PMEL p.L18del associates with beef quality of Kumamoto sub-breed of Japanese Brown cattle.

Japanese Brown cattle is the second most popular breed among Wagyu breeds and raised mainly in Kumamoto and Kochi Prefectures. Typical coat color of the Kumamoto sub-breed is solid brown, but individuals with diluted coat color are sometimes born. We previously detected four SNPs in PMEL gene and identified p.L18del as the causative polymorphism of this diluted phenotype. The current study examined the association between the SNPs in PMEL gene and carcass traits of the Kumamoto sub-breed. Our association analysis revealed that p.L18del had significant effects on BMS (p = 0.0263), meat brightness (p = 0.0179), meat firmness (p = 0.0102), and meat texture (p = 0.0252) and that del allele of this SNP might be useful to improve these carcass traits.

Producing Plasmid DNA Template for Clinical Grade RNA Vaccine Manufacture.

A plasmid production process has been established to manufacture plasmid DNA at a large scale in High-Quality grade. This is used as a starting material to produce mRNA vaccines for clinical trials. Recently, the World Health Organization (WHO) has released regulatory guidelines related to the quality, safety, and efficacy for DNA- as well as for mRNA-based vaccines. Following an extraordinary year of scientific, regulatory, and manufacturing developments, the scientific community today stands considerably better equipped to deal with urgent production requirements in large scale for nucleic acid-based vaccinations and therapies. Going forward, work needs to be done in better coordinating the supply and logistics of essential raw materials for biological manufacturing, especially under emergency conditions.

Quality grade evaluation of Nvjin Pills based on traditional Chinese medicine reference drug and network pharmacology of target-focused compounds.

To improve the effectiveness of marketed drugs related to active ingredients, it is necessary to designate a more unified quality evaluation standard. Taking Nvjin Pills as an example, this study reported the development of a novel principle of analysis in traditional Chinese medicine. The core of the experiment is to prepare three batches of traditional Chinese medicine reference drugs by high-quality Chinese materia medica. The active ingredients identified in the herbal formula including glycyrrhizic acid, cinnamaldehyde, paeonol, baicalin, hesperidin, paeoniflorin, and ferulic acid were analyzed in traditional Chinese medicine reference drugs by the high-performance liquid chromatography method combined with wavelength switching. The simple prediction results of network pharmacological analysis verified the feasibility and reliability of the established quantitative analysis method for seven target-focused compounds in Nvjin Pills, which were recommended as candidate indicators for quality evaluation ultimately. Using the seven target-focused compounds as the scientific ruler, quality grade specifications of Nvjin Pills were proposed by comprehensive analysis. Accordingly, 16, 47, and 13 batches of samples were primarily graded as first grade, second grade, and unqualified grade, respectively. This study will provide a chemical basis for quality control of Nvjin Pills, which is necessary for the production process of pharmaceutical development.

Correlation between Colour Traits and Intrinsic Quality of Dalbergiae Odoriferae Lignum.

Dalbergia odorifera T. Chen is traditionally referred to as "Dalbergiae Odoriferae Lignum" in traditional Chinese medicine. Its quality is typically assessed subjectively based on colour and texture observations and lacks a universal grading system. Our objective was to establish a relationship between heartwood colour and the content of key constituents, including total flavonoids, six specific flavonoids, alcohol-soluble extracts, and volatile oils, to assess their impact on heartwood quality. Substantial correlations were observed between the colour depth (L*), red-green direction (a*), and yellow-blue direction (b*), as well as the content of the extract, volatile oil, total flavonoids, naringenin, formononetin, pinocembrin, and isoliquiritigenin. Specifically, a* was correlated with the extract, total flavonoids, and isoliquiritigenin, whereas b* was correlated with the extract, volatile oil, total flavonoids, naringenin, formononetin, pinocembrin, and isoliquiritigenin. The results suggested that L*, b*, and chemical composition indices, such as extract, volatile oil, total flavonoids, and naringenin, could serve as primary criteria for classifying the quality of medicinal materials. This is consistent with market classification based on colour and texture, which facilitates material identification and guides the cultivation, harvesting, and processing of D. odorifera. This study provides a scientific foundation for its future development and use.

Using untargeted metabolomics and volatile aroma compounds to predict expert sensory descriptors and consumer liking of beef loin steaks varying in quality grade, aging time, and degree of doneness.

Precursors to flavor are important to its development, yet little is known about the intrinsic products of metabolism that influence flavor. Our objective was to use untargeted metabolomics and volatile aroma compounds to predict expert and consumer sensory traits. USDA Select and upper 2/3 Choice beef strip loins were wet aged for 10 or 20 d and then cut into steaks, vacuum-packaged, and frozen. Steaks were cooked to 63 °C, 71 °C, or 80 °C end-point internal steak temperature. USDA Choice steaks had more intense beef flavor identity, brown, roasted, fat-like, salty, sweet, sour, umami, buttery, and overall sweet flavors compared to USDA Select steaks (P < 0.05). Steaks cooked to 80 °C had more intense beef identity, brown, roasted, and umami flavors than steaks cooked to a lower degree of doneness. Steaks cooked to either 63 °C or 71 °C had more intense bloody, metallic, and sour flavors and were juicier, more tender, and had less connective tissue than steaks cooked to a higher degree of doneness. Volatile aroma compounds increased (P < 0.05) in Choice steaks aged for 20 d, while cooking steaks to 80 increased aldehydes, ketones, and pyrazines. Raw steaks had 69 small-molecule metabolomic compounds shared across all four quality grade x aging combinations, and discriminant analysis correctly categorized (P < 0.05) these metabolites. Metabolites and volatiles can be used to predict (r2 > 0.85) expert and consumer sensory panel descriptors and liking.

Objective Meat Quality from Quality Grade and Backfat Thickness of Hanwoo Steers.

The objective of this study was to determine the effects of quality grade (QG), and back-fat thickness on the carcass traits and meat quality properties of Hanwoo steers. Fifty carcasses were sorted into two QG (QG 1+ and 1) and three back-fat thickness (<10 mm, 10 to 19 mm and ≥19 mm) groups. After investigating the carcass traits (rib eye, back-fat thickness, weight, color, yield index, maturity, marbling score, and texture), the longissimus lumborum muscles from the carcass groups were collected and analyzed for meat quality (pH, color, cooking loss, and moisture), texture profiles [Warner-Bratzler shear force (WBSF), and tensile tests], and fatty acid. Results showed that marbling score (p<0.001), moisture (p<0.05) and tensile tests values (p<0.05) had a significant differences between QG1+ and QG1. No differences in pH, color traits, cooking loss and WBSF values occurred between the QG groups. Regarding the back-fat thickness effect, we observed that the carcass weight, yield index (p<0.001), yield grade (p<0.001) and marbling score (p<0.05) had a significant differences among the back-fat thickness groups. Regarding the meat quality, moisture content and WBSF values (p<0.01) among the back-fat thickness groups. The back-fat thickness did not affect the pH, color, cooking loss and tensile tests. The QG and back-fat thickness did not affect the fatty acids contents (p>0.05). It may be concluded that the carcass traits and meat quality were significantly affected the QG and back-fat thickness.

Carcass and meat quality traits in Brangus steers.

The quality grade system used in the United States to identify carcasses with superior eating satisfaction to consumers is based on the amount of marbling within the ribeye and the maturity of the carcass. However, the most important quality attribute for consumers is tenderness. The objective of this study was to investigate the phenotypic correlations between carcass and meat quality traits of strip loin steaks from Brangus steers, particularly the relation between the United States Department of Agriculture (USDA) quality grade and tenderness. Warner-Bratzler shear force (WBSF) values in this study averaged 5.10 ± 0.96 kg, slightly higher than the national average of 4.55 ± 1.14 kg. Average WBSF across all quality grades ranged from 4.90 to 5.27 kg with standard deviations ranging from 0.78 to 1.40 kg. In the present Brangus steer population, there was a weak negative (-0.13) but favorable correlation (P < 0.05) between marbling score and tenderness measured through WBSF. The USDA quality grade had a significant (P = 0.02) effect on WBSF. The WBSF least square means were significantly higher in the Select compared with the Choice¯, and Choiceº quality grades. The Choice⁺ and Prime quality grades were not significantly different from any quality grades regarding the WBSF. The standard quality grade did not have significantly different WBSF least square means from any other quality grade. The range of WBSF values was large, especially in the lower quality grade categories, indicating that there is considerable variation in tenderness, even within quality grade. The high level of variation in tenderness within USDA quality grades highlights the limitation of the USDA grading system to predict eating quality or tenderness.

Crossbreeding beef sires to dairy cows: cow, feedlot, and carcass performance.

Genetic and reproductive advancements in the dairy industry, volatile milk markets, and beef packer restrictions on dairy carcasses have increased the popularity of crossbreeding beef sires to dairy cows in the United States. This observational study aimed to understand performance of dairy cows bred to beef sires and feedlot and carcass performance of crossbred beef × dairy cattle. For dairy cow performance, archived records from two dairies representing two successive lactations were evaluated in cows (Dairy A: n = 72/group; Dairy B: n = 456/group) representing 1) All Dairy, where previous sire type of conception was Holstein for both lactations, or 2) Beef on Dairy, where previous sire type of conception was Holstein for the preceding lactation and a beef breed for the subsequent lactation. For feedlot performance, closeout data from pens (n = 26/cattle type) of beef and beef × dairy steers and heifers were evaluated. For carcass performance, individual carcass data were compared between conventional beef (n = 966), beef × dairy (n = 518), and Holstein (n = 935) steers sampled across a variety of processing facilities, harvest lots, and geographical regions. Cow lactation performance was minimally impacted by sire type of previous conception. Cows conceived to beef sires exhibited a 2 to 3 d greater (P < 0.01) gestation length than cows conceived to Holstein sires. Beef × dairy cattle were not largely different in weight gain at the feedlot but exhibited 1-unit lesser (P < 0.01) dressing percentage than beef cattle. Beef × dairy carcasses possessed 18% lesser (P < 0.05) 12th rib fat thickness than beef cattle and 5% greater (P< 0.05) ribeye area than dairy cattle. Additionally, beef cattle produced nearly double (P < 0.05) the percentage of yield grade 4 carcasses produced by beef × dairy and Holstein cattle.

Leptin gene contributes to beef marbling standard, meat brightness, meat firmness, and beef fat standard of the Kumamoto sub-breed of Japanese Brown cattle.

The Kumamoto sub-breed of Japanese Brown cattle has unique characteristics, such as great growth rate, and their contribution as future breeding materials is expected. To develop a DNA marker for their breeding, we investigated the effects of Leptin gene, controlling energy homeostasis, on carcass traits of the Kumamoto sub-breed. Sequence comparison identified five single nucleotide polymorphisms (SNPs): four linked synonymous mutations and one nonsynonymous mutation. Statistical analysis revealed that c.239C > T (p.A80V) had significant effects on the traits related with quality grade: beef marbling standard (p = 0.0132), meat brightness (p = 0.0383), and meat firmness (p = 0.0115). The C allele showed favorable effects; these scores of the C/C cattle were significantly higher than those of the C/T cattle. On the other hand, the effect of c.399T > C was observed on meat firmness (p = 0.0172) and beef fat standards (BFS) (p = 0.0129). The C/C cattle showed higher values of these traits than the T/T cattle. Our data suggested that these SNPs in Leptin gene could be used as a DNA marker for breeding of the Kumamoto sub-breed.

Ageing as a method to increase bloom depth and improve retail colour in beef graded AUS-MEAT colour 4.

Meat colour is an important attribute for consumer acceptance but there is an interval between colour grading and retail display. This experiment investigates the effect of time post-slaughter (5, 14 and 40 days) on colour and bloom depth (after 1 and 24 h) for beef carcasses graded AUS-MEAT colour 4 (MC 4). Sixteen carcasses were selected at grading, 8 carcasses were graded MC 4 and 8 as compliant colour (AUS-MEAT score 2 or 3). At 5 days post-slaughter, compliant loins had greater overall bloom depth and were more red than MC 4 loins. Bloom depth (24 h) increased with ageing time but reached maximum bloom at 14 days for both treatments. After ageing for 14 and 40 days, the bloom depth of MC 4 loin was no different to the 5 day aged compliant loins after 24 h on display. Colour at grading may not be a reliable measure of retail colour considering the changes post slaughter.

Study on quality grade standard of premature Forsythia suspensa / 中国药房

OBJECTIVE To study the quality grade stand ard of the premature Forsythia suspensa . METHODS A total of 138 batches of premature F. suspensa were collected from the main producing areas of F. suspensa in China. According to 2020 edition of Chinese Pharmacopoeia ，the contents of impurities ，moisture，ethanol-soluble extract ，volatile oil ，forsythin and forsythoside A in the premature F. suspense were determined ，and the qualified samples were screened. AHP-PCA mixed weighting method was used to give comprehensive weight to the indicators （except for the limit of impurity ）. The comprehensive score of the samples was calculated. The suggestions on the quality grade division of premature F. suspensa were put forward according to cluster analysis of K-mean value. RESULTS & CONCLUSIONS The contents of impurities ，moisture，ethanol-soluble extract ，volatile oil ，forsythin and forsythoside A in the premature F. suspense were 0-7.80％，1.60％-8.18％，13.13％-61.60％，0.21％-3.47％，0.02％-2.15％ and 0.79％-14.04％，respectively；average contents of them were 1.24％，4.97％，34.88％，2.01％，0.42％，6.86％，respectively. Totally 47 batches of 138 batches were qualified in all indexes. It is suggested that the quality grade of the premature F. suspense can be divided into three grades ：in first grade of F. suspense ，the contents of volatile oil ，forsythin，forsythoside A ， ethanol-soluble extract and moisture were ≥2.40％，≥0.59％，≥8.34％，≥38.66％ and ≤4.99％，respectively；in second grade of F. suspense ，the contents of above indicators were ≥2.26％，≥0.41％，≥7.47％，≥32.58％ and ≤5.33％，respectively；in third grade of F. suspense ，the contents of above indicators were ≥2.15％，≥0.32％，≥4.60％，≥31.52％ and≤7.23％，respectively.

Sensory Quality and Histochemical Characteristics of Longissimus Thoracis Muscles between Hanwoo and Holstein Steers from Different Quality Grades.

This study compared the meat quality characteristics, palatability, and histochemical characteristics of low-marbled Hanwoo and Holstein steers of different beef quality grades (1, 2, and 3). No differences were observed in muscle pH24 h and cooking loss between the groups (p>0.05); however, quality grade 1 of Hanwoo steers (HA1) showed a darker muscle surface compared to grade 1 of Holstein steers (HO1) (30.9 vs. 33.9, p<0.05). The HA2 group exhibited a lower value of Warner-Bratzler shear force compared to the HO1 and HO3 groups (60.8 vs. 69.2 and 87.8 N, p<0.001). For sensory quality attributes, steaks from the HA1 group showed higher scores of softness, initial tenderness, and amount of perceptible residue than steaks from the HO1 group (p<0.001). Within the quality grade 2, Hanwoo steers had a higher score of softness compared to Holstein steers (p<0.001). There were no differences in juiciness and flavor intensity between Hanwoo and Holstein steers at the same quality grade (p>0.05). This difference in tenderness attributes between the breeds within the quality grade was associated with morphological traits of muscle bundle, and Hanwoo steers had smaller bundle area (0.37 vs. 0.50 mm2, p<0.05) and higher fiber number per bundle (88.2 vs. 121, p<0.05) compared to Holstein steers. Therefore, bundle characteristics of longissimus thoracis muscle can be crucial for explaining factor for the explanation of tenderness variations between different breeds at the same beef quality grade or marbling.

Quantitative assessment of the habitat quality dynamics in Yellow River Basin, China.

Habitat quality is an important indicator for measuring regional biodiversity and ecosystem service value. A change in habitat quality is the direct result of the interaction between human activities and the natural environment. In this study, the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model was used to evaluate the habitat quality of the Yellow River Basin (YRB) from 1980 to 2018. We further analyzed the quantity and spatial transfer status of habitat quality quantitatively using the Geo-informatic Tupu method. The results show that the habitat degradation degree under human disturbance showed a trend of increasing first and then decreasing, with values of 0.0196 in 1980, 0.0200 in 2000, and 0.0199 in 2018. In addition, it presents two ring structures: light-severe-high-moderate and light-moderate-high-severe in space. The overall level of habitat quality in the basin is relatively good, but there is a trend of decline, which are 0.6091, 0.6069, and 0.6049 in the three stages respectively. The spatial distribution of habitat quality showed a pattern of high in the middle and low on both sides. The habitat quality has been restored in some areas. The transition between good and medium and good and excellent in the Tupu change units of the habitat quality grade is the most intense. Both stages are mainly the transformation from high-grade to low-grade habitat quality, but there is a trend of gradual improvement. The findings could have theoretical support and policy implications for the maintenance of biodiversity and the protection of the natural environment in the Yellow River Basin.

Analysis of Heavy Metal Pollution in Cultivated Land of Different Quality Grades in Yangtze River Delta of China.

The distribution of heavy metal pollution in cultivated land is closely related to the quality of the cultivated land. In this study, 533 soil samples were collected from cultivated land in the Yangtze River delta region in China for Cd, Pb, and Hg analyses. Spatial statistical analysis was used to study the heavy metal pollution in the cultivated land, and the driving forces of heavy metal distribution in different cultivated land quality subdivisions were analyzed with GeogDetector. The conclusions are as follows: (1) Among the three heavy metals in the study area, the coefficient of variation of Cd is the largest, and that of Pb is the smallest. The proportion of Cd and Hg exceeding the standard value (the standard of level two in GB 15618-2018) is relatively large, both of which are 5%; (2) From the perspective of the spatial distribution of soil heavy metal pollution, only four counties (CX, HN, WY, and LH) were free of heavy metal pollution. Soil heavy metal pollution in AJ, SY, QJ, and DS counties is relatively serious, and the pollution may come from agricultural activities, manufacturing, and prevalent coastal shipping industries in these counties; (3) The heavy metal pollution levels of cultivated land with different quality levels are different. The high-quality cultivated land has no high contamination, while the medium and the general cultivated land both have high contamination. High contamination is related to Cd for medium and general cultivated lands, and to Hg in only general cultivated land; (4) The main driving factors of heavy metal concentration in cultivated soil were GDP, followed by soil organic matter, and pH. These results indicate that the spatial distribution of heavy metal concentration in cultivated soil was affected by the level of economic development, followed by the ecological environment, indicating that human activities had a critical impact on the ecological environment of cultivated land.

Gene Expression and Carcass Traits Are Different between Different Quality Grade Groups in Red-Faced Hereford Steers.

Fat deposition is important to carcass value and some palatability characteristics. Carcasses with higher USDA quality grades produce more value for producers and processors in the US system and are more likely to have greater eating satisfaction. Using genomics to identify genes impacting marbling deposition provides insight into muscle biochemistry that may lead to ways to better predict fat deposition, especially marbling and thus quality grade. Hereford steers (16) were managed the same from birth through harvest after 270 days on feed. Samples were obtained for tenderness and transcriptome profiling. As expected, steaks from Choice carcasses had a lower shear force value than steaks from Select carcasses; however, steaks from Standard carcasses were not different from steaks from Choice carcasses. A significant number of differentially expressed (DE) genes was observed in the longissimus lumborum between Choice and Standard carcass RNA pools (1257 genes, p < 0.05), but not many DE genes were observed between Choice and Select RNA pools. Exploratory analysis of global muscle tissue transcriptome from Standard and Choice carcasses provided insight into muscle biochemistry, specifically the upregulation of extracellular matrix development and focal adhesion pathways and the downregulation of RNA processing and metabolism in Choice versus Standard. Additional research is needed to explore the function and timing of gene expression changes.

Investigation of Physicochemical and Sensory Quality Differences in Pork Belly and Shoulder Butt Cuts with Different Quality Grades.

The objective of this study was to investigate the effects of quality grade (QG) on the physicochemical composition and eating quality attributes of pork belly and shoulder butt. Seventy-two growing-finishing crossbred pigs were slaughtered and their carcasses were graded according to the Korean pork carcass grading system. Based on the grading criteria, the carcasses were classified into: QG 1+ (n=23), QG 1 (n=23) and QG 2 (n=26) groups. At 24 h postmortem, belly and shoulder butt cuts were collected from the QG groups and used for analysis of meat quality, flavor compounds and eating quality attributes. Results showed that the variation in fat content among QG was approximately 2% in the both cut types. The QG showed no effects on all the quality traits: cooking loss, pH and color of the belly or shoulder butt (p>0.05). Thirty-five flavor compounds comprising mainly fatty acids oxidation/degradation-derived products (e.g., aldehydes) and only few Maillard reaction-derived products (e.g., sulfur-and nitrogen-containing compounds) were identified. However, the QG showed a minor effect on the flavor profiles in both the belly and shoulder butt. Regarding the sensory quality, no effects of the QG were found on all the eating quality attributes (color, flavor, juiciness, tenderness and acceptability) for both the belly and shoulder butt cuts (p>0.05). Thus, it may be concluded that the current pork carcass grading standards do not reflect the real quality and value of the belly and shoulder butt cuts.

The Effects of Total Mixed Ration Feeding with High Roughage Content on Growth Performance, Carcass Characteristics, and Meat Quality of Hanwoo Steers.

This study investigated the dietary effect of total mixed ration (TMR) based on high roughage content on the growth performance, carcass characteristics, and meat quality of Hanwoo steers. Twenty-four Hanwoo steers (average body weight, 195.3±4.7 kg; age, 8.5 mon) were randomly allocated to three experimental groups according to forage and concentrate ratio (DM basis): 25:75 (control), 50:50 (T50), and 70:30 (T70). Productivity in the fattening period and final body weight were significantly higher in the control. Average daily gain and feed conversion ratio were the same among treatments. Serum parameters, cholesterol, blood urea nitrogen, and total protein were higher in the control. Carcass weight was comparable in the control and T50 but feeding more roughage was significantly correlated with a higher intramuscular fat. Shear strength and drip loss were higher while n-6/n-3 was lower in T70 compared to the other groups. However, meat color was not significantly different among treatments. In terms of free amino acid contents, glutamic acid and glycine were higher in the control than T50 and T70. Overall, feeding Hanwoo steers with high forage content TMR had the lowest n-6/n-3 ratio of fatty acid content but highest intramuscular fat, shear strength, and drip loss. High forage content TMR is the best feed for Hanwoo steers that gives more benefits for human health and consumption but also provides the best meat grade and quality, which is important in the beef market in Korea.

Relationships among carcass traits, auction price, and image analysis traits of marbling characteristics in Korean cattle beef.

Marbling score (MS) is related to beef auction price (AP) in Korea, but how these relate to marbling texture (i.e. number and distribution of marbling particles [MPs]) is not known. We examined relationships among carcass traits, carcass AP, and image analysis marbling texture traits. In experiment 1, carcass data and longissimus thoracis (LT) were obtained from Korean cattle steers reared under similar feeding conditions. MS, quality grade (QG), and AP were related (P < 0.001) to numbers of coarse MPs and fine MPs and fineness index. In experiment 2, LT images photographed at a slaughterhouse were used in regression analysis within individual QG classes (QGs: 1 [middle], 1+, and 1++ [best]). AP was related (P < 0.001) to numbers of coarse MPs and fine MPs and fineness index in both QGs 1+ and 1++ but not in QG 1. Overall, several marbling texture traits were related to AP, but both MS and QG were more strongly related to AP.

Prediction of quality traits and grades of intact chicken breast fillets by hyperspectral imaging.

1. In this study, hyperspectral imaging was evaluated for its usefulness to predict quality traits and grading of intact chicken breast fillets. 2. Lightness of colour (L*) and pH of the fillets were measured as quality traits, and samples were then selected and graded to three different quality categories, i.e., dark, firm and dry (DFD), normal (NORM), and pale, soft and exudative (PSE) based on these two quality traits. Based on the prediction performance of full wavelength partial least square regression (PLSR) models, the spectral range of visible and near-infrared (Vis-NIR) was more suitable for the evaluation of quality traits and grading than the range of near-infrared (NIR). Key wavelengths of each quality trait and grade value were selected by the regression coefficient (RC) method. 3. The new key wavelength PLSR models showed good predictive performances (Rp = 0.85 and RMSEp = 2.18 for L*, Rp = 0.84, and RMSEp = 0.13 for pH, and Rp = 0.80 and RMSEp = 0.44 for quality grading). The classification accuracy for grades was 85.71% (calibration set) and 81.82% (prediction set), respectively. Finally, distribution maps showed that quality traits and grades of samples were able to be visualised. 4. These results suggested that hyperspectral imaging has the potential for quality prediction of fresh chicken meat.

Effects of quality grade and intramuscular location on beef semitendinosus muscle fiber characteristics, NADH content, and color stability.

The objective of this study was to determine the impact of quality grade and steak location on color stability of semitendinosus (ST) steaks during a 9-d refrigerated study. Twenty-one ST muscles (12 Choice and 9 Select) were purchased from a commercial beef packing plant and fabricated into twelve 2.54-cm thick steaks per muscle. Steaks 1, 6, and 12 were designated for immunohistochemistry while remaining steak locations of proximal (steaks 2 to 4), middle (5 to 8), and distal (9 to 11) were randomly assigned to 0, 4, or 9 d of simulated retail display. Surface color attributes of day-9 steaks were recorded daily by a visual color panel and spectrophotometer. On days 0, 4, and 9 of display, steaks were analyzed for metmyoglobin reducing ability (MRA) and oxygen consumption (OC). Grade × day of display (DOD) interactions were detected for L*, a*, surface oxymyoglobin (OMb) and metmyoglobin (MMb) percentages, and visual panel surface redness and discoloration scores (P ≤ 0.02); however, no Grade × DOD interactions were observed for MRA or OC (P > 0.17). There were location main effect (LOC) × DOD interactions for L*, a*, surface MMb, visual panel surface redness and discoloration, and MRA (P ≤ 0.02). Distal steaks had lower L* values compared with the other locations (P < 0.01), which coincided with steaks being rated visually darker red (P < 0.01). Proximal steaks had greater a* values and had less surface discoloration than middle steaks (P < 0.05), which had an increased percentage of surface MMb (P ≤ 0.04). Distal and proximal steaks had increased MRA compared with middle steaks on days 0 and 4 (P < 0.05), and distal steaks had greater OC than the other locations throughout display (P < 0.01). There were fewer type I fibers at the proximal end with a greater percentage located at the middle and distal ends, and an increased percentage of type IIX fibers at the middle and proximal locations (P ≤ 0.01). Less type IIA fibers were detected at the middle LOC compared with the other two locations (P < 0.10). Larger type I, IIA, and IIX fibers were located at the proximal and middle locations compared with the distal LOC (P < 0.01). ST color and color-stability characteristics were influenced by DOD and LOC, which may partially be explained by differences in fiber types among locations.