used to develop prediction equations using stepwise regression. Final models using live animal variables included live weight (FWT), UFAT, ULMA, and URPFAT for KGRPRD (R2 = 0.83) and UFAT, URPFAT, ULMA, FWT, and UBDWALL for PRPRD (R2 = 0.67). Equations developed from USDA yield grade variables resulted in R2 values of 0.87 and 0.68 for KGRPRD and PRPRD, respectively. When these equations were applied to steers born in Year 2 (n = 252), correlations between values predicted from live animal models and actual carcass values were 0.92 for KGRPRD, and ranged from 0.73 to 0.76 for PRPRD. Similar correlations were found for equations developed from carcass measures (r = 0.94 for KGRPRD and 0.81 for PRPRD). Both live animal and carcass equations overestimated (P < 0.01) actual KGRPRD and PRPRD. Regression of actual values on predicted values revealed a similar fit for equations developed from live animal and carcass measures. Results indicate that composition prediction equations developed from live animal and ultrasound measurements can be useful to estimate carcass composition.

On-line prediction of yield grade, longissimus muscle area, preliminary yield grade, adjusted preliminary yield grade, and marbling score using the MARC beef carcass image analysis system

The present experiment was conducted to evaluate the ability of the U.S. Meat Animal Research Center's beef carcass image analysis system to predict calculated yield grade, longissimus muscle area, preliminary yield grade, adjusted preliminary yield grade, and marbling score under commercial beef processing conditions. In two commercial beef-processing facilities, image analysis was conducted on 800 carcasses on the beef-grading chain immediately after the conventional USDA beef quality and yield grades were applied. Carcasses were blocked by plant and observed calculated yield grade. The carcasses were then separated, with 400 carcasses assigned to a calibration data set that was used to develop regression equations, and the remaining 400 carcasses assigned to a prediction data set used to validate the regression equations. Prediction equations, which included image analysis variables and hot carcass weight, accounted for 90, 88, 90, 88, and 76% of the variation in calculated yield grade, longissimus muscle area, preliminary yield grade, adjusted preliminary yield grade, and marbling score, respectively, in the prediction data set. In comparison, the official USDA yield grade as applied by online graders accounted for 73% of the variation in calculated yield grade. The technology described herein could be used by the beef industry to more accurately determine beef yield grades; however, this system does not provide an accurate enough prediction of marbling score to be used without USDA grader interaction for USDA quality grading.

Beef customer satisfaction: trained sensory panel ratings and Warner-Bratzler shear force values

Trained sensory panel ratings and Warner-Bratzler shear force (WBS) values from the Beef Customer Satisfaction study are reported. Carcasses were chosen to fit into USDA quality grades of Top Choice (upper two-thirds of USDA Choice), Low Choice, High Select, and Low Select. A trained, descriptive attribute panel evaluated top loin, top sirloin, and top round steaks for muscle fiber tenderness, connective tissue amount, overall tenderness, juiciness, flavor intensity, cooked beef flavor intensity, and cooked beef fat flavor intensity. Four steaks from each of the three cuts from each carcass were assigned randomly to one of four cooking endpoint temperature treatments (60, 65, 70, or 75 degrees C) for WBS determination. For all trained panel measures of tenderness and WBS, regardless of USDA quality grade, top loin steaks were rated higher than top sirloin steaks, which were rated higher than top round steaks (P < 0.05). There were significant interactions between USDA quality grade and cut for most of the trained sensory panel traits: USDA quality grade influenced ratings for top loin steaks more than ratings for top round steaks or top sirloin steaks. Three interactions were significant for WBS values: USDA quality grade x endpoint temperature (P = 0.02), USDA quality grade x cut (P = 0.0007), and cut x endpoint temperature (P = 0.0001). With the exception of High Select, WBS values increased (P < 0.05) for each grade with increasing endpoint temperature. Choice top loin and top round steaks had lower (P < 0.05) WBS values than Select steaks of the same cut; however, only Top Choice top sirloin steaks differed (P < 0.05) from the other USDA grades. As endpoint temperatures increased, WBS values for top sirloin steaks increased substantially compared to the other cuts. When cooked to 60 degrees C, top sirloin steaks were closer to top loin steaks in WBS values, when cooked to 75 degrees C, top sirloin steaks were closer to top round steaks in WBS values. Simple correlation coefficients between consumer ratings and trained sensory muscle fiber tenderness, connective tissue amount, overall tenderness, juiciness, flavor intensity, and cooked beef fat flavor were significant (P < 0.05), but values were low. While relationships exist between consumer and trained sensory measures, it is difficult to predict from objective data how consumers will rate meat at home.

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.

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.

National Beef Quality Audit-2000: survey of targeted cattle and carcass characteristics related to quality, quantity, and value of fed steers and heifers

The National Beef Quality Audit-2000 was conducted to assess the current status ofthe quality and consistency of U.S. fed steers and heifers. Between May and November 2000, survey teams assessed hide condition (n = 43,415 cattle for color, brands, mud/manure), bruises (n = 43,595 carcasses), offal and carcass condemnation (n = 8,588 cattle), and carcass quality and yield information (n = 9,396 carcasses) in 30 U.S. beef packing plants. Hide colors were black (45.1%), red (31.0%), yellow (8.0%), Holstein (5.7%), gray (4.0%), white (3.2%), brown (1.7%), and brindle (1.3%). Brand frequencies were no (49.3%), one (46.2%), and two or more (4.4%), and brands were located on the butt (36.3%), side (13.7%), and shoulder (3.6%). Most cattle had no (18.0%) or a small amount (55.8%) of mud/manure on their hides, and they had no (77.3%) horns. Most carcasses (53.3%) were not bruised, 30.9% had one bruise, and 15.8% had multiple bruises. Bruise location and incidence were round (14.9%), loin (25.9%), rib (19.4%), chuck (28.2%), and brisket, flank, and plate (11.6%). Condemnation item and incidence were liver (30.3%), lungs (13.8%), tripe (11.6%), heads (6.2%), tongues (7.0%), and carcasses (0.1%). Carcass evaluation revealed these traits and frequencies: steer (67.9%), heifer (31.8%), and bullock (0.3%) sex-classes; dark-cutters (2.3%); A (96.6%), B (2.5%), and C or older (0.9%) overall maturities; and native (90.1%), dairy-type (6.9%), and Bos indicus (3.0%) breed-types. Mean USDA yield grade traits were USDA yield grade (3.0), carcass weight (356.9 kg), adjusted fat thickness (1.2 cm), longissimus muscle area (84.5 cm2), and kidney, pelvic, and heart fat (2.4%). USDA yield grades were Yield Grade 1 (12.2%), Yield Grade 2 (37.4%), Yield Grade 3 (38.6%), Yield Grade 4 (10.4%), and Yield Grade 5 (1.3%). Mean USDA quality grade traits were USDA quality grade (Select85), marbling score (Small23), overall maturity (A66), lean maturity (A65), and skeletal maturity (A67). Marbling score distribution was Slightly Abundant or higher (2.3%), Moderate (4.8%), Modest (13.1%), Small (33.3%), Slight (43.3%), and Traces (3.4%). USDA quality grades were Prime (2.0%), Choice (49.1%), Select (42.3%), Standard (5.6%), and Commercial, Utility, Cutter, and Canner (0.9%). This information will help the beef industry measure progress compared to the past two surveys and will provide a benchmark for future educational and research activities.

Effects of photostimulatory light intensity on ovarian morphology and carcass traits at sexual maturity in modern and antique egg-type pullets

The effects of light intensity during sexual maturation on ovarian and carcass morphology at first oviposition [sexual maturity (SM)] were examined in two Single Comb White Leghorn (SCWL) strains. A modern commercial layer strain (COMM; Shaver Starcross 288) and an antique randombred control strain (ANT) were used to compare the effects of changes in laying stock on their response to varying light intensities from photostimulation (PS) until SM. Two hundred pullets from each strain were reared following COMM breeder guidelines. At 18 wk of age, 32 COMM and 32 ANT pullets were individually caged in individually lit cages and photostimulated with light intensities of 1, 5, 50, and 500 lx. Each bird was processed when it reached SM, and carcass and ovarian morphology were assessed. The ANT birds came into production 9.1 d later than the COMM birds, on average. The ANT pullets consumed 7.0% more feed per day than COMM pullets but gained at a slower rate (ANT = 12.9 g/d; COMM = 15.0 g/d). The ANT birds reached SM at a greater weight and with a smaller ovary than did COMM birds. Although the number of large yellow follicles (LYF) was similar between strains (mean = 6.72), both LYF weight and first egg weight were lower in ANT birds than in COMM birds. The COMM layer strain was more growth efficient and had a greater emphasis on ovary maintenance. Light intensity had no effect on the timing of SM or on BW at SM, indicating that all intensities used were effectively able to stimulate the sexual maturation process. However, ovary weight and number of LYF exhibited an increasing dose response to light intensity, particularly in the COMM birds. Overall, the birds photostimulated with 1 lx of light had reduced ovary development and were heavier than their counterparts exposed to 50 and 500 lx. Within the ANT strain, LYF numbers were not significantly affected by light intensities, whereas, within the COMM strain, LYF numbers were 4.88, 6.63, 7.88, and 8.13 for the 1-, 5-, 50-, and 500-lx intensity groups, respectively. Although light intensity did not affect the rate of sexual maturation, it altered ovarian morphology and carcass lipid stores. A light intensity of 1 lx was limiting to ovarian follicle formation and caused increased carcass weight compared with birds on higher light intensity treatments. The COMM birds were more negatively affected by low light intensity than were the ANT birds, indicating that light intensity may be a more critical environmental factor with modern, highly efficient SCWL strains than has previously been thought. Light intensity can affect the reproductive development and likely the associated egg production potential of modern layer stocks.

Carcass traits, ovarian morphology and egg laying characteristics in early versus late maturing strains of commercial egg-type hens

Three hundred commercial Single Comb While Leghorn (SCWL) pullets of two strains differing in age at first oviposition (early maturing = EARLY; later maturing = LATE) were reared and photostimulated at 18 wk. Selected birds of each strain were killed at weekly intervals from 17 to 23 wk, at sexual maturity, or at 68 wk of age for the study of carcass and reproductive organ traits. Egg production was recorded for surviving hens to 68 wk of age. The two strains differed in age at sexual maturity (EARLY, 137.5 d; LATE, 142.1 d). The EARLY strain birds appeared to allocate a greater proportion of nutrients to reproductive development (oviduct) from 19 to 22 wk of age than did the LATE group, which showed greater breast muscle development during this same period. The LATE strain hens were significantly heavier than the EARLY hens at sexual maturity, and this difference in BW persisted to the end of the laying period. Although total egg production did not differ between strains, the LATE strain hens had a longer prime egg-laying sequence length (LATE, 70.2 d; EARLY, 52.6 d) as well as a longer mean sequence length (LATE, 12.8 d; EARLY, 8.7 d). Egg weight did not differ between strains. These data suggest that LATE lines of egg-type hens offer equivalent production efficiency due to improved rates of lay, albeit starting later.

Tenderness classification of beef: II. Design and analysis of a system to measure beef longissimus shear force under commercial processing conditions

The objectives of this study were to evaluate the efficacy of a system for classifying beef for tenderness based on a rapid, simple method of measuring cooked longissimus shear force. Longissimus steaks (2.54 cm thick) were trimmed free of s.c. fat and bone and rapidly cooked using a belt grill. A 1-cm-thick, 5-cm-long slice was removed from the cooked longissimus parallel with the muscle fibers for measurement of shear force. Slices were sheared with a flat, blunt-end blade using an electronic testing machine. The entire process was completed in less than 10 min. Therefore, in commercial application, this process could be completed during the 10- to 15-min period that carcasses are normally held to allow the ribeye to bloom for quality grading. In Exp. 1, the repeatability of slice shear force (SSF), as determined by evaluation of duplicate samples from 204 A-maturity carcasses, was .89. In Exp. 2, A-maturity carcasses (n = 483) were classified into three groups based on SSF (< 23, 23 to 40, and > 40 kg) at 3 d postmortem that differed (P < .001) in mean trained sensory panel tenderness ratings (7.3 +/- .04, 6.4 +/- .06, and 4.4 +/- .20) and the percentages (100, 91, and 28%) of samples rated "Slightly Tender" or higher at 14 d postmortem. Therefore, this tenderness classification system could be used to accurately segregate beef carcasses into expected tenderness groups. Further research is needed to test the feasibility and accuracy of this system under a variety of commercial processing conditions.

[Moisture, total lipids and fatty acids in raw longissimus muscle from Venezuelan cattle]

Randomly selected groups of slaughter cattle, crossbreds of dairy (n = 14) and zebu (n = 131) types were classified by age (2.5, 3.0, 3.5 and 4.0 yr., estimated by dentition), and carcass fatness (as described by different criterion, including marbling levels) to study variation in moisture (M), lipid (L), and fatty acid (FA) contents (g/100 g of fresh tissue) of longissimus muscle trimmed to zero fat cover. Overall means +/- standard deviations per 100 g of raw product for M and L were 73.9 +/- 1.36 and 2.9 +/- 1.04, respectively. Analyses of variance by the least squares (LS) method showed age, breed type, marbling, backfat thickness and carcass finish affected (p < 0.05) fatty acid (FA) profiles. The oldest cattle group (4 yr. or older) trended to present a lower intramuscular lipid content (2.72 g/100 g) and showed the highest (2.04) unsaturation (unsaturated/saturated FA) index (p < 0.05). Breed type had little effect on the FA profile. Comparison of LS means showed intramuscular concentrations of myristic and linolenic acids were slightly higher in samples from dairy types (p < 0.05). Carcasses with poor, "patch-like" fat distribution, showed muscles with the highest (0.16) polyunsaturated/saturated FA index (p < 0.05). Unsaturation indexes for trimmed beef samples with the prevailing marbling levels (1.76 for "Traces" to 1.92 for "Devoid") show a clear predominance of unsaturates, relatively larger than that estimated from compositional FA data reported for the same cut in the United States.

Tenderness classification of beef: IV. Effect of USDA quality grade on the palatability of "tender" beef longissimus when cooked well done

The objective of this experiment was to determine the impact of USDA quality grade on the palatability of "tender" longissimus when cooked well done. Warner-Bratzler shear force was determined on longissimus thoracis steaks aged 3 or 14 d postmortem (cooked to 70 degrees C) from carcasses of 692 steers and heifers. Steaks from 31 carcasses with Modest or Moderate marbling scores (Top Choice) and steaks from 31 carcasses with Slight00 to Slight40 marbling scores (Low Select) were selected for this experiment from carcasses identified as "tender" (shear force < 5.0 kg at 3 d postmortem). Longissimus thoracis steaks with 3 or 14 d of postmortem aging were cooked to 80 degrees C and evaluated by a trained sensory descriptive attribute panel. Top Choice steaks had higher (P < .05) juiciness (5.8 vs 5.3) and beef flavor intensity ratings (4.9 vs 4.6) than Low Select steaks. Aging of steaks for 14, rather than 3, d postmortem improved (P < .05) beef flavor intensity rating (4.8 vs 4.7) but not (P > .05) juiciness rating (5.6 vs 5.5). The interaction (P < .05) of quality grade and aging time for tenderness rating indicated that Top Choice steaks were more tender (P < .05) with 3 d of aging than steaks from Low Select carcasses (6.3 vs 5.8), but steaks from Top Choice and Low Select carcasses had similar (P > .05) tenderness ratings after 14 d of aging (7.0 and 6.8). Compared to palatability of steaks from Low Select carcasses, the palatability of steaks from Top Choice carcasses was less affected by elevated degree of doneness in "tender" longissimus thoracis, especially when steaks were aged for only 3 d. Although differences in sensory traits between Top Choice and Low Select steaks were small, the consumers who cook beef well done may benefit from implementation of tenderness classification in conjunction with USDA quality grade.

Tenderness classification of beef: III. Effect of the interaction between end point temperature and tenderness on Warner-Bratzler shear force of beef longissimus

The objectives of this experiment were to determine 1) whether end point temperature interacts with tenderness to affect Warner-Bratzler shear force of beef longissimus and 2) if so, what impact that interaction would have on tenderness classification. Warner-Bratzler shear force was determined on longissimus thoracis cooked to either 60, 70, or 80 degrees C after 3 and 14 d of aging from carcasses of 100 steers and heifers. Warner-Bratzler shear force values (3- and 14-d aged steaks pooled) for steaks cooked to 70 degrees C were used to create five tenderness classes. The interaction of tenderness class and end point temperature was significant (P < .05). The increase in Warner-Bratzler shear force as end point temperature increased was greater (P < .05) for less-tender longissimus than more-tender longissimus (Tenderness Class 5 = 5.1, 7.2, and 8.5 kg and Tenderness Class 1 = 2.4, 3.1, and 3.7 kg, respectively, for 60, 70, and 80 degrees C). The slopes of the regressions of Warner-Bratzler shear force of longissimus cooked to 60 or 80 degrees C against Warner-Bratzler shear force of longissimus cooked to 70 degrees C were different (P < .05), providing additional evidence for this interaction. Correlations of Warner-Bratzler shear force of longissimus cooked to 60 or 80 degrees C with Warner-Bratzler shear force of longissimus cooked to 70 degrees C were .90 and .86, respectively. One effect of the interaction of tenderness with end point temperature on tenderness classification was to increase (P < .01) the advantage in shear force of a "Tender" class of beef over "Commodity" beef as end point temperature increased (.24 vs .42 vs .60 kg at 14 d for 60, 70, and 80 degrees C, respectively). When aged 14 d and cooked to 80 degrees C, "Commodity" steaks were six times more likely (P < .01) than "Tender" steaks to have shear force values > or = 5 kg (24 vs 4%). The end point temperature used to conduct tenderness classification did not affect classification accuracy, as long as the criterion for "Tender" was adjusted accordingly. However, cooking steaks to a greater end point temperature than was used for classification may reduce classification accuracy. The beef industry could alleviate the detrimental effects on palatability of consumers cooking beef to elevated degrees of doneness by identifying and marketing "Tender" longissimus.

Effects of the halothane genotype and slaughter weight on texture of pork

The objective of this study was to investigate the effects of the halothane (HAL) genotype, slaughter weight (SW), and the HAL x SW interaction on compositional and textural traits of raw and cooked pork. Pigs were bred to exhibit one of the three HAL genotypes (NN, Nn, and nn) with otherwise equivalent genomes. The nn halothane reactors are known to typically produce PSE pork, whereas NN pigs do not typically produce PSE pork. Pietrain x Large White gilts and boars, all with verified Nn genotype (by DNA test), were mated to obtain F2 littermates of the three HAL genotypes. These pigs were slaughtered at either 101 +/- 3 ("light") or 127 +/- 3 ("heavy") kg BW and were evaluated for longissimus muscle traits. The pH at .5 h after death (pH1) was 6.35, 6.13, and 5.68 in NN, Nn, and nn pigs, respectively. Sarcomere length was greater in nn than in NN and Nn pigs (1.94 vs 1.83 and 1.85 microm, respectively). Mechanical resistance was higher in nn than in NN pigs for both raw and cooked meat. Meat from nn pigs was judged by a trained panel to be less rough, more cohesive, harder, more fibrous, less granular, more elastic, and less easy to swallow than meat from NN pigs. For most traits under study, the heterozygotes were intermediate between the homozygotes but closer to NN than to nn pigs. Muscle from heavy pigs had longer sarcomeres and less moisture than muscle from light pigs. The n allele of the HAL gene unfavorably affects pork texture, and this effect is maintained throughout the range of 101 to 127 kg BW.

Derivation of an equation to estimate marrow content of bovine cervical vertebrae

Marrow content of bovine cervical vertebrae from Choice- and Select-grade carcasses weighing 294 to 343 kg was determined so that a method to monitor the amount of marrow in meat from advanced meat/bone separation machinery and recovery (AMR) systems could be developed. The marrow determination requires cleaning and then ashing bones. Because a large difference in ash content of bone and bone marrow exists and because cartilage content of cervical vertebrae in Choice and Select beef is relatively constant, it was possible to derive the following equation: Weight of marrow = [weight of cartilage (% ash in cartilage - % ash in bone) + % ash in bone (total weight) - (total ash)]/[(% ash in bone - % ash in marrow)]. Constants for ash in fresh bone, marrow, and cartilage were 58.51, .57, and 2.14% with SD of 2.23, .15, and .30%, respectively. A cartilage content of 9.5% along with cervical vertebrae weight and total ash weight were also used to calculate 33.9% marrow in cervical vertebrae. Means for marrow pressed or centrifuged from bovine cervical vertebrae were lower than those obtained from the equation. Therefore, pressing and centrifuging left some marrow in spongy bone. Our ashing method for determining the amount of marrow in whole cervical vertebrae should be useful for determining marrow remaining in cervical vertebrae of bone cakes from AMR systems. Percentage ash in pressed bones is higher and the calculated marrow content is lower when pressed bones are compared to cervical vertebrae that are not pressed. The amount of marrow in whole cervical vertebrae minus the amount left in cervical vertebrae from bone cakes equals the amount in meat from AMR systems.