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The aim of this study was to investigate the biological inhibiting effect of a beef‐derived Latilactobacillus sakei (RS‐25) on the spoilage of beef steaks in overwrapped packaging during the 12 days of storage at 4°C. Beef quality as well as microbial indicators were determined at different intervals during the storage after the inoculation of RS‐25 at the 6 log CFU/g, and the high‐throughput sequencing was applied to investigate the changes of microbial community structure during the storage. The inoculation of RS‐25 on beef had no effect (p >.05) on pH, TBARS, and TVB‐N during storage indicating the weak effect of such strain on the eat quality. Furthermore, the rise of L* and the delayed decline of a* and b* reveal the protection effect of RS‐25 on the meat color. RS‐25 reduced the re‐contaminated Salmonella typhimurium by 1.16 log CFU/g (p <.01), and the growth of Brochothrix thermosphacta was also inhibited but no inhibition was found on the Pseudomonas spp. at the first 6 days of storage. The inhibiting effect of RS‐25 was covered by the rapid growth of other microorganism during the following 6 days of storage. Consistent with the microbial counts results, high‐throughput sequencing analysis confirmed that the inoculated L. sakei RS‐25 was dominant at first 6 days, and then replaced by Pseudomonas spp. The findings obtained from the current study may provide basic information for the further application of bioprotective bacteria in preservation of beef steaks in the overwrapped packaging. [ABSTRACT FROM AUTHOR]

This study investigated the proteome basis for color stability variations in beef steaks packaged under two modified atmosphere packaging (MAP) methods: HiOx-MAP (80% O 2 /20% CO 2 ) and CO-MAP (0.4% CO/30% CO 2 /69.6% N 2 ) during 15 days of storage. The color stability, pH, and sarcoplasmic proteome analysis of steaks were evaluated on days 0, 5, 10 and 15 of storage. Proteomic results revealed that the differential expression of the sarcoplasmic proteome during storage contributed to the variations in meat color stability between the two MAP methods. Compared with HiOx-MAP steaks, some glycolytic and energy metabolic enzymes important in NADH regeneration and antioxidant processes, antioxidant peroxiredoxins (thioredoxin-dependent peroxide reductase, peroxiredoxin-2, peroxiredoxin-6) and protein DJ-1 were more abundant in CO-MAP steaks. The over-expression of these proteins could induce CO-MAP steaks to maintain high levels of metmyoglobin reducing activity and oxygen consumption rate, resulting in CO-MAP steaks exhibiting better color stability than HiOx-MAP steaks during storage. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of modified atmosphere packaging (MAP) systems on shelf-life and quality of beef steaks with high marbling. Four packaging types were used including 80% O 2 MAP (80% O 2 + 20% CO 2 ), 50% O 2 MAP (50% O 2 + 30% CO 2 + 20% N 2 ), carbon monoxide MAP (0.4% CO + 30% CO 2 + 69.6% N 2 ) and vacuum packaging (VP). Steaks were displayed under simulated retail conditions at 4 °C for 12 days. Purge loss, pH, color stability, oxidative stability and microbial counts were monitored. Aerobically packaged steaks exhibited a bright-red color at the first 4 days. However, discoloration and oxidation became major factors limiting their shelf-life to 8 days. Compared with aerobic packaging, anaerobic packaging extended shelf-life of heavily marbled beef steaks, due to better color stability, together with lower oxidation and microbial populations. Among all packaging methods, CO-MAP had the best preservation for steaks, with more red color than other packaging types. [ABSTRACT FROM AUTHOR]

The current research evaluated the combined effect of oxygen concentration (20%, 50% and 80% O 2) and storage temperature (4°C or −1.5°C) on the fresh and internal cooked color of dark-cutting (DC) beef. Steaks were packaged in modified atmosphere packaging (MAP) over a 12-day storage period. Although the metmyoglobin reducing activity (MRA) of DC steaks decreased with increasing O 2 levels, lower oxygen consumption (OC) and deeper oxygen penetration depth (OPD) improved the surface color of 50%O 2 -MAP and 80%O 2 -MAP DC steaks. 80%O 2 -MAP resulted in the highest (P < 0.05) percentage myoglobin denaturation and alleviated the phenomenon of persistent pink (PP) observed in DC beef. Compared with normal chilling, superchilling significantly increased the redness values of DC steaks through inhibition of lipid oxidation and enhancement of MRA, while it had no effects on PP due to the limited OPD. The results suggest that 80%O 2 -MAP combined with superchilling can be used to improve fresh color and minimize PP of DC beef. • 50%O 2 -MAP and 80%O 2 -MAP effectively improved the surface color of DC steaks. • 80%O 2 -MAP relieved the development of persistent pinking (PP) in cooked DC steaks. • Superchilled beef had higher MRA and redness, but lower TBARS than chilled beef. • Superchilling did not improve the PP of DC steaks due to the limited OPD. [ABSTRACT FROM AUTHOR]

[Display omitted] • The microbiota and quality of HiOx-MAP beef with various CO 2 levels were studied. • Different microbiota dynamics occurred in 50%O 2 /40%CO 2 /10%N 2 and 50%O 2 /50%N 2 MAP. • High CO 2 MAP extended the shelf-life over 20 d and maintained a good color. • Pseudomonas and Brochothrix were the dominant bacteria under both MAP. • P. fragi and P. weihenstephanensis were inhibited by high level of CO 2. The objective of this study was to establish the effect of CO 2 on the bacterial community in beef steaks held under both high-oxygen modified atmosphere packaging (HiOx-MAP) types (CO 2 treated MAP: 50% O 2 /40% CO 2 /10% N 2 ; control MAP: 50% O 2 /50% N 2). Steaks were stored at 2 °C for 20 days. Gas composition, meat color, pH values, total volatile basic nitrogen values, total viable counts (TVC) and microbial community dynamics were monitored. Compared to the control MAP, the high level of CO 2 in the contrast MAP significantly delayed bacterial growth, resulting in a bright red color as well as extending the shelf-life to over 20 days. The microbial diversity decreased with prolonged storage in both MAP types, but it was more complex in high-CO 2 treated MAP steaks. When TVC values approached the shelf-life threshold for the control MAP, Pseudomonas and Brochothrix were the predominant bacteria, while Pseudomonas and Serratia under the CO 2 containing MAP were at a lower abundance than under the control MAP. The dominant Pseudomonas species causing spoilage in the control MAP steaks was P. fragi , and this species was inhibited significantly by CO 2 , followed by P. weihenstephanensis. Inversely, P. versuta instead of P. fragi became the dominant Pseudomonas species under the CO 2 treated MAP. Overall, the application of CO 2 in HiOx-MAP influenced microbiota succession, which played an important role in retaining beef quality. [ABSTRACT FROM AUTHOR]

The impacts of adding calcium chloride (CaCl2) and calcium lactate (CaLac) with different concentrations (0%, 0.2%, 0.4%, and 0.7%) on the physicochemical properties of cured beef sausages were investigated in this study. Meat color, pH, lipid oxidation, and cooking loss were measured at respective manufacturing stages (ground beef, raw chopped batter, and after cooking). Additionally, meat color, pH, lipid oxidation, nitrosylhemochrome, residual nitrite, and texture profiles of vacuum-packaged sausages were evaluated during seven days of storage. Compared with the control (no Ca added), both calcium salts resulted in deteriorative color and texture properties, and promoted pH decline, cooking loss, and lipid oxidation of sausages during manufacturing and storage. However, increased calcium salt addition led to the reduction of residual nitrite over time. Compared to CaCl2 addition, 0.2–0.4% CaLac resulted in greater redness and oxidative stability and softer texture. These results may be useful when considering calcium salt additions in sausages, for the purpose of co-extruded sausages coated with alginate where Ca salts are used to form the casing during the co-extrusion of the sausages. [ABSTRACT FROM AUTHOR]

This study compared the proteomics of beef patties under high‑oxygen modified atmosphere packaging (HiOx-MAP) and vacuum packaging (VP) during heating. The color and oxidation stability of fresh patties, and myoglobin denaturation of cooked patties were also measured. The results suggested that HiOx-MAP patties contained more oxymyoglobin in fresh meat and had higher myoglobin denaturation during heating than VP patties, resulting in premature browning (PMB) during cooking. Proteomic analysis found that the overabundance of proteasome subunit beta type-2 (PSMB2) and peroxiredoxin-2 (PRDX2) in HiOx-55 °C, which can remove the damaged proteins and inhibit oxidation respectively, are of benefit to meat color stability during storage, however, this was still insufficient to inhibit the occurrence of PMB during cooking. The high abundance of lamin B1 (LMNB1) in VP-55 °C can maintain the stability of meat color. This research provides greater understanding, based on proteomic perspectives, of the molecular mechanism of PMB. • Myoglobin forms alter denaturation during heating, impacting cooked meat color. • HiOx packaged beef patties were more prone to premature browning than VP patties. • The overabundance of PSMB2 and PRDX2 in HiOx-55 °C was insufficient to inhibit PMB. • The high abundance of LMNB1 in VP-55 °C helped maintain the stability of meat color. [ABSTRACT FROM AUTHOR]

• HiOx-MAP aggravated microbial-induced meat discoloration compared to CO-MAP. • B. thermosphacta and Pseudomonas dominated in HiOx-MAP, but the latter prevailed. • Pseudomonas enhanced beef discoloration by elevating OCR in HiOx-MAP. • The dominated LAB (Lactobacillus & Lactococcus) in CO-MAP improved beef color. The microbiota influence on meat color stability of chilled beef steaks under two modified atmosphere packaging (MAP) systems was studied: HiOx-MAP (80% O 2 /20% CO 2) and CO-MAP (0.4% CO/30% CO 2 /69.6% N 2). Steaks were stored for up to 20 days at 2 °C. Headspace gas composition and color stability were evaluated. High-throughput sequencing analyses were performed to characterize bacterial community dynamics. For HiOx-MAP steaks, Pseudomonas spp. became the dominant species, and an increased oxygen consumption caused by these bacteria contributed to metmyoglobin (MetMb) formation from day 10. Functional analysis based on 16S rDNA sequencing predicted higher abundance of genes related to amino acid and lipid metabolism in HiOx-MAP bacterial communities compared to CO-MAP bacterial communities, which probably accelerated meat discoloration. Lactic acid bacteria dominated in CO-MAP steaks, in which Lactobacillus spp. and Lactococcus spp. contributed to improve redness and chroma, and reduce MetMb%, respectively. These findings help our understanding of color stability in CO-MAP steaks in comparison to HiOx-MAP steaks as influenced by the microbial community. [ABSTRACT FROM AUTHOR]

Abstract: The objectives were to compare the effects of packaging methods on color stability, metmyoglobin-reducing-activity (MRA), total-reducing-activity and NADH concentration of different bovine muscles and to explore potential mechanisms in the enhanced color stability by carbon monoxide modified atmosphere packaging (CO-MAP, 0.4% CO/30% CO2/69.6% N2). Steaks from longissimus lumborum (LL), psoas major (PM) and longissimus thoracis (LT) packaged in CO-MAP, high-oxygen modified atmosphere packaging (HiOx-MAP, 80% O2/20% CO2) or vacuum packaging were stored for 0day, 4days, 9days, and 14days or stored for 9days then displayed in air for 0day, 1day, or 3days. The CO-MAP significantly increased red color stability of all muscles, and especially for PM. The PM and LT were more red than LL in CO-MAP, whereas PM had lowest redness in HiOx-MAP. The content of MetMb in CO-MAP was lower than in HiOx-MAP. Steaks in CO-MAP maintained a higher MRA compared with those in HiOx-MAP during storage. After opening packages, the red color of steaks in CO-MAP deteriorated more slowly compared with that of steaks in HiOx-MAP. [Copyright &y& Elsevier]

Label-free proteomics was applied to understand the color and color stability development of dark cutting beef (DC). The color traits of DC (pH = 6.86) and normal beef (pH = 5.49) were determined during 7 days of display. DC had a lower redness and greater color stability, which was attributed to its higher deoxy-myoglobin content, greater oxygen consumption, as well as higher metmyoglobin reducing activity and lower lipid oxidation. A total of 28 differentially expressed mitochondrial proteins (fold change >1.8) between the two groups were identified, with 21 proteins overexpressed in DC mainly involved in oxidative phosphorylation, generation of reducing equivalent, TCA cycle and chaperones. These enhance the level of mitochondrial respiration, the stability of reducing MetMb and myoglobin and mitochondria function, leading to color characteristics of DC. Moreover, Glutaryl-CoA dehydrogenase was for the first time reported to be significantly associated with color parameters and its direct relationship with meat color is worthy investigation. [ABSTRACT FROM AUTHOR]

The storage quality characteristics of fresh pork patties were investigated under 80% O 2 modified atmosphere packaging (MAP80:20 = 80% O 2 /20% CO 2) and 40% O 2 MAP with various CO 2 levels (MAP40:20 = 40% O 2 /20% CO 2 /40% N 2 ; MAP40:40 = 40% O 2 /40% CO 2 /20% N 2 ; MAP40:60 = 40% O 2 /60% CO 2). Packaged patties were stored for 16 days at 4 °C to monitor their physicochemical (pH, instrumental color, oxidative stability, and fatty acid profile), microbial, and sensorial changes. Results suggested that decreasing O 2 levels from 80% to 40% significantly inhibited the lipid oxidation of patties but led to a lower (P < 0.05) color stability. Elevating CO 2 levels from 20% to 60% in combination with 40% O 2 significantly suppressed bacterial growth and total volatile basic nitrogen production, and thus rendered patties with a better sensory quality and a similar meat color to 80% O 2. However, increased CO 2 levels promoted lipid oxidation through reducing the antioxidant capacity of patties, which was attributed to a CO 2 -induced reduction in superoxide dismutase and glutathione peroxidase activities during storage rather than a pH reduction or changes in fatty acid composition. Overall, 40% O 2 /40% CO 2 /20% N 2 is a realistic alternative for pork patties to improve meat quality and extend the shelf-life to over 16 days. • The quality of pork patties was explored under HiOx-MAP with various CO 2 levels. • 40% O 2 combined with 40–60% CO 2 gave patties a similar color to 80% O 2 /20% O 2. • High levels of CO 2 promoted the lipid oxidation of HiOx-MAP pork patties. • CO 2 reduced superoxide dismutase and glutathione peroxidase activities in patties. [ABSTRACT FROM AUTHOR]

The physicochemical parameters of hot-boned bovine semimembranosus muscles after s ous vide cooking were investigated. Hot-boned or wet-aged steaks were collected, and cooked by different cooking methods, including sous vide (57 °C, 11 h, SV), grilling (at 200 °C to the central temperature of 72 °C, GR) or boiling (100 °C, 2 h, BO). The meat color, tenderness, water-holding capacity, degree of oxidation, myoglobin denaturation and sensory quality traits were determined, as well as the changes in the microstructure. Compared to other cooking methods, SV reduced the degree of oxidation and muscle shortening, and significantly improved the water holding capacity (WHC), tenderness, connective tissue content and overall acceptability for both hot-boned and wet-aged steaks. The oxidation and muscle shortening were reduced in hot-boned SV steaks (P < 0.05), and the water-holding capacity and sensory scores for juiciness, connective tissue content and overall acceptability were increased (P < 0.05) compared to the wet-aged steaks. The combination of hot-boning and SV cooking resulted in an acceptable tenderness, better overall sensory acceptability and higher WHC than other combinations of muscle states and cooking methods. Therefore, it is a good choice to cook hot-boned semimembranosus muscles using SV to improve the eating quality, which can eliminate the need for aging, benefiting the beef industry. [ABSTRACT FROM AUTHOR]

Pseudomonas fragi is a dominant meat spoilage organism under high-oxygen modified atmosphere packaging (HiOx-MAP). This work investigated the effects of CO 2 on P. fragi growth and the related spoilage phenomena of HiOx-MAP beef. Minced beef incubated with P. fragi T1, a strain owning the strongest spoilage potential among isolates, was stored under CO 2 -enriched HiOx-MAP (TMAP; 50% O 2 /40% CO 2 /10% N 2) or non-CO 2 HiOx-MAP (CMAP; 50% O 2 /50% N 2) at 4 °C for 14 days. Compared to CMAP, TMAP maintained sufficient O 2 levels to endow beef with higher a * values and meat color stability due to lower P. fragi counts from day 1 (P < 0.05). TMAP samples also showed lower (P < 0.05) lipase activity and protease activity within 14-days and 6-days than CMAP samples respectively. TMAP delayed the significantly increased pH and total volatile basic nitrogen contents occurred in CMAP beef during storage. Despite TMAP markedly promoted the lipid oxidation associated with higher concentrations of hexanal and 2,3-octanedione than CMAP (P < 0.05), TMAP beef retained an acceptable organoleptic odor due to a CO 2 -inhibition on the microbial-induced 2,3-butanedione and ethyl 2-butenoate formation. This study provided a comprehensive insight into the antibacterial mechanism of CO 2 on P. fragi in HiOx-MAP beef. [Display omitted] • CO 2 inhibited P. fragi growth and retained satisfactory sensory acceptability. • P. fragi extracellular lipase and protease activity were influenced by CO 2. • CO 2 reduced the 2,3-butanedione and ethyl 2-butenoate levels produced by P. fragi. • HiOx-MAP enriched in CO 2 promoted lipid oxidation associated with abundant VOCs. [ABSTRACT FROM AUTHOR]

This study investigated whether beef m. longissimus lumborum (LL) can be merchandised under retail conditions, following long-term superchilled storage (−1 °C). At 24 h post-mortem , the LL from left side of beef carcasses (n = 5) were fabricated into vacuum packaged beef thick-cuts, and then stored for 0, 2, 4, 8, 12, 16, or 20 weeks under superchilled conditions (−1 °C). Following storage, beef cuts were fabricated into steaks and aerobically displayed (0– 4 °C) for 5 days. Instrumental color, percentage of myoglobin redox forms, metmyoglobin reducing activity, oxygen consumption, and lipid oxidation were evaluated. After 4 weeks, the steaks had the highest a *, b * and chroma values between 1 and 3 days of display. Longer superchilled storage resulted in a rapid increase in discoloration and lipid oxidation which were observed in samples during display. Specifically, the a * values of steaks superchilled for 16 and 20 weeks approached the unacceptability threshold (a * ≥ 14.5) after 3 days of display. • Color stability was evaluated for the superchilled storage beef during 20 weeks. • At 4 weeks, steaks had the highest color parameters at 1–3 days of display. • Longer superchilled storage reduced color and lipid stability. • The steaks from beef superchilled for 16 and 20 weeks only can be displayed for 3 days. [ABSTRACT FROM AUTHOR]

This study investigated the effect of superchilling (−30 °C until the core temperature achieved −3 °C, and − 1 °C until 24 h, SC) on shelf-life and bacterial community dynamics of beef loins, with a typical very fast chilling (−30 °C until the core temperature achieved 0 °C, and − 1 °C until 24 h, VFC) and conventional chilling (0– 4 °C for 24 h, CC) as controls. The super-chilled storage (−1 °C) was adopted after each chilling procedure, and physicochemical traits and microbiological quality were evaluated during a long-term storage. No remarkable adverse impact on meat color and lipid oxidation were observed in SC treatment. The bacterial composition results showed that Carnobacterium spp. were the main bacteria in SC treatment in the late storage period (63– 84 days). The loss of Lactobacillus spp., due to the "ultra-low temperature" during the superchilling, might be the reason that the SC did not result in a longer shelf-life compared with CC samples. • The SC (−30 °C until the core temperature reached −3 °C within 5 h) was applied on the beef loins. • The effect of SC and the following superchilled storage on the shelf life of beef loins was studied. • SC was more superior in decreasing the initial bacterial load than VFC treatment. • The shelf-life of SC samples was longer than VFC samples. • The loss of Lactobacillus spp. in SC samples might cause the similar shelf-life of SC and CC samples. [ABSTRACT FROM AUTHOR]