Milk Samples Research Articles

ANÁLISE DA QUALIDADE DE LEITE EM TANQUES DE ORDENHA MECÂNICA, DE ORDENHA MANUAL E TANQUES COMUNITÁRIOS

This study aims to analyze bacterial contamination in milk produced by three different milking systems: manual, mechanical, and community tanks. The research involved collecting milk samples from rural properties in Presidente Médici, focusing on the count of mesophilic aerobic and facultative anaerobic bacteria. The analysis of results showed that the manual milking system had the highest contamination levels due to greater manipulation and the use of simple equipment. On the other hand, the mechanical milking system exhibited an intermediate level of contamination, while community tanks, which generally face challenges regarding hygiene and management, surprisingly showed lower contamination levels than expected. These findings indicate that proper hygiene and management practices are essential to ensure milk quality, regardless of the milking system used. The study emphasizes the importance of training producers and investing in infrastructure to enhance the competitiveness of Brazilian milk in both the domestic and international markets.

Portable foodborne pathogen detection via ratiometric fluorescence nanoprobe for adenosine triphosphate quantification based on DNA-functionalized metal-organic framework.

The increasing incidence of foodborne illnesses highlights the need for rapid, sensitive, and portable methods to detect pathogenic bacteria in food. In this work, we develop a portable method that utilizes a ratiometric fluorescence nanoprobe for adenosine triphosphate (ATP) quantification. The nanoprobe is constructed by encapsulating Ru(bpy)32+ within a zirconium-based metal-organic framework, followed by functionalization of double-stranded DNA (dsDNA). This design permits SYBR Green I (SGI) to intercalate into dsDNA, conferring the nanoprobe with dual-emission property. The presence of ATP disrupts dsDNA structure, quenching SGI fluorescence while maintaining Ru(bpy)32+ fluorescence, providing a stable reference signal. This differential response enables the nanoprobe to achieve ratiometric ATP detection with high precision and sensitivity, with a detection limit of 0.63 μM. Since ATP is a reliable biomarker for viable bacterial cells, a portable hydrogel kit was further developed by integrating the ratiometric fluorescence nanoprobe into an agarose hydrogel matrix. The validation of the kit was conducted using a smartphone application for color recognition, enabling the rapid and on-site detection of pathogens in milk samples. The kit exhibits exceptional sensitivity with a detection limit of 10 CFU/mL, making it a promising tool for real-time bacteria detection in food safety monitoring.

SARS-CoV-2 antibodies in breast milk of women given one and two doses of COVID-19 vaccine

Background & objectives The COVID-19 pandemic underscores the significance of vaccination in mitigating disease spread, with Covishield and Covaxin serving as pivotal vaccines in India. Breast milk, rich in vital antibodies like IgA and IgG, plays a crucial role in enhancing the immune defence of breastfeeding infants. However, limited research exists on the antibody responses in breast milk among individuals receiving single versus double doses of the COVID-19 vaccine. This study aimed to bridge this gap by exploring IgA and IgG antibody levels in breast milk and assessing the correlation with COVID-19 vaccination status. Methods This hospital-based descriptive study aimed to assess the relationship between COVID-19 vaccination and the presence of anti-SARS-CoV-2 IgA/IgG antibodies in breast milk. Breast milk samples were collected using a sterile, closed-system electric breast pump and stored at -20°C. ELISA testing, utilizing commercially available kits, was utilized to assess anti-SARS-CoV-2 IgA and IgG antibodies. Results Among the 151 women participants, 76 (50.3%) received COVID-19 vaccination. Of these vaccinated women, 70 (92.1%) received Covishield, and 6 (7.9%) received Covaxin. Within the vaccinated cohort, 32 (42.1%) completed the recommended double-dose regimen, while 44 (57.9%) received a single dose. While no significant association was found between vaccination status and IgA positivity (P=0.491), a notable association emerged for IgG positivity (P<0.001). Notably, individuals who completed the recommended double-dose regimen exhibited higher IgA (63.6%) and IgG (65.4%) positivity compared to those receiving a single dose. Interpretation & conclusions This study underscores the significance of COVID-19 vaccination in impacting IgA and IgG antibody presence in breast milk. Completing the double-dose regimen correlated with higher IgA and IgG levels, emphasizing the benefits of complete vaccination. These findings contribute to understanding vaccination’s impact on maternal-infant health.

Early postnatal effects of maternal obesity on breast milk composition and breastfeeding outcomes.

Breastfeeding can be challenging in mothers with overweight or obesity-related chronic low-grade inflammation, resulting in negative consequences for the newborn. The pre-gestational body mass index is negatively associated with lactogenesis II, the onset of colostrum secretion. Herein, we evaluated mothers' inflammation, metabolic status, and components of breast milk after birth to associate these factors with their nutritional and breastfeeding status. The study included volunteer mothers, categorized based on their nutritional status and anthropometric parameters, who gave birth in a tertiary maternity hospital. Serum and breast milk samples were collected 24 and 48 hours after birth to determine inflammatory biomarkers (SAA, leptin, CRP, IL-1β, TNF-α, IL-8, IL-6, MCP-1, IL-10, and IFN-γ), reproductive hormones (prolactin and progesterone), as well as the breast milk composition (total protein, fatty acid, percentage of fat and Kcal). Furthermore, we conducted a six-month follow-up to assess breastfeeding outcomes. Interestingly, the composition of breast milk did not vary in the different situations analyzed, indicating the stability of the breast milk´s composition in meeting infant needs, regardless of age, nutritional status, and type of birth. Our findings revealed a higher concentration of pro-inflammatory biomarkers (SAA, CRP, TNF-α, IL-8, and IFN-γ) than anti-inflammatory, IL-10, in breast milk. Our study showed that mothers who were overweight after pregnancy had a newborn with a higher birth weight compared to healthy post-pregnancy weight. Our study elucidates the intricate dynamics between maternal weight, inflammation, and breastfeeding outcomes. While maternal overweight or obesity-related inflammation may pose challenges to lactogenesis II and influence newborn birth weight, breast milk remains a stable and reliable source of essential nutrients for infant nourishment. However, the presence of pro-inflammatory biomarkers in breast milk warrants further investigation into its potential implications for infant health.

Effects of a Dietary Multi-Mineral Bolus on Udder Health in Dairy Cows: A Clinical Assessment

The clinical effects on the udder health of several trace elements—copper, iodine, cobalt, and selenium—contained in an intraruminal slow-release bolus were explored for the first time. Fifty-four dairy cows received the bolus (treated group, TG), while fifty-three were left untreated (control group, CG). Monthly composite milk samples were collected from 30 to 300 days in milk to measure somatic cell count (SCC); milk production was also recorded on the same days. Cows with SCC > 200 × 103 cells/mL were considered as affected by mastitis (with or without clinical signs). The effects on udder health were evaluated using several clinical indices employed for mastitis monitoring. The TG cows had a higher average daily milk yield than CG (p < 0.001), as well as a lower overall daily average of SCC (p < 0.0001). Fewer overall mastitis cases were detected in TG than in CG (p < 0.0001), although no significant differences were observed in new or cured mastitis cases. Finally, fewer failures of existing mastitis to cure cases were detected in TG as compared to CG (p < 0.0001), as well as fewer chronic mastitis cases (p < 0.0001). By looking at the clinical findings, some potential benefits on udder health might be hypothesized; nevertheless, additional studies are necessary to confirm these encouraging results.

The Health-Related Fatty Acid Profile of Milk from Holstein–Friesian Cows as Influenced by Production System and Lactation Stage

This study aimed to evaluate the effect of production system and lactation stage (LS) on the yield, centesimal composition, and fatty acid profile of milk from Holstein–Friesian cows. A total of 539 milk samples were collected in winter from cows in six certified organic dairy herds (ODHs) and eight conventional dairy herds (CDHs). The samples were collected randomly from up to 30% of cows at a given stage of lactation (7–45, 46–90, 91–135, 136–180, 181–225, 226–270, 271–315, and 316–360 days after calving). Milk samples were analyzed for proximate composition and the concentrations of fatty acids. The average daily milk yield was 11.4 kg higher (p < 0.01) in CDHs than in ODHs (28.1 kg vs. 16.7 kg). The concentrations of milk fat, protein, and lactose were also higher in CDHs than in ODHs. The fatty acid profile of milk fat was more desirable in ODHs than in CDHs (higher concentrations of polyunsaturated fatty acids (PUFAs), including n-3 PUFAs, trans-vaccenic acid, linolenic acid, and conjugated linoleic acid, and a higher desaturase index). Milk yield decreased (the decrease was more pronounced in ODHs), the concentrations of milk constituents increased, and the proportion of short-chain fatty acids in milk fat decreased (p < 0.05) with advancing lactation.

Maternal Nutrition and Human Milk Nutrients: A Scoping Review.

To explore the influence of maternal nutrition factors, including body mass index, nutritional supplementation, and dietary intake during the breastfeeding period, on macro and micronutrient composition in human milk. We conducted a scoping review using the PRISMA-ScR checklist, initially identifying 5,984 original studies published in the English language from PubMed, Scopus, and Web of Science that presented findings on the association of maternal nutritional factors on human milk nutrient composition. After screening the title and abstract, we selected 69 studies for full review, including 3 studies found through checking reference lists. After full review, we included 23 studies in this scoping review. Most studies found maternal body mass index and supplement consumption affected human milk macro and micronutrient composition, whereas inconsistent results were found on the relationship between maternal diet and human milk nutrients. Methodologies varied substantially across studies, especially for milk sample collection methods and maternal nutrition assessments. Maternal nutrition factors may affect levels of human milk nutrients, requiring maternal nutrition monitoring during breastfeeding. However, given the considerable variability in the results between studies and methodological approaches, further studies should use standardized and validated procedures to strengthen the findings on this topic.

Risk assessment of antibiotic residues in raw cow’s milk in Bangladesh

ABSTRACT This study evaluated the presence of residual levels of commonly utilised antibiotics, including oxytetracycline (tetracyclines), ciprofloxacin, enrofloxacin, and levofloxacin (fluoroquinolones), in milk samples. Fifty raw milk samples were collected from five farms in Keraniganj, Dhaka. A validated RP-HPLC method was applied to detect and quantify antibiotic residues, demonstrating good linearity with coefficients ranging from 0.999 to 1.0 in the concentration range of 1.25–15.00 µg/mL. The study revealed that oxytetracycline was detected in 90% of the samples, followed by levofloxacin (66%), enrofloxacin (64%), and ciprofloxacin (62%). One farm showed the highest antibiotic prevalence, with oxytetracycline in all samples and levofloxacin, enrofloxacin, and ciprofloxacin in 80% of the samples. About 30% of the oxytetracycline-positive samples exceeded the MRL, while none surpassed the MRL for enrofloxacin and ciprofloxacin. Calculated human health risks appeared to be low, but children might face potential risks due to prolonged exposure.

Rumen-protected methionine supplementation improves lactation performance and alleviates inflammation during a subclinical mastitis challenge in lactating dairy cows

This study aimed to evaluate the effects of rumen-protected Met on lactation performance, inflammation, and immune response, and liver glutathione of lactating dairy cows during a subclinical mastitis challenge (SMC). Thirty-two Holstein cows (145 ± 51 DIM) were enrolled in a randomized complete block design. At -21 d relative to the SMC, cows were assigned to dietary treatments, and data were collected before and during the SMC. Cows were blocked according to parity, DIM, and milk yield and received a basal diet (17.4% CP; Lys 7.01% MP and Met 2.14% MP) plus 100 g/d of ground corn (CON; n = 16) or a basal diet plus 100 g/d of ground corn and rumen-protected Met (SM, Smartamine M at 0.09% of dietary DM; n = 16), fed as a top-dress. At 0 d, the mammary gland's rear right quarter was infused with 100,000 cfu of Streptococcus uberis (O140J). Milk yield was recorded twice daily from 0 until 3 d relative to SMC. Milk samples were collected during each milking from 0 to 3 d relative to SMC, blood samples were collected at 0, 6, 12, 24, 48, and 72 h relative to SMC. The mTOR pathway activation was assessed in immune cells in blood and milk samples by measuring quantity and phosphorylation status of mTOR-related proteins, including AKT, S6RP, and 4EBP1. For the ratio of phosphorylated to total AKT, S6RP, and 4EBP1, blood samples were collected at 0, 12, and 24 h, and milk samples at 24 h relative to SMC. Liver biopsies were performed at -10 d and 24 h relative to SMC for measurement of glutathione. Linear mixed models with repeated measures were used to analyze the results. There was a trend for greater milk yield per milking (+ 0.8 kg) and per day (+1.7 kg) after SMC in SM cows compared with CON. The DMI was not affected by dietary treatments. Reactive oxygen metabolites were lower in SM cows than in CON. Milk somatic cell linear score was not affected by dietary treatments, and a score >4 at 24 h confirmed subclinical mastitis. The SM cows had greater milk fat percentage at 24 and 36 h post SMC, resulting in overall greater milk fat. Milk protein tended to be greater in SM cows than in CON. We observed greater liver glutathione in SM cows than in CON. Among inflammation biomarkers, ceruloplasmin was lower for SM cows compared with CON. In milk, greater phosphorylated (p) AKT:AKT and pS6RP:S6RP ratios were observed in immune cell populations from SM cows compared with CON. Blood neutrophils had a greater p4EBP1:4EBP1 ratio in SM cows compared with CON. Overall, our results show that Met supplementation during an SMC positively affected milk performance, lowered the risk of oxidative stress, and attenuated inflammation partially by increasing liver glutathione and immune cells' protein synthesis via mTOR signaling.

INVITED REVIEW: Antimicrobial Resistance Genes in Milk: a 10-year-systematic review and critical comment.

The occurrence of antimicrobial resistance genes in milk is eagerly discussed as a public health risk, and frequently investigated. Here, we perform a systematic review on the abundance of antimicrobial resistance genes in milk from primary production over a 10-year-period. We aimed to provide a comprehensive data set on known and emerging antimicrobial resistance genes in major mastitis pathogens, occurring worldwide in milk at primary production, and to critically discuss the relevance and constraints of these findings. We searched Pubmed for peer-reviewed studies published between 2012 and 2022 that fit fixed combinations of keywords and did not meet exclusion criteria such as "mixed with other sources." For synthesis, data on occurrence was extracted from studies and supplements. To address plausibility issues, we performed an NCBI BLAST search. Results & limitations. Our search revealed 2222 publications in total. Of them, 500 studies were eligible for full-text reads and 306 publications were included in data compilation. An overwhelming majority of studies dealt with mecA in Staphylococcus aureus, followed by extended-spectrum β-lactamase-encoding genes such as blaCTXM in Escherichia coli, while other mastitis pathogens such as Streptococcus spp. were scarcely investigated. In most cases, < 5% of milk samples were positive for major pathogens bearing the antimicrobial resistance gene of interest. However, huge study-to-study differences were found between regions, but also on a national level. For instance, the estimate prevalence of Escherichia coli-borne blaCTXM in mastitis milk samples ranged from 0.0% to 55%, with a median value of 8.02%, while in healthy individuals and bulk milk, the prevalence ranged from 0.0% to 20.0%, with a median value of 0.8%. Several studies reported antimicrobial resistance genes for the very first time in a species, but did not stand up to scrutiny. As an example, frequent detection of TEM-genes in streptococci is most likely attributed to contamination of molecular reagents, as reported elsewhere. Despite the huge amount of data, there is a need for more quality control, more representative sampling of milk, more quantitative research, and deeper insights into bacterial genomics, to identify relevant and/or emerging antimicrobial resistance genes in milk. Considering a low percentage of contaminated milk samples, unknown ARG-concentrations and an unproven role in human disease, the risk attributed to ARGs in milk seems to be exaggerated by far. However, the risk of ARG-selection on farm, resulting in low treatment success in cattle, is a real one and should be met by prudent use of antibiotics.

Characterization of circulating miRNA in cow milk and colostrum.

MicroRNAs (miRNAs) are short RNA molecules, typically 21-25 nucleotides long, synthesized within eukaryotic cells. They play a crucial role in coordinating complex gene expression regulatory networks. The miRNAs are involved in post-transcriptional regulation, either by degrading target mRNA or suppressing their transcription, thereby influencing protein translation. Also, the variation of miRNAs expression in different milk components suggests diverse metabolic pathways. Additionally, characteristics of farm production systems exert a noticeable influence on miRNAs profiles, shaping the functional properties of bovine milk. In this study, milk and colostrum samples of Holstein cows (Bos taurus) were collected for RNA extraction and sequencing. Sequencing data underwent quality controls, and short non-coding RNA reads were analyzed to identify and compare miRNAs profiles. The sequencing runs yielded 73,567,661 and 44,283,978 reads for milk and colostrum samples, respectively. Following trimming, 8,335,860 and 7,778,212 reads for milk and colostrum samples were retained. A total of 4.3% milk and 37.8% colostrum reads were identified as miRNAs. Overall, 157 miRNAs were common to milk and colostrum, 2 were unique to milk, and 90 were unique to colostrum. After applying a minimal cutoff of 100 reads per miRNA, 146 miRNAs were considered as expressed. In milk, bta-miR-101 was unique; in colostrum, bta-miR-18a, bta-miR-262-3p, bta-miR-130a, and bta-miR-224 were unique; and 141 miRNAs were common to colostrum and milk. Chromosome distribution of these miRNAs varied, with higher representation on autosome 19 and sexual chromosome X. Overall, colostrum contained a greater number of miRNAs, although specific miRNAs such as miR-11-988b, miR-140, and miR-146b were more abundant in milk. Conversely, miRNAs such as miR-7a-5p, let-7e, and miR-16a were more prevalent in colostrum. Validation through qPCR confirmed the expression levels of selected miRNAs from RNA sequencing, establishing concordance between the methods. Analysis of gene regulation by specific miRNAs identified key miRNAs (e.g., miR-223, miR-181a, and miR-155) involved in regulating various genes. Distinct miRNAs profiles in milk and colostrum suggest various functionalities, potentially influencing calf development and immune responses. The study unveils a comprehensive map of miRNAs in milk and colostrum and highlights their potential roles in regulating biological processes, as they play an essential role in calf development, disease resistance, and metabolism.

A newly NH2-UiO-66 composite functionalized by molecularly imprinted polymer for selective and rapid removal of sulfamethoxazole

Metal–organic frameworks (MOFs) are used as novel adsorption materials owing to their large surface area and tunable pore size. However, the lack of selectivity considerably limits their application. Consequently, designing functionalized MOFs with specific recognition abilities is essential for enhancing their adsorption performance. Herein, we synthesized a functionalized NH2-UiO-66 composite modified by molecularly imprinted polymers (MIP@NH2-UiO-66) via a one-step polymerization process in which NH2-UiO-66 and MIP were formed simultaneously. Results demonstrate that MIP@NH2-UiO-66 effectively recognized sulfamethoxazole (SMX) in complex matrices. The adsorption equilibrium was reached in only 30 min, and this fast SMX adsorption on MIP@NH2-UiO-66 was described by the Avrami kinetic model, which indicates a spontaneous and exothermic adsorption process. Within the pH range of 3.0–10.0, MIP@NH2-UiO-66 exhibited an optimal binding capacity for SMX, and the maximum adsorption of SMX was 68.36 mg g−1 at 25°C, which exceeded those of existing adsorption materials (< 60.10 mg g−1). Additionally, MIP@NH2-UiO-66 was regenerated for ∼17 cycles compared to less than eight cycles for the other adsorbents. MIP@NH2-UiO-66 effectively removed 90.58%–99.60% of SMX from river water, rainwater, soil, sediment, chicken, pork, and milk samples, with a relative standard deviation of less than 4.43%. The superior adsorption of SMX on MIP@NH2-UiO-66 was primarily driven by the synergistic effects of the imprinting sites, hydrogen bonding, and electrostatic forces. The one-step polymerization method substantially simplified the synthesis process and reduced the costs, which are promising factors for the synthesis of MOFs with high selectivity.

Associations of per- and polyfluoroalkyl substances with human milk metabolomic profiles in a rural North American cohort.

Per- and polyfluoroalkyl substances (PFAS) are a class of persistent synthetic chemicals that are found in human milk and are associated with negative health effects. Research suggests that PFAS affect both lactation and the human metabolome. We measured perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in the milk of 425 participants from the New Hampshire Birth Cohort Study using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A nontargeted metabolomics assay was performed using LC with high-resolution MS, and metabolites were identified based on in-house database matching. We observed six metabolic profiles among our milk samples using self-organizing maps, and multinomial logistic regression was used to identify sociodemographic and perinatal predictors of these profiles, including infant sex, parity, participant body mass index, participant age, education, race, smoking status, gestational weight gain, and infant age at time of milk collection. Elevated PFOA was associated with profiles containing higher amounts of triglyceride fatty acids, glycerophospholipids and sphingolipids, and carnitine metabolites, as well as lower amounts of lactose and creatine phosphate. Lower concentrations of milk PFOS were associated with lower levels of fatty acids. Our findings suggest that elevated PFOA in human milk is related to metabolomic profiles consistent with enlarged milk fat globule membranes and altered fatty acid metabolism. Further, our study supports the theory that PFAS share mammary epithelial membrane transport mechanisms with fatty acids and associate with metabolic markers of reduced milk production.

MOF-derived Mn, N Co-doped Co-C nanomaterials and exo I-driven dual signal amplification for sensitive detection of florfenicol using an electrochemical aptasensor

Florfenicol (FF) is a broad-spectrum antibiotic with potent bactericidal effects against most Gram-positive and Gram-negative bacteria. However, its misuse can pose significant threats to human health. In this study, we successfully developed an electrochemical aptasensor based on MOF-derived Mn, N Co-doped Co-C nanomaterials (CoMnN-Cs) derived from metal-organic frameworks (MOF) and a dual signal amplification strategy utilizing Exonuclease I (Exo I) for target recycling, aimed at achieving high-sensitivity detection of FF. This aptasensor depended on the CoMnN-Cs nanomaterials loaded with gold nanoparticles (AuNPs), which features a hierarchical porous structure that enhanced the specific surface area, conductivity, and electrocatalytic activity while improving the loading efficiency of signal molecules and the binding strength of biomolecules, leading to the first amplification of the electrochemical signal. In the presence of FF, Exo I-catalyzed target recycling was triggered, achieving further amplification of the electrochemical signal. Utilizing these unique features, the developed aptasensor exhibited outstanding FF detection performance, with a low detection limit of 5.28 × 10−4 ng mL−1, a wide linear range from 1 × 10−3 to 1 × 103 ng mL−1, and the recovery rates for milk, egg, and shrimp samples were 98.0 % to 100.3 %, 96.3 % to 100.9 %, and 97 % to 100.5 %, respectively. With its diverse signal amplification capabilities, this aptasensor offers a new strategy for the analysis of FF and even other antibiotics or biomolecules.

Preparation of rabbit monoclonal antibody against T-2 toxin and development of enzyme-linked immunosorbent assay in milk, feed and pork samples

T-2 toxin (T-2) is a fungal toxin commonly found in contaminated grains. It can remain in animal-derived products after eating contaminated feed, and has potential teratogenic and carcinogenic effects. Previous T-2 toxin immunoassay detection methods often utilize mouse monoclonal antibodies (MmAbs). However, in comparison to MmAbs, rabbit monoclonal antibodies (RmAbs) demonstrate higher affinity and sensitivity. This study successfully prepared an RmAb targeting T-2 using single B cell clone technology, with an IC50 of 0.089 ng/ml. By optimizing the working concentrations of the coating antigen and antibody, a one-step ic-ELISA method for detecting T-2 in milk, feed and Pork Samples was established based on RmAb, with a detection limit 0.32 to 1.42 µg/kg. This method reduces reaction time to under 1 h and achieves average recovery rates of 75.5–100.8 %, and the CV was less than 11.6 %, indicating high accuracy, repeatability, and reproducibility of the ic-ELISA. In conclusion, this study developed a highly specific and sensitive RmAb and established a one-step ic-ELISA based on this antibody for detecting T-2. The method proved to be reliable and rapid, providing a valuable reference for advancing T-2 residue detection techniques in foods.

CRISPR/Cas12a-mediated fluorescent aptasensor based on DNA walker amplification for oxytetracycline detection

Nowadays, although most oxytetracycline (OTC) are used only in animals, their leaching into the environment and residues in food lead to noticeable health problems. Fortunately, by studying the molecular dynamics of OTC aptamers and the mutations of key bases, aptamer’s base fragments involved in identifying OTC was confirmed for the first time, which provided theoretical guidance for the ingenious design of aptamer detection. Thereafter, benefiting from the amplification impact by DNA walker, the disadvantage of low efficiency caused by CRISPR/Cas12a was effectively avoided. In the established delicate aptasensing platform, small quantity of OTC promoted DNA walker to produce a massive of activators, which stimulated the trans-cleavage activity of CRISPR/Cas12a. By implying nanoclusters (NCs) with covalent organic framework (COF), the sensitive fluorescence “turn-on” method for OTC detection was realized. Under the optimum conditions, the linear range of aptasensor was 0.05-50 μM, and the detection limit was 0.041 μM. In addition, the aptasensing method can be successfully used for the quantitative detection of OTC in milk and honey samples with a recovery rate of 95.67%-104.10% and 95.33%-109.70%, implying excellent analytical performance and practical application prospect.

Characteristics of maternal antibodies transferred to foals raised through maternal equine rotavirus A vaccination

Equine rotavirus A (ERVA) can cause foal diarrhoea and the most common ERVA genotypes are G3P[12] and G14P[12]. Since the introduction of a monovalent killed G3P[12] vaccine, infection in neonates has decreased. We aimed to determine the dynamics and longevity of maternally derived anti-G3P[12] neutralizing antibodies (NAbs) in foals and what, if any, cross-reactivity exists between maternally derived NAbs against G14P[12]. Serum samples were collected from 50 mare-foal pairs before each vaccination and up to 6 months post-foaling for mares and up to 7 months of age for foals. These samples were then used for virus-neutralization antibody assays with both G3P[12] and G14P[12] viruses. We observed that vaccination of mares could increase their serum NAb titers. Pre-nursing serum samples of foals collected at birth before the first nursing contained no detectable NAbs. In contrast, post-nursing serum samples of foals showed a significant amount of NAb levels, thereby confirming that these NAbs are passed through the mare’s colostrum. Our study demonstrated that there is variation in the ratio of NAbs transferred from the serum of mares to the serum of their foals. Results also confirmed evidence of cross-reactivity between maternal antibodies in the serum of G3P[12] vaccinated dams and G14P[12]. Heterologous (G14P[12]) NAb titers were about 2- to 4-fold lower than homologous (G3P[12]) titers in colostrum, milk, and serum samples of both mares and their foals. Our data demonstrate that G3 and G14 NAbs in the serum of foals decreased steadily over time with the lowest point measured at approximately 4 months of age.

Metagenomics reveals differences in spore-forming bacterial diversity in raw milk in different regions and seasons in China

The spore-forming bacteria in the dairy industry are notable for their spores resilience and capacity to survive heating processes, allowing them to germinate and enter the vegetative stage, potentially leading to spoilage of the milk. Additionally, these spores can form biofilms, becoming a persistent source of contamination in processing environments. In this study, we collected a total of 165 raw milk from six different parts in China in spring, summer, autumn, and winter, respectively. Metagenomics sequencing method was used to explore and compare the differences in spore-forming bacterial composition and diversity in raw milk samples. Among these samples, four genera and 207 species of spore-forming bacteria were identified, with the genus Bacillus and the species Paenibacillus darwinianus dominant. Seasonal variations had a greater impact on the composition and abundance of spore-forming bacteria in raw milk than regional differences. Notable, raw milk samples collected during the spring and summer exhibited a higher number of unique spore-forming bacterial species compared to those collected in other seasons. Moreover, different regions and seasons have their own dominant bacteria. Metabolism of cofactors and vitamins, energy metabolism, carbohydrate metabolism, and amino acid metabolism were the main metabolic pathways. Hence, specific strategies need to be adopted to prevent and control spore-forming bacteria in raw milk in different regions and seasons.

A simple lable-free aptasensor based on liquid exfoliated graphene modified electrode for chloramphenicol detection in milk

Antibiotic residues in animal derived foods considered as one of the most serious food contamination poses significant risks to human health. Conventional methods for antibiotic residue detection rely on expensive and bulky instruments, complicated sample pretreatment and time-consuming, thus limiting their applications. Consequently, developing miniaturized and low-cost analytical technology for ultrasensitive monitoring and accurate evaluation of antibiotic residues in foods is of great significance. Herein, a simple and label-free electrochemical sensing platform for the highly sensitive detection of chloramphenicol (CAP) in milk was demonstrated by employing aptamer specific for CAP as a biological recognition element and liquid exfoliated graphene (LEG) modified indium tin oxide electrode (LEG/ITO) as substrate. LEG is believed to be the most economic few-layer graphene with remarkable electrical properties and larger specific surface area not only promotes electron transfer but also provides a large number of binding sites for aptamers to be assembly immobilized via the π–π stacking of DNA bases. Under optimal experimental factors, the aptasensor displayed a wider linear range for detecting CAP (1 fM ∼ 100 nM), accompanied by a limit of detection (LOD) (1 fM), as well as satisfactory performance with specificity, reproducibility, and stability. In addition, the designed strategy allowed the direct analysis of actual milk samples and the recovery rates were from 97.92 % to 103.34 %, rendering a ideal sensing strategy for quantitative determination of various analytes in food by adapting the specific aptamer.

Health risk assessment of lead and cadmium in milk-based products of Iran

The primary objective of this study is to assess the health risks associated with lead (Pb) and cadmium (Cd) contamination in dairy products consumed in Iran. To conduct the research, 132 samples of cow milk, yogurt, cream, and doogh (a traditional Iranian beverage) were collected from both traditional and industrial livestock farms in Zanjan, Iran. The samples were microwave-digested, and an atomic absorption spectrophotometer equipped with a graphite furnace was used to determine toxic metals contents. The findings of the study revealed that the average concentrations of Pb in milk and dairy product exceeded the permitted limits. The mean ± se levels of Pb and Cd in milk, yogurt, doogh, and cream were 92.64 ± 8.73, 52.19 ± 8.42, 78.80 ± 12.89, 106.07 ± 8.94 μg/kg and 2.34 ± 0.22, 1.21 ± 0.20, 2.59 ± 0.57, 5.61 ± 0.63 μg/kg, respectively. For the purpose of exposure assessment, the chronic daily intake (CDI) was utilized, while the Hazard Quotient (HQ) and Total Hazard Quotient (THQ) were employed for non-carcinogenic risk assessment. Additionally, the Incremental Lifetime Cancer Risk (ILCR) was utilized for carcinogenic risk assessment. The results revealed that the highest exposure to Pb and Cd in the P 95th of CDI were observed in milk, followed by yogurt, doogh, and cream. According to our finding, the HQ and THQ values for potentially toxic elements (PTEs) related to the consumption of dairy products in the P 95th of cumulative probability were below 1. The results indicate that the ILCR of Cd (P 95th) due to the consumption of dairy products falls within the acceptable risk range (10−4 to 10−6). While our findings indicate levels of Cd in dairy products, it is important to note that there are currently no established standards for permissible Cd concentrations in Iran. Therefore, further research and regulatory frameworks are needed to ensure public safety.