Journal of Dairy Research最新文献

Changes in waxed dry cheese during the ripening process, over periods of 7 and 30 days, were analysed using near-infrared spectroscopy (FT-NIR) and mid-infrared spectroscopy (FT-MIR) by attenuated total reflection (ATR). FT-NIR was employed to determine the proximate composition of the cheese (protein, fat, moisture, total solids, and salt content), identifying changes directly associated with the ripening process. FT-MIR data were used to identify spectral bands associated with chemical changes occurring during the cheese maturation. Additionally, chemometric techniques were applied to demonstrate the potential of FT-MIR infrared spectroscopy for cheese differentiation and fingerprint profiling. Subsequently, partial least squares discriminant analysis (PLS-DA) of the FT-MIR spectra was performed, revealing two distinct clusters representing the cheese ripening times. Functional groups related to lipids (-CH₂ - and - CH₃), proteins (amide bands I and II), and carbohydrates (C-O) were identified, correlating to lipolysis, proteolysis, and lactose catabolism. Infrared spectroscopy in combination with chemometric methods proved to be a robust and reliable tool for monitoring changes during the ripening of waxed dry cheese. The results obtained highlight its usefulness as an alternative approach for the analysis and fingerprinting of traditional Mexican foods, aiming to add value to local products.

Cheese-whey is a valuable byproduct of the dairy industry, rich in various nutritional components such as minerals, lactose, and proteins. Whey proteins, often used in concentrate form, are widely applied in the food industry due to their diverse chemical, physical, and techno-functional properties. This study aimed to investigate the physicochemical composition and biochemical characteristics of camel and bovine whey after partial demineralization at a laboratory scale. Camel whey exhibited lower pH values compared to bovine whey, while showing comparable levels of total solids, ash, and lactose, but significantly higher protein content. Analysis of both types of whey, before and after dialysis filtration, demonstrated partial demineralization, a significant reduction in lactose content, and a decrease in β-lactoglobulin levels in bovine whey. These findings suggest that demineralized camel and bovine whey hold significant potential for applications in the agricultural and food industries.

This Research Paper addresses the hypothesis that wastewater characteristics in the dairy industry vary with product type and operational procedures, and that current treatment methods face limitations in managing such variability. The study examined raw and clean-in-place (CIP) wastewater from a Serbian dairy plant over three years. Physico-chemical and microbiological analyses included pH, protein, fat, carbohydrates, total solids, total microorganisms, E. coli, Enterobacteriaceae, chemical oxygen demand (COD), total suspended solids (TSS), nitrogen (N), phosphorus (P), and dissolved oxygen (O₂).Dairy plants produced 0.2-10 L wastewater per litre of milk. Protein content ranged 0.07-0.31 g/100 ml, fat 0.01-0.19 g/100 ml, and carbohydrates up to 1.37%. Total solids were 0.13-2.95%. pH varied from 4.41 to 12.76, affected by lactic fermentation and cleaning agents. COD values (529-12,476 mg/l) indicated strong organic loads. Microbiological counts were highly variable, with E. coli up to 10³ cfu/ml and total microorganisms up to 1 × 10⁸ cfu/ml. Nitrogen ranged 36-104 mg/l and phosphorus reached 10.91 mg/l, sometimes exceeding limits. Principal component analysis (PCA) explained 61.86% of variance, driven by N, pH, P, E. coli, Enterobacteriaceae, and oxygen content. Seasonal patterns were identified: higher TSS during spring and summer, and increased microbial loads, COD, and oxygen fluctuations in autumn and winter. The findings demonstrate that dairy wastewater is complex and variable, requiring adaptive treatment strategies. Optimised management, including pH control, nutrient removal, and combined biological and advanced technologies, can improve treatment efficiency, support reuse, and mitigate environmental impact.

This research communication hypothesizes that superstimulation with follicle-stimulating hormone (FSH) would not impact behavior and performance of Holstein cows. The objectives were to investigate the effect of FSH superstimulation on follicular dynamics, animal behaviour, body surface temperature and milk yield of Holstein cows. Cows were blocked by parity and body condition score (BCS), and within a block, they were assigned randomly to receive either normal saline (CON = 7) or 500 IU of FSH (n = 8). The estrous cycle of cows was synchronized by using two injections of prostaglandin F₂-alpha (PG), 11 days apart. The dominant follicle was ablated at the time of the second PG injection, and an intra-vaginal controlled internal drug release (CIDR) was inserted (day 0). Two days later, FSH treatment was initiated and continued for 3 days in six equal doses of 83.33 IU after 12 h. Follicles were counted and their sizes were measured from day-0 to day-5. Behavior, including activity and feeding time, was recorded using SmartTag Neck from day 0 to 6. The surface temperatures of the eye, shoulder, flank, and vulva were measured by using infrared thermal imaging every 12 h from day-2 to day-5. Milk was recorded from day-0 to day-6. Mixed effects models were used to analyse the data using SAS statistical software. The number of small and medium follicles did not differ between treatments. However, FSH-treated cows had a more (P = 0.01) large and total follicles compared with CON cows. FSH treatment did not affect activity, feeding time, body surface temperature, or milk yield. In conclusion, FSH superstimulation increased the number of large follicles but did not influence behaviour, body surface temperature, or performance in dairy cows.

This study aimed to investigate the potential association between the breeding values for somatic cell scores in milk (SCS) and polymorphisms in genes that encode for cytokines (CXCL8, TGF-β1 and IFN-γ) and CD4. These genes were selected because of their critical roles in immune regulation and their known involvement in mastitis-related inflammatory processes. To gain a comprehensive breeding perspective, the association study was conducted simultaneously with breeding values for productive traits in 558 Italian Simmental cows, a widespread dual-purpose dairy and beef bovine breed that is adaptable to harsh farming and breeding conditions.The association analysis showed that only three of the nine chosen markers, one in IFN-γ and two in CD4, significantly associated with somatic cell breeding values, without effects on the other dairy traits. Only one of the two CD4 SNPs has been considered, being in linkage disequilibrium. The two remaining SNPs were grouped into three haplotypes (A-G, 88%; A-A, 5%; and T-G, 7%, respectively), and Haplotype-3 significantly affected the breeding values for SCS. The combination of Haplotype-1 with Haplotype-2 resulted in a significant decrease, while with Haplotype-3 led to a considerable improvement in SCS breeding values. It was noted that the functional haplotypic combinations examined did not significantly affect the production breeding values. This research could provide interesting polymorphisms for genomic evaluation of Italian Simmental dairy cows, increasing the accuracy of breeding values, assisting breeders in selecting animals with enhanced immune responses, minimising the economic impact of mastitis, and improving overall herd health and productivity.

This Research Communication describes a pilot study to validate a rumination sensor for pre-weaned dairy calves. There is increasing interest in precision livestock farming (PLF) tools to capture behaviours and health parameters in farm animals. However, much of the research has focused on devices suitable for adult animals, and few devices have been validated for young animals. The aim of our pilot study was to validate the rumination estimates from Nedap rumination sensors® (NRS) when worn by dairy calves less than 2 months of age. Eight Norwegian Red dairy calves were raised in a cow-directed cow-calf-contact system such that cows could visit their calves through a smartgate. At 21 days of age, an NRS was secured around the neck of each calf, to record the amount of time spent ruminating/24 h. Cameras were placed above the calf areas to record the calves for the entirety of the study. When the calves were 28 and 58 d old, four trained observers recorded rumination behaviour 24 h/d from the video recordings. The video data and the NRS data recorded over 24 h on the same days were compared using the Wilcoxon signed-rank test, the Spearman's rank correlation and concordance correlation. NRS estimates were moderately correlated with calf rumination behaviour as measured from video observations but underestimated the duration of time spent ruminating by approximately 76%. Perhaps the calves' rumination movements were too subtle for the NRS to detect, or the NRS needed a different placement on the calf's small neck to record the behaviour accurately. Although automatic recordings from PLF tools may save observation time, our results indicate that the NRS may not yet accurately detect rumination behaviour in pre-weaned dairy calves.

Whey, a greenish-yellow liquid resulting from curd separation in cheese manufacturing, was historically considered economically insignificant in the dairy industry and often discarded into the environment without proper oversight. However, recognizing its high nutritional value, whey has become a valuable ingredient in the food industry. Unprocessed whey (raw material) is highly susceptible to contamination, as it can serve as a substrate for the multiplication of a range of microorganisms, including spoilage, spore forming, pathogenic and toxin producing bacteria, particularly if stored at inappropriate temperatures. Staphylococcus aureus is one of these potential pathogenic bacteria often associated to dairy, that can also persist in the environment through biofilm formation and, once reaching the food matrix, can grow and produce enterotoxins. During the processing of whey powder production, there are points where S. aureus might find its way into the final product. Here we demonstrate critical contamination steps, and we highlight the need for more research to assess the microbiological integrity of whey powder, especially in Brazil, where its production has been growing in recent years. Considering the increasing use of whey powder as an ingredient for various formulations, continuous surveillance for the presence of spoilage microbiota and potentially pathogens, including S. aureus and associated enterotoxins is indispensable to prevent food poisoning outbreaks.

We aimed to develop a new ice cream made from goat milk inoculated with the probiotic bacteria Limosilactobacillus fermentum CABA16. The physicochemical characteristics, meltdown behaviour and sensory properties of ice cream produced with and without the probiotic bacteria were analysed. The ice cream with added L. fermentum was further evaluated for probiotic viability during frozen storage and simulated gastrointestinal conditions. Results showed that the addition of L. fermentum CABA16 decreased the pH to 6.25 (P < 0.05), but had no effect on physicochemical properties such as overrun and melting behaviour of ice cream samples. The viable probiotic count was 6.71 log CFU/g with a survival rate of 90%, which was registered after 120 days of frozen storage. Considering the probiotic cell viability during gastrointestinal conditions, exposure to bile and pancreatin for 6 hours resulted in a decline of 3.6 log CFU/g cycles in ice cream samples previously stored at -18 °C for 120 days. Overall, the goat milk ice cream inoculated with L. fermentum received good sensory scores, and satisfactory probiotic viability (6.7-7 log CFU/g) was maintained throughout the 120 days of frozen storage.

The aim of this Research Communication was to develop new flow cytometric tools for the fine identification and characterization of milk somatic cells in water buffalo (Bubalus bubalis). Four multicolour panels of antibodies were designed to identify different subsets of live leukocytes and epithelial cells in bulk milk samples. Panel 1, including the CD18/CD172a/CD14/CD16 markers and Live/Dead vitality dye, allowed us to identify total lymphocytes, polymorphonuclear neutrophils (PMN) and monocyte/macrophage subsets. Panel 2 (CD18/CD4/CD8/δ chain/CD335 and Live/Dead dye) allowed us to identify T helper (CD4⁺), T cytotoxic (CD8⁺), γδ lymphocytes and NK cells. Panel 3 (CD18/CD79a/CD21 and Live/Dead dye) allowed us to identify total and CD21⁺ B lymphocytes. Finally, with Panel 4 (CD18/MHC-I/pan Cytokeratin and Live/Dead dye) the epithelial cells were distinguished from leukocytes. In conclusion, we propose a fine characterization of live milk somatic cell (live differential cell count (LDCC)) in buffalo species. In the future the determination of LDCC could used to identify new markers for detecting early inflammatory states of the mammary gland or for monitoring the technological properties of milks of different somatic cell composition.

The blood-milk barrier (BMB) forms at parturition when the gland switches form a non-lactating state to one of copious milk production and becomes leaky again when milk removal ceases and mammary involution is initiated. In this review the importance of the BMB in milk production and, in particular, its hormonal regulation is explored. Tight junctions (TJ) between adjacent mammary epithelial cells form a barrier to the two-directional paracellular movement of small molecules between the blood and milk and are responsible for establishing and maintaining the BMB. They form part of the cell's junctional complex and consist of transmembrane proteins that are linked to the mammary cell's cytoskeleton. This means that when, during lactation, TJ become "leaky" the resulting perturbation of the cytoskeleton interferes with the cell's secretory function. As such, TJ are involved in regulating and maintaining milk production. Mammary TJ are under hormonal control, with progesterone, glucocorticoids, prolactin, parathyroid hormone-related peptide (PTHrP) and serotonin (5-HT) being the key hormones. Progesterone prevents closure of TJ and the immediate prepartum drop in its concentration is a prerequisite for TJ closure. A simultaneous increase in the levels of glucocorticoids and prolactin is necessary for full TJ closure and initiation and maintenance of lactation. Both PTHrP and 5-HT are important hormones in maintaining extracellular calcium concentrations, a requirement for maintaining TJ integrity. Whereas PTHrP reduces TJ permeability, necessary for establishing and maintaining milk production, 5-HT has an opening effect on TJ. The latter may help speed up mammary involution and facilitate the movement of immune factors into the gland, preventing intramammary infections. In summary, mammary TJ make up the BMB and play a role in establishing and maintaining milk production and are under hormonal control, with progesterone, glucocorticoids, PTHrP and 5-HT being key regulatory hormones and prolactin likely playing a supporting role.