Dairy, Volume 5, Issue 4 (December 2024) – 18 articles

In this study, the integration of a 3D printed turbulence promoter into a stirred membrane separation cell during dairy wastewater ultrafiltration was investigated. Its effects, along with the effects of stirring, on the permeate flux and membrane fouling were examined. The experiments were carried out at different transmembrane pressures (0.1, 0.2, and 0.3 MPa) and stirring speeds (RPM: 100–400 min⁻¹), both with and without the application of the turbulence promoter. Various parameters were employed to characterize the membrane performance, such as the permeate flux, the flux decline ratio, and the fouling coefficient. To further investigate the membrane fouling mechanisms, mathematical models were used: the resistance-in-series model, the Makardij model, and the Hermia model. With the resistance-in-series model, we examined whether the membrane fouling was reversible (the deposit could be easily removed by washing operations) or irreversible (irreversible fouling) for each measurement, and with the Makardij model, we investigated whether the rate constant of the fouling or the rate constant of the deposit removal was the most important. In the case of the Hermia model, changes in the cake filtration rate constant were monitored. The results indicate that the combination of the 3D printed turbulence promoter and the stirring speed could effectively reduce membrane fouling during dairy wastewater ultrafiltration. Full article

Plant-derived rennet sources have been recognized as effective alternatives to traditional animal-derived rennet in cheese processing, producing various cheeses for vegetarians and Halal consumers. The aim of the present study was to assess the quality and identify potential chemical and sensory markers of Canestrato cheese made from pasteurized mixed cow/sheep milk (50:50 ratio) using a kiwifruit extract (prepared in the laboratory) as a rennet source of vegetable origin. The milk was curdled with an aqueous kiwi extract (cK group), with commercial calf rennet (cT group), or with commercial microbial rennet obtained from the controlled fermentation of Rhizomucor miehei (cH group). For each cheesemaking process, 30 L of mixed milk was used, resulting in 10 forms, each weighing approximately 1 kg. Cheese produced using kiwifruit rennet exhibited improved nutritional characteristics, such as lower total lipid, cholesterol, and sodium content and greater levels of polyphenols, potassium, and phytosterols compared with the cheese of the cT group. The cheese of the cK group had a slightly more pronounced bitterness compared to cheeses made with conventional rennets (cH and cT). Overall, the use of kiwifruit extract as a milk coagulant has proved to be a promising alternative, improving both the nutritional profile and functional properties of the resulting cheese. Full article

Milk coagulants play a crucial role in defining curd characteristics. The objective of this study was to compare the coagulation dynamics of two commonly used coagulants in cheesemaking: cardoon flower extract (Cynara cardunculus L.) and commercial chymosin, using sheep milk from four different origins in the Baixo Alentejo region of Portugal, as the substrate. Milk composition was determined using the MilkoScan 133B, while the milk-clotting time (MCT) was measured following ISO 23058/IDF 199:2006 guidelines with slight modifications and coagulation kinetics, and technological properties were evaluated using the Optigraph apparatus. The results demonstrate that the type of coagulant impacts the coagulation properties of sheep milk. Pearson’s correlation analysis indicated that milk samples with higher protein content exhibited longer coagulation times but resulted in firmer curds. On the other hand, the use of cardoon flower extract introduced greater variability compared to chymosin, with a delayed onset of coagulation, reduced curd firmness, and increased variability in enzymatic kinetics. These results suggest that cardoon extract, while traditional, introduces greater heterogeneity in curd formation compared to the more consistent action of chymosin. Full article

The objective of this study was to determine the enteric methane (CH₄) emission factor (EF) at the national level for Peruvian dairy cattle following the IPCC Tier II (2006, 2019) methodology. Data were collected from seven regions of Peru and classified according to the type of feeding as intensive, semi-intensive or extensive. It included farm information (geolocation) and livestock information for two seasons of the year. At the national level, lactating cows obtained the highest EF with 117 kg CH₄/head/year, followed by heifers from 15 to 24 months of age (91 kg), non-lactating cows (74 kg), heifers from 12 to 15 months of age (67 kg), calves (62 kg) and pre-weaned calves (16 kg). Additionally, the highest EF was reported for lactating cows in the intensive system (151.8 kg CH₄/head), which is 46.8 kg CH₄/head more per year than that reported in the semi-intensive and extensive systems in the same animal category. The combined uncertainty in all animal categories was low to very low (between 9.4 and 18.72%), except for that of lactating cows, which was low to medium (22.24 and 26.72%). These results allowed us to find the EF that exerts the most pressure according to the level of intensity in Peruvian dairy farming. Full article

In this study, two methods for assessing the purity of A2 fermented milk and β-casein genotypes in dairy cows were examined. The need for rapid and precise methods for herd screening and A2 milk quality control justified this study. Accordingly, an ELISA test was developed to identify β-casein A1 in fermented milk, and a commercial Lateral Flow Immunoassay (LFIA) was evaluated to determine A2A2 genotypes and the purity of A2 milk. The results demonstrated 100% sensitivity and specificity of the ELISA test in identifying β-casein A1. The LFIA test successfully identified A2A2 genotypes and confirmed the purity of A2 milk, with a minimum detectable contamination of 5% for raw milk and 10% for fermented milk. Both tests exhibited 100% sensitivity and specificity, resulting in positive and negative predictive values of 100%. The positive likelihood ratio was infinite, while the negative was zero, indicating a precise and reliable test with no false diagnoses. Compared to traditional genotyping, these methods proved to be more practical and showed potential for large-scale screening. It was concluded that ELISA and LFIA are valuable tools for ensuring the quality and authenticity of A2 milk, meeting the demands of producers and consumers for safe and healthy dairy products. Full article

Cheese is a biologically active food product, characterised by its colour, texture, and taste. Due to its rich matrix of fats and proteins, as well as the fact that the cheese’s surface acts as its own packaging, the cheese becomes more susceptible to contamination by microorganisms during the ripening process, particularly bacteria and fungi. The ripening of cheese involves several biochemical reactions, with the proteolytic activity of the cheese microbiota being particularly significant. Proteolysis results in the presence of free amino acids, which are precursors to various metabolic mechanisms that can cause discolouration (blue, pink, and brown) on the cheese rind. Surface defects in cheese have been documented in the literature for many years. Sporadic inconsistencies in cheese appearance can lead to product degradation and economic losses for producers. Over the past few decades, various defects have been reported in different types of cheese worldwide. This issue also presents opportunities for innovation and development in edible and bioactive coatings to prevent the appearance of colour defects. Therefore, this review provides a comprehensive analysis of cheese colour globally, identifying defects caused by microorganisms. It also explores strategies and innovation opportunities in the cheese industry to enhance the value of the final product. Full article

The existence of repeat breeder cows (RBCs) causes low reproductive performance. The causes of RBCs include low-quality oocytes and embryos, hormonal dysregulation, and unsuitable uterine environments. To improve unsuitable uterine conditions for RBCs, we focused on nobiletin (NOB), a natural citrus flavone with various beneficial roles. The role of NOB in bovine endometrial epithelial cells (BEECs) was examined. An analysis of BEECs showed that gene expression and altered pathways differed between the control and NOB treatment, with NOB regulating the pathways of steroid biosynthesis, lysosomal function, and inflammatory responses. NOB treatment significantly increased the number and activation of endosomes and lysosomes in BEECs. Moreover, we performed phagocytosis assays using fluorescence-conjugated lipopolysaccharide (LPS) with lysosomes in NOB-treated BEECs, which resulted in an increase in the co-localization of phagocytosed LPS with lysosomes. NOB treatment stimulated the mRNA expression of various lysosomal hydrolases, including cathepsin B and cathepsin K, and suppressed the gene expression of cytokines in inflammation-associated pathways (rheumatoid arthritis, the IL-17 signaling pathway, etc.). NOB significantly suppressed the LPS-induced mRNA expression of the inflammatory cytokine IL-8 and its secretion in BEECs. In conclusion, NOB activates the endosome–lysosomal system via phagocytosis to eliminate the bacterial component LPS and suppress inflammatory responses to defense mechanisms in BEECs. Full article

Olive leaf by-products may be an important feed source for ruminants in the Mediterranean area, due to their nutritional value and high levels of functional metabolites. Additionally, their use can enhance the environmental and economic sustainability of the productions. To evaluate the effect of olive leaf supplementation on the fatty acid profile of sheep cheese, two farms with Comisana breed sheep with free access to pasture and fedwith 300 g/head/day of concentrate were considered. One farm supplemented the feed with clover hay ad libitum (NOL) and the other farm replaced hay with olive leaves (OLI) in the autumn period. Cheese analyses were performed at 15, 30, and 60 days of ripening. Saturated fatty acids were lower in OLI cheese than NOL cheese, while MUFA and PUFA n-3 and n-6 were higher in OLI cheese. Myristic acid (C14:0) and palmitic acid (C16:0) were lower in OLI cheese compared to NOL (8.31% vs. 8.90% and 21.52% vs. 24.95%, respectively), while oleic acid (C18:1 cis-9) was higher in OLI cheese (20.66% vs. 18.78%). Also, CLA cis-9 trans-11 (0.98% vs. 0.84%), and other isomers were higher in OLI cheese. Health indexes, such as the thrombogenic and atherogenic index, were lower in OLI than in NOL cheese (1.96 vs. 2.38 and 1.69 vs. 2.05, respectively) showing the improvement in the health quality of cheese due to olive leaf integration in directly on farm sheep feeding. Full article

Kashkaval Pindou is a traditional semi-hard cheese produced in Greece since the beginning of last century. Its production was halted in the last decades but has recently been revitalized using modern techniques. In this study, the quality and organoleptic criteria for this “recently introduced to the market” cheese in the dishes of selected restaurants and hotels was studied. Research was conducted in the city of Ioannina, Greece using two types of questionnaires via a survey which was carried out in person between September and December 2023, distributed to 18 experts, chefs, and owners of restaurants utilizing the Kashkaval Pindou cheese. The statistical analysis used was an approach of the Delphi methodology, which seeks consensual agreement within a group of experts. Following the two rounds of survey, the experts evaluated the 11 quality criteria for the use of the cheese in order of their preference (10–9 mean values): “Greek Tradition”, “ease of consumption”, “quality, healthy and safe properties”, “easy to be used product” and “ease of integration in the menu”. Of medium preference (9–8 mean values) was the cheese’s “geographic origin”, “producers’ and suppliers’ capacity”, “enhancement of the kitchen’s creativity”, and “value for money”. Last in the order of selection (8–7 mean values) was the cheese “reputation in the market” and “attractive packaging”. Regarding the organoleptic evaluation, the experts indicated the cheese’s pleasant taste, creamy texture, uniformity of the color, and buttery, milky foam aroma as high in their preference. These results, in agreement with findings in the existing literature, prove that Kashkaval Pindou fulfils the required quality and organoleptic criteria to become an appealing new cheese in the global market. Full article

A large portion of the world’s population has lactose intolerance. Fundamentally, this condition occurs when the small intestine does not produce enough of the lactase enzyme, which digests the disaccharide lactose in milk. Lactose avoiders might unconsciously decide to limit or exclude milk and dairy products from their diets. This group includes people with lactose intolerance, people with an allergy to milk protein, vegans, and those expressing personal preferences. Lactose avoiders are often self-reported as being milk intolerant. In this review, specific amounts of lactose in different types of milk and milk products are presented. The amounts of micro- and macronutrients in them are compared with the daily requirements established by accepted sources. Foods are suggested that can play vital roles in permanently avoiding lactose-containing dairy products, for example, brussels sprouts, as a good source of vitamin B1; kale, as a source of vitamin K; and cereals at breakfast for vitamin B6. Attention is paid to mature cheeses as they are extremely beneficial for health due to their rich vitamin and elemental compositions, and they are also suitable for people with lactose intolerance due to their low lactose content. This information is rarely provided on packaging. In addition, the current state of labeling for the presence of lactose in food and pharmaceutical products is discussed. The term “hidden lactose” is introduced to include added lactose in unexpected foods, drinks, and even medicines. Full article

The food sector is constantly responding to consumers’ increased demands concerning healthy nutrition and beneficial ingredients. This study presented the development of three pudding alterations using lyophilized fruit (apricots, plum–apricots, and plums) powders. The same concentrations of fruit powder fully substituted the sugar in each formulation. The results showed that each new formulation formed a thick gel consistency and had full water-holding capacity at 24 h of storage. The color differed according to the established CIE-lab data. The lightness varied from 42.57 ± 1.97 (pudding formulation using plum powder) to 81.91 ± 1.18 (control sample). The total soluble solids and titratable acidity showed that the control sample was different from each new formulation. The water activity was similar in all studied samples varying from 0.978 ± 0.003 to 0.989 ± 0.001, and the plum and plum–apricot formulations had a pH near the control samples, at 6.54 and 7.23, respectively. The antioxidant activity, total polyphenol content, and total flavonoid content were also evaluated. The ABTS assay revealed the highest results compared to the other three applied methods. The sensory evaluation showed that it is necessary to further improve the recipes for better consumer perception. Full article

Fatty liver is a more common than expected metabolic disease affecting dairy cattle around parturition, which generates high economic losses for the dairy industry. The disease has evolved from a low incidence of moderate cases to a greater increase of severe cases in recent years. This evolution could be explained by the higher rate of genetic selection that has been carried out for milk production, which concomitantly brings pleiotropic genes that determine greater abdominal adiposity, ketosis, and other diseases. Abdominal fat is much more reactive, pro-inflammatory, saturated, and low in adiponectin than subcutaneous fat. In this review, we will mainly address the epidemiological aspects, the pathophysiology concerning the different types of fat depots (subcutaneous and abdominal), and the early diagnosis of the disease to carry out efficient control and preventive strategies. Full article

Dairy cow management has evolved tremendously in recent decades, particularly regarding reproductive techniques. The widespread adoption of synchronization protocols, sexed semen, beef semen in dairy cows, reproductive biotechnologies such as in vivo-derived (IVD) or in vitro-produced embryos (IVP), and precision livestock farming is transforming the daily practices of dairy farmers and veterinarians. These implementations are typically adapted in different ways when applied to the breeding of heifers or cows. Considering these developments, dystocia—a significant welfare and productivity concern—may warrant reevaluation. The aforementioned changes are likely to have a substantial impact on its prevalence, severity, and outcome. This review aims to address the main aspects of dystocia in dairy cows and heifers, with a particular focus on the potential impact of recent advances in reproductive and calving management. Full article

Late blowing is a prevalent and costly cheese defect caused by clostridia. In organic cheese production, the use of additives that inhibit the growth of clostridia is prohibited. Furthermore, mechanical methods for the removal of clostridia are impractical in organic dairies due to the small batch sizes involved and separation process temperatures (~55 °C) that are incompatible with the standards required for raw milk cheese production. The aim of this study was to investigate whether sufficient spore reduction can be achieved at lower temperatures (10, 35 °C) with a downsized separator (CSC18-01-077, GEA Westfalia) by varying the process parameters to describe the influence on the suitability of the treated milk for cheese production. In addition to spore reduction, total mesophilic bacteria count, the effects of separation on fat and casein losses, and damage to milk fat globules were assessed, as they can affect the yield and cheese quality. A significant reduction (p < 0.01) in spore concentration and total bacteria count in milk was achieved, regardless of the process parameters employed. Casein losses are reduced at 35 °C compared to 55 °C. The extent of fat loss in the sludge at 35 °C was minimal. The reduction in milk fat globule size was significant. Nonetheless, the results of this study demonstrate that a downsized centrifuge can be employed to augment the quality of small-batch raw milk cheese, particularly at a temperature of 35 °C. Full article

In this study, butter and the corresponding buttermilk samples were produced with cream fermented by aromatic (A) or probiotic (P) cultures with or without complementary bioprotective culture (BC). The samples were characterised for their composition and colour parameters. Texture and rheological properties were evaluated at 10 and 20 °C. Microbiological (lactobacilli, lactococci, and yeast and mould counts) and sensory (aroma, taste, texture, and global evaluation) analyses were also performed. All butter sample characteristics were in accordance with the Portuguese standard. Regarding colour, the sample obtained with cream fermented by probiotics plus bioprotective culture (PBC) presented higher L* and b* values, indicating a slightly higher yellow chroma. However, colour differences (ΔEab*) in the butter samples were, in most cases, not detectable by a common observer. Butter samples P and PBC presented a significantly higher viscous modulus and consequently higher dynamic viscosity values (ca. log 6.5 Pa.s at 10 °C and log 5 Pa.s at 20 °C). Butter samples presented a pseudoplastic behaviour, and rheological parameters showed a high dependence on temperature. The counts of lactobacilli and lactococci in the butter samples were of the order of log 7–8 CFU/g, while yeast and mould counts were lower than log 2 CFU/g until the 30th day of storage, after which they showed a sharp increase to ca. log 5 CFU/g between the 30th and the 60th days of storage. Regarding sensory attributes of butter, sample P received the highest overall liking, followed by samples ABC and PBC. Sample A was the least appreciated. Buttermilk samples presented significant differences regarding their composition, viscosity, and colour parameters. In all cases, lactobacilli and lactococci counts exceeded log 7 CFU/mL after 30 days of storage, but yeast and mould counts were of the order of log 5–6 CFU/mL at the 15th day of storage. Samples P and PBC presented yeast and mould counts ca. 1–2 log cycles lower than samples A and ABC, indicating the potential of probiotic and bioprotective cultures to extend the shelf life of the product. Regarding the sensory attributes of buttermilk, samples P and PBC received the highest overall liking, followed by sample ABC. Sample A received the lowest scores, as had occurred with the butter samples. However, in all cases, the scores obtained by the buttermilk samples were lower compared to the ones of the corresponding butter. It can be concluded that both probiotic butter and buttermilk present high levels of lactobacilli and lactococci and can maintain their probiotic potential throughout the storage period. Full article

Both hydrodynamic cavitation (HC) and temperature elevation are important pretreatments for improving the performance of liquid food processing by reducing viscosity. In this study, we assessed the impact of HC and elevated temperature on the functionality of milk protein concentrate powder with 80% protein (MPC80) prepared from nanofiltration (NF) of ultrafiltration (UF) retentate. Skim milk was concentrated using UF, and the retentate was further subjected to HC and concentrated using NF, then spray dried to obtain MPC80 powder. The functionality of these powders processed using NF at 22 °C, NF at 50 °C, HC and NF at 22 °C, and HC and NF at 50 °C were evaluated. Rennet coagulation time of reconstituted MPC80 from different NF treatments was like skim milk when treated with 0.1% CaCl₂. High-temperature NF reduced the water solubility of MPC80 powder (70.03 to 79.20%) at room temperature, but it was similar when measured at 50 °C (86.05 to 92.91%). The HC improved foaming (92.22 to 112.89%) but did not impact the emulsifying capacity (59.58 to 61.38%) and heat stability (18.04 to 20.22 min). Results showed that the HC and high-temperature NF utilized to increase the production efficiency of MPC80 also maintained the functionality of the powders after spray drying. Full article

Fermented milk with probiotic bacteria is a functional food, and adding fruit can enhance its taste. Juçara, the fruit of the Euterpe edulis Martius palm tree, is known for its natural antioxidant properties. This study aimed to assess the antioxidant capacity of milk fermented by Limosilactobacillus reuteri LR92 with juçara pulp (JFM) over 30 days of storage at 4 °C and its protective effect on probiotic cells against reactive oxygen species (ROS). Phenolic compounds and antioxidant activities were measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power (FRAP) assays during storage. The resistance of L. reuteri to hydrogen peroxide, superoxide anions, and hydroxyl radicals was also tested. The results indicated that JFM maintained stability in its composition, except for color, which showed reduced brightness by the end of the 30 days. Although antioxidant activity measured by DPPH and FRAP decreased (83.92–67.03 µmol TEAC.g⁻¹ and 1185.64–830 g TEAC.100 g.mL⁻¹, respectively), it remained higher than the control (21.90–24.50 µmol TEAC.g⁻¹ and 235.77–229.87 g TEAC.100 g.mL⁻¹, respectively). Phenolic content remained consistent. In addition, juçara pulp significantly protected L. reuteri cells from ROS. Therefore, juçara-enriched fermented milk not only improved antioxidant properties but also shielded probiotics from oxidative stress, highlighting its potential as a functional food with added health benefits. Full article

The objective of this study was to determine whether the parity and age of dams affect the longevity of their offspring in dairy cows in pasture-based systems. A total of 12,792 dairy cows born between 2000 and 2017 across five farms were evaluated using records from the Dairy Herd Improvement Database at Instituto Nacional para el Control y Mejoramiento Lechero (Uruguay). Dams were classified as primiparous or multiparous, and parity number and age were considered. The effect of parity status on herd life (HL), the length of productive life (LPL), and the productive life index (PLI) was evaluated using a generalized mixed model. Associations between parity number and dam age with HL, LPL, and PLI were evaluated using regression models. HL, LPL, and PLI were significantly higher for daughters of multiparous cows. Dams with more parities gave birth to longer-living daughters, with an average HL difference of 4.4 months between the first and seventh parity of the dams. The parity number and age of the dam showed a significant association with HL, LPL, and PLI. In conclusion, the parity and age of the dam influence the longevity of dairy cows in pasture-based systems, with older dams and higher parity yielding daughters with greater longevity. Full article