Sheep Cheese Research Articles

Magnetic Resonance Imaging (MRI) of Spanish Sheep Cheese: A Study on the Relationships between Ripening Times, Geographical Origins, Textural Parameters, and MRI Parameters.

The evolution of structural changes and the textural features during the ripening process of four varieties of Spanish sheep cheese were studied using Magnetic Resonance Imaging (MRI). Specifically, longitudinal (T1) and transverse (T2) relaxation times and apparent diffusion coefficient maps were analyzed. Also, proton density was used to improve the description of the structure of the cheeses. The MRI results displayed important information about cheese matrix structure, associated with different manufacturing processes (industrial vs. traditional), ripening times (RTs, from 2 to 180 days), and geographical origins. A significant interaction between RT and cheese variety related to the variations in physicochemical and textural parameters was found. Linear regression models were developed per the abundant literature. Logarithmic regression models showed the highest R2 when monitoring the dependency on T1 and T2 parameters of water content, water activity, RT, and some texture parameters. Therefore, these results support that MRI is a useful technology to monitor the ripening process, predict textural behavior and physicochemical variables, and characterize the structure of different varieties of sheep cheese.

A CASE STUDY OF IMPLEMENTATION OF CIRCULAR ECONOMY PRINCIPLES TO WASTE MANAGEMENT: INTEGRATED TREATMENT OF CHEESE WHEY AND HI-TECH WASTE

In a global context characterized by severe environmental problems and increasing resource scarcity, waste represents both a challenge and an opportunity. This study aims to demonstrate with a real case the potential for optimizing the waste valorization action attainable through the synergic application of different treatments to residues of equally different nature and origin. In particular, bio-chemical (dark fermentation), chemical-physical (selective leaching) and thermo-chemical (hydrothermal carbonization) treatments were applied for the integrated valorization of whey from sheep cheese production and Hi-Tech waste (discarded electrical and electronic equipment). The treatments were applied at a laboratory scale on real samples of these residues. The organic acids used for selective leaching of valuable metals from Hi-Tech waste were obtained by dark fermentation of the cheese whey, while hydrothermal carbonization was used to convert the waste from previous stages into hydrochar feasible as solid fuel or soil improver. The dark fermentation tests have highlighted the possibility of recovering ≈ 100 g of organic acids from 1 L of whey; furthermore, it is also possible to recover bio-hydrogen depending on the operating conditions applied and the type of targeted organic acids. The leaching tests have demonstrated how the organic acids from whey fermentation have selective and quantitative mobilization capacities comparable to those of the same acids available on the market. The carbonization tests produced carbon-enriched hydrochar with promising fuel properties, as well as process waters suitable for anaerobic digestion with methane production. The results of the project led to the filing of an international patent.

Pathogenic and Harmful Bacteria in Dairy Technology: Genomic Characterization and Its Correlation with Physicochemical Parameters of Sheep’s Cheese Sold in Southern Brazil

The distinct microbiological and physicochemical characteristics of sheep milk enable the production of cheeses with unique organoleptic properties. The scenario of sheep cheeses in Brazil is still uncertain, lacking data and regulations. This study aims to characterize the diversity of bacterial groups with potential pathogenic and/or harmful properties to milk technology and correlate the presence of these bacteria with the physicochemical properties of sheep cheese. Additionally, it investigates the presence of virulence genes, resistance genes, and toxins in reference genomes. The main steps were (a) sample preparation and fractionation; (b) physicochemical analysis; (c) analysis of the free fatty acids profile by GC-FID; (d) analysis of the volatile compounds profile by GC-MS; (e) molecular analysis—Next Generation Sequencing of the 16S rRNA gene (V3-V4 region); and (f) in silico analysis—Genomics. A total of 1,061,392 sequences were identified, corresponding to 45 genera and 57 species. Of the total abundance, 95.7% were considered beneficial, while 3.9% were classified as bacteria with pathogenic potential (BPP) and/or bacteria harmful to milk technology (BHMT). Five phyla were identified: Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidota, and Fusobacteriota. The genera Acinetobacter, Pseudomonas, and Staphylococcus stood out in the BPP and BHMT groups, showing higher abundance. Alpha diversity of the cheese samples showed that the cheese origin significantly influences the richness, evenness, and abundance of bacterial species. Some physicochemical parameters, fatty acids, and volatile organic compounds showed a negative correlation with Staphylococcus. Reference genomes of two species exhibited a higher number of resistance and virulence genes. This reinforces the need to monitor bacteria considered of lesser relevance to prevent the transmission, through food, of potentially resistant and virulent pathogens.

AUTHENTICITY ANALYSIS OF 100% SHEEP'S BRYNDZA FROM SELECTED ESTABLISHMENTS IN THE SLOVAK REPUBLIC

Cheese was in the past, and still is today, one of the leading commodities. The production of “bryndza” has been preserved over the years, and today it is represented by the Protected Geographical Indication “Slovenská bryndza” (Slovenská bryndza). There are two types of “Slovenská bryndza”, mixed or 100% sheep. However, the name 'traditional' belongs only to sheep's bryndza. The high demand for a particular foodstuff also brings risks associated with its quality and fairness. The same is true of the national heritage product, sheep's bryndza. Identifying the originality or authenticity of various animal food products has received considerable attention recently. Our work has focused on the control of adulteration of 100% sheep's bryndza. Purchased samples from different parts of Slovakia were analyzed with a focus on the addition of cow's milk to sheep's bryndza. The reference method for determining the presence of cow's milk in sheep's cheese is based on detecting cow's γ2- and γ3-caseins from cheese after electrophoretic separation on urea-polyacrylamide gels. This method has proven to be reliable and sensitive. We tested sheep's bryndza made from both raw milk and heat-treated milk. The method of checking for adulteration of the cheese proved successful and in one sample we found the presence of cow casein in smaller amounts, probably due to accidental contamination. Isoelectric focusing of γ-caseins after plasmolysis is suitable for qualitatively determining sheep and cow proteins in traditional Slovak bryndza.

A Sustainable Material for Sheep's Cheese Wedges Stored under Different Atmosphere Conditions.

This study is based on the need to improve packaging sustainability in the food industry. Its aim was to assess the performance of a recyclable plastic material for semi-hard sheep's cheese wedges packaging as an alternative to conventional non-sustainable plastic materials. Four different packaging treatments (air, vacuum, and CO2/N2 gas mixtures 50/50 and 80/20% (v/v)) were studied. Changes in gas headspace composition, sensory properties, cheese gross composition, weight loss, pH, colour, and texture profile were investigated at 5 ± 1 °C storage for 56 days. The sensory analysis indicated that vacuum packaging scored the worst in paste appearance and holes, and air atmosphere the worst in flavour; it was concluded that cheeses were unfit from day 14-21 onwards. Air and vacuum packaging were responsible for most of the significant changes identified in the texture profile analysis, and most of these happened in the early stages of storage. The colour parameters a* and b* differentiated the air packaging from the rest of the conditions. As in previous studies using conventional plastic materials, modified atmosphere packaging, either CO2/N2 50/50 or 80/20% (v/v), was the most effective preserving technique to ensure the quality of this type of cheese when comparing air and vacuum packaging treatments.

Cocoa byproduct inclusion in dairy sheep diet: Effects on sensory, volatile, and antioxidant properties of cheese

The possibility of inclusion of agro-industrial byproducts in the diet of small ruminants represents both an economic and an environmental strategy for reducing waste management by industries and costs of feeding as well as the impact of livestock farming. Large amounts of wastes from the cocoa industry are produced annually, with a considerable part represented by cocoa bean shells, considered a suitable ingredient to be included in the diet of ruminants within the limits established by European legislation. The aim of this study was to assess the effect of including cocoa bean shells in the diet of dairy sheep on the sensory, volatile, and antioxidant properties of cheese. To this purpose, 20 lactating Comisana ewes were randomly assigned to 2 experimental groups: control (CTRL) and cocoa bean shells (CBS), and received alfalfa hay ad libitum and 800 g of conventional (CTRL) or experimental (CBS) concentrate containing 11.7% CBS to partially replace corn and barley of the CTRL concentrate. Bulk milk collected from each group was used to produce a total of 15 cheeses per group, obtained in 5 different days of cheesemaking (3 cheeses a day per group). After 60 d of aging, each cheese of each experimental group was sampled for the analyses. The results on chemical composition revealed a greater content of monounsaturated fatty acids and an increase in the nutritional indices, suggesting a favorable role of cocoa bean shell dietary inclusion on the nutritive value of cheese. The cheese sensory profile was affected by the cocoa bean shell inclusion, with more pronounced appearance, odor, aroma, and taste attributes in the product. The volatile profile showed only a few significant differences, mainly related to the cheese ripening process, and no differences were found in α-tocopherol contents in cheese fat between the 2 groups. Therefore, the inclusion of coca bean shells in the diet of dairy sheep allowed us to obtain a good-quality cheese, without altering the characteristics associated with the typical profiles of sheep cheese. Furthermore, the use of this byproduct could contribute to decreasing feed costs and waste management, representing a good practice for increasing the sustainability of dairy products.

Elemental Fingerprinting of Pecorino Romano and Pecorino Sardo PDO: Characterization, Authentication and Nutritional Value.

Sardinia, located in Italy, is a significant producer of Protected Designation of Origin (PDO) sheep cheeses. In response to the growing demand for high-quality, safe, and traceable food products, the elemental fingerprints of Pecorino Romano PDO and Pecorino Sardo PDO were determined on 200 samples of cheese using validated, inductively coupled plasma methods. The aim of this study was to collect data for food authentication studies, evaluate nutritional and safety aspects, and verify the influence of cheesemaking technology and seasonality on elemental fingerprints. According to European regulations, one 100 g serving of both cheeses provides over 30% of the recommended dietary allowance for calcium, sodium, zinc, selenium, and phosphorus, and over 15% of the recommended dietary intake for copper and magnesium. Toxic elements, such as Cd, As, Hg, and Pb, were frequently not quantified or measured at concentrations of toxicological interest. Linear discriminant analysis was used to discriminate between the two types of pecorino cheese with an accuracy of over 95%. The cheese-making process affects the elemental fingerprint, which can be used for authentication purposes. Seasonal variations in several elements have been observed and discussed.

Development of value-added beverages using sheep and goat cheese whey and secondary whey

Fermented (F) and neutral (non-fermented) (N) beverages were developed to add value to cheese whey (CW) and secondary whey (SW) from goat (G) and sheep (S) cheese. All products were microbiologically safe. Regarding physical stability, sedimentation of 3–20% was observed, with higher values at the beginning of storage for SW beverages (P < 0.05) due to protein agglomeration (explained by the 22%-larger size of small particles, P < 0.05). F beverages exhibited pseudoplastic behavior (n < 0.8) and higher apparent viscosity (napp). Sensory evaluation showed that the ingredients/additives used masked the unpleasant taste of whey; however, N samples were preferred due to coffee and sweet/vanilla flavors (P < 0.05). The overall results indicated that treatment (N or F) overcame any differences observed in relation to animal source (G or S) or whey type (CW or SW) and that, for the fermented samples, the animal source was more important than the type of whey.

Dried Herbs as an Easy-to-Use and Cost-Effective Alternative to Essential Oils to Extend the Shelf Life of Sheep Lump Cheese.

The objective of this research was to assess the effectiveness of three specific dried herbs (rosemary, thyme, and oregano) in combating microbial spoilage in sheep lump cheese. This was achieved by comparing them with a control group and cheeses treated with corresponding 1% essential oils (Rosmarinus officinalis, Origanum vulgare, Thymus vulgaris). All cheese samples were vacuum-sealed and stored at 4 °C for 15 days. Analysis of total viable counts of viable bacteria (TVC), coliform bacteria (CB), lactic acid bacteria (LAB), and microscopic filamentous fungi (MFF) was conducted on days 0, 5, 10, and 15. The results revealed that, at the end of the storage period, dried oregano-treated samples exhibited the lowest TVC count (5.80 log CFU/g), while dried rosemary-treated samples showed the lowest CB count (3.27 log CFU/g). Moreover, the lowest MFF count (2.40 log CFU/g) was observed in oregano essential oil-treated samples. Additionally, dried oregano-treated samples displayed the highest LAB count (4.49 log CFU/g) at the experiment's conclusion. Furthermore, microorganism identification from sheep cheese was performed using MALDI-TOF MS Biotyper technology, revealing that the most frequently isolated bacteria were Citrobacter braakii and Hafnia alvei (Enterobacteriaceae family), along with Lacticaseibacillus paracasei (Lactobacillaceae family). In summary, all the natural substances examined exhibited inhibitory effects against the studied microorganisms, with oregano essential oil and dried oregano demonstrating the strongest inhibitory effects. This supports their potential use as cost-effective natural preservatives to extend the shelf life of sheep lump cheese.

Sheep cheese allergy in Alpha-gal Syndrome.

Sheep cheese allergy in Alpha-gal Syndrome.

Effects of reduced-sodium brine on the physicochemical, textural and flavor characteristics of sheep cheeses during maturation

Effects of reduced-sodium brine on the physicochemical, textural and flavor characteristics of sheep cheeses during maturation

EVALUATION OF BIOGENIC AMINES IN GOAT AND SHEEP CHEESES OF SLOVAK ORIGIN

Goat cheese and sheep cheese can offer a range of unique flavors and potential health benefits, making them popular choices among cheese lovers. Both types of cheese contain biogenic amines, which are naturally present in many types of food. The purpose of this study was to assess the levels of the seven most commonly occurring biogenic amines in semi-hard and hard goat and sheep cheeses intended for the Slovak market. The HPLC-DAD method with pre-column derivatization using dansylchloride was employed for the analysis of the hard and semi-hard cheese samples. The presence of biogenic amines was confirmed in all cheese samples, with total levels ranging from 14.4 mg.kg-1 to 1322 mg.kg-1. The most abundant compounds found in the samples were tyramine and tryptamine, followed by 2-phenylethylamine and spermine. Histamine was present in 54.5% of the samples, but its concentration did not exceed 68.7 mg.kg-1. Statistically significant differences in the levels of individual biogenic amines were observed between goat and sheep cheeses, except for spermidine and spermine.

Consumer Acceptance of a New Brand of Telemea Cheese. A Descriptive Sensory Analysis

Descriptive sensory analysis may reveal information necessary to improve or maintain product quality and to understand consumers buying intentions. This study aimed to understand, by means of using descriptive sensory analysis, the consumer acceptance of a new brand of white sheep cheese ‘Telemea’ and to reveal its position in respect to competitive products. The evaluation was performed by a group of panelists who assessed four brands. The appearance-exterior, appearance-interior, odour, taste, and consistency were evaluated according to the DLG 5-point scheme as a descriptive sensory analysis method. Data were analyzed using descriptive statistics and statistical tests. Further, the principal component analysis was used to better understand the differences and similarities between the four brands belonging to the same type of cheese. Results indicate that consumers highly appreciate the new brand and show high degree of acceptance compared to the other brands. The results of the descriptive sensory analysis represent the starting point in developing marketing strategies for producers of cheese, in close connection with consumers’ perceptions. Developing marketing strategies that take into account consumer preferences is vital for a product to succeed on the market in the long term.

Impact of ultrasound and protease addition on the fermentation profile and final characteristics of fermented goat and sheep cheese whey.

The online version contains supplementary material available at 10.1007/s13197-023-05767-3.

Implementation of Novel Autochthonous Microencapsulated Strains of Lactiplantibacillus plantarum, Lactococcus lactis, and Lamb’s Rennet in the Production of Traditional “Paški Sir” Cheese

This study aimed to implement a microencapsulated form of selected autochthonous lactic-acid bacteria (LAB) isolated from the cheese-production chain and natural rennet obtained from suckling lambs in the traditional production of hard sheep cheese, “Paški sir”, from the island of Pag, Croatia. Two different formulations of microparticles were prepared: (i) microparticles containing the strain of both Lactiplantibacillus plantarum and Lactococcus lactis (S2) and (ii) microparticles containing both strains and natural rennet (S3). These formulations were used in the production of Paški sir cheese simultaneously with standard production using non-encapsulated commercial starter cultures and commercial rennet (S1). The number of Lc. lactis isolates decreased at day 30 and were not isolated during the remaining ripening process, whereas the number of L. plantarum remained stable throughout the ripening process. The level of LAB and the release of the rennet from microsphere formulations at the end allowed for the production of cheese with the same characteristics as the commercial product, indicating no negative interactions of natural rennet, bacterial culture, and chemical components of microparticles. To our knowledge, this is the first report of a microencapsulated L. plantarum (isolated from the abomasum of lambs) coupled with natural lamb’s rennet used in the production of hard sheep cheese. This pilot study showed the great potential for maintaining authenticity in cheese production by combining traditional and sustainable innovative technologies.

Tejsavbaktérium-izolátumok egyes probiotikus tulajdonságainak in vitro vizsgálata

Bacteria carrying genes responsible for antibiotic resistance cannot be used in food production. For this reason,exploring the antibiotic resistance profile of probiotic candidates and the antimicrobial substances theyproduce are essential for probiotic strain selection. The aim of this study was to develop and evaluate additionalelements of a complex in vitro test system for rapid and efficient selection of a large number of putativeprobiotic isolates. In a previous work, we had tested bacterial strains (n=217) isolated from Transylvanian rawsheep milk, cultured sheep milk, and sheep cheese samples and we reduced the sample number to a totalof six Gram-positive, non-hemolytic, catalase-negative, well-aggregating, good acid and bile acid toleratingstrains. In this research, we investigated the antibiotic resistance and antimicrobial production capacity of thepre-selected strains (n=6). The antimicrobial activity of the isolates was determined by the agar well diffusionassay. Strains E15, E66, E173, E198, and E216 were found to inhibit the growth of both Salmonella EnteridisATCC 13076 and the control strain (i.e., Lactobacillus acidophilus ATCC 4356). Antibiotic resistance testswere performed by the agar disk diffusion method. All six isolates belonging to the species of Levilactobacillusbrevis and Lactiplantibacillus plantarum were found to be resistant to several antibiotics and, therefore,cannot be used for the manufacture of commercial probiotic products. In conclusion, our in vitro test systemproved to be capable of effectively screening out unsafe isolates.

Changes in physicochemical, microbiological and fatty acid composition during the ripening period of artisan sheep cheese from Bulgaria

The composition of artisan sheep's milk cheese during the ripening period was studied. The raw material used for cheese production, was obtained from an indigenous Karakachan sheep from Bulgaria. It was found that the main physicochemical parameters of the cheese have changed during the study period. During the ripening process, chaaracteristics such as dry matter, total protein and fat content increased by approximately 7.0%, 3.0% and 4.0% respectively, while the water content of the samples decreased by up to 7.0%. A smooth acidification process was observed, which correlated with the high number of lactic acid bacteria. The fatty acid analysis showed that the saturated fatty acid composition was 66.0% and unsaturated fatty acids were 34.0%. During the biochemical ripening at the 60th day of the test period, the presence of linoleic polyunsaturated fatty acid was found to be 0.12%.

Probiotic Whey-Based Beverages from Cow, Sheep and Goat Milk: Antioxidant Activity, Culture Viability, Amino Acid Contents.

Recently, the demand for goat and sheep cheese has increased mainly because of its nutritional and health benefits. As a result, an enormous amount of whey from various animal species is produced as a waste/by-product. The production of functional probiotic fermented beverages from different types of whey protein concentrates (WPC) could be a good way to valorize whey. Meanwhile, reduced environmental pollution and economic sustainability will be provided. In this study, probiotic beverages enriched with 1% kiwi powder were produced from goat, sheep, and cow WPC (15%). Moreover, Streptococcus salivarius subsp. thermophilus and the probiotic bacteria Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis were used for fermentation. The results showed that WPC significantly increased the protein content and acidity of beverages (p < 0.05). Production with WPC also improved the viability of probiotic bacteria and S. thermophilus, total phenolic compound (TPC), and antioxidant activity of beverages. The highest viability of probiotic bacteria (9.67 log CFU/mL for Bb-12 and, 9.35 log CFU/mL for L. acidophilus) was found in beverages produced from goat WPC. In addition, WPC increased the free amino acid content of beverages, and the highest essential amino acids and branched-chain amino acids were found in beverages produced from goat WPC as 146.19 mg/100 g and 70.31 mg/100 g, respectively (p < 0.05). Consequently, while production with goat, cow, and sheep WPC improved quality compared to the control, beverages produced from goat WPC excelled. The production of a functional probiotic beverage with goat WPC is promising for dairy technology.

Quality indicators of traditional Bulgarian artisanal sheep’s cheese

The aim of the present study is focused on the evaluation of the quality parameters of artisan sheep cheese produced by old Bulgarian technology. The study was carried out in three stages - at the end of the ripening process (45th day), during and at the end of storage (180th and 360th day). An increase of 9.0% in dry matter and a decrease in water content and titratable acidity values were observed over the entire period studied. There was a decrease in oleic fatty acid (C18:1n9c) from 28.16% at day 45 to 26.09% at day 360 of ripening. In the case of palmitic acid (C16:0) the values recorded were similar from 30.24% (45th day) to 30.74% (360th day). Changes in the composition of organic acids were observed, with lactic acid levels decreasing from 27.66% at day 45 to 8.62% at day 360. After microbiological analysis, it was found that the main microflora present in the samples were representatives of lactic acid microorganisms as compared to the non-starter microflora.

Evaluation of bacterial consortia associated with dairy fermentation by ribosomal RNA (rrn) operon metabarcoding strategy using MinION device

The ability of the third generation sequencing technologies to provide longer sequence reads contributes to the use of the longest possible amplicons as specific bacterial markers for metabarcoding studies. Nanopore sequencing technologies are increasingly used worldwide to profile microbiomes in environmental and food samples. The identification of beneficial or pathogenic bacteria in dairy fermented foods is related to their valuable health properties and also contributes to food safety issues. Here we described and optimised a PCR-based methodology of almost the entire ribosomal operon sequences (16S-ITS-23S) and their subsequent sequencing by MinION device. We used three different sequencing data processing and analysis strategies. Two of those utilized user-friendly software without the need of being conversant with any programming language. We tested all workflows on a simple mock community composed of a mixture of 7 bacterial DNA. Our scripted bioinformatics pipeline denoted as “AEROS”, representing an approach based on taxonomic classification with our reference database called AEROS-DB (Almost Entire Ribosomal Operon Sequences), was applied to traditional Slovak sheep cheese made from unpasteurized milk. All bacterial genera included in the mock community were detected with relatively small differences compared to the expected relative abundance using each of the three approaches. The AEROS approach provided more accurate composition data on this community at the species level as well. The results suggested that the use of almost entire rrn operon sequences in metabarcoding studies is suitable to analyze the bacterial consortia in cheeses and related dairy fermented products.