RSS 1.0Food Programme
The Teagasc Food Programme focuses on quality, safety and food product innovation. It is undertaken in collaboration with universities and research institutes in Ireland, the European Union and the USA. The Food Programme is internationally competitive from a scientific point of view while being targeted and applied to generate new opportunities for the Irish food industry The Teagasc Food Programme encompasses many aspects of food science and technology: Food Processing and Functionality, Food Safety, Foods for Health, Food Cultures, Food Quality and Structure, Meat and Meat Products, Prepared Consumer Foods. The Food Programme is run from the Teagasc Food Research Centres at Ashtown, Dublin 14 and Moorepark, Fermoy, Co. Cork
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Food Biosciences [481]
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Food Safety [180]
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Theses - Food Programme [5]
Doctoral and Masters Theses
Recent Submissions
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Molecular-genetic characterization of human parvovirus B19 prevalent in Kerala State, IndiaBackground Human parvovirus B19V is a DNA virus, and a member of the family Parvoviridae, that causes various clinical manifestations, from asymptomatic to persistent infection that is associated with different autoimmune diseases. The parvovirus B19 evolves with a very high mutation rate that is closer to those of existing RNA viruses. Globally circulating B19V is currently classified into three genotypes, but their distribution is not spatially and temporally correlated. Except for a few recent reports on B19V entry into the human host and its genetic diversity, there is a lack of sufficient studies on this virus from distinct geographical locations and no clear understanding of its evolution has been documented. Methods To better understand the evolution of the Human parvo B19V virus from India's southern part, a geographically distinct location with no reports of B19V genomes, we have screened for B19V in 456 suspected cases using VP1/2 surface marker genes, and its characteristics were studied in detail. Amongst 456 clinically suspected B19V samples, 7.2% (33/456) were found positive by nested PCR (nPCR) were subsequently validated by real-time PCR, Sanger sequencing, and metagenome analysis. Results Human parvovirus B19 infection was shown among 33 of 456 patients when tested by nPCR; 30 among these were also positive by qPCR and were subsequently confirmed by sequencing 75% nPCR positive samples and 76% qPCR positive samples were from patients with age. ≥ 50 years respectively (Additional file 1: Table S1). The complete VP1/2 gene assembly from the South Indian strain showed three novel mutations (T122A, V128I, I283V), which might significantly impact the stability and virulence of the B19V virus circulating in this part of the world. These mutations might be crucial for its adaptive evolutionary strategies facilitating the spread and infectivity potential of the virus. In maximum likelihood phylogeny of VP1/2 sequences, the South Indian B19V strain forms a separate clade closer to the existing genotype two strains circulating worldwide. Conclusion Our study contributes to a better understanding of the human parvovirus's genetic and evolutionary characteristics in South India. Also, it highlights the possibility that a positive selection pressure acting on VP1/2 could increase the survival and replication capabilities of the viruses.
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Modulation, microbiota and inflammation in the adult CF gut: A prospective studyBackground Cystic Fibrosis (CF) has prominent gastrointestinal and pancreatic manifestations. The aim of this study was to determine the effect of Cystic fibrosis transmembrane conductance regulator (CFTR) modulation on, gastrointestinal inflammation, pancreatic function and gut microbiota composition in people with cystic fibrosis (CF) and the G551D-CFTR mutation. Methods Fourteen adult patients with the G551D-CFTR mutation were assessed clinically at baseline and for up to 1 year after treatment with ivacaftor. The change in gut inflammatory markers (calprotectin and lactoferrin), exocrine pancreatic status and gut microbiota composition and structure were assessed in stool samples. Results There was no significant change in faecal calprotectin nor lactoferrin in patients with treatment while all patients remained severely pancreatic insufficient. There was no significant change in gut microbiota diversity and richness following treatment. Conclusion There was no significant change in gut inflammation after partial restoration of CFTR function with ivacaftor, suggesting that excess gut inflammation in CF is multi-factorial in aetiology. In this adult cohort, exocrine pancreatic function was irreversibly lost. Longer term follow-up may reveal more dynamic changes in the gut microbiota and possible restoration of CFTR function.
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Reagent Free Electrochemical-Based Detection of Silver Ions at Interdigitated Micro Electrodes Using in Situ pH ControlSilver ions, the most toxic form of silver, can be present in drinking water due to their release from silver nanoparticles which are widely used in consumer products. Due to their adverse health effects, a quick portable approach for detection in drinking water is needed. Herein we report on the development of an electrochemical sensor for silver ions detection in tap water using linear sweep voltammetry with in situ pH control; enabled by closely space interdigitated electrode arrays. The in situ pH control approach, allows the pH of a test solution to be tailored to pH 3 thereby eliminating the current need for acid addition. A calibration curve between 0.2 - 10 µM was established for silver detection in sodium acetate when 1.25 V and 1.65 V was applied at the protonator electrode during deposition and stripping, respectively, as a proof of concept study. For the final application in tap water, 1.65 V was applied at the protonator electrode during deposition and stripping. The chlorine ions, present in tap water as a consequence of the disinfection process, facilitated the silver detection and no additional electrolyte had to be added. Combination of complexation of silver ions with chlorine coupled with in situ pH control resulted in linear calibration range between 0.25 and 2 µM in tap water without the need for acidification.
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Validation and robustness testing of a HPLC method for the determination of avermectins and moxidectin in animal liver samples using an alumina column clean-upA multi-residue method has been developed for the quantitative determination of moxidectin, abamectin, doramectin and ivermectin in liver samples, with capability for qualitative identification of the presence of eprinomectin. Liver samples are extracted with isooctane, followed by clean-up on alumina-N solid phase extraction (SPE) cartridges. Extracts are derivatised and determined by high-performance liquid chromatography (HPLC) with fluorescence detection. The method was validated using bovine liver fortified at levels of 4 and 20 μg kg−1 with the drugs. The mean recovery from bovine liver ranged between 90 and 96%. The intra and inter-assay variations showed RSD typically of <5% and <10%, respectively. The procedure was applied also to ovine and porcine liver, giving similar results. A robustness study, carried out on the alumina clean-up step, indicated that the step is relatively insensitive to method changes. However, significant differences overall were found for the type of alumina and/or commercial SPE cartridge used. The limit of quantitation of the method is 2 μg kg−1 (ppb).
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Detection of stx2 from Shiga toxin-producing Escherichia coli (STEC) by a surface enhanced Raman spectroscopy (SERS) sensor using recycled silicon chipsIn this research, a selective, cost-efficient, and highly sensitive Ag nanostructure Surface Enhanced Raman Spectroscopy (SERS) sensor was developed as a methodological approach to rapidly detect a targetss-DNA (stx2) in STEC (Shiga toxin-producing Escherichia coli). The Ag nanostructure-based SERS substrate was functionalized by two types of thiols: thiol-ss-DNA for bonding target ss-DNA and 6-Mercapto-1-hexanol (HS(CH2)6OH) for blocking the Ag nanostructure surface. Methylene Blue (MB) was used as a Raman marker to quantify target ss-DNA, as well as a model molecule to characterize the electrodeposited Ag nanostructure SERS substrate. Ag nanostructure SERS substrates showed good sensitivity and repeatability towards MB detection, with a LOD = 0.3158 μM, and RSD = 12.48% (at 45 different random points for 0.1 μM MB). More importantly, the Ag nanostructure/ss-DNA SERS substrate showed good selectivity towards STEC O157 stx2 target DNA, as well as good linearity and sensitivity towards its detection in a buffer solution. A limit of detection of 0.4900 aM and a wide linear range from 1 aM to 100 pM were demonstrated. The SERS sensors were able to identify target DNA (stx2) in a STEC strain and the study showed proof of principle that SERS substrate has potential as a cost-effective, highly selective, highly sensitive DNA and bacteria sensor without the aid of DNA amplification. With further development and validation, this methodological approach has the potential for point-of-use detection for instance on a farm or in the food industry.
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Low temperature microfiltration of skim milk: Impact of membrane type, configuration and concentration factor on serum protein permeation efficiencyProtein transmission, permeate flux and energy consumption during MF of skim milk was evaluated at 7 °C using two discrete 800 kDa polymeric MF membranes. Filtration trials determined optimum process parameters (i.e., transmembrane pressure and volume concentration factor) and membrane configuration (in-series or in-parallel) to maximise serum protein permeation. This study demonstrated that a combination of higher VCF (3) and lower TMP (75 kPa), with an in-parallel membrane configuration resulted in the most efficient rate of permeation of serum protein per kg of permeate produced. However, from an energy perspective, an in-parallel configuration with a TMP of 75 kPa and a lower VCF2 was the most efficient process, consuming between 1.28 and 1.57 kW h kg−1 of crude protein permeated. Additionally, the permeation of serum β-casein at low temperature was governed by the uniformity of the pore size distribution in discrete MF membranes with the same nominal molecular mass cut-off.
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An investigation of extracellular vesicles in bovine colostrum, first milk and milk over the lactation curveExtracellular vesicles (EVs) in milk have claimed benefits ranging from conveying immunological privilege to infants to being suitable as natural delivery vehicles for therapeutic drugs. However, a longitudinal study of bovine EVs quantities and characteristics in colostrum (COL), first milk (FM) and throughout the lactation curve of mature milk (MM) had never been performed and so was our aim. COL, FM and 9 months of MM samples were collected. Caseins -overlapping size with EVs- were removed. EVs were collected by density gradient ultracentrifugation and characterised by SDS-PAGE, Bradford assay, nanoparticle tracking analysis, immunoblotting, imaging flow cytometry analysis, and transmission electron microscopy. COL and FM had substantially more EVs than MM, with COL enriched in small EVs. No significant differences were observed between months 1–9 of MM. Altogether, although COL and FM are particularly rich sources of EVs, mature milk throughout the lactation curve is also an abundant source of intact EVs.
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Food for thought: The role of nutrition in the microbiota-gut–brain axisRecent research has provided strong evidence for the role of the commensal gut microbiota in brain function and behaviour. Many potential pathways are involved in this bidirectional communication between the gut microbiota and the brain such as immune mechanisms, the vagus nerve and microbial neurometabolite production. Dysbiosis of gut microbial function has been associated with behavioural and neurophysical deficits, therefore research focused on developing novel therapeutic strategies to treat psychiatric disorders by targeting the gut microbiota is rapidly growing. Numerous factors can influence the gut microbiota composition such as health status, mode of birth delivery and genetics, but diet is considered among the most crucial factors impacting on the human gut microbiota from infancy to old age. Thus, dietary interventions may have the potential to modulate psychiatric symptoms associated with gut–brain axis dysfunction. Further clinical and in vivo studies are needed to better understand the mechanisms underlying the link between nutrition, gut microbiota and control of behaviour and mental health.
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Investigation of breakage behavior and its effects on spray-dried agglomerated whey protein-lactose powders: Effect of protein and lactose contentsParticle breakage of dairy powders occurs easily during many processes, reducing the powder functionality. The characteristics of particles and the applied stress from processing conditions on the particles are 2 main factors that can be manipulated to reduce breakage. In this study, we explored the effect of whey protein and lactose contents on dynamic breakage in agglomerated whey protein-lactose powders to provide useful information, in terms of particle characteristics, for controlling unwanted dairy powder breakage. A series of model agglomerates with different whey protein:lactose ratios were produced under the same spray-drying conditions, through a pilot plant trial. We evaluated physical characteristics, composition, and structure of samples; analyzed dynamic breakage under different mechanical stresses; and investigated the rehydration and water adsorption properties of model powders before and after breakage. The particle size and irregularity of agglomerates with more lactose was significantly higher than of samples that contained more protein. This resulted in higher particle breakage during dynamic breakage for samples with more lactose. The breakage of agglomerates was affected by the moisture content of powders and fatigue, where particle breakage happens when mechanical loads, lower than the strength of particles, occur multiple times. Breakage changed the morphology and surface composition of particles and decreased particle size. It also decreased the dispersibility of powders and increased the wetting time of wettable samples but decreased the wetting time of powders with poor wettability. Breakage accelerated time-dependent crystallization and decreased the crystallization temperature but did not affect the glass transition temperature of samples. Thus, under the same drying conditions, composition of powders significantly affected breakage, mainly by altering the physical properties of their particles, which resulted in deteriorated functionality.
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Alteration of Physicochemical Properties and Heating Stability of Reconstituted Acid Whey Powder by Calcium Chelating SaltsTrisodium citrate (TSC) and ethylenediaminetetraacetic acid disodium salt (Na2-EDTA) were applied in reconstituted acid whey powder (AWP) at 20% w/w, which mimicked acid whey concentration during industrial whey processing. Physicochemical properties and heat stability of the AWP suspensions with 0–50 mM TSC and Na2-EDTA at pH 6.2 were investigated. TSC-containing suspensions prior to heating had decreasing Ca2+ activity, levels of sedimentation, and subtle reduction of aggregate size with increasing TSC concentrations (0–50 mM). Unheated Na2-EDTA-containing suspensions had lower levels of sedimentation and smaller aggregate sizes than unheated TSC-containing suspensions; however, reduction of Ca2+ activity was only observed up to 20 mM Na2-EDTA. Stronger effects of Na2-EDTA than TSC on levels of sediment, viscosity, and aggregate size of AWP suspensions were observed after heating, except for 50 mM Na2-EDTA. A remarkable difference between TSC and Na2-EDTA addition was the nature of aggregates formed in heated suspensions. TSC-containing suspensions contained larger aggregates than corresponding Na2-EDTA-containing suspensions, which exhibited increasing shear thinning behavior as a function of concentration. In contrast, the smaller aggregates in the corresponding Na2-EDTA-containing suspension showed shear thickening. The inverse relationship between aggregate size and levels of sediment for TSC-containing suspensions post-heat treatment may indicate the formation of loose aggregates that resist sedimentation.
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Effect of a bacteriocin-producing Streptococcus salivarius on the pathogen Fusobacterium nucleatum in a model of the human distal colonThe gut microbiome is a vast reservoir of microbes, some of which produce antimicrobial peptides called bacteriocins that may inhibit specific bacteria associated with disease. Fusobacterium nucleatum is an emerging human bacterial pathogen associated with gastrointestinal diseases including colorectal cancer (CRC). In this study, fecal samples of healthy donors were screened for potential bacteriocin-producing probiotics with antimicrobial activity against F. nucleatum. A novel isolate, designated as Streptococcus salivarius DPC6993 demonstrated a narrow-spectrum of antimicrobial activity against F. nucleatum in vitro. In silico analysis of the S. salivarius DPC6993 genome revealed the presence of genes involved in the production of the bacteriocins salivaricin A5 and salivaricin B. After 6 h in a colon fermentation model, there was a significant drop in the number of F. nucleatum in samples that had been simultaneously inoculated with S. salivarius DPC6993 + F. nucleatum DSM15643 compared to those inoculated with F. nucleatum DSM15643 alone (mean ± SD: 9243.3 ± 3408.4 vs 29688.9 ± 4993.9 copies/μl). Furthermore, 16S rRNA amplicon analysis revealed a significant difference in the mean relative abundances of Fusobacterium between samples inoculated with both S. salivarius DPC6993 and F. nucleatum DSM15643 (0.05%) and F. nucleatum DSM15643 only (0.32%). Diversity analysis indicated minimal impact exerted by S. salivarius DPC6993 on the surrounding microbiota. Overall, this study highlights the ability of a natural gut bacterium to target a bacterial pathogen associated with CRC. The specific targeting of CRC-associated pathogens by biotherapeutics may ultimately reduce the risk of CRC development and positively impact CRC outcomes.
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Use of Probiotic Bacteria and Bacteriocins as an Alternative to Antibiotics in AquacultureIn addition to their use in human medicine, antimicrobials are also used in food animals and aquaculture, and their use can be categorized as therapeutic against bacterial infections. The use of antimicrobials in aquaculture may involve a broad environmental application that affects a wide variety of bacteria, promoting the spread of bacterial resistance genes. Probiotics and bacteriocins, antimicrobial peptides produced by some types of lactic acid bacteria (LAB), have been successfully tested in aquatic animals as alternatives to control bacterial infections. Supplementation might have beneficial impacts on the intestinal microbiota, immune response, development, and/or weight gain, without the issues associated with antibiotic use. Thus, probiotics and bacteriocins represent feasible alternatives to antibiotics. Here, we provide an update with respect to the relevance of aquaculture in the animal protein production sector, as well as the present and future challenges generated by outbreaks and antimicrobial resistance, while highlighting the potential role of probiotics and bacteriocins to address these challenges. In addition, we conducted data analysis using a simple linear regression model to determine whether a linear relationship exists between probiotic dose added to feed and three variables of interest selected, including specific growth rate, feed conversion ratio, and lysozyme activity.
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The impact of pasture and non-pasture diets on the sensory and volatile properties of whole milk powderThis study evaluated the impact of three distinct diets; perennial ryegrass (GRS), perennial ryegrass/white clover (CLV) and total mixed ration (TMR), on the sensory properties and volatile profile of whole milk powder (WMP). The samples were evaluated using a hedonic sensory acceptance test (n = 99 consumers) and by optimised descriptive profiling (ODP) using trained assessors (n = 33). Volatile profiling was achieved by gas chromatography mass spectrometry using three different extraction techniques; headspace solid phase micro-extraction, thermal desorption and high capacity sorptive extraction. Significant differences were evident in both sensory perception and the volatile profiles of the WMP based on the diet, with WMP from GRS and CLV more similar than WMP from TMR. Consumers scored WMP from CLV diets highest for overall acceptability, flavour and quality, and WMP from TMR diets highest for cooked flavour and aftertaste. ODP analysis found that WMP from TMR diets had greater caramelised flavour, sweet aroma and sweet taste, and that WMP from GRS diets had greater cooked aroma and cooked flavour, with WMP derived from CLV diets having greater scores for liking of colour and creamy aroma. Sixty four VOCs were identified, twenty six were found to vary significantly based on diet and seventeen of these were derived from fatty acids; lactones, alcohols, aldehydes, ketones and esters. The abundance of δ-decalactone and δ-dodecalactone was very high in WMP derived from CLV and GRS diets as was γ-dodecalactone derived from a TMR diet. These lactones appeared to influence sweet, creamy, and caramelised attributes in the resultant WMP samples. The differences in these VOC derived from lipids due to diet are probably further exacerbated by the thermal treatments used in WMP manufacture.
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Thermal Death Kinetics of Three Representative Salmonella enterica Strains in Toasted Oats CerealSeveral reports have indicated that the thermal tolerance of Salmonella at low-water activity increases significantly, but information on the impact of diverse food matrices is still scarce. The goal of this research was to determine the kinetic parameters (decimal reduction time, D; time required for the first decimal reduction, δ) of thermal resistance of Salmonella in a previously cooked low water activity food. Commercial toasted oats cereal (TOC) was used as the food model, with or without sucrose (25%) addition. TOC samples were inoculated with 108 CFU/mL of a single strain of one of three Salmonella serovars (Agona, Tennessee, Typhimurium). TOC samples were ground and equilibrated to aw values of 0.11, 0.33 and 0.53, respectively. Ground TOC was heated at temperatures between 65 °C and 105 °C and viable counts were determined over time (depending on the temperature for up to 6 h). Death kinetic parameters were determined using linear and Weibull regression models. More than 70% of Weibull’s adjusted regression coefficients (R2adj) and only 38% of the linear model’s R2adj had values greater than 0.8. For all serovars, both D and δ values increased consistently at a 0.11 aw compared to 0.33 and 0.53. At 0.33 aw, the δ values for Typhimurium, Tennessee and Agona were 0.55, 1.01 and 2.87, respectively, at 85 °C, but these values increased to 65, 105 and 64 min, respectively, at 0.11 aw. At 100 °C, δ values were 0.9, 5.5 and 2.3 min, respectively, at 0.11 aw. The addition of sucrose resulted in a consistent reduction of eight out of nine δ values determined at 0.11 aw at 85, 95 and 100 °C, but this trend was not consistent at 0.33 and 0.53 aw. The Z values (increase of temperature required to decrease δ-value one log) were determined with modified δ values for a fixed β (a fitting parameter that describes the shape of the curve), and ranged between 8.9 °C and 13.4 °C; they were not influenced by aw, strain or sugar content. These findings indicated that in TOC, high thermal tolerance was consistent among serovars and thermal tolerance was inversely dependent on aw.
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Sensorial, cultural and volatile properties of milk, dairy powders, yoghurt and butter: A reviewCountries with an established dairy tradition consume milk, milk powder, yoghurt and butter directly or as an ingredient; however, in countries without this tradition the lack of familiarity and unknown expectations can be challenging to overcome. Therefore, having a better understanding of the volatile properties that influence their sensory appeal can aid overcoming these challenges. This review focusses on traditional and novel sensory methods used to research milk, milk powders, yoghurt and butter as well as the extraction techniques used in gas chromatography mass spectrometry and gas chromatography olfactometry to identify volatiles in these products that influence sensory perception.
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Impact of Cattle Feeding Strategy on the Beef MetabolomeThe present study explored changes in the meat metabolome of animals subjected to different finishing systems and growth rates. Thirty-six Angus × Nellore crossbred steers were used in a completely randomized design with four treatments: (1) feedlot system with high average daily gain (ADG; FH); (2) feedlot system with low ADG (FL); (3) pasture system with high ADG (PH); and (4) pasture system with low ADG (PL). After harvest and chilling, Longissimus thoracis (LT) muscle samples were taken for metabolite profile analysis using nuclear magnetic resonance. Spectrum was analyzed using chenomx software, and multi- and mega-variate data analyses were performed. The PLS-DA showed clear separation between FH and PL groups and overlap among treatments with different finishing systems but similar for matching ADG (FL and PH) treatments. Using a VIP cut-off of around 1.0, ATP and fumarate were shown to be greater in meat from PL cattle, while succinate, leucine, AMP, glutamate, carnosine, inosine, methionine, G1P, and choline were greater in meat from FH. Comparing FL and PH treatments, glutamine, carnosine, urea, NAD+, malonate, lactate, isoleucine, and alanine were greater in the meat of PH cattle, while G6P and betaine were elevated in that of FL cattle. Relevant pathways were also identified by differences in growth rate (FH versus PL) and finishing system were also noted. Growth rate caused a clear difference in meat metabolism that was highlighted by energy metabolism and associated pathways, while the feeding system tended to alter protein and lipid metabolism.
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Lactobacillus salivarius UCC118™ Dampens Inflammation and Promotes Microbiota Recovery to Provide Therapeutic Benefit in a DSS-Induced Colitis ModelThe use of probiotics such as Lactobacillus and Bifidobacterium spp. as a therapeutic against inflammatory bowel disease (IBD) is of significant interest. Lactobacillus salivarus strain UCC118TM is a commensal that has been shown to possess probiotic properties in vitro and anti-infective properties in vivo. However, the usefulness of UCC118 TM as a therapeutic against colitis remains unclear. This study investigates the probiotic potential of Lactobacillus salivarius, UCC118™ in a mouse model of colitis. DSS-induced colitis was coupled with pre-treatment or post-treatment with UCC118TM by daily oral gavage. In the pre-treatment model of colitis, UCC118TM reduced the severity of the disease in the early stages. Improvement in disease severity was coupled with an upregulation of tissue IL-10 levels and increased expression of macrophage M2 markers. This anti-inflammatory activity of UCC118TM was further confirmed in vitro, using a model of LPS-treated bone marrow-derived macrophages. Taken together, these results suggest that UCC118TM may promote the resolution of inflammation. This was supported in a mouse model of established DSS-induced colitis whereby UCC118TM treatment accelerated recovery, as evidenced by weight, stool, histological markers and the recovery of microbiome-associated dysbiosis with an increased abundance of beneficial commensal species. These results demonstrate the potential of Lactobacillus salivarius UCC118TM as a probiotic-based therapeutic strategy to promote health through the upregulation of anti-inflammatory IL-10 and protect against dysbiosis during IBD.
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What is the impact of amino acid mutations in the primary structure of caseins on the composition and functionality of milk and dairy products?The impact of amino acid mutations within the peptide structure of bovine milk protein is important to understand as it can effect processability and subsequently effect its physiological properties. Genetic polymorphisms of bovine caseins can influence the chemical, structural, and technological properties, including casein micelle morphology, calcium distribution, network creation upon gelation, and surface activity. The A1 and A2 genetic variants of β-casein have recently acquired growing attention from both academia and industry, prompting new developments in the area. The difference between these two genetic variants is the inclusion of either proline in β-casein A2 or histidine in β-casein A1 at position 67 in the peptide chain. The aim of this review was to examine the extent to which milk and ingredient functionality is influenced by β-casein phenotype. One of the main findings of this review was although β-casein A1 was found to be the dominant variant in milks with superior acid gelation and rennet coagulation properties, milks comprised of β-casein A2 possessed greater emulsion and foam formation capabilities. The difference in the casein micelle assembly, hydrophobicity, and chaperone activity of caseins may explain the contrast in the functionality of milks containing β-casein from either A1 or A2 families. This review provides new insights into the subtle variations in the physicochemical properties of bovine milks, which could potentially support dairy producers in the development of new dairy products with different functional properties.
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X-ray computerized microtomography and confocal Raman microscopy as complementary techniques to conventional imaging tools for the microstructural characterization of Cheddar cheeseThis study explored the use of X-ray computerized microtomography (micro-CT) and confocal Raman microscopy to provide complementary information to well-established techniques, such as confocal laser scanning microscopy (CLSM), for the microstructural characterization of cheese. To evaluate the potential of these techniques, 5 commercial Cheddar cheese samples, 3 with different ripening times and 2 with different fat contents, were analyzed. Confocal laser scanning microscopy was particularly useful to describe differences in fat and protein distribution, especially between the 2 samples with different fat contents. The quantitative data obtained through image analysis correlated well with the nutritional information provided in the product labels. Conversely, micro-CT was more advantageous for studying the size and spatial distribution of microcrystals present within the cheese matrix. Two types of microcrystals were identified that differed in size, shape, and X-ray attenuation. The smallest, with a diameter of approximately 10 to 20 μm, were more abundant in the samples and presented a more uniform roundish shape and higher X-ray attenuation. Larger and more heterogeneous crystals with diameters reaching 50 μm were also observed in scarcer numbers and showed lower X-ray attenuation. Confocal Raman microscopy was useful not only for identifying the distribution of all these components but also allowed comparing the presence of micronutrients such as carotenoids in the cheeses and provided compositional information on the crystals detected. Small and large crystals were identified as calcium phosphate and calcium lactate, respectively. Overall, using micro-CT, confocal Raman microscopy, and CLSM in combination generated novel and complementary information for the microstructural and nutritional characterization of Cheddar cheese. These techniques can be used to provide valuable knowledge when studying the effect of milk composition, processing, and maturation on the cheese quality attributes.
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The microbiology of beef from carcass chilling through primal storage to retail steaksThe primary objective of this study was to investigate if alternative time-temperature carcass chilling combinations resulted in lower microbial (TVC, Enterobacteriaceae, Lactic Acid Bacteria, Pseudomonas spp. And Brochothrix thermosphacta) counts and, if achieved, would reduced levels remain throughout the beef chain. Physicochemical (temperature, pH, water activity) characteristics were also recorded. A secondary objective was to investigate the effect of primal maturation periods (2 versus 5 weeks) on the sensory properties of steaks by a trained panel for colour, odour, tenderness, and flavour. While microbial populations reduced by over 1 log10 cfu/cm2 by fast carcass chilling, these reductions were lost due to cross contamination in the boning hall and cutting room. The pH and water activity remained stable throughout the study and there was no significant difference for colour or sensory characteristics in retail steaks from the different treatment groups. It was concluded that there was no improvement to the microbial shelf-life of retail steaks from modified chilled carcasses or in the sensory shelf-life of primals which were aged for an extended period.
