Supplementation of rumen-protected lysine during the close-up period improves vaginal discharge clearance in Holstein dairy cows.

We aimed to evaluate the effects of rumen-protected lysine (RPL) supplementation during the close-up period on uterine involution and the resumption of ovarian function in dairy cows. Fifty-two multiparous Holstein cows were categorized based on parity and expected calving date and randomly assigned to the RPL or control (CON) groups. The RPL group received 80 g of RPL daily from day 21 before the expected calving date until parturition. Blood samples were obtained twice weekly from pre-supplementation to 6 weeks postpartum. The onset of luteal activity postpartum was determined via ultrasonography twice weekly for up to 6 weeks postpartum. Uterine involution was tracked at 3 and 5 weeks postpartum through the vaginal discharge score, percentage of polymorphonuclear cells (PMN) in endometrial cytology samples, presence of intrauterine fluid, and gravid horn diameter via ultrasonography. Before supplementation, the RPL group showed amino acid imbalance, which was improved by RPL supplementation. There were no significant differences in the onset of luteal activity, percentage of PMN, intrauterine fluid, or the diameter of the uterine horn between the two groups. The vaginal discharge score in the RPL group decreased from 3 to 5 weeks postpartum, whereas that in the CON groups did not decrease. The number of cows with clinical endometritis was lower in the RPL group. Overall, RPL supplementation during the close-up period enhanced vaginal discharge clearance, potentially averting clinical endometritis, but did not affect the first ovulation in dairy cows.

Advanced Tandem Mass Spectrometric Analysis of Complex Mixtures of Triacylglycerol Regioisomers: A Case Study of Bovine Milk Fat.

Comprehensive analysis of triacylglycerol (TAG) regioisomers is extremely challenging, with many variables that can influence the results. Previously, we reported a novel algorithmic method for resolving regioisomers of complex mixtures of TAGs. In the current study, the TAG Analyzer software and its mass spectrometric fragmentation model were further developed and validated for a much wider range of TAGs. To demonstrate the method, we performed for the first time a comprehensive analysis of TAG regioisomers of bovine milk fat, a very important and one of the most complex TAG mixtures in nature containing FAs ranging from short to long carbon chains. This analysis method forms a solid basis for further investigation of TAG regioisomer profiles in various natural fats and oils, potentially aiding in the development of new and healthier foods and nutraceuticals with targeted lipid structures.

Intraday and interday variations of milk fatty acids in dairy cows in early and late lactation.

The composition of milk fatty acid (FA) was determined using Fourier-transform mid-infrared spectroscopy, which enables the rapid measurement of many samples. Milk FA is one indicator supporting the management of dairy cows and herds. This study aimed to determine an appropriate sampling method for milk FA in a practical farm condition based on intraday and interday variations in milk FA composition during early and late lactation stages. Milk samples were collected in the morning (07:00-08:00 h) and afternoon (16:30-17:30 h) for five consecutive days during early and late lactation. Within the day, de novo FA as the total FA basis was higher in the morning than in the afternoon, whereas preformed FA as the total FA basis was lower in the morning than in the afternoon. The weighted averages of milk FA composition according to milk yield collected in the morning and afternoon were significantly different between cows in early and late lactation; however, these were not significantly different among the consecutive five sampling days in each period. It was concluded that milk samples collected in the morning and afternoon for 1 day are suitable for milk FA determination. These results provide basic data for determining precise sampling methods for practical farms.

Preparation and characterization of vitamin E/calcium/soy protein isolate nanoparticles for soybean milk beverage fortification.

Soybean milk is a rich plant-based source of protein, and phenolic compounds. This study compared the nutritional value of soybean milk, flour, soy protein isolate (SPI) and evaluated the impact of prepared vitamin E/calcium salt/soy protein isolate nanoparticles (ECSPI-NPs) on fortification of developed soybean milk formulations. Results indicated that soybean flour protein content was 40.50 g/100 g, that fulfills 81% of the daily requirement (DV%), the unsaturated fatty acids (USFs), oleic and linoleic content was 21.98 and 56.7%, respectively, of total fatty acids content. In soybean milk, essential amino acids, threonine, leucine, lysine achieved 92.70, 90.81, 77.42% of amino acid scores (AAS) requirement values respectively. Ferulic acid was the main phenolic compound in soybean flour, milk and SPI (508.74, 13.28, 491.78 µg/g). Due to the moisture content of soybean milk (88.50%) against (7.10%) in soybean flour, the latest showed higher nutrients concentrations. The prepared calcium (20 mM/10 g SPI) and vitamin E (100 mg/g SPI) nanoparticles (ECSPI-NPs) exhibited that they were effectively synthesized under transmission electron microscope (TEM), stability in the zeta sizer analysis and safety up to IC50 value (202 ug/mL) on vero cell line. ECSPI-NPs fortification (NECM) enhanced significantly phenolic content (149.49 mg/mL), taste (6.10), texture (6.70) and consumer overall acceptance (6.54). Obtained results encourage the application of the prepared ECSPI-NPs for further functional foods applications.

Exploring the Effect of Milk Fat on Fermented Milk Flavor Based on Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) and Multivariate Statistical Analysis.

Milk fat is a premium nutritional health product, yet there is a lack of high-fat dairy products for daily consumption in the current market. This study investigated the influence of different milk fat contents on the physicochemical and textural properties of fermented milk. The research revealed that an increase in milkfat content significantly improved the water-holding capacity, syneresis, color, hardness, springiness, gumminess, and chewiness of fermented milk, while showing minimal changes in pH and total titratable acidity. Response surface analysis indicated that fermented milk with 25% milk fat, 2.5% inoculum, a fermentation time of 16 h, and a fermentation temperature of 30 °C exhibited the highest overall acceptability. Using GC-IMS technology, 36 volatile compounds were identified, with an increase in milk fat content leading to elevated levels of ketone compounds, and 14 compounds were defined as key aroma compounds (ROAV > 1). Electronic nose distinguished samples with different milk fat contents. The results demonstrate that an increase in milk fat content enhances the physicochemical and flavor attributes of fermented milk. This work provides theoretical references for the production and development of high-fat fermented milk.

Progress and Challenge of Sensors for Dairy Food Safety Monitoring.

One of the most consumed foods is milk and milk products, and guaranteeing the suitability of these products is one of the major concerns in our society. This has led to the development of numerous sensors to enhance quality controls in the food chain. However, this is not a simple task, because it is necessary to establish the parameters to be analyzed and often, not only one compound is responsible for food contamination or degradation. To attempt to address this problem, a multiplex analysis together with a non-directed (e.g., general parameters such as pH) analysis are the most relevant alternatives to identifying the safety of dairy food. In recent years, the use of new technologies in the development of devices/platforms with optical or electrochemical signals has accelerated and intensified the pursuit of systems that provide a simple, rapid, cost-effective, and/or multiparametric response to the presence of contaminants, markers of various diseases, and/or indicators of safety levels. However, achieving the simultaneous determination of two or more analytes in situ, in a single measurement, and in real time, using only one working 'real sensor', remains one of the most daunting challenges, primarily due to the complexity of the sample matrix. To address these requirements, different approaches have been explored. The state of the art on food safety sensors will be summarized in this review including optical, electrochemical, and other sensor-based detection methods such as magnetoelastic or mass-based sensors.

Fermentation Characteristics of Fermented Milk with Streptococcus thermophilus CICC 6063 and Lactobacillus helveticus CICC 6064 and Volatile Compound Dynamic Profiles during Fermentation and Storage.

The lactic acid bacteria Streptococcus thermophilus and Lactobacillus helveticus are commonly used as starter cultures in dairy product production. This study aimed to investigate the characteristics of fermented milk using different ratios of these strains and analyze the changes in volatile compounds during fermentation and storage. A 10:1 ratio of Streptococcus thermophilus CICC 6063 to Lactobacillus helveticus CICC 6064 showed optimal fermentation time (4.2 h), viable cell count (9.64 log10 colony-forming units/mL), and sensory evaluation score (79.1 points). In total, 56 volatile compounds were identified and quantified by solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS), including aldehydes, ketones, acids, alcohols, esters, and others. Among these, according to VIP analysis, 2,3-butanedione, acetoin, 2,3-pentanedione, hexanoic acid, acetic acid, acetaldehyde, and butanoic acid were identified as discriminatory volatile metabolites for distinguishing between different time points. Throughout the fermentation and storage process, the levels of 2,3-pentanedione and acetoin exhibited synergistic dynamics. These findings enhance our understanding of the chemical and molecular characteristics of milk fermented with Streptococcus thermophilus and Lactobacillus helveticus, providing a basis for improving the flavor and odor of dairy products during fermentation and storage.

Recent Advances in the Chromatographic Analysis of Emerging Pollutants in Dairy Milk: A Review (2018-2023).

Emerging pollutants (EPs) encompass natural or synthetic substances found in the environment that pose potential risks, but which have only recently been recognized or monitored. EPs consist of various categories, including pesticides, pharmaceuticals, hormones, mycotoxins, and endocrine-disrupting chemicals (EDCs). Through several pathways, EPs can access food, potentially leading to health impacts when safe concentrations are exceeded. Milk, being a highly nutritious food product that is heavily consumed by many consumers of different ages, is a crucial food matrix where EPs should be regularly monitored. In the literature, a large number of studies have been dedicated to the determination of different EPs in dairy milk, employing different analytical techniques to do so. Chromatography-based techniques are the most prevalent means used for the analysis of EPs in milk, demonstrating significant efficiency, sensitivity, and accuracy for this specific purpose. The extraction of EPs from a complex matrix like milk is essential prior to performing chromatographic analysis. This review comprehensively covers relevant research papers on the extraction and subsequent detection and determination of EPs in milk using chromatographic methods from 2018 to 2023.

A Chiral-LC-MS Method for the Simultaneous Quantification of Short-Chain Fatty Acids and D/L-Lactate in the Ruminal Fluid of Dairy Cows.

Short-chain fatty acids (SCFA) and lactate in ruminal fluid are products resulting from the microbial fermentation of substrates and can be used to reflect the composition and activity of the ruminal microbiome. Determination of SCFA and D-/L-lactate in ruminal fluid currently requires two separate protocols, which is time-consuming and costly. In this study, we have optimised and validated a simple and unified 3-nitrophenylhydrazine (3-NPH) derivatisation protocol and a 20 min chiral-LC-MS method for the simultaneous quantification of all SCFA and D- and L-lactate in ruminal fluid. This method, which requires no sample pretreatment or purification shows adequate sensitivity (limit of detection (LOD): 0.01 µg/mL), satisfactory accuracy (recovery: 88-103%), and excellent reproducibility (relative standard deviation (RSD) for repeated analyses < 3% for most analytes). The application of this method to a cohort of 24 animals allowed us to reveal a large inter-cow variation in ruminal SCFA and lactate level, the concentration range for each species, the widespread correlation between different SCFA, and the strong correlation between D- and L-lactate.

Assessment of essential and potentially toxic metals in raw cow milk from Mukaturi town, Oromia Regional State, Ethiopia.

Cow milk is a complete and highly nutritious source of food for humans. However, the quality of milk products has become a significant health concern for consumers, particularly infants and children, in many developing nations, including Ethiopia. The objective of this study was to determine the heavy metal levels in raw cow milk collected from dairy producers and collection centers in Mukaturi town, Ethiopia. Sixty raw cow milk samples (40.0 milk samples from dairy farms and 20.0 milk samples from collection centers) were randomly collected and digested using a mixture of nitric acid (HNO3), hydrogen peroxide (H2O2) and perchloric acid (HClO4) on a hot plate. The amounts of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the milk samples were determined using inductively coupled plasma atomic emission spectroscopy (ICP-OES). The findings showed that the average concentrations of Pb (2.31 ± 0.127), Fe (0.566 ± 0.130), Ni (0.210 ± 0.0189), Cd (0.0372 ± 0.0230), Cr (0.369 ± 0.0162), and Co (0.225 ± 0.0150) in mgL-1 were higher than the allowable limits. This could pose a health risk to the public. However, the concentrations of Mn (0.044 ± 0.0369), Cu (0.195 ± 0.0450) and Zn (2.90 ± 0.0570) in mg L-1 were lower than or within the recommended limits and cannot pose any threat to consumers. The validity of the digestion processes was checked by the recovery test. The percentage recoveries of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were found to be in the range of 80.7-122 %, which is within the acceptable range. Therefore, special attention should be given to the continuous monitoring of heavy metal levels in raw milk among dairy producers and collection centers to minimize economic losses and the risk to consumer safety.

Initial diet shapes resistance-gene composition and fecal microbiome dynamics in young ruminants during nursing.

This study was conducted to examine how colostrum pasteurization affects resistance genes and microbial communities in calf feces. Forty female Holstein calves were randomly assigned to either the control (CON) group, which received unheated colostrum, or the pasteurized colostrum (PAT) group. The calves body weight was measured weekly before morning feeding. Calf starter intake were measured and recorded daily before morning feeding. Samples of colostrum were collected before feeding. Blood was collected on d 1 and 70 before morning feeding. Ten calves were randomly selected from each group (n = 20 calves total) for fecal sampling on d 3, 28, 56 and 70 for subsequent DNA extraction and metagenomic sequencing. Total bacterial counts in the colostrum were markedly higher in the CON group than in the PAT group. Pasteurized colostrum administration substantially reduced the ARO diversity and diminishes the abundance of Enterobacteriaceae, thereby decreasing their contribution to resistance genes. Pasteurization also reduced glucoside hydrolase-66 activity in 3-day-old calves which led to an increase in the activity of aminoglycoside antibiotics, resulting in 52.63 % of PAT-enriched bacteria acquiring aminoglycoside resistance genes. However, from the perspective of overall microbial community, the proportion of aminoglycoside, beta-lactam and tetracycline resistance genes carried by microbial community in PAT group was lower than CON group (P < 0.05). Fecal samples from the PAT group contained greater abundances of Subdoligranulum (P < 0.05) and Lachnospiraceae_NK4A136_group (P < 0.05) on days 28 and 70 compared to CON. Network analysis and abundance variations of the different bacteria obtained by linear discriminant analysis effect size analysis showed that pasteurized colostrum feeding reduced the interactions among related bacteria and maintained stability of the hind-gut microbiome. In conclusion, these findings underscore the intricate interactions between early diet, calf resistance-gene transmission and microbial dynamics, which should be carefully considered in calf-rearing practices.

A review of endocrine disrupting chemicals migration from food contact materials into beverages.

A significant and pressing issue revolves around the potential human exposure to endocrine disrupting chemicals (EDCs), which pose a substantial risk primarily through contaminated beverages. However, a comprehensive review for comparison of the migration rates of EDCs into these matrixes is currently lacking. This study reviews the beverages contamination with EDCs, including phthalates (PAEs), bisphenol A (BPA), hormone-like compounds, elements, and other organic EDCs. Also, the EDCs migration into milk and other dairy products, coffee, tea, and cold beverages related to their release from contact materials, preparation components, and storage conditions are briefly summarized. The data illustrates that besides the contamination of raw materials, the presence of EDCs associated with the type of food contact materials (FCMs)and their migration rate is increased with acidity, temperature, and storage time. The highest concentration of PAEs was detected from plastic and synthetic polymer films, while BPA strongly leaches from epoxy resins and canned metal. Furthermore, the presence of elements with endocrine disrupting characteristics was confirmed in cold beverages, soft drinks, hot drink and milk. Moreover, hormone-like compounds have been found to be released from coffee preparation components. Despite the few data about the migration rate of other EDCs including UV-stabilizers, surfactants, and antibacterial compounds into beverages, their presence was reported into milk, coffee, and different beverages, especially in packed samples. Studies on the EDCs leaching have primarily focused on PAEs and BPA, while other compounds require further investigation. Regardless, the possible risk that EDCs pose to humans through beverage consumption cannot be overlooked.

Maternal Cannabis Use during Lactation and Potential Effects on Human Milk Composition and Production: A Narrative Review.

Cannabis use has increased sharply in the last 20 y among adults, including reproductive-aged women. Its recent widespread legalization is associated with a decrease in risk perception of cannabis use during breastfeeding. However, the effect of cannabis use (if any) on milk production and milk composition is not known. This narrative review summarizes current knowledge related to maternal cannabis use during breastfeeding and provides an overview of possible pathways whereby cannabis might affect milk composition and production. Several studies have demonstrated that cannabinoids and their metabolites are detectable in human milk produced by mothers who use cannabis. Due to their physicochemical properties, cannabinoids are stored in adipose tissue, can easily reach the mammary gland, and can be secreted in milk. Moreover, cannabinoid receptors are present in adipocytes and mammary epithelial cells. The activation of these receptors directly modulates fatty acid metabolism, potentially causing changes in milk fatty acid profiles. Additionally, the endocannabinoid system is intimately connected to the endocrine system. As such, it is probable that interactions of exogenous cannabinoids with the endocannabinoid system might modify release of critical hormones (e.g., prolactin and dopamine) that regulate milk production and secretion. Nonetheless, few studies have investigated effects of cannabis use (including on milk production and composition) in lactating women. Additional research utilizing robust methodologies are needed to elucidate whether and how cannabis use affects human milk production and composition.

The ABCG2 protein in vitro transports the xenobiotic thiabendazole and increases the appearance of its residues in milk.

Thiabendazole (TBZ) is a broad-spectrum anthelmintic and fungicide used in humans, animals, and agricultural commodities. TBZ residues are present in crops and animal products, including milk, posing a risk to food safety and public health. ABCG2 is a membrane transporter which affects bioavailability and milk secretion of xenobiotics. Therefore, the aim of this work was to characterize the role of ABCG2 in the in vitro transport and secretion into milk of 5-hydroxythiabendazole (5OH-TBZ), the main TBZ metabolite. Using MDCK-II polarized cells transduced with several species variants of ABCG2, we first demonstrated that 5OH-TBZ is efficiently in vitro transported by ABCG2. Subsequently, using Abcg2 knockout mice, we demonstrated that 5OH-TBZ secretion into milk was affected by Abcg2, with a more than 2-fold higher milk concentration and milk to plasma ratio in wild-type mice compared to their Abcg2-/- counterpart.

Assessment of some chemical residues in Egyptian raw milk and traditional cheese.

Background: The assessment of risks related to food safety is becoming a challenge in developing countries with its consequent health hazards. Chemical risk assessment in dairy products is important to maintain consumer health locally and internationally. Since milk and dairy products are essential foods for a wide range of customers, mostly children, patients, and pregnant women, it is very important to estimate the risks of some chemical residues, such as pesticides, some heavy metals, and aflatoxins. Aim: This work aims to determine the levels of chemical contamination in milk and traditional Egyptian cheese. Methods: Heavy metals were determined in samples by atomic absorption spectrometry. GC-mass spectrometry (MS)/MS and LC-MS/MS were also used for measuring pesticide residues. The Aflatoxin M1 was determined by enzyme-linked immune-sorbent assay. Results: Raw milk samples were tested and showed elevated concentrations of lead and cadmium, (46% and 4%, respectively). The heavy metals detected in the Egyptian cheese samples were variable depending on the type of cheese. Moreover, p.p.-DDE phenofose was present in 45% and 29% of raw milk and Ras cheese samples, respectively. For Aflatoxin M1, only 7% of milk samples and 2.9% of Ras cheese samples exceeded the acceptable limits. Conclusion: More surveying and risk assessment of chemical residues in milk and milk products are essential for controlling health risks to consumers.

A common regulatory haplotype doubles lactoferrin concentration in milk.

BACKGROUND: Bovine lactoferrin (Lf) is an iron absorbing whey protein with antibacterial, antiviral, and antifungal activity. Lactoferrin is economically valuable and has an extremely variable concentration in milk, partly driven by environmental influences such as milking frequency, involution, or mastitis. A significant genetic influence has also been previously observed to regulate lactoferrin content in milk. Here, we conducted genetic mapping of lactoferrin protein concentration in conjunction with RNA-seq, ChIP-seq, and ATAC-seq data to pinpoint candidate causative variants that regulate lactoferrin concentrations in milk. RESULTS: We identified a highly-significant lactoferrin protein quantitative trait locus (pQTL), as well as a cis lactotransferrin (LTF) expression QTL (cis-eQTL) mapping to the LTF locus. Using ChIP-seq and ATAC-seq datasets representing lactating mammary tissue samples, we also report a number of regions where the openness of chromatin is under genetic influence. Several of these also show highly significant QTL with genetic signatures similar to those highlighted through pQTL and eQTL analysis. By performing correlation analysis between these QTL, we revealed an ATAC-seq peak in the putative promotor region of LTF, that highlights a set of 115 high-frequency variants that are potentially responsible for these effects. One of the 115 variants (rs110000337), which maps within the ATAC-seq peak, was predicted to alter binding sites of transcription factors known to be involved in lactation-related pathways. CONCLUSIONS: Here, we report a regulatory haplotype of 115 variants with conspicuously large impacts on milk lactoferrin concentration. These findings could enable the selection of animals for high-producing specialist herds.

Human proinsulin production in the milk of transgenic cattle.

BACKGROUND: The worldwide growing demand for human insulin for treating diabetes could be supplied by transgenic animals producing insulin in their milk. METHODS AND RESULTS: Pseudo-lentivirus containing the bovine ß-casein promoter and human insulin sequences was used to produce modified adult fibroblasts, and the cells were used for nuclear transfer. Transgenic embryos were transferred to recipient cows, and one pregnancy was produced. Recombinant protein in milk was evaluated using western blotting and mass spectrometry. One transgenic cow was generated, and in milk analysis, two bands were observed in western blotting with a molecular mass corresponding to the proinsulin and insulin. The mass spectrometry analysis showed the presence of human insulin more than proinsulin in the milk, and it identified proteases in the transgenic milk that could convert proinsulin into insulin and insulin-degrading enzyme that could degrade the recombinant protein. CONCLUSION: The methodologies used for generating the transgenic cow allowed the detection of the production of recombinant protein in the milk at low relative expression compared to milk proteins, using mass spectrometry, which was efficient for detecting recombinant protein with low expression in milk. Milk proteases could act on protein processing converting recombinant protein to functional protein. On the other hand, some milk proteases could act in degrading the recombinant protein.

Ohmic heating application with different electric fields on inactivation of Listeria monocytogenes in protein-enriched cow milk.

The aim of this study was to determine the effects of an ohmic heating (OH) process with different electric field intensities on Listeria monocytogenes inactivation in protein-enriched cow milk. Protein powder was added at rates of 2.5%, 5% and 7.5% in 1.5% fat content milk, and L. monocytogenes (ATCC 13932) strain was then inoculated into the samples. The OH process was carried out in a laboratory-type pilot unit created using stainless steel electrodes, a K-type thermocouple, a datalogger and power supply providing AC current at 0-250 V, 10 A. The inoculated milk samples were heated to 63°C by applying an electric field intensity of 10V/cm and 20V/cm. L. monocytogenes counts, pH, color measurement and hydroxymethylfurfurol levels were then determined. OH applied with an electric field intensity of 10 V/cm caused an average decrease of 5 logs in L. monocytogenes level in the samples containing 2.5% protein and decreased below the detection limit (<1 log) at the 9th minute (p<0.05). Similarly, application of an electric field intensity of 20 V/cm in milk containing 2.5% and 5% protein caused the L.monocytogenes level to decrease below the detection limit (<1 log) at 2 minutes 30 seconds (p<0.05). No change was observed in the L* (brightness) values of the samples but it was determined that there was a slight increase in pH, a* (redness) and b* (yellowness) values compared to the control group. It was observed that the inactivation of L. monocytogenes by OH depends on the duration of the OH process, protein concentration in the milk and the applied voltage gradient.

Physicochemical and Sensory Characterization of Whey Protein-Enriched Semihard Cheese.

In view of potential future changes of German food legislation with regard to cheese product quality parameters, this study aimed to evaluate the quality of whey protein-enriched semihard cheese (WPEC). Model WPEC was produced in a pilot plant and on an industrial scale by adding defined amounts of high-heat (HH) milk to the cheese milk and comprehensively analyzed during cheese processing. The dry matter, total protein, pure protein, fat, and sodium chloride content of six-week ripened cheese samples were not significantly different (p < 0.05) when the technologically necessary heating of the curd was adapted to the amount of HH milk. However, the ripening, firmness, and melting behavior of WPEC was different compared to cheese without HH milk. During ripening, no formation of whey protein peptides was observed, but differences in the amount of some bitter peptides deriving from the casein fraction were found. Sensory data suggested a slightly more bitter taste perception by the panelists for the WPEC. Further technological adjustments are recommended to obtain marketable WPEC.