Meat Science最新文献

Pork color is crucial for assessing its safety and freshness, and traditional methods of observing through human eyes are inefficient and subjective. In recent years, several methods have been proposed based on computer vision and deep learning have been proposed, which can provide objective and stable evaluations. However, these methods suffer from a lack of standardized data collection methods and large-scale datasets for training, leading to poor model performance and limited generalization capabilities. Additionally, the model accuracy was limited by an absence of effective image preprocessing of background noises.To address these issues, we have designed a standardized pork image collection device and collected 1707 high-quality pork images. Base on the data, we proposed a novel deep learning model to predict the color. The framework consists of two modules: image preprocessing module and pork color classification module. The image preprocessing module uses the Segment Anything Model (SAM) to extract the pork portion and remove background noise, thereby enhancing the model's accuracy and stability. The pork color classification module uses the ResNet-101 model trained with a patch-based training strategy as the backbone. As a result, the model achieved a classification accuracy of 91.50 % on our high quality dataset and 89.00 % on the external validation dataset. The Porkolor online application is freely available at https://bio-web1.nscc-gz.cn/app/Porkolor.

Fermented sausages are popular meat products with many different varieties. The aroma of fermented sausages depends on the metabolic activities of microbiota, mainly involving lactic acid bacteria and catalase-positive cocci, the group of coagulase-negative staphylococci (CNS) in particular. Regarding staphylococci, this work elucidated their generation of aroma precursors from hydrolase, metabolic activities contributing to aroma development, antioxidant effects that improve aroma via preventing excessive lipid oxidation. The metabolic pathways of staphylococci that play a role in aroma formation involve carbohydrate fermentation, amino acid degradation, fatty acid β-oxidation, and esterase activities. Their antioxidant activities are associated with superoxidase dismutase and catalase activities, as well as the production of antioxidant peptides. Processing conditions may influence CNS communities and affect aroma characteristics of fermented sausages. Implementation of genome sequencing and editing to select and customize CNS with specific biosynthetic metabolic pathways was proposed forward, offering a great potential for enhancing aroma development during sausage fermentation.

During fermentation, meat is pre-treated and cured to cultivate a diverse microflora, resulting in fermented meat products with distinctive flavors. Coagulase-negative staphylococcus holds a crucial role in all fermented meat products, contributing to the breakdown of proteins, carbohydrates, and fats, and the creation of flavor compounds. Fermentation technology has important research value and significance in fermented meat products. The optimization and improvement of flavor by CNS can be achieved by regulating the fermentation environment, initial microflora and processing conditions. The review explores the ways in which coagulase-negative staphylococci contribute to the flavors in fermented meat products. The mechanism of flavor substance formation and means of regulation in coagulase-negative staphylococci were also investigated. The review concludes by summarizing future development trends and drawing conclusions.

This research aimed to explore the changes in two sampling locations (internal and external) of the Longissimus thoracis et lumborum (LTL) beef muscle proteomes subjected to ultraviolet light before dry-aging. It further compared the biological processes and associated proteins at interplay at the external locations of UV pre-treated and control dry-aged samples. Before dry-aging, proteins related to external stimuli were differentially abundant between both locations possibly due to the early post-mortem energy metabolism attempting to compensate for energy deficiencies and stress derived from slaughter and processing. The biochemical status of muscle during chilling and hanging of the carcasses and the impact of the UV pre-treatment may have also influenced the abundance of these proteins before dry-aging. Proteins associated to muscle structure, energy and fatty acids metabolism were differentially abundant between locations after 21 days of dry-aging. These dynamic changes in the meat proteome and related biological processes suggested that both evolved differently between the two sampling locations during dry-aging, and these may underlie the development of dry-aged beef properties. The proteome of the external locations sampled from UV pre-treated beef loins was compared to control counterparts during dry-aging. The results show that aging time appeared to outweigh the effect of UV since the differentially abundant proteins between both groups decreased as dry-aging progressed. These proteins were associated with mRNA stabilization, the matrisome, energy pathways and heat shock proteins (HSPs). Further research is warranted to better understand the role of these proteins in the production of dry-aged beef and their relation to the UV pre-treatment.

The current study evaluated the impact of dietary curcumin nano-micelles (CNM) on the quality of Longissimus lumborum (LL) muscle in lambs during long-term freezing storage. Thirty-two crossbred male lambs were assigned into four groups receiving 0, 20, 40, or 80 mg CNM daily over a 97-day fattening period. Meat samples were analyzed for quality attributes over nine months of freezing. Supplementation with CNM, especially at 40 mg, improved carcass characteristics and reduced saturated and branched-chain fatty acids. Notably, CNM preserved meat color, enhanced water-holding capacity, and reduced drip and cooking losses, with the 40 mg dosage showing the most significant effects. While meat tenderness was unaffected, CNM exhibited antioxidant properties by reducing lipid peroxidation and stabilizing enzyme activities and total antioxidant capacity. These results indicate that CNM, particularly at 40 mg, enhances meat quality during long-term freezing, especially after six months. The findings underscore CNM's potential as a natural additive to improve lamb meat stability and quality during extended frozen storage, with implications for both the meat industry and consumer satisfaction.

This study assessed postmortem proteolysis over 14 d in bovine Masseter (MS), Longissimus thoracis (LT), and Cutaneous trunci (CT) muscles. First, the metabolic, contractile, and connective tissue properties were characterized to establish their intrinsic differences. The MS contained the highest levels of oxidative markers and myosin heavy chain-I (MyHC-I), whereas the CT possessed the greatest glycolytic capacity, MyHC-IIx, and connective tissue proteins (P < 0.05). The LT had intermediate metabolic characteristics, a heterogeneous mixture of MyHC isoforms, and the lowest amount of connective tissue proteins (P < 0.05), confirming the muscles' intrinsic divergence. Proteolytic analysis revealed increased desmin and slow troponin-T (TT-slow) degradation, with a higher 110 kDa band intensity in the MS than in the CT (P < 0.05). In comparison, the CT exhibited greater TT-fast degradation and higher 30 kDa fragment intensity (P < 0.05). The LT demonstrated the greatest overall proteolysis, indicated by increased TT-fast and TT-slow degradation and the highest intensity of the 30 kDa band (P < 0.05). This is likely due to protease activity, as the LT and MS exhibited more calpain-1 autolysis and less calpastatin abundance than the CT (P < 0.05). However, caspase-3 activity was highest in the MS and lowest in the LT. A principal component analysis incorporating proteolytic indicators further demonstrated the distinct proteolytic profiles in the three muscles. Overall, findings suggest that the progression of postmortem proteolysis is muscle-specific and that a single proteolytic indicator does not sufficiently describe proteolysis when comparing muscles differing in contractile and metabolic properties.

Clostridium spp. poses a significant problem in meat sausages, particularly semi-dry fermented meat products, during storage. The present study evaluated the anti-clostridial effects of nisin (0.05-0.1 %) and mixed lactic acid bacteria (LAB) cultures (Lactiplantibacillus plantarum, Lactococcus lactis subsp. lactis) on Clostridium sporogenes endospores in vacuum-packaged, nitrite-reduced heat-treated Turkish-type dry fermented sausage (sucuk). Also, it examined the effect on the products' technological properties and microbiological safety over a 45-day storage period at 4 °C. The reduction in total spore-forming bacteria (TSFB) and anti-clostridial efficacy were determined using 0.05 % nisin in nitrite-reduced sucuk and 0.1 % nisin in nitrite-free sucuk, indicating a significant interaction between treatment and storage day (P < 0.001). The combination of 150 ppm sodium nitrite (NaNO₂) and 0.05 % nisin in nitrite-reduced sucuk resulted in the lowest thiobarbituric acid reactive substances (TBARS) values (P < 0.001). Furthermore, using 150 ppm NaNO₂ and 0.1 % nisin in nitrite-free sucuk more effectively preserved the initial color values compared to the control group (P < 0.001). While reducing or removing NaNO₂ in heat-treated sucuk did not compromise safety regarding C. sporogenes endospores under the conditions tested, the antimicrobial role of NaNO₂ should not be disregarded. Therefore, 0.05 % nisin in nitrite-reduced sucuk is recommended to effectively inhibit C. sporogenes endospores and improve the oxidative stability of heat-treated Turkish-type dry fermented sucuk.

This study aimed to investigate the performance differences of low-sodium myofibrillar protein (MP) gels substituted by different chloride salt mixtures from the perspective of gelation process. The results revealed that low-sodium MP substituted by KCl/CaCl₂ exhibited higher turbidity and particle size at 40 % substitution, and formed protein aggregates earlier at 53 °C. During the gelation process, KCl/CaCl₂ increased the extent of cross-linking as the substitution level increased from 10 % to 40 %, which was prone to forming final gels with poor palatability. Microstructural and binarization results visually indicated that an irregular reticular structure composed of partial clusters formed when the temperature heated over 53 °C, and the cross-linked cluster blocks further shrunk from 53 °C to 73 °C. Rheological amplitude sweeps revealed that KCl/CaCl₂-substitued MP displayed a faster fracture of the ductile structure, and this influenced the distribution of cluster blocks inside the network. The introduction of salt mixtures altered protein conformation, and more unordered structures were found in low-sodium MP containing CaCl₂, rather than MP containing MgCl₂. Additionally, Ca²⁺ ions increased the thermo-denatured temperature of MP, and extended the relaxation time of bound water at 53 °C, and Mg²⁺ ions slowed down the degree of liquid loss at 53 °C. As a result, the low-sodium MP containing CaCl₂ exhibited a lower expansion of protein structure accompanied by the involvement of less proteins in gel formation and more liquid loss in the final gel.

Salmonella is a foodborne pathogen of global significance and is highly prevalent in pork. This study investigated the prevalence, contamination distribution, virulence genes and antibiotic resistance of Salmonella in 3 pork processors in the Shandong Province of China. Samples were collected from 13 different sampling sources across the slaughter procedures (600 samples) as well as at retail outlets supplied by these processors (45 samples). The prevalence was 18.9 % among all the samples, with the highest prevalence observed in feces (40.0 %), lairage pens (38.0 %), and hides (34.0 %). A total of 6 serotypes were identified, with S. Rissen (46.3 %) and S. typhimurium (32.0 %) found to be the most prevalent serotypes. 86.8 % of Salmonella isolates were multi-drug resistant, with the majority of strains resistant to erythromycin, sulfisoxazole, and ampicillin. The multilocus sequence typing analysis revealed 6 STs were obtained from 45 isolates, with the dominant type ST469 accounting for 40.0 % of the total, which suggested a high possibility of cross-contamination between the plant processing chain and retail outlets. This work reveals the prevalence and correlation of Salmonella isolates between pork slaughter and retail outlets and acts as a case-study for stakeholders wishing to improve pork supply chain hygiene, control cross-contamination between the various slaughtering processes, and obtain continuous updates on Salmonella surveillance.

Dry-cured ham is a traditional Mediterranean meat product consumed throughout the world. This product is very variable in terms of composition and consumer's acceptability is influenced by different factors, among others, visual intramuscular fat and its distribution across the slice, also known as marbling. On-line inter and intramuscular fat evaluation and marbling assessment is of interest for classification purposes at the industry. Currently, this assessment can only be performed by visual inspection and traditional sensory panels. The current work presents the software MarblingPredictor, which predicts the marbling score of the three most representative ham muscles from square regions of interest automatically extracted from a ham slice. It also estimates the rate of subcutaneous and intermuscular fat content in the ham slice. Using MarblingPredictor, the mean absolute error between the true and predicted marbling scores was 0.53, very similar to the error of sensory panellist, which is 0.50. The correlation between the computer and sensory scores is 0.68, which means a moderate to good recognition. This result underscores the relevance of this tool for its application in the ham industry for quality control and categorization purposes. As part of this work, we also present the dataset HamMarbling of annotated ham slices used to train and test the software with the marbling scores provided by the panellists. The MarblingPredictor software and images are available from https://citius.usc.es/transferencia/software/marblingpredictor for Windows- and Linux-based systems for research purposes.