Characteristics of key microorganisms and metabolites in irradiated marbled beef

Revealing the effects of compound curing agents on the microbial community and metabolites of Nuodeng ham based on high-throughput sequencing and metabolomics

To elucidate the effects of compound curing agent on the microbial community and metabolite composition of Nuodeng ham. The microbial community and small molecule metabolites of Nuodeng ham were analyzed using high-throughput sequencing and UPLC-QE-MS technology in this study. Staphylococcus, Acinetobacter, and Lactobacillus were found to be the dominant bacterial genera in Nuodeng ham. The compound curing agent promoted the formation of L-proline, phenylalanine, L-aspartic acid, and taurine. Through correlation analysis, it was found that Staphylococcus was positively correlated with L-proline and phenylalanine, while Acinetobacter was positively correlated with taurine. This study provides scientific theoretical support for compound curing agents, as well as insight into Nuodeng ham quality.

Integrated microbiome and metabolomics analysis of spoilage characteristics of modified atmosphere packaged pork

The interactions between pork microbial communities and metabolites in modified atmosphere packaged (MAP) storage remain unclear. This study exposed the core microbial communities and metabolite profiles during refrigerated pork storage under MAP and illuminated the relationship between them by high-throughput sequencing and non-targeted metabolomics to comprehend the spoilage mechanism induced by microbial activity in MAP pork during storage. The results showed that Pseudomonas and Serratia were the predominant spoilage bacteria in the preliminary stages of refrigerated pork, while Brochothrix gradually dominated in the final stages of storage. 76 differential metabolites were identified from 822 metabolites, consisting of small-molecule metabolites including glycerophospholipids, bitter amino acids, amines, and nucleotides. The metabolic pathways involved in these metabolites were 10 metabolic pathways inclusive of purine metabolism, nucleotide metabolism, and glycerophospholipid metabolism. Correlation results revealed that bacterial genera like Pseudomonas, Brochothrix, Stenotrophomonas, Acinetobacter, and Aeromonas were significantly correlated with metabolites such as lipids, organic acids and nucleotides. These findings enhance our understanding of the spoilage mechanism of refrigerated pork stored in MAP.

Research Progress on Bacteria-Reducing Pretreatment Technology of Meat

Reducing the initial bacteria number from meat and extending its shelf life are crucial factors for ensuring product safety and enhancing economic benefits for enterprises. Currently, controlling enzyme activity and the microbial survival environment is a common approach to reducing the rate of deterioration in raw meat materials, thereby achieving the goal of bacteria reduction during storage and preservation. This review summarizes the commonly used technologies for reducing bacteria in meat, including slightly acidic electrolyzed water (SAEW), organic acids, ozone (O3), ultrasound, irradiation, ultraviolet (UV), cold plasma, high-pressure processing (HPP), and biological bacterial reduction agents. This review outlines the mechanisms and main features of these technologies for reducing bacteria in meat processing. Additionally, it discusses the status of these technologies in meat storage and preservation applications while analyzing associated problems and proposing solutions. The aim is to provide valuable references for research on meat preservation technology.

Recent advances in spoilage mechanisms and preservation technologies in beef quality: A review

Beef is a popular meat product that can spoil and lose quality during postharvest handling and storage. This review examines different preservation methods for beef, from conventional techniques like low-temperature preservation, irradiation, vacuum packing, and chemical preservatives, to novel approaches like bacteriocin, essential oil, and non-thermal technologies. It also discusses how these methods work and affect beef quality. The review shows that beef spoilage is mainly due to enzymatic and microbial activities that impact beef freshness, texture, and quality. Although traditional preservation methods can extend beef shelf life, they have some drawbacks and limitations. Therefore, innovative preservation methods have been created and tested to improve beef quality and safety. These methods have promising results and potential applications in the beef industry. However, more research is needed to overcome the challenges and barriers for their commercialization. This review gives a comprehensive and critical overview of the current and emerging preservation methods for beef and their implications for the beef supply chain.

Correlation study on microbial communities and volatile flavor compounds in cigar tobacco leaves of diverse origins

To elucidate the significant influence of microorganisms on geographically dependent flavor formation by analyzing microbial communities and volatile flavor compounds (VFCs) in cigar tobacco leaves (CTLs) obtained from China, Dominica, and Indonesia. Microbiome analysis revealed that the predominant bacteria in CTLs were Staphylococcus, Aerococcus, Pseudomonas, and Lactobacillus, while the predominant fungi were Aspergillus, Wallemia, and Sampaiozyma. The microbial communities of CTLs from different origins differed to some extent, and the diversity and abundance of bacteria were greater than fungi. Metabolomic analysis revealed that 64 VFCs were identified, mainly ketones, of which 23 VFCs could be utilized to identify the geographical origins of CTLs. Sixteen VFCs with OAV greater than 1, including cedrol, phenylacetaldehyde, damascone, beta-damascone, and beta-ionone, play important roles in shaping the flavor profile of CTLs from different origins. Combined with the correlation analysis, bacterial microorganisms were more closely related to key VFCs and favored a positive correlation. Bacillus, Vibrio, and Sphingomonas were the main flavor-related bacteria. The study demonstrated that the predominant microorganisms were essential for the formation of key flavor qualities in CTLs, which provided a theoretical reference for flavor control of CTLs by microbial technology. KEY POINTS: • It is the high OAV VFCs that determine the flavor profile of CTLs. • The methylerythritol phosphate (MEP) pathway and the carotenoid synthesis pathway are key metabolic pathways for the formation of VFCs in CTLs. • Microbial interactions influence tobacco flavor, with bacterial microorganisms contributing more to the flavor formation of CTLs.

Lipidomics reveals alterations of lipid composition and molecular nutrition in irradiated marble beef

Electron beam irradiation can effectively inhibit microbial growth, but the changes of lipid during irradiation have not been comprehensively analyzed in marble beef. Here, UHPLC-MS/MS was used to detect lipids changes of irradiated marble beef. A total of 1032 lipids were identified and classified into 3 lipid classes and 8 subclasses in irradiated marble beef. 9 lipid biomarkers were screened with increasing irradiation dose. 122 differential lipids were generated and involved in 4 metabolic pathways included Glycerophospholipid metabolism, Linoleic acid metabolism, alpha-Linolenic acid metabolism and Arachidonic acid metabolism though PC(18:0/14:0), PE(16:0/16:0) and PE(18:0/16:0) in irradiated. Our results showed that irradiation had effect on the lipid of marbled beef, but the increase of irradiation dose from 2.5 kGy to 4.5 kGy had little effect on lipids. These results help us to understand the dynamic changes of irradiated meat lipids and lay a foundation for the application of irradiation in meat preservation.