Milk Cheese Research Articles

Production and Evaluation of Sheep's Milk Cheese Analogues Fortified with Milk Protein Concentrate and Native or Modified Starch with Guar Gum

Production and Evaluation of Sheep's Milk Cheese Analogues Fortified with Milk Protein Concentrate and Native or Modified Starch with Guar Gum

Onopordum platylepis (Murb.) Murb. as a novel source of thistle rennet: First application to the manufacture of traditional Italian raw ewe’s milk cheese

In this study, for the very first time, aqueous extracts obtained from flowers of spontaneously grown or cultivated Onopordum platylepis (Murb.) Murb. thistles were used as coagulating agents for the pilot-scale manufacture of Caciofiore, a traditional Italian raw ewe’s milk cheese. Cheese prototypes were compared to control cheeses curdled with a commercial thistle rennet obtained from flowers of Cynara cardunculus L. After 45 days of ripening under controlled conditions, both the experimental and control cheese prototypes were analyzed for: cheese yield, physico-chemical (pH, titratable acidity, aw, proximate composition), morpho-textural (color and texture), and microbiological parameters (viable cell counts and species composition assessed by Illumina sequencing), as well as volatile profile by SPME-GC–MS. Slight variations in titratable acidity, color, and texture were observed among samples. Based on the results overall collected, neither the yield nor the proximate composition was apparently affected by the type of thistle coagulant. However, the experimental cheese prototypes curdled with extracts from flowers of both spontaneous or cultivated thistles showed 10 % higher values of water-soluble nitrogen compared to the control prototypes. On the other hand, these latter showed slightly higher loads of presumptive lactococci, thermophilic cocci, coliforms, and eumycetes, but lower counts of Escherichia coli. No statistically significant differences were revealed by the metataxonomic analysis of the bacterial and fungal biota. Though most volatile organic compounds (VOCs) were consistent among the prototypes, significant variability was observed in the abundance of some key aroma compounds, such as butanoic, hexanoic, and octanoic acids, ethanol, propan-2-ol, isobutyl acetate, 2-methyl butanoic acid, and 3-methyl butanal. However, further investigations are required to attribute these differences to either the type of coagulant or the metabolic activity of the microorganisms occurring in the analyzed cheese samples. The results overall collected support the potential exploitation of O. platylepis as a novel source of thistle coagulant to produce ewe’s milk cheeses.

Investigation of some probiotic and technological properties of lactic acid bacteria strains isolated from artisanal sheep milk cheese and their growth in goat milk

The objective of this study was to assess the probiotic and technological properties of lactic acid bacteria (LAB) isolated from artisanal sheep milk cheeses for potential use in dairy products made from goat milk. Strains studied were Lacticaseibacillus paracasei LC6, Lactiplantibacillus plantarum LP48, Lactococcus lactis subsp. hordniae LH69 and Leuconostoc mesenteroides LM99. The criteria studied were fermentative capacity, carbohydrate fermentation profile, β-galactosidase (lactase) activity, auto-aggregation capacity, hydrophobicity, antimicrobial activity, resistance to simulated gastric secretion, bile resistance, and resistance to different pH and salts concentrations, as well as growth and viability in goat milk. In general, the strains studied showed characteristics compatible with potential probiotic effects. However, according to criteria studied, L. plantarum LP498 best met the conditions; it was compatible with probiotic potential under all the conditions considered and showed noteworthy differences compared to the other micro-organisms studied, particularly in its capacity for self-aggregation and pH resistance. Therefore, L. plantarum LP48 could be adequate for the manufacture of artisanal goat milk products.

Multipathogen quantitative risk assessment in raw milk soft cheese

We propose a multipathogen Quantitative Microbiological Risk Assessment (QMRA) model to estimate the risk of foodborne illness from bacterial pathogens in raw milk soft cheese. Our work extends an existing QMRA model for pathogenic Shiga toxin-producing Escherichia coli (STEC) (Basak et al.,under review; Perrin et al., 2014) by incorporating the effects of Salmonella and Listeria monocytogenes. This multipathogen model integrates microbial contamination of raw milk at the farm level, as well as the growth and survival of these bacteria during cheese fabrication, ripening, and storage. The public health impact of multipathogen risk associated with raw milk cheese consumption is assessed using Disability-Adjusted Life Years (DALYs). The model evaluates intervention strategies at both pre- and post-harvest stages to estimate intervention costs. Furthermore, it tests various scenarios of these strategies and optimizes intervention parameters to minimize multipathogen risk and associated costs. This article discusses challenges in QMRA model validation, emphasizes model limitations, and explores future perspectives for improvement.

Sex-Moderated Divergence between Adult Child and Parental Dietary Behavior Patterns in Relation to Body Mass Condition-Evaluating the Mediating Role of Physical Activity: A Cross-Sectional Study.

The main objective of this study was to explore the dietary behaviors of parents and their adult children, focusing on patterns, potential intrinsic and extrinsic predictors of body mass, and determinants of becoming overweight. Non-probability, cross-sectional sampling was used to select participants from a university student population. Young adults (19-21 years of age, n = 144) and their parents were examined. The data of those family pairs with complete sets of results were used. Dietary patterns and physical activity were assessed with questionnaires (QEB and IPAQ), and body height, weight measurements, and body mass indexes were calculated. A cophylogenetic approach with tanglegrams and heatmaps was used to study patterns, while predictors of body mass index were identified using multiple linear regression, stepwise logistic regression, and mediation analysis procedures. Cophenetic statistics confirmed significant incongruence between fathers and sons, confirmed by Baker's Gamma correlation (rBG = 0.23, p = 0.021), and mothers and daughters (rBG = 0.26, p = 0.030). The relationships between the dietary patterns of the fathers and daughters, as well as mothers and sons, were of medium strength (rBG = 0.33, p = 0.032, rBG = 0.43, p = 0.031; respectively). Most of the patterns were mixed. Fast food, fried meals, alcoholic drinks, energy drinks, and sweetened beverages were associated significantly with being overweight. Significant intrinsic predictors of excessive weight in young adults were sex (b = 2.31, p < 0.001), PA (b = -0.02, p < 0.001), and eating fermented milk and curd cheese (b = -0.55, p = 0.024), while extrinsic (parental) predictors included eating fast food and fried meals (b = -0.44, p = 0.049). Both physical activity and dietary behaviors independently determined the sons' overweight status (b = -1.25, p = 0.008; b = -0.04, p < 0.001; respectively); while only PA did in daughters (b = -0.04, p < 0.001). No mediating effects of physical activity were observed. Adult children and parental dietary patterns were divergent, reflecting the influence of multiple factors on a child's dietary habits. However, this divergence is moderated by sex. Reciprocal interactions between dietary intake-particularly positive dyads such as fruits and vegetables, fermented milk, and curd cheese-and physical activity significantly impacted children's body mass index (BMI). The study of dietary patterns in conjunction with physical activity (both as independent determinants), particularly in relation to the link between overweight/obese children and overweight/obese parents, presents a separate challenge.

Effect of Calcium Chloride and Trisodium Phosphate Fortification on Low Fat Buffalo Milk Cheeses

Cheese is a dairy product that is highly preferred by consumers. Cheese is a delectable and nutritious food item. Enhancing the quality of cheese necessitates innovation in cheese processing. The objective of the study was to determine the impact of calcium chloride and trisodium phosphate on the physical, chemical, microbiological, and rheological characteristics (namely firmness) of low-fat buffalo milk cheeses. This study had a fully randomized design, consisting of nine treatments and three replications. The cottage cheese, mozzarella, and cheddar were treated with varying quantities of calcium chloride and trisodium phosphate (10, 20, and 30 mM) and then stored for a period of 30 days. The cheeses supplemented with salt exhibited a noteworthy (p≤0.05) rise in pH, total nitrogen (TN), non-casein nitrogen (NCN), and non-protein nitrogen (NPN) for nearly all treatments. However, a subsequent decline was noted after storage. Similarly, the hardness (N) significantly improved (from 330.33 to 454) among treatments and reduced (from 427 to 276.33) after 30 days of storage, with a p-value of ≤0.05. In addition, the total plate count (TPC) and total viable count (TVC) showed an upward trend during the ripening phase. In conclusion, it was observed that the physicochemical, rheological, and microbiological quality characteristics of cheeses can be effectively regulated with appropriate mineral fortification.

Estimation of genetic parameters for production, composition and processability of milk from dairy sheep in a New Zealand flock

ABSTRACT This paper aimed to estimate the heritability and genetic correlations for processability (milk coagulation properties, cheese yield, and heat stability), milk production, and milk composition of dairy sheep in a New Zealand flock. Test-day records from 169 ewes were obtained during the 2021–2022 season. Heritability estimates for yield traits (milk, fat, protein, and lactose yield) were moderate and ranged from 0.33 to 0.38. Whereas heritability estimates for processability traits were lower and ranged from 0.17 to 0.27. The genetic correlations indicated that poorer milk coagulation properties were associated with lower mammary health indicated by higher SCS, higher pH, and lower lactose content. Additionally, a higher ratio of casein to calcium i.e. lower availability of soluble calcium was associated with poorer milk coagulation properties. Higher yields of milk, fat, protein, and lactose were associated, but to a smaller degree, with better MCP. It is proposed that genetic improvement of dairy sheep for higher yields of fat and protein, and for lower SCS, could indirectly improve milk processability for cheese-making. However, it is recommended that larger studies involving more dairy sheep flocks are conducted to validate the present results before developing a selection index for this industry.

Physicochemical and organoleptic changes in goat’s milk cheddar cheese with the addition of Lactobacillus casei as a starter during ripening

Abstract The fermentation process using lactic acid bacteria (LAB) in cheese manufacturing plays important roles to enhance the nutritional content of cheese. This study aims to observe the effect of the addition of Lactobacillus casei in goat’s milk cheese manufacturing. Changes in physicochemical and organoleptic characteristics were observed during cheese ripening. Cheese was made using 8% of L. casei as starter and its changes were observed for 8 weeks of ripening. The results showed that the acidification process in cheese by L. casei resulted in a yield value of 10.85%. The ripening period affects significant changes in physical and chemical indicators, except for pH. Observations during cheese ripening from the 4th to the 8th week indicate that pH tends to stabilize at pH 5, protein increases by approximately 16%, and the decrease in moisture and fat content was by 18% and 15%, respectively. The best quality of cheese was obtained by 8 weeks of ripening. After 8 weeks of ripening, the cheese was yellow in color, has a hard texture with cheesy aroma, sour taste, and contains approximately 1.8 × 106 CFU/ml of LAB. The study of LAB application in goat’s milk cheddar cheese will provide an innovation in cheese production.

Unveiling the Potential of Lactic Acid Bacteria from Serbian Goat Cheese.

This study aimed to unleash the potential of indigenous lactic acid bacteria (LAB) originating from traditionally made Serbian goat cheese. Following the isolation and identification of the LAB, the safety aspects of the isolates were evaluated through tests for hemolytic activity and antibiotic sensitivity. The selected isolates were then tested for various technological properties, including growth in methylene blue, proteolytic activity, acidification, curd formation ability in both pure and enriched goat milk, diacetyl production, antagonistic potential against other LAB, and biofilm formation ability. The results indicated that Lactococcus spp., Lacticaseibacillus spp., and Lactiplantibacillus spp. did not exhibit α or β hemolysis, while enterococci displayed α hemolysis. A higher number of isolates demonstrated sensitivity to ampicillin, tetracycline, and streptomycin, while sensitivity to gentamicin and vancomycin was strain-dependent. Based on the evaluation of technological properties, Lacticaseibacillus paracasei M-1 and Lactiplantibacillus plantarum C7-7, C7-8, and C14-5 showed promising characteristics. Additionally, Lactococcus lactis subsp. lactis strains C0-14 and C21-8 emerged as promising candidates with notable technological properties. Notably, certain indigenous strains LAB exhibit promising technological properties and safety profiles. These characteristics make them suitable candidates for use as starter or adjunct cultures in goat's milk cheese production, potentially enhancing the quality and safety of the cheese as well as hygiene practices among small-scale dairy producers.

ROSMOSE: A web-based decision support tool for the design and optimization of industrial and urban energy systems

Energy efficiency is crucial for the sustainable operation of industrial and urban sectors. However, practicing engineers seldom have access to open-source tools that can readily evaluate and compare scenarios. In this work, a novel web-based tool called ROSMOSE is developed and proposed for analyzing the energy efficiency of industrial and urban systems and comparing potential process integration options. This optimization framework computes and graphically represents the minimum energy requirements, the pinch temperatures, and the Grand and integrated Carnot composite curves of process systems. Results are used to design utility systems that meet energy demands, while minimizing a specified objective function, such as total cost or environmental impacts. The Quarto environment, in which ROSMOSE is built upon, allows the integration of various open-source software and tools, such as database handling software, process modeling suites, and optimization solvers, along with interactive data visualization and reporting tools. This paper discusses the application of ROSMOSE for the energy integration and total site optimization of a dairy process consisting of milk treatment, and cream and cheese production to demonstrate the tool features. Other integration options, such as the use of heat pumps or solar panels, and the production of soft drinks or biogas as value-added byproducts, are also proposed and evaluated. As a result, from 75 % to 90 % in fuel savings and up to 80 % CO2 emissions reduction in the dairy plant are identified by optimizing the utility systems integration. Moreover, complete electrification via heat pumps eliminates any fossil fuel needs and it results in 85 % energy savings and up to 96 % CO2 emissions reduction. The activation of renewable electricity sources, such as solar power, made plausible this fully electrified scenario. Finally, optimized waste management strategies led to in-house fuel production and net export of biogas to the grid, but they also reduce cheese yield by prioritizing the biogas production from whey upgrading process. In this way, decision-makers have access to a clear performance comparison for a list of system configurations to draw informed trade-offs. A similar approach could be adopted to aid decision-making for the design and operation of other industrial and urban energy systems using ROSMOSE.

Advantages and disadvantages of autochthonous enterococci strains for their potential use in cheese ripening: a preliminary study

SummaryThe enzymatic activity exhibited by native enterococci could, in turn, result in a reduction in the cheese ripening time. However, they may also carry virulence factors or resistance to antibiotics that prevent their use in food. A total of 69 enterococci isolates were obtained from a Spanish traditional raw goat's milk cheese and identified by Maldi‐Tof/MS. Different enzymatic activities of technological interest were evaluated and the safety of those with greater technological suitability was studied. The strains were identified as E. malodoratus, E. italicus, E. gilvus, E. faecium, E. durans, E. casseliflavus and E. faecalis. Some strains had very high acidifying and proteolytic activities. Most strains had medium or low amino and carboxypeptidase activities and high dipeptidase activities, while esterase activities were medium. A total of 10 strains were selected based on their enzymatic activities. Of these, five showed β‐haemolysin activity, eight showed gelatinase activity and eight produced tyramine. These activities represent virulence factors that could potentially affect food safety. Finally, all selected strains were susceptible to the antibiotics tested.

Influence of thermophilic and mesophilic cultures blended with buffalo milk on camel milk cheese quality and proteolysis

SummaryCamel milk and its products are gaining higher demand due to their attractive nutritional and therapeutic profile. However, manufacturing of camel milk cheese (CMC) is a challenging task. This study aimed to compare the quality of camel milk cheese made using different starter cultures. Four groups CM (camel milk + mesophilic cultures), CT (camel milk + thermophilic cultures), CBM (camel milk + 10% buffalo milk using mesophilic cultures), and CBT (camel milk + 10% buffalo milk using thermophilic cultures) were created. The cheeses were stored for 60 days at 4 °C to assess their physicochemical, sensory, and proteolytic properties. Results indicated highest moisture content in CM (70.19%) as opposed to the lowest moisture in CBT (55.19%). In addition, CM and CBM revealed lower acidity (0.63% and 0.66%) in contrast with CT and CBT (0.78% and 0.83%, respectively). On the other hand, CBM and CBT exhibited higher contents of protein (21.04, 21.57%) and fat (17.65, 17.70%) during storage. All quality indices of cheese samples significantly declined (P &lt; 0.01) during storage excluding acidity. Sensory analyses revealed that panellists highly preferred CBT treatment followed by CBM and CT. Furthermore, urea‐PAGE and RP‐HPLC were performed for the proteolytic study of cheese samples. The study revealed that the presence of buffalo milk and thermophilic cultures in cheese resulted in a decrease concentration of intact caseins (αs1, β‐, and κ‐caseins) as storage days passed. The degree of proteolysis was found to be higher in CBT compared to CBM, CT, and CM. Based on the results, it was concluded that the use of pasteurisation at 65 °C for 30 min, pH of 5.5, 0.06% CaCl2, and the incorporation of 10% buffalo milk using thermophilic cultures (Lactobaccilus bulgaricus and Streptococcus thermophilus) resulted in desirable quality characteristics.

One-Year Monitoring of Prevalence and Diversity of Dairy Propionic Acid Bacteria in Raw Milk by Means of Culture-Dependent and Culture-Independent Methods.

Even low levels of dairy propionic acid bacteria (dPAB) can cause cheese defects, resulting in severe economic losses for the producers of selected raw milk cheeses. Therefore, routine quality control of raw cheese milk for dPAB contamination is essential if propionic acid fermentation is undesired. Although knowledge of dPAB contamination of raw milk is important to understand cheese spoilage, long-term dPAB screening data are outdated, and studies taking into account different farm management parameters and their potential influence on dPAB levels are scarce. This study aims to provide insight into the dPAB levels of raw milk over time, to identify farm management factors that potentially influence dPAB levels, and to compare a cultural yeast extract lactate agar (YELA) and lithium glycerol agar (LGA) and a culture-independent method (qPCR) for dPAB quantification with respect to their applicability in routine quality control for the dairy industry. For this purpose, bulk tank milk from 25 dairy farms was screened for dPAB contamination over a one-year period. We were able to identify significant differences in the dPAB contamination levels in raw milk depending on selected farm-specific factors and observed relationships between the different types of milking systems and dPAB contamination levels in raw milk. When dPAB were quantified by cultivation on YELA, strong overgrowth of commensal microbiota impeded counting. Therefore, we conclude that quantification on LGA or by qPCR is preferable. Both methods, colony counting on LGA as well as quantification of dPAB using qPCR, have advantages for the application in (routine) quality control of raw milk, one being low-tech and inexpensive, the other being fast and highly specific, but the detection of (low level) dPAB contamination in raw milk remains a challenge.

A Snapshot, Using a Multi-Omic Approach, of the Metabolic Cross-Talk and the Dynamics of the Resident Microbiota in Ripening Cheese Inoculated with Listeria innocua.

Raw milk cheeses harbor complex microbial communities. Some of these microorganisms are technologically essential, but undesirable microorganisms can also be present. While most of the microbial dynamics and cross-talking studies involving interaction between food-derived bacteria have been carried out on agar plates in laboratory-controlled conditions, the present study evaluated the modulation of the resident microbiota and the changes of metabolite production directly in ripening raw milk cheese inoculated with Listeria innocua strains. Using a proxy of the pathogenic Listeria monocytogenes, we aimed to establish the key microbiota players and chemical signals that characterize Latteria raw milk cheese over 60 days of ripening time. The microbiota of both the control and Listeria-inoculated cheeses was analyzed using 16S rRNA targeted amplicon sequencing, while direct analysis in real time mass spectrometry (DART-HRMS) was applied to investigate the differences in the metabolic profiles of the cheeses. The diversity analysis showed the same microbial diversity trend in both the control cheese and the inoculated cheese, while the taxonomic analysis highlighted the most representative genera of bacteria in both the control and inoculated cheese: Lactobacillus and Streptococcus. On the other hand, the metabolic fingerprints revealed that the complex interactions between resident microbiota and L. innocua were governed by continuously changing chemical signals. Changes in the amounts of small organic acids, hydroxyl fatty acids, and antimicrobial compounds, including pyroglutamic acid, hydroxy-isocaproic acid, malic acid, phenyllactic acid, and lactic acid, were observed over time in the L. innocua-inoculated cheese. In cheese that was inoculated with L. innocua, Streptococcus was significantly correlated with the volatile compounds carboxylbenzaldheyde and cyclohexanecarboxylic acid, while Lactobacillus was positively correlated with some volatile and flavor compounds (cyclohexanecarboxylic acid, pyroxidal acid, aminobenzoic acid, and vanillic acid). Therefore, we determined the metabolic markers that characterize a raw milk cheese inoculated with L. innocua, the changes in these markers with the ripening time, and the positive correlation of flavor and volatile compounds with the resident microbiota. This multi-omics approach could suggest innovative food safety strategies based on the enhanced management of undesirable microorganisms by means of strain selection in raw matrices and the addition of specific antimicrobial metabolites to prevent the growth of undesirable microorganisms.

How to Improve Surveillance Program for Shiga Toxin-Producing E. coli (STEC): Gap Analysis and Pilot Study.

Several pathotypes of enteric E. coli have been identified. The group represented by Shiga toxin-producing E. coli (STEC) is of particular interest. Raw milk and raw milk products are significant sources of STEC infection in humans; therefore, identifying pathogens at the herd level is crucial for public health. Most national surveillance programs focus solely on raw milk and raw milk cheeses that are ready for retail sale, neglecting the possibility of evaluating the source of contamination directly at the beginning of the dairy chain. To assess the viability of the application of new molecular methodologies to STEC identification in raw milk filters and in calf feces, we analyzed 290 samples from 18 different dairy herds, including 88 bulk tank milk (BTM), 104 raw milk filters (RMF), and 98 calf feces samples. In total 3.4% of BTM, 41.4% of RMF, and 73.4% of calves' feces were positive for stx, supporting our hypothesis that BTM is not a suitable matrix to assess the presence of STEC at herd level, underestimating it. Our conclusion is that the surveillance program needs critical and extensive improvements such as RMF and calves' feces analysis implementation to be more efficient in detecting and preventing STEC infections. The epidemiology of these infections and the characteristics of the pathogen clearly show how a One Health approach will be pivotal in improving our capabilities to control the spread of these infections.

The influence of different stress factors on the production and quality of sheep milk

Around 10.5 million tonnes of sheep milk are produced worldwide, and around 3.1 million tonnes in Europe. In Europe, sheep milk production has stagnated slightly in recent years and currently accounts for around 1/3 of the global production. Due to its high content of dry matter, milk fat, total protein and casein, sheep milk is an excellent raw material for cheese production. Milk processing and cheese making are not only economically important, but also part of the cultural heritage based on a long tradition, often taking place in rural and less developed areas. Milk production and quality are very complex and are influenced by numerous factors, the most important of which are breed, feeding and body condition, parity and stage of lactation, milking and udder health, and environmental factors. In addition, different types of stress such as heat stress, nutritional stress, weaning stress, shearing stress, stress of regrouping, etc. have a significant impact on the welfare and health of the sheep as well as on the quantity of milk produced, its chemical composition, processing characteristics and the economic efficiency of the flock. In recent years, due to climate change, there has been an increasing number of studies on the effects of heat stress on the reproductive and production characteristics of sheep, as well as on their welfare and health. In addition, heat stress is often associated to the feed and the lack of water. The effects of stress are particularly pronounced in extensive sheep farming and milk production, which are prevalent in sheep farming. The aim of this paper is to describe the effects of the main types of stress on the quantity and chemical composition of sheep milk and on animal welfare.

Climate Change and Photochemical Ozone Creation Potential Impact Indicators of Cow Milk: A Comparison of Different Scenarios for a Diet Assessment

An estimate of the environmental impact of dairy farms in Northern Italy producing milk for hard cheese (protected designation of origin) has been obtained through a comprehensive life cycle assessment. The estimate focused on climate change (CC) and photochemical ozone creation potential (POCP) indicators, which were evaluated according to the Intergovernmental Panel on Climate Change (IPCC) guidelines and interpreted with the aid of the feeds’ composition evaluated using near-infrared reflectance spectroscopy (Foss NIR-System 5000) as well as with a diet evaluation according to the NRC (National Research Council) or the CNCPS (Cornell Net Carbohydrate and Protein System) nutrient requirement modeling. Herds were classified into high-, mid-, and low-performing based on the daily milk yield per cow. A lower impact on indicators was observed as herd performance increased. The high-performing herds had a lower contribution from enteric fermentation (6.30 × 10−1 kgCO2-eq), and the more milk that they produced allowed for a differentiation of CC from land use and transformation (2.39 × 10−1 kgCO2-eq), compared to low-performing herds (3.66 × 10−1 kgCO2-eq). Compared to the IPCC approach, the CC and POCP indicator estimates were reduced when addressing the feed’s quality, particularly in mid- and high-performing herds. The results could be helpful in the dairy sector as they provide an insight into how diet quality affects the environmental impact of milk.

Assessment of protein and phospholipid bioaccessibility in ultrafiltered buttermilk cheese using TIM-1 in vitro gastrointestinal methods

To meet the high consumer demand, butter production has increased over the last few years. As a result, the buttermilk (BM) co-produced volumes require new ways of adding value, such as in cheese manufacturing. However, BM use in cheese milk negatively influences the cheesemaking process (e.g., altered coagulation properties) and the product’s final quality (e.g., high moisture content). The concentration of BM by ultrafiltration (UF) could potentially facilitate its use in cheese manufacturing through an increased protein content while maintaining the milk salt balance. Simultaneously, little is known about the digestion of UF BM cheese. Therefore, this study aimed to characterize the impact of UF BM on cheese manufacture, its structure, and its behavior during in vitro digestion. A 2-fold UF concentrated BM was used for cheese manufacture (skim milk [SM] – control). Compositional, textural, and microstructural analyses of cheeses were first conducted. In a second step, the cheeses were fed into an in vitro TNO gastrointestinal digestion model (TIM-1) of the stomach and small intestine and protein and phospholipid (PL) bioaccessibility was studied. The results showed that UF BM cheese significantly differed from SM cheese regarding its composition, hardness (p < 0.05) and microstructure. However, in TIM-1, UF BM and SM cheeses showed similar digestion behavior as a percentage of protein and PL intake. Despite relatively more non-digested and non-absorbed PL in the ileum efflux of UF BM cheese, the initially higher PL concentration contributes to an enhanced nutritional value compared to SM cheese. To our knowledge, this study is the first to compare the bioaccessibility of proteins and PL from UF BM and SM cheeses.

Description of “Ovino Belmontese”, a new semisoft sheep's milk cheese processed using “Italico” cheese technology

The objective of this study was to create a new semisoft sheep's milk cheese called “Ovino Belmontese” cheese (OBCh) by applying the “Italico” cheese-making technology. The cheese production took place under industrial conditions, with the addition of a commercial starter formulation containing Streptococcus thermophilus. The microbiological, physicochemical, and sensory characteristics of OBCh were assessed and compared to those of a commercially available cow's Italico cheese (CICh). Streptococcus thermophilus dominated the microbial community during the cheese-making process, reaching levels of approximately 9.0 Log CFU/g in both OBCh and CICh. Among physical characteristics, no statistically significant difference (p ≥ 0.05) was registered in terms of lightness, redness, yellowness, and hardness between the two cheeses. OBCh exhibited a twofold higher short-chain fatty acid content compared to CICh. Both cheeses displayed similar classes of volatile organic compounds, although their relative percentages differed. The application of Italico cheese technology to process sheep's milk did not negatively affect sensory attributes. This study highlighted that utilizing a cheese-making technology not commonly used for processing sheep's milk represents a promising strategy to diversify Sicilian dairy productions.

Sources of propionic acid bacteria contamination in the milking parlor environment on Alpine dairy farms

High-quality raw milk is an important prerequisite for the production of long-ripened raw milk cheeses. This implies not only the absence of pathogenic microorganisms in raw milk, but also low levels of spoilage bacteria, including dairy propionic acid bacteria (dPAB), that can cause blowing and sensory defects in cheese, resulting in severe economic losses for producers. Raw milk contamination with dPAB has been primarily associated with improperly cleaned milking systems, but dPAB have also been detected in feed, soil, feces, and on the teat skin. The objective of this study was to identify potential sources of raw milk contamination with dPAB in the barn and milking parlor environments. We also wanted to know more about the prevalence of the dPAB species in these environments and the levels of contamination. For this purpose, 16 small scale Alpine dairy farms were visited in August 2022. Samples were taken from the barn environment (e.g., swab samples, air, feed, bedding) and the milking system (swab samples, residual cleaning water, cleaning sponges, milk filters), and milk samples were collected at various sampling points along the milking system. Samples were analyzed for dPAB contamination, and results showed contamination at multiple sampling locations. We observed potential adverse effects of improperly set cleaning parameters of the milking system, as well as of farm-specific practices. In addition, we identified cleaning water residues as an important source of contamination. Based on these findings, we propose potential mitigation strategies to reduce the risk of raw milk contamination with cheese spoilage bacteria, thereby contributing to a more sustainable food production.