Dairy, Volume 6, Issue 2 (April 2025) – 10 articles

The dairy industry relies on the health and well-being of dairy cows for the optimal production of milk and dairy products. Mastitis, a prevalent and economically burdensome disease characterized by udder inflammation, poses significant challenges to dairy farmers worldwide. In this study, we employed peptidomics to explore the peptide profiles of dry secretions collected from dairy cows at specific intervals during the dry-off period. We hypothesized that alterations in peptide composition during the dry period may influence pathogen proliferation and immune cell functioning, thereby impacting mastitis susceptibility. Our objectives were to investigate the following: (i) differences in peptide composition and alterations between healthy cows and those with subclinical mastitis, potentially serving as biomarkers for early mastitis detection and offering insights into udder bioprocesses; (ii) variations in peptide profiles between the early (day 2) and later (day 21) stages of the dry-off period during both health conditions. Dry secretions were collected from 16 udder quarters of 8 cows at two defined time points—Day 2 (D2) and Day 21 (D21)—during the dry period. Our results revealed distinct peptide patterns between healthy and subclinical mastitis cows, as well as temporal variations in peptide profiles throughout the dry-off period. A total of 1235 peptides, originating from 59 distinct proteins (primarily β-casein), were detected across the four groups: subclinical mastitis day 21 (SCM-D21), subclinical mastitis day 2 (SCM-D2), healthy day 21 (H-D21), and healthy day 2 (H-D2). Furthermore, 56 out of the 1235 peptides identified in total matched known functional peptides, with a total of 17 different functions including antimicrobial, antioxidant, and immunomodulatory, suggesting their potential roles in mastitis pathogenesis and mammary gland physiology. Comparative analyses revealed changes in the levels of these functional peptides across the four different groups, suggesting their potential roles in regulating immune responses, oxidative stress, inflammatory processes, and other biological activities during subclinical mastitis and the dry-off period. These findings provide valuable insights into mastitis detection, management strategies, and dairy cow health monitoring, offering promising avenues for enhancing milk quality and dairy industry sustainability. Full article

The prevention of human infectious diseases associated with waterborne pathogens is reliant on the effective disinfection of water supplies by drinking water treatment plants and adequately maintained distribution networks. For decades, the chlorination of water has safeguarded public health, where chlorine is broadly applied in both water disinfection and food production facilities, including the dairy industry, from farm to fork. The identification of chlorine disinfection byproducts in water supplies and dairy food produce is of great concern, however, due to their cytotoxic, genotoxic, mutagenic, teratogenic, and potential endocrine-disrupting activity. The association between the trihalomethanes (THMs) and haloacetic acids (HAAs) and tumour formation is documented and has led to the implementation of maximum contaminant levels enforced by the European Union. Furthermore, chlorine resistance in bacterial species is associated with multidrug resistance in clinically relevant pathogens, where antibiotic- and biocidal-resistant genes are also environmental pollutants. Increasing the concentration of chlorine to surmount this resistance will ultimately lead to increasing concentrations of byproducts in both water and food products, exceeding the EU requirements. This article provides insight into chlorine DBPs as a toxicological public health risk and the relationship between chlorine resistance and antibiotic resistance in microbes relevant to dairy food production. Full article

This pilot study investigated whether reductions in enteric CH₄ emissions could be obtained without affecting dry matter intake (DMI) when iodoform was mixed into total mixed rations (TMRs). The experiment consisted of four periods of 14 d with four rumen-cannulated Holstein dairy cows. In the pre-period, no iodoform was added to TMR, while either 8, 16, or 20 mg iodoform/kg DM was added to TMR in the remaining periods in a change-over design. However, the experiment was not balanced across treatments and periods due to unexpected animal responses in the second period. Dry matter intake and gas exchange were measured the last 3 d in each period using respiration chambers. Rumen grab samples were collected for microbial analyses on d 14. Dry matter intake was unaffected by the addition of iodoform to TMR at or below 20 mg/kg DMI. Methane and H₂ yields (g/kg DMI) quadratically decreased (up to 46%) and increased (up to 1127%), respectively, with the increasing dose. This pilot study indicated that CH₄ reductions can be obtained with an addition of up to 20 mg iodoform/kg DM in the diets of dairy cows without affecting DMI. However, high iodine concentration in iodoform limits its use in commercial herds within the EU. Full article

Use of pair housing for preweaning calves has shown positive benefits in terms of health and production, with it also being thought to offer social support in times of stress such as when calves are disbudded. Calf disbudding through thermal cautery is a common procedure, with recognized physiological and behavioral implications. This study’s objective was to utilize continuous monitoring accelerometers to compare the impact of disbudding on the behavior of pair and individually housed calves. Data from an all-year-round dairy herd in the southwest of England were collected via an accelerometer (ABS breeder tag, Genus, Cheshire, UK) fitted to a forelimb of a convenience subset of calves (n = 265) within two weeks of age. Data were collected between March and December 2020 and covered the period 7 days prior to disbudding until 30 days post disbudding. Calves underwent thermal cautery disbudding by farm staff using local anesthesia and a systemic nonsteroidal anti-inflammatory drug. Data from 205 calves (125 pair-housed and 80 individually housed) were included in analysis through generalized estimating equations models. The calf activity (p = 0.98), number of lying bouts (p = 0.40), and lying time per day (p = 0.75) were not associated with the housing treatment of the calves. Calf activity was associated with the day compared to disbudding (p < 0.001), with both housing treatments having decreased activity in the days following disbudding, taking approximately 14 days to return to pretreatment levels. Full article

Cow’s milk is an important part of the human diet, primarily due to its high nutritional content, particularly proteins and fats. The processing of milk enhances its safety while modifying its composition and structure, influencing bioactive peptide release, which impacts protein quality, digestion, and allergenicity. Recently, filtered milk, which undergoes pasteurisation and microfiltration, has become available in UK supermarkets, offering a longer shelf life than pasteurised milk. This study aimed to evaluate the effects of microfiltration on the protein structure of cow’s milk, compared with pasteurisation, including analysis of the peptide profile released after in vitro gastrointestinal digestion of commercially available semi-skimmed filtered and pasteurised cow’s milk. Dynamic light scattering analysis revealed that the Z-average particle size of filtered milk was significantly (p < 0.05) larger than that of pasteurised milk across all brands. Additionally, filtered milk exhibited a significantly (p < 0.05) lower free thiol concentration compared with pasteurised milk, indicating structural modifications in proteins. Confocal laser scanning microscopy (CLSM) further highlighted heterogeneities in the distribution of fat and protein, with filtered milk samples showing increased interaction between fat globules and proteins. After gastrointestinal digestion, the numbers of peptides released from filtered milk exceeded those of peptides released from pasteurised milk by an average of 5%. These results provide new insights into the potential impact of microfiltration on the microstructure of milk. Further investigations using advanced analytical techniques are needed to assess the implications of these changes on protein bioavailability and human health. Full article

Colostrum is a nutrient-dense food rich in proteins, immune modulators, and growth factors essential for neonatal development. Its lipids serve as a key energy source and facilitate cellular functions. While yak colostrum (YC) and buffalo colostrum (BC) exhibit high nutritional value, their lipid compositions remain unclear. This study employed lipidomics to analyze and compare the lipid profiles of YC and BC with cow colostrum (CC), identifying 872 lipids across 33 subclasses. Differential analysis revealed 137, 100, and 131 lipids, with significant expression differences between YC vs. CC, BC vs. CC, and YC vs. BC, respectively. YC exhibited higher levels of α-linolenic acid and docosahexaenoic acid, suggesting a potential role in enhancing neurodevelopment and cognitive function. In contrast, the upregulation of specific lipid components in BC, such as phosphatidylethanolamine (PE) and phosphatidylinositol (PI), coupled with the downregulation of specific lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE), indicated a potential benefit for lipid metabolism and inflammatory regulation. These findings suggest that YC may be particularly suitable for neonates requiring enhanced energy support, while BC may offer advantages in lipid metabolism modulation. The study provides critical insights into the distinct lipid compositions of YC and BC, laying a scientific foundation for the development of tailored nutritional supplements. These results also hold significant implications for the dairy industry, driving innovation and optimization of colostrum-based products to meet diverse nutritional demands. Full article

Pseudomonas aeruginosa is a ubiquitous environmental bacterium that causes a variety of infections in humans and animals. Although antibiotic resistance in livestock has been extensively documented, continuous surveillance remains crucial for tracking emerging resistance trends and assessing control measures. During 2017 and 2018, 234 strains of P. aeruginosa were identified from 1063 strains of pathogenic and nonpathogenic bacteria isolated from raw milk of healthy and mastitis cows. In this study, 132 convenience P. aeruginosa isolates were recovered and tested for antimicrobial susceptibility and the presence of antimicrobial resistance genes and virulence factors. Antimicrobial susceptibility testing revealed that these P. aeruginosa isolates were resistant to three (gentamicin, tobramycin, and ceftazidime) out of eight antibiotics. Real-time PCR targeting 21 antibiotic resistance genes indicated that aminoglycoside modifying enzyme (AME) gene ant(3″)-I was most frequently identified in both antimicrobial-resistant and -susceptible P. aeruginosa isolates, followed by aac(6′)-II and aac(6′)-Ib. The β-lactamase encoding gene, bla_PDC, was mainly identified in susceptible P. aeruginosa isolates. Virulence factors screening revealed the presence of exoS, exoT, exoU, pyo, aprA, toxA, plcH, algD, lasB, lasI, lasR, rh1L, and rh1R in resistant isolates, with the detection rates ranging from 16.7% to 88.9%. Additionally, next-generation sequencing was conducted on three resistant isolates to validate these findings. This study showed the antibiotic resistance of P. aeruginosa in raw milk samples from large-scale dairy farms in Jiangsu and Shandong provinces, China. Full article

In this study, the total phenolic and anthocyanin contents, antioxidant activity, color, pH, serum separation, water holding capacity (WHC), rheology, texture and viscosity of cranberry (Cornus mas L.)-enriched yogurt were determined. The addition of cranberries (5–15%) to yogurt resulted in a proportional increase in antioxidant activity, total anthocyanin and phenolic contents. In yogurt samples to which cranberries were added, the WHC increased, while the serum separation values decreased. Due to the red color of the cranberry fruits, the L* (lightness) and b* (yellowness) values decreased, and the a* (redness) values increased (p < 0.05). The sensory evaluation showed that the 10% (w/w) cranberry-added yogurt had the highest general acceptability score when compared to the other samples. Also, it was found that the addition of 10% (w/w) cranberries to the yogurt samples contributed positively to the physicochemical (textural properties, rheological behavior, color and serum separation) and biochemical (antioxidant activity, phenolics and anthocyanins) properties of the samples. The addition of cranberries to yogurt influenced the growth of microbial populations. The number of starter bacteria (counts for Lactobacillus delbrueckii subsp. bulgaricus) in the yogurt samples with cranberries was slightly lower than in the control sample; but was at an acceptable level. E. coli and coliform bacteria were not detected in either the control yogurt sample or the samples with added cranberries. In conclusion, the addition of 10% (w/w) cranberries to yogurt can be recommended in order to achieve acceptable physical and sensory properties as well as the enrichment of yogurt with nutritional and functional aspects. Full article

This study aims to clarify the use of Limosilactobaillus reuteri (Lmb. reuteri) in dairy products, emphasizing its main characteristics and limitations through a comprehensive literature review. Lmb. reuteri, previously classified as Lactobacillus reuteri, is a lactic acid bacterium (LAB) generally present in the gastrointestinal tracts of humans and other animals, such as sheep, chickens, and rodents. Lmb. reuteri was reclassified as part of the genus Limosilactobacillus in April 2020, reflecting advancements in biomolecular research that identified distinct metabolic and biochemical characteristics among strains. This species is an important producer of reuterin, an antimicrobial compound facilitated through glycerol fermentation via specific enzymatic pathways. In addition, selected strains of Lmb. reuteri can be considered probiotic bacteria with numerous health benefits and that lead to well-being improvements. It is consistently related to improvements in gut health, immune function enhancement, and cholesterol reduction. Furthermore, its application in dairy products has gained prominence and is increasingly reported in the literature due to its technological and sensory benefits. Despite the challenges of its incorporation into the dairy matrix, largely due to the need to supplement these products, it has already demonstrated significant effects on several dairy products’ technological, sensory, and quality characteristics. Future research should address challenges like strain-specific efficacy and regulatory hurdles for the application of Lmb. reuteri in foods. Full article

Doce de leite is a caramel-like confection, mainly produced in several Latin American countries, with increasing popularity worldwide. This overview outlines nine distinct industrial technologies for the production of doce de leite: (1) total batch manufacturing process; (2) batch manufacturing system with fractionated mix addition; (3) manufacturing with pre-concentration in a vacuum evaporator and finishing in an open pan; (4) manufacturing with pre-concentration in a vacuum evaporator, finishing in an open pan, and lactose micro-crystallization; (5) continuous flow manufacturing with total concentration in a vacuum evaporator and a viscosity control holding tank (hot well); (6) manufacturing with total concentration in a vacuum evaporator and sterilization in an autoclave system; (7) manufacturing with sucrose pre-caramelization and a total batch system; (8) manufacturing in colloidal mill without an evaporation process; and (9) manufacturing based of doce de leite bars with a sucrose crystallization stage. We conducted a literature review to gather data on the discussed processes and their principal characteristics, which may be pertinent to doce de leite manufacturers. The choice of a specific process will depend on the desired doce de leite characteristics, the type of doce de leite to be produced, and the manufacturing company’s requirements. When properly integrated, these technologies contribute to efficient and profitable production, yielding high-quality products with appropriate chemical, microbiological, and sensory characteristics at an industrial scale. Full article