Beef Carcasses Research Articles

Regional and dynamic specialization of beef production in Mexico (2000-2018)

Objective: To determine the growth, specialization, and dynamics of beef carcass production in eight regions of Mexico, in the 2000-2018 period. Design/Methodology/Approach: The annual growth rates from 2000 to 2018 in each of the regions were calculated. Based on this information, we were able to determine the relative and dynamic specialization of beef production through Regional Analysis Techniques, such as the Location Quotient and the Differential-Structural Method. Results: During the 2000-2018 period, the domestic beef carcass production had diverse annual growth. Most of the location quotients greater than the unit were obtained in Chiapas and Sonora, while Sinaloa and Chihuahua obtained lower location quotients. The results of the Differential-Structural Method showed that Sinaloa was the most dynamic region, while Veracruz and Sonora have been left behind and showed little specialization in all sub-periods. Limitations/Implications: The differentiated annual growth between regions implied underdevelopment and intra-regional dynamism over time. The change in the productive calling of some regions involved a transformation from being specialized to non-specialized. The dynamics of the regions was determined by hypothetical gains, while the underdevelopment was related to hypothetical losses of various magnitudes. Findings/Conclusions: Sinaloa had the highest growth and dynamism of all the regions. Veracruz and Sonora were left behind and showed little specialization throughout the analyzed period.

Verification of image analysis accuracy of beef carcass cross section with new beef carcass camera

Verification of image analysis accuracy of beef carcass cross section with new beef carcass camera

Agents of Campylobacteriosis in Different Meat Matrices in Brazil.

We aimed to identify the prevalence of thermophilic species of Campylobacter in meats of different species available on the Brazilian commercial market and to determine the genetic diversity, antimicrobial resistance and virulence potential of the isolates. A total of 906 samples, including chicken, beef and pork carcasses and chicken and beef livers, were purchased in retail outlets, and prevalences of 18.7% (46/246), 3.62% (5/138), 10.14% (14/138), 3.62% (5/138) and 4.47% (11/132), respectively, were identified, evidencing the dissemination of genotypes in the main producing macro-regions. Of all isolates, 62.8% were classified as multidrug resistant (MDR), with resistance to amoxicillin-clavulanate (49.4%), tetracycline (51.8%) and ciprofloxacin (50.6%) and co-resistance to macrolides and fluoroquinolones (37.1%). Multivirulent profiles were identified mainly in isolates from chicken carcasses (84.8%), and the emergence of MDR/virulent strains was determined in pork isolates. All isolates except those from chicken carcasses showed a high potential for biofilm formation (71.4% luxS) and consequent persistence in industrial food processing. For chicken carcasses, the general virulence was higher in C. jejuni (54.3%), followed by C. coli (24%) and Campylobacter spp. (21.7%), and in the other meat matrices, Campylobacter spp. showed a higher prevalence of virulence (57.2%). The high rates of resistance and virulence reinforce the existence of strain selection pressure in the country, in addition to the potential risk of strains isolated not only from chicken carcasses, but also from other meat matrices.

Physical and Biochemical Mechanisms Associated with Beef Carcass Vascular Rinsing Effects on Meat Quality: A Review.

Carcass vascular rinsing and chilling involves infusing a chilled isotonic solution (98.5% water and a blend of mono- and di-saccharides and phosphates) into the vasculature immediately upon exsanguination. Primary purposes of carcass vascular rinsing are to (1) effectively remove residual blood from the carcass; (2) lower internal muscle temperature rapidly; and (3) optimize pH decline by effective delivery of glycolytic substrates in the rinse solution. Previous studies have revealed that the beef carcass vascular rinsing early postmortem positively affects meat quality, product shelf-life, and food safety. Thus, the objective of this review is to provide a more comprehensive understanding of the physical and biochemical mechanisms associated with beef carcass vascular rinsing, focusing on the relationship between quality attributes (CIE L*, a*, b*; chemical states of myoglobin; oxygen consumption and sarcomere length) and muscle metabolic response to various substrate solutions (Rinse & Chill®, fructose, sodium phosphate, and dipotassium phosphate) that stimulate or inhibit the rate of glycolysis early postmortem. In addition, this review discusses the absence of metabolite residues (phosphorus, sodium, and glucose) related to the application of the chilled isotonic solution. This review primarily focuses on beef and as such extending the understanding of the mechanisms and meat quality effects discussed to other species associated with vascular rinsing, in particular pork, may be limited.

Detection of Antimicrobial Resistance, Pathogenicity, and Virulence Potentials of Non-Typhoidal Salmonella Isolates at the Yaounde Abattoir Using Whole-Genome Sequencing Technique.

One of the crucial public health problems today is the emerging and re-emerging of multidrug-resistant (MDR) bacteria coupled with a decline in the development of new antimicrobials. Non-typhoidal Salmonella (NTS) is classified among the MDR pathogens of international concern. To predict their MDR potentials, 23 assembled genomes of NTS from live cattle (n = 1), beef carcass (n = 19), butchers’ hands (n = 1) and beef processing environments (n = 2) isolated from 830 wet swabs at the Yaounde abattoir between December 2014 and November 2015 were explored using whole-genome sequencing. Phenotypically, while 22% (n = 5) of Salmonella isolates were streptomycin-resistant, 13% (n = 3) were MDR. Genotypically, all the Salmonella isolates possessed high MDR potentials against several classes of antibiotics including critically important drugs (carbapenems, third-generation cephalosporin and fluoroquinolone). Moreover, >31% of NTS exhibited resistance potentials to polymyxin, considered as the last resort drug. Additionally, ≤80% of isolates harbored “silent resistant genes” as a potential reservoir of drug resistance. Our isolates showed a high degree of pathogenicity and possessed key virulence factors to establish infection even in humans. Whole-genome sequencing unveiled both broader antimicrobial resistance (AMR) profiles and inference of pathogen characteristics. This study calls for the prudent use of antibiotics and constant monitoring of AMR of NTS.

Deep learning feature extraction for image-based beef carcass yield estimation

Recently, there has been increased adoption of automation technologies in production facilities that help to curb mistakes, increase production speed and consistency, and reduce costs. Industrial automation owes its success to the advent of capable computers, smart algorithms, and data availability. In the modern-day slaughterhouse, automation technologies have been employed for operations such as cutting, deboning, grading. As one of the vital operations in the slaughterhouse, carcass grading is usually completed manually by grading staff, which is a bottleneck for production speed and consistency. However, due to the complexity of the problem, most of the technologies available for carcass grading suffer from low performance. This study aims to develop an image-analysis system that uses deep-learning tools for the prediction of key beef yield parameters. The image data collected from the carcass samples were used to develop deep-learning models that extract key features, which were then used to model and predict 23 beef carcass yield parameters using multiple linear regression. The models developed achieved good prediction performance for yield parameters such as lean meat percentage (with R 2 = 0.90, RMSE = 1.98%) and other yield parameters using a few selected features. The results from this study can be used as a foundation for developing an online beef carcass grading system. • Deep learning and image analysis are used to detect and extract useful features from carcass images. • The extracted features are used to effectively estimate 23 key beef carcass yield parameters. • Because of the simplicity of the proposed analysis approach, it can be a useful, cheap, and real time alternative to conventional carcass grading methods.

Meta-analysis to evaluate the effect of yeast as a feed additive on beef cattle performance and carcass traits

Yeast (Saccharomyces cerevisiae) is a group of feed additives widely used in ruminant diets to improve rumen health and consequently animal performance. The present study evaluated the effect of yeast inclusion on beef cattle's performance and carcass traits by meta-analysis. We hypothesized that the variables experimental period, supply period, and statistical design affect beef cattle's performance and carcass traits supplemented with yeast. Thirty-one peer-reviewed publications with 106 treatment means were included in the data set. Yeast effect as an additive in beef cattle diets was evaluated by examining the weighted mean differences (WMD) between yeast treatment (diets with yeast inclusion as an additive) and control treatment (diet with no additive). Heterogeneity was explored by meta-regression and subgroup analysis using genetic group, experimental design, experimental period, yeast in diet (g/day), yeast type, feeding system, and concentrate in diet (g/kg of dry matter). The experimental period was the variable that most influenced the variability of responses with yeast in the diet. Yeast addition in the diets increased average daily gain (ADG; WMD= 0.03 kg/d; P = 0.001) and carcass weight (WMD=3.12 kg; P = 0.046). The experimental period and yeast supply for up to 90 days increased the animals’ final body weight. The effect of yeast inclusion in the diet on the variable final body weight was only affected by the inclusion period or yeast supply. For the other ADG, carcass weight, and dressing, the response's variation was dependent only on the level of yeast inclusion in the diet. The diet's inclusion levels between 10 and 15 g yeast/day increase average daily gain and carcass weight.

Color attributes and myoglobin chemistry exhibit relationships with tenderness and calpain-1 abundance in postmortem Longissimus lumborum muscles from Holstein heifers

The objective of this study was to determine the extent that myoglobin and beef color are associated with calpain-1 relative abundance relative and tenderness. Longissimus lumborum (LL) samples from the left side of Holstein beef carcasses (n = 31) were collected immediately post-evisceration for 0 h analyses. At 48 h postmortem six steaks were removed from the right side of each carcass for analyses at 48 and 336 h postmortem. Myoglobin concentrations resulted in negative correlations (P < 0.05) to Warner-Bratzler shear force (WBSF) values at 336 h postmortem. L*, a*, and b* values at 48 h resulted in positive correlations (P < 0.05) with WBSF values at 48 and 336 h. Values for b* at 336 h had positive correlations with calpain-1 concentration at 0 and 336 h. Data from this study indicate a potential relationship between myoglobin concentration and meat color with tenderness aspects and calpain-1 relative abundance.

Genetic Profiles and Invasion Ability of Listeria monocytogenes Isolated from Bovine Carcasses in Southern Brazil

The goals of this study were to evaluate the persistence and the virulence potential of Listeria monocytogenes isolated from beef carcasses obtained in processing facilities in the southern region of Rio Grande do Sul, Brazil, based on pulsed-field gel electrophoresis (PFGE), invasion ability in human colorectal carcinoma cells (HCT-116), internalin A (InlA) expression by Western blot, and identification of mutation points in inlA. PFGE profiles demonstrated that L. monocytogenes isolates were grouped based on their previously identified lineages and serogroups (lineage I: serogroup IIb, n = 2, and serogroup IVb, n = 5; lineage II: serogroup IIc, n = 5). Isolates with indistinguishable genetic profiles through this method were obtained from different slaughterhouses and sampling steps, with as much as a 3-year interval. Seven isolates showed high invasion ability (2.4 to 7.4%; lineage I, n = 6, and lineage II, n = 1) in HCT and expressed InlA. Five isolates showed low cell invasion ability (0.6 to 1.4%; lineage I, n = 1, and lineage II, n = 4) and did not express InlA, and two of them (lineage II, serogroup IIc) presented mutations in inlA that led to premature stop codon type 19 at position 326 (GAA → TAA). The results demonstrated that most L. monocytogenes isolates from lineage I expressed InlA and were the most invasive in HCT, indicating their high virulence potential, whereas most isolates from lineage II showed attenuated invasion because of nonexpression of InlA or the presence of premature stop codon type 19 in inlA. The obtained results demonstrated that L. monocytogenes with indistinguishable PFGE profiles can persist or be reintroduced in beef processing facilities in the studied region and that differences in their virulence potential are based on their lineages and serogroups.

Coliform and Escherichia coli Contamination on External and Internal Surfaces of Beef Carcasses with and without Tissue Adhesion Excision

Following removal of hides and viscera during beef processing, carcasses are inspected for tissue adhesions that can affect meat quality or harbor bacteria. Carcasses with pleural or abdominal adhesions may be diverted from the production line for manual excision and then returned to the line. No published data indicate whether adhesion excision is associated with bacterial contamination. Therefore, our objective was to determine the presence and concentration of generic Escherichia coli and non-E. coli coliforms from the internal and external surfaces of carcasses that were, or were not, diverted for adhesion excision. During 9 processing days over a 4-month period in a large commercial beef processing facility, 1,738 carcass sponge samples from 2,730 cm2 areas on both the internal and the external surfaces of carcasses with and without tissue adhesions were collected. Coliforms and E. coli were cultured and enumerated using Petrifilm procedures, and data were analyzed with mixed models. Coliforms were present at higher concentrations than E. coli, and prevalence and mean log concentrations of both coliforms and E. coli were significantly higher for samples from the external than from the internal surfaces of carcasses. However, differences in prevalence and concentration of coliforms between external and internal surfaces varied significantly based on whether carcasses had adhesions excised. The difference was greatest for coliforms present on the external (2.06 log CFU/100 cm2) versus the internal (0.93 log CFU/100 cm2) carcass surfaces without adhesions, whereas the difference in concentrations from the external (1.80 log CFU/100 cm2) and the internal (1.31 log CFU/100 cm2) surfaces of carcasses with adhesions was not as large. These results indicate that surveillance of carcass bacteria may be affected by whether the external versus the internal surfaces are sampled and whether carcasses are diverted for excision of adhesions.

Beef Carcass Size and Aging Time Effects on Yield and Color Characteristics of Top Round Steaks

Variation in cut size and weight of fabricated subprimals is a challenge of increased beef carcass weights. Subsequently, variation in carcass size has resulted in consistency challenges during retail display. The objective of this study was to assess three aging periods of commercially available top rounds from varying carcass weights as it relates to yield and color characteristics. In the current study, 21 industry average weight (AW; 340 to 409 kg; no industry discount) beef carcasses and 21 oversized (OS; exceeding 454 kg; receive a discount) beef carcasses were evaluated. Carcasses were selected at a commercial beef packing plant, where the left and right (paired) top round subprimals of each carcass were procured. Paired top rounds were assigned to a short (8 d), average (23 d), or extended (42 d) postmortem aging period. After wet-aging, subprimals were fabricated into steaks for additional analysis. Steaks were evaluated as whole top round steaks or further fabricated into “ superficial ” and “ deep ” portions at 5.08 cm from the superficial edge of the Semimembranosus and the Adductor muscle. Top rounds and steaks from OS carcasses were larger (P &amp;lt; 0.01) than those from AW carcasses. Quantitative color of the anatomically deep locations of the OS steaks had the greatest mean L* (lightness; P &amp;lt; 0.01), a* (redness; P &amp;lt; 0.01) and b* (yellowness; P &amp;lt; 0.01) values. Extending the aging timeline increased L* (lightness; P &amp;lt; 0.01), decreased a* (redness; P &amp;lt; 0.01), and decreased b* (yellowness; P &amp;lt; 0.01). Alternative top round steak fabrication that separates the deep and superficial anatomical locations could be an effective means of providing more uniform steaks.

Differential Expression of MicroRNAs in Dark-Cutting Meat from Beef Carcasses

“Dark-cutting” meat in beef carcasses can result from conditions such as long-term stress and depleted glycogen stores, but some aspects of the physiological mechanisms that cause dark-cutting phenotypes remain poorly understood. Certain responses to stress factors in fully developed tissues are known to be regulated by specific microRNAs. We investigated microRNA expression in Longissimus lumborum biopsies from carcasses derived from a contemporary group of 78 steers from which a high incidence of dark-cutting meat occurred. Our objective was to identify any potential microRNA signatures that reflect the impact of environmental factors and stresses on genetic signaling networks and result in dark-cutting beef (also known as dark, firm, and dry, or DFD) in some animals. MicroRNA expression was quantified by Illumina NextSeq small RNA sequencing. When RNA extracts from DFD muscle biopsy samples were compared with normal, non-DFD (NON) samples, 29 differentially expressed microRNAs were identified in which expression was at least 20% different in the DFD samples (DFD/NON fold ratio ≤0.8 or ≥1.2). When correction for multiple testing was applied, a single microRNA bta-miR-2422 was identified at a false discovery probability (FDR) of 5.4%. If FDR was relaxed to 30%, additional microRNAs were differentially expressed (bta-miR-10174-5p, bta-miR-1260b, bta-miR-144, bta-miR-142-5p, bta-miR-2285at, bta-miR-2285e, bta-miR-3613a). These microRNAs may play a role in regulating aspects of stress responses that ultimately result in dark-cutting beef carcasses.

Estimating the Conditional Variance Volatilities of Beef Carcass, Lamb Carcass, and Fodder Wheat Markets in the Context of Exchange Rate Using VAR(2)- Asymmetric BEKK-GARCH (1,1) Model

Estimating the Conditional Variance Volatilities of Beef Carcass, Lamb Carcass, and Fodder Wheat Markets in the Context of Exchange Rate Using VAR(2)- Asymmetric BEKK-GARCH (1,1) Model

Effects of Chilling Duration on Marbling Score of Beef Carcasses

Two hundred and nine beef carcasses (body weight of 361±53 kg) from crossbred, grain-finished cattle were harvested in a commercial abattoir and subjected to continuous chilling for 96 h at 0°C to 3°C in a commercial hot box with a wind speed of 3.1 m/s and 153 lux of fluorescent light. At 24, 48, 72, and 96 h, the carcasses were analyzed for fatty acid composition,marbling score, pH, shrinkage, color, and aerobic plate count (n = 50). Carcasses reached 3°C after 12 to 16 h of chilling. There were minimal changes in shrinkage among time point (−0.4% to 1.2%; P ≤ 0.002), pH (5.56 to 5.69; P ≤ 0.001), and aerobic plate count (0.1 to 0.7 log; P &amp;lt; 0.001). Initial 24-h grading by a USDA grader revealed a grade composition of 21.1% Slight (n = 44), 34.0% Small (n = 71), 17.2% Modest (n = 37), 17.7% Moderate (n = 36), and 10.1% Slightly Abundant (n = 21). With a marbling score in numeric values between 200 (Practically Devoid00) and 1100 (Abundant00), carcasses that had Small or greater marbling score at 24 h experienced a decrease of 34 to 60 points after 96 h of chilling (P ≤ 0.042). Comparatively, the marbling scores of the Slight carcasses increased from 442 points at 24 h to 469 points at 96 h. Moreover, Slight carcasses had a greater percentage of polyunsaturated fatty acids (P &amp;lt; 0.001). Results indicate that chilling for 96 h increases the marbling score of USDA Select but has minimal impacts on the marbling score of greater USDA quality grades.

50 Implications of a Thermoforming Vacuum Packaging or Overwrap Packaging Method on a Simulated Retail Display of Longissimus Lumborum Steaks

Abstract Fresh surface color of beef remains a focus for consumers at the time of purchasing in the retail sector. The objective of this study was to evaluate instrumental surface color, expert color evaluation, and lipid oxidation (TBARS) on beef longissimus lumborum steaks packaged using recycle-ready film (RRF) or polyvinyl chloride overwrap (PVC). Paired strip loins (IMPS # 180), fabricated from beef carcasses (n = 7) 10 d postmortem, cut into 2.54 cm-thick steaks, and assigned to one of two packaging treatments RRF (OTR = 0.8 cc/m2/24 h) or PVC (OTR = 14,000 cc/m2/24 h). Steaks were stored under simulated retail conditions (3 °C ± 1.5 °C) in a LED (2297 lux) lighted, three-tiered retail cabinet, rotated daily among shelves for 35 days. From d 0 to 35 objective surface color was captured every 5 days to record changes in lightness (L*), redness (a*), yellowness (b*), Chroma, Hue Angle, and calculated values of spectral wavelengths (Red to Brown, Oxymyoglobin, Deoxymyoglobin, &amp; Metmyoglobin) using a HunterLab colorimeter. Steaks packaged in RRF became lighter (L*) as display period increased (P &amp;lt; 0.05), whereas steaks packaged in PVC became darker (P &amp;lt; 0.05). Redness (a*) values were greatest (P &amp;lt; 0.05) for PVC steaks until day 5, whereas RRF steaks had greater (P &amp;lt; 0.05) surface redness from day 10 to 35 of the display period. Calculated spectral values red to brown were greater (P &amp;lt; 0.05) for steaks in RRF than PVC. Expert color evaluators rated RRF steaks having less browning and less discoloration (P &amp;lt; 0.05) from day 5 to 35 of display. Lipid oxidation was greater (P &amp;lt; 0.05) for PVC steaks from day 10 through day 35 of the display. These results suggest that the use of RRF vacuum packaging for beef steaks is plausible and can maintain surface color characteristics during extended display periods.

Nondestructive estimation of beef carcass yield using digital image analysis

Assessment of beef carcass quality and yield is commonly done in a hands-on manner by experts who undertake lengthy tasks to quantify the yield and assign respective grades for every carcass on the slaughter line. Recently, there has been an outburst of technologies to speed up and support the expert’s carcass yield assessment. However, due to the complexity of the problem, most of these technologies have low performances. The goal of this research is to develop a novel image analysis system for prediction of beef yield and quality with acceptable accuracy. This study aims to combine image processing and statistical modelling to predict key beef carcass yield parameters. Using image data from 140 beef carcass samples, we were able to develop models that achieved good prediction performance for yield parameters like lean meat percentage (with R2 = 0.89, RMSE = 1.99%), and other parameters (with R2 > 0.86) using a few selected features from image analysis and multiple linear regression. Given the current industrial trend in beef carcass yield grading, the results we achieved could potentially serve as a basis for online beef carcass grading.

Tumbling and subsequent aging improves tenderness of beef longissimus lumborum and semitendinosus steaks by disrupting myofibrillar structure and enhancing proteolysis.

Tenderness is an important sensory attribute to the overall eating experience of beef. Identifying novel methods to ensure consistent tenderness, especially in inherently tough cuts, is critical for the industry. This study investigated if tumbling without brine inclusion could be an effective method to improve the quality and palatability attributes of beef longissimus lumborum (LL) and semitendinosus (ST) steaks. Furthermore, interactions with postmortem aging were evaluated to determine how tumbling might affect protein degradation and muscle ultrastructure. At 5 d postmortem, pairs of LL and ST muscles from beef carcasses (n = 16) were bisected, vacuum packaged, and tumbled for 0, 40, 80, or 120min. Sections were divided and subsequently aged an additional 0 or 10 d at 2 °C. Tumbling for any duration improved instrumental tenderness of LL (P < 0.001) but not ST (P > 0.05) steaks, regardless of aging time. Tumbling exacerbated moisture loss in both muscles shown by greater purge and cooking losses (P < 0.05). Myofibrillar fragmentation was induced through tumbling in both muscles (P < 0.001), which was supported by transmission electron microscopy images. Tumbling for 120min followed by 10 d of aging resulted in less abundant intact troponin-T in both LL and ST (P < 0.05), as well as less intact desmin in ST (P < 0.05); however, calpain-1 autolysis was not affected by tumbling (P > 0.05). No effects of tumbling, aging, nor the interaction were found for the content and solubility of collagen (P > 0.05). Consumer panelists (n = 120/muscle) rated LL steaks tumbled for any duration higher for tenderness and overall liking compared to control steaks (P < 0.05). For ST, significant interactions were found for consumer liking of tenderness and juiciness. In general, tumbling without subsequent aging resulted in poorer juiciness than non-tumbled (P < 0.05), while at 10 d no differences in juiciness were found between treatments (P > 0.05). For ST steaks that were aged 10 d, 120min of tumbling resulted in greater tenderness liking than non-tumbled steaks (P < 0.05). These results suggest that tumbling would result in myofibrillar fragmentation and may benefit the degradation of myofibrillar proteins; however, there would be negligible impacts on collagen. Accordingly, tumbling without brine inclusion alone may be sufficient to improve tenderness and overall liking of LL steaks, while combined tumbling with subsequent postmortem aging would be necessary to improve tenderness liking of ST.

The impact of carcass size, chilling, and electrical stimulation on beef postmortem temperature and pH decline

Variability in carcass size can influence carcass chilling rates which could result in issues associated with beef tenderness and color. Moreover, the usage of electrical stimulation can affect postmortem metabolism and meat quality. However, few studies have looked at the combined impact of chilling and electrical stimulation on temperature decline, postmortem biochemistry, and color among the current consist of US beef. Beef carcasses (N =162, &amp;lt; 30 months) were randomly selected from two beef processing plants. One side of each carcass was electrically stimulated (ES), while the opposing side was not electrically stimulated (NES). Matched sides were subjected to either conventional spray chilling (CONV) or delayed-spray chilling (DELAY). Deep tissue (10.5-cm under the pelvic bone) and surface temperature (1.5-cm under the loin fat) were continuously monitored during chilling in addition to temperature and pH measurements from the semimembranosus (SM), longissimus lumborum (LL), and psoas major (PM) muscles at an initial time (45 to 60 min), 6 h, 12 h, and after chilling (28 to 36 h) postmortem. Further, the instrumental (L*, a*, and b*) and visual color of the PM were evaluated. For data analysis, carcasses with hot carcass weights above or below the average were considered heavy or light, respectively. A nonlinear regression model was fitted to the continuous deep and surface temperatures, whereas other parameters were evaluated using a mixed model. Electrical stimulation improved (P &amp;lt; 0.05) the color of PM in light weight carcasses, but not (P &amp;gt; 0.05) in heavy weight carcasses. Temperature decline was faster (P &amp;lt; 0.05), and pH decline slower (P &amp;lt; 0.05) in the SM and LL of light weight carcasses under CONV. Exponential decay models for deep and surface temperatures indicated the rate of cooling differed (P &amp;lt; 0.05) due to the combination of treatment factors. Heavy weight carcasses in DELAY had slower rates of temperature decline (P &amp;lt; 0.05). Overall, the variability in carcass size affected temperature decline and postmortem metabolism. Therefore, postmortem management practices should consider carcass weights to ensure homogeneous meat quality.

Effect of Myostatin Gene Mutation on Slaughtering Performance and Meat Quality in Marchigiana Bulls.

Simple SummaryThe aim of this work was the evaluation of slaughtering performance in a sample of 78 Marchigiana bulls with different allelic situation at the myostatin locus; in addition, the qualitative composition of meat samples collected from Longissimus thoracis muscle was evaluated. At the myostatin gene, 67 homozygotes normal, 11 heterozygotes, and no double-muscled homozygote bulls were detected. Heterozygote bulls showed high values in final live weight and dressing yield; moreover, they were characterized by a low incidence of fat at steak dissection, as well as in meat chemical composition. A better muscular conformation in heterozygote bulls’ carcasses was highlighted, with a higher incidence of their carcasses in class E and evident convexity of round, back, and shoulder muscular masses compared to the carcasses of Marchigiana bulls which were normal at the myostatin gene.The myostatin gene also called Growth Differentiation Factor 8 gene (GDF8) is one of the most investigated loci that can be responsible for several quantitative and qualitative carcass and meat traits in double-muscled beef cattle. The objective of the study was to bring to light the effect of the myostatin polymorphism on slaughtering performance and meat quality in Marchigiana beef cattle. The experiment was carried out on 78 bulls reared according to the “cow-calf” extensive managing system. At the end of the fattening period, in vivo and carcass data were recorded. From each carcass, a steak of Longissimus thoracis was taken and used to determine the meat’s analytical composition and colorimetric properties. Finally, from each steak a sample of Longissimus thoracis was collected, then used for DNA extraction and genotyping at the myostatin locus. The heterozygous bulls showed slight superiority in the carcass data (e.g., hot carcass weight: 426.09 kg—heterozygotes vs. 405.32 kg—normal) and meat quality parameters, although not always with statistical significance. Only fat and ashes content were significantly affected by the myostatin genotype (heterozygotes: 2.01%, 1.26%; normal: 3.04%, 1.15%). The greater muscularity of heterozygous animals compared to normal ones could be a starting point to improving productive efficiency in Marchigiana beef cattle.

Assessing chemometric models developed using Raman spectroscopy and fatty acid data for Northern and Southern Australian beef production systems

A total of 960 beef carcases from northern and southern Australian production regions were assessed by examining the subcutaneous fat. Carcases from four different production systems within each region were assessed, by Raman spectroscopy and the fatty acid composition determined to develop models that best classified the various production systems. As a result, 12 Partial Least Square Discriminant Analysis models were developed. A two-class model based on fatty acid composition was able to correctly classify 99% of grass and grain fed animals. The best Raman spectroscopic model correctly classified 94% of grass vs grain carcases produced in the northern region. For the southern production region, the models had the following classification accuracies; southern long-term grain fed (98%), southern short-term grain fed (95%), southern grass (96%), southern grass supplemented (97%), and the southern model classified grass vs grain (97%). Raman spectroscopy is considered a useful rapid method for classification of beef carcases based upon production system.