Spray chilling on carcass weight loss, and physicochemical and microbiological quality of beef cuts during storage

ABSTRACT: Different chilling treatments are used before meat storage. The effect of spray chilling (SC) on meat quality appears to vary. Here, we investigated the effects of SC on beef carcass weight loss and meat quality during subsequent storage. The 2-h SC program tested involved 180-s initial spraying, followed by 60-s spray cycles at 540-s intervals. Deboned chuck tender (IMPS 116B) beef cuts were vacuum-packaged and stored for up to 60 d. Purge and cooking losses, Warner-Bratzler shear force, meat colour [CIE L*, a*, b*], and microbiological quality were evaluated. SC reduced carcass weight loss (P<0.001) compared with conventional chilling. However, storage time affected the purge and cooking losses, and Warner-Bratzler shear force. CIE a* and b* values increased (P<0.05) after 30-d aging in both chilling treatments. Pronounced psychrotrophic growth was observed during storage after both treatments. In conclusion, SC can be used to reduce the economic losses associated with meat chilling, without affecting meat quality attributes.

Caveolae mediated endocytosis of VLDL particles in macrophages requires NPC1 and STARD3 for further lysosomal processing

Macrophages accumulate triglycerides under certain pathological conditions such as atherosclerosis. Triglycerides are carried in the bloodstream as part of very low-density lipoproteins (VLDL) and chylomicrons. How macrophages take up and process VLDL-lipids is not very well known. Here, using VLDL-sized triglyceride-rich emulsion particles, we aimed to study the mechanism by which VLDL-triglycerides are taken up, processed, and stored in macrophages. Our results show that macrophage uptake of emulsion particles mimicking VLDL (VLDLm) is dependent on lipoproteins lipase (LPL) and requires the lipoprotein-binding C-terminal domain of LPL but not the catalytic N-terminal domain. Subsequent internalization of VLDLm-triglycerides by macrophages is carried out by caveolae-mediated endocytosis, followed by triglyceride hydrolysis catalyzed by lysosomal acid lipase. Transfer of lysosomal fatty acids to the ER for subsequent storage as triglycerides is mediated by Stard3, whereas NPC1 was found to promote the extracellular efflux of fatty acids from lysosomes. Our data provide novel insights into how macrophages process VLDL-derived triglycerides and suggest that macrophages have the remarkable capacity to excrete part of the internalized triglycerides as fatty acids.

Physicochemical, Oxidative Stability and Sensory Properties of Frankfurter-Type Sausage as Influenced by the Addition of Carrot (Daucus carota) Paste

This study examined the addition of carrot paste (CP) at levels of 3%, 5%, and 10% as a potential antioxidant in frankfurter-type sausages, denoted as F1, F2, and F3. F0, was a control sample with no addition of CP. All formulated samples were stored for 14 days during which their physicochemical, oxidative stability, and sensory properties were evaluated. Results showed that the pH of frankfurter-type sausages was not affected by the addition of CP, however, higher pH values were observed in CP-enriched samples on the first day of production and subsequent storage days. Cooking loss (CL) in frankfurter-type sausages was in the range of 2.20% to 2.87%, with the CP-enriched samples having a lower CL percentage, particularly F3 samples, compared to the control. Protein and fat content were lower in CP-enriched samples, but ash content increased. CP-enriched frankfurter-type sausages recorded significantly higher polyphenol contents compared to the control. Total polyphenol content in CP-enriched samples F1, F2, and F3 was higher throughout storage compared to the control. Lower peroxide values were also recorded in CP-enriched samples F1 (2.5 meq/kg), F2 (2.4 meq/kg), and F3 (2.2 meq/kg) compared to the control (2.9 meq/kg), demonstrating greater 2,2-Diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity than the control samples. Formulations treated with 10% CP gained significantly higher scores for color, texture, and overall acceptability. Principal component analysis showed that higher inclusion levels of CP in formulation improved the sensory quality and oxidative stability. In conclusion, CP could be used to enhance the oxidative stability of frankfurter-type sausage without negatively influencing the sensory quality.

Implications of Seed Vault Storage Strategies for Conservation of Seed Bacterial Microbiomes

Global seed vaults are important, as they conserve plant genetic resources for future breeding to improve crop yield and quality and to overcome biotic and abiotic stresses. However, little is known about the impact of standard storage procedures, such as seed drying and cold storage on the seed bacterial community, and the ability to recover seed-associated bacteria after storage. In this study, soybean [Glycine max (L.) Merr.] seeds were analyzed to characterize changes in the bacterial community composition and culturability under varying storage conditions. The G. max bacterial microbiome was analyzed from undried seed, dried seed, and seed stored for 0, 3, 6, and 14months. Storage temperatures consisted of −20°C, 4°C, and room temperature (RT), with −20°C being commonly used in seed storage vaults globally. The seed microbiome of G. max was dominated by Gammaproteobacteria under all conditions. Undried seed was dominated by Pantoea (33.9%) and Pseudomonas (51.1%); however, following drying, the abundance of Pseudomonas declined significantly (0.9%), Pantoea increased significantly (73.6%), and four genera previously identified including Pajaroellobacter, Nesterenkonia, env.OPS_17, and Acidibacter were undetectable. Subsequent storage at RT, 4, or −20°C maintained high-abundance Genera at the majority of time points, although RT caused greater fluctuations in abundances. For many of the low-abundance Genera, storage at −20°C resulted in their gradual disappearance, whereas storage at 4°C or RT resulted in their more rapid disappearance. The changes in seed bacterial composition were reflected by cultured bacterial taxa obtained from the stored G. max seed. The main taxa were largely culturable and had similar relative abundance, while many, but not all, of the low-abundance taxa were also culturable. Overall, these results indicate that the initial seed drying affects the seed bacterial composition, suggesting that microbial isolation prior to seed drying is recommended to conserve these microbes. The standard seed storage condition of −20°C is most suitable for conservation of the bacterial seed microbiome, as this storage temperature slows down the loss of seed bacterial diversity over longer time periods, particularly low-abundance taxa.

Desiccation survival in Salmonella enterica, Escherichia coli and Enterococcus faecium related to initial cell concentration and cellular components

Salmonella enterica is well-known for its ability to survive and persist in low-moisture environments. Previous studies have indicated a link between the initial cell concentration and the population of Salmonella that survive upon desiccation and subsequent storage; however, how the initial cell concentration affects survival is unknown. This study examined the basis of this phenomena and whether it occurred in other microorganisms, specifically Shiga toxigenic Escherichia coli (STEC), and Enterococcus faecium . Salmonella, STEC, and E. faecium were grown as lawns on TSAYE and harvested using buffered peptone water (BPW). To determine recovery at different initial cell levels, cultures were diluted to 9, 7, and 5 log CFU/mL and applied to filters. Filters were dried for 24 h, then stored for 28 d at 25°C/33% RH. During storage, cells were recovered from filters using BPW and cultivated on TSAYE. Both Salmonella and E. coli , but not E. faecium , showed non-proportional recovery. Less viability remained with lower initial starting population after 24 h desiccation such that ≥10 log CFU/mL were recovered when 11 log CFU/mL was desiccated, but &lt;3 log CFU/mL were recovered when 5 log CFU/mL was desiccated. Once dried, persistence did not appear affected by initial cell concentration. When dead cells (heat-treated) were added to the diluent, recovery of Salmonella was proportional with respect to the initial cell concentration. To further examine the response on desiccation, Salmonella was diluted in BPW containing one of 11 different test cell components related to quorum sensing or known to affect desiccation resistance to assess recovery and persistence. Of the 11 additions only cell debris fractions, cell-free extract, and peptidoglycan improved recovery of Salmonella . Desiccation survival appears related to cell wall components, however, the exact mechanism affecting survival remains unknown.

A Study of the Antimicrobial Activity of Combined Black Pepper and Cinnamon Essential Oils against Escherichia fergusonii in Traditional African Yoghurt

The antimicrobial activity of the essential oils of black pepper (BPE) and cinnamon bark (CE) extracts against E. fergusonii was assessed in pasteurized full cream milk during and post-fermentation. The milk was fermented with 1% (v/v) of Lactobacillus delbrueckii subspecies bulgaricus (NCIMB 11778) and Streptococcus thermophilus (NCIMB 10387) (approx. 106 cfu/mL each) and incubated and stored at 25 °C for 5 days (144 h) or at 43 °C for 24 h and then stored at 25 °C for 120 h. The milk was spiked with E. fergusonii at the start of fermentation by the lactic acid bacteria (pre-fermentation contamination) for after fermentation (post fermentation contamination). BPE and CE were applied at concentrations based on their minimum inhibitory concentration of 0.5% and 0.25% respectively as follows: 0.5% BPE alone; 0.125% BPE with 0.1875% CE; 0.25% BPE with 0.125% CE; 0.375% BPE with 0.0625% CE; 0.25% CE alone. Results showed that during fermentation at 25 °C, E. fergusonii grew to a similar level (approx. 109 CFU/mL) in control samples and 108 CFU/mL when BPE or CE were added alone. Whereas, in the samples with the combined essential oils, the bacterium grew to 106–107 CFU/mL only. During the milk fermentation at 43 °C, E. fergusonii grew to approx. 109 CFU/mL in samples without treatment. However, it was not detected in samples containing mixed BPE with CE after 8, 10 and 12 h of fermentation. Subsequent storage at 25 °C resulted in undetectable levels of the bacterium in all the samples treated with BPE or CE after 24 h of storage. These results indicated that BPE in combination with CE reduced growth during fermentation and was bactericidal during storage.

Microwave treatment for improved quality and safety of dehydrated pitted apricots

Dehydrated pitted apricots are widely used as a ready meal ingredient, which renders control of their quality and safety a relevant issue. Pitted apricots are rich in sugars, moisture and organic acids that serve a good medium for microorganisms. Therefore, these products require presale processing. Microwave treatment proved effective for the processing of raw and finished food products. Its impact on microorganisms depends on variant criteria, including taxonomic affiliation, total counts, dielectric cell properties and the treatment dose. The research aimed to study death kinetics in the native dried apricot surface microflora and its growth during subsequent storage. In this respect, we have studied the microwave treatment impact on dried apricot surface microflora depending on treatment dose and determined the residual microflora growth rate during subsequent storage. The doses of 120, 180 and 240 kJ at a 200 W radiation power have been shown to reduce baseline contamination of dehydrated pitted apricots by three orders of magnitude. Statistical kinetics analyses demonstrated a retarded surface microflora growth during subsequent storage. Microwave doses of 120–240 kJ (accounting for ±0.4 lg CFU/g error) exhibited a similar microflora dynamics in subsequent storage. The exposure of dried apricots to a lowest microwave field of 120 kJ ensured stability of the product microbiological dynamics.

Mechanical properties of native and decellularized aortic wall after long-term storage in biocide solutions

Objective: to determine the optimal method for long-term wet storage of donor material (50 days after collection), with maximum ability to preserve the original mechanical characteristics.Materials and methods. Porcine aortic wall fragments were used as objects of study. Half of the original material underwent detergent-based decellularization. The entire material (native and processed) was placed for 50 days in biocidal solutions: complex alcohol solution; ethanol and glycerol mixture; antibiotics mixture. Then the tests for mechanical strength of native and decellularized samples were carried out by the method of uniaxial longitudinal and circumferential stress.Results. Storage of native material in all media resulted in a significant increase in tensile strength. In the «complex alcohol solution», «ethanol and glycerol mixture», and «antibiotic mixture» group, tensile strength increased by 1.38-, 1.72- and 1.62-fold compared to the native control in circumferential tension. Also, in the «complex alcohol solution» group, the decellularized material was 1.57-fold stronger than the native in circumferential tension. In the «antibiotic mixture» group, the decellularized material was 1.33-fold less strong than the native in longitudinal tension. According to elongation to rupture data, significantly greater plasticity was noted in the «ethanol-glycerol» storage group for the decellularized aortic wall compared to the control group (1.5-fold). Young’s modulus did not reliably differ from those of control in all experimental groups regardless of the stress direction. Notably, decellularized specimens clearly tended to be stiffer under circumferential stress.Conclusion. Detergent-based decellularization of the porcine aortic wall and subsequent storage of these samples in our chosen experimental solutions for 50 days does not significantly affect the elastic properties of the material. Our proposed treatment methods partially increase the stiffness of the material after storage in alcohol-containing solutions.

Microstructural Evolution and Tensile Testing of a Bi–Sn (57/43) Alloy Processed by Tube High-Pressure Shearing

Tube high-pressure shearing (t-HPS) processing was performed on a eutectic Bi–Sn (57/43) alloy for 0.25, 1, 5 and 20 turns. The selected samples were stored at room temperature for up to 56 days to examine the strain weakening and self-annealing behavior of the alloy. The results showed that t-HPS processing gradually refined the microstructure and led to decreasing of microhardness, but microhardness increased slowly during the subsequent storage at room temperature. Shear localization of the eutectic structure during t-HPS processing was observed as large amounts of narrow dense lamellar zones were visible in the deformed microstructures. The Bi–Sn (57/43) alloy processed by t-HPS exhibited significantly enhanced superplastic properties with elongations up to >1800% in a sample after t-HPS processing for 20 turns. This high elongation is attributed to the breaking of the lamellar structure and the very small grain size.

A Recyclable Dipping Strategy to Stabilize Herring (Clupea harengus) Co-products During Ice Storage

Applying value-adding techniques to fish filleting co-products is rendered difficult due to their high susceptibility to lipid oxidation, microbial spoilage, and amine formation. In this study, a recyclable dipping strategy was developed and investigated for its ability to stabilize herring (Clupea harengus) co-products (head, backbone, caudal fin, intestines, belly flap, skin, and in some cases roe) against oxidation and microbial spoilage. From initial screening of seven antioxidative components/formulas in minced herring co-products during ice storage, an oil-soluble rosemary extract (RE-B) and isoascorbic acid (IAA) were identified as most promising candidates. These compounds were then formulated to a recyclable solution to be used for dipping of the herring co-products. The commercial Duralox MANC antioxidant mixture was used as a positive control. Dipping in 0.2% RE-B solution ± 0.5% IAA or in 2% Duralox MANC solutions remarkably increased the oxidation lag phase from < 1 day to > 12 days during subsequent storage on ice (0–1 °C) of minced or intact co-products, respectively, even when the antioxidant solutions were re-used up to 10 times. The dipping also reduced microbiological growth and total volatile basic nitrogen, but the effect became weaker with an increased number of re-using cycles. The presented dipping strategies could hereby facilitate more diversified end use of herring co-products from current fish meal to high-quality minces, protein isolates, or oils for the food industry.