Cow Milk Samples Research Articles

Antimicrobial Susceptibility Profile of Bacteria in Mastitis Cow Milk Samples

Bovine mastitis is a cause of major financial losses in the dairy industry worldwide. Bovine mastitis is defined as the inflammatory response of the udder tissue due to either physical trauma or infections caused by different microorganisms, especially bacteria. More than 135 pathogenic agents have been identified from bovine mastitis. The aim of the study was to identify the bacterial genera involved in mastitis etiology in cattle and to test the antimicrobial susceptibility to antibiotics. The samples were collected before morning milking and evaluated by microscopic and cultural examination, and further identified using biochemical methods. The evaluation of antimicrobial susceptibility was performed using Kirby-Bauer disk diffusion test. Overall, Staphylococcus spp., Bacillus spp., Streptococcus spp., Micrococcus spp., Escherichia spp. and Trueperella spp. were identified. The most frequent bacterial associations were observed for Staphylococcus-Bacillus, Bacillus-Streptococcus and Staphylococcus-Micrococcus. Regarding the antimicrobial sensitivity profile, the majority of the bacterial strains we have isolated were classified as sensitive, with the exception of Escherichia coli, with one strain being resistant to all tested antibiotics. Among the antimicrobials, the Amoxicillin and clavulanic acid was the most efficient one and Trimethoprim/Sulfamethoxazole did not exhibit an inhibitory activity in 19 milk samples.

Simultaneous quantifications of four purine derivatives biomarkers in cow milk by SPE HPLC-DAD

In this study, simultaneous quantification of allantoin, uric acid, xanthine, and hypoxanthine in cow milk by solid phase extraction (SPE) and high performance liquid chromatography-diode array detection (HPLC-DAD) method was perform. Five different SPE cartridges were tested in order to evaluate the isolation of purine derivatives (PD) from cow milk. Chromatography was carried out on ODS-2 Hypersil column and 0.05 M (NH<sub>4</sub>)<sub>2</sub>HPO<sub>4</sub> buffer solution (pH = 7.76) as mobile phase. The HPLC-DAD validated method showed a linearity with regression coefficients higher than 0.999 and the limits of detection and quantification with values in the range 0.09–0.74 µg mL<sup>–1</sup> and 0.27–2.24 µg mL<sup>–1</sup>, respectively. The method showed good precision with a relative standard deviation (RSD) below 4.48%, while the accuracy ranged from 95.34 to 104.47% for all analytes. The best recovery degree of PD by SPE were obtained on Strata SCX cartridge for xanthine (87.79%) and hypoxanthine (89.02%); on Strata NH<sub>2</sub> for allantoin (35.09%) and on Strata C8 for uric acid (101.08%). Finally, the HPLC-DAD method with SPE on SCX cartridges was applied to quantify the PD in a batch of thirty cow milk samples.

PROBIOTIC POTENTIAL OF SOME LACTOBACILLUS STRAINS ISOLATED FROM RAW MILK

A total of 25 samples of raw cow milk, were collected randomly from street vendors and supermarkets in Zagazig city, Egypt for detection of the probiotic potential of some isolated Lactobacillus strains from raw milk. The obtained results revealed that the Lactobacillus Strains were detected in all the examined samples. The isolated strains were slightly affected by pH 3 and bile condition (0.5%). The obtained results displayed resistance against Erythromycin, Gentamycin and Tetracycline. Meanwhile, Ampicillin, Chloromphnicol, Steptomycin and Vancomycin exhibited an effect against some strains. The isolated strains produced ?-hemolysis, NaCl tolerance was positive for these strains. Also, ? galactosidase was produced.

Rapid determination of 13 organophosphorus flame retardants in milk by using modified quick, easy, cheap, effective, rugged, and safe technique, solid-phase extraction, and HPLC-MS/MS.

Organophosphorus flame retardants are a class of widely used plasticizers and flame retardants. In this study, an analytical methodology for the simultaneous determination of 13 organophosphorus flame retardants in milk was developed by using high-performance liquid chromatography-tandem mass spectrometry in combination with a modified quick, easy, cheap, effective, rugged, and safe technique and solid-phase extraction. The experimental parameters of the sample purification procedure and high-performance liquid chromatography-tandem mass spectrometry were optimized. The developed method was validated in terms of linearity, limits of detection, recovery, and precision. The method showed a linear response in the 1-100ng/mL concentration range and the limits of detection ranged from 0.001 to 0.3ng/mL. The mean recoveries for most organophosphorus flame retardants were in the ranges of 75.0-115.8% (spiked at 2.5ng/mL) and 76.7-124.8% (spiked at 25ng/mL), with relative standard deviations of <13.09%. The developed methodology was successfully applied to the analysis of nine human milk samples and nine commercial cow milk samples. Eleven organophosphorus flame retardants were detected in the human milk samples, with median concentrations that ranged from lower than the limit of detection to 1.47ng/mL, and only nine organophosphorus flame retardants were detected in cow milk samples, with median levels of <0.32ng/mL.

Non-aureus Staphylococci and Bovine Udder Health: Current Understanding and Knowledge Gaps.

Despite considerable efforts to control bovine mastitis and explain its causes, it remains the most costly and common disease of dairy cattle worldwide. The role and impact of non-aureus staphylococci (NAS) in udder health are not entirely understood. These Gram-positive bacteria have become the most frequently isolated group of bacteria in milk samples of dairy cows and are associated with (mild) clinical and subclinical mastitis. Different species and strains of NAS differ in their epidemiology, pathogenicity, virulence, ecology and host adaptation, and antimicrobial resistance profiles. They have distinct relationships with the microbiome composition of the udder and may also have protective effects against other mastitis pathogens. Some appear to persist on the skin and in the teat canal and udder, while others seem to be transient residents of the udder from the environment. Analyzing genotypic and phenotypic differences in individual species may also hold clues to why some appear more successful than others in colonizing the udder. Understanding species-level interactions within the microbiome and its interactions with host genetics will clarify the role of NAS in bovine mastitis and udder health.

Determination of antibiotics and their metabolites in milk by liquid chromatography-tandem mass spectrometry method

The aim of this study was to investigate the presence of antibiotic residues and metabolites in the samples of colostrum, raw cow milk, raw goat milk, and ultra-high temperature treated milk by liquid chromatography-tandem mass spectrometry. The calibration curves for all the studied compounds showed good linear correlation coefficients (r2 ≥ 0.999). The recovery rates were 73.33–87.78%, also the limit of detection and limit of quantification values were 0.68–3.16 μg/kg and 2.24–10.43 μg/kg, respectively. Antibiotic residues including tetracycline, 4-epitetracycline, 4-epioxytetracycline, 4-epichlorotetracycline, and ciprofloxacin were detected in 72 (55.38%) out of 130 milk samples. However, 6 (28.57%) of 21 raw goat milk and 6 (8.82%) of 68 raw cow milk samples were found to be above maximum residue limits for the sum of tetracycline and its 4-epimer. Since residues of antibiotics were detected, the results suggest that good veterinary practices are not followed by all milk producers.

Analysis of A1-type and A2-type β-casein in Maiwa Yak and Pien-niu milk by HPLC-high-resolution MS and tandem MS.

In this study, a peptide-based method employing ultra high performance liquid chromatography electrostatic field orbitrap high-resolution mass spectrometry and triple quadrupole mass spectrometry was developed for quantification of A1-type and A2-type β-casein in milk from Yak, cows, and their offspring of crosses, Pien-niu. The specific peptides of A1-type and A2-type β-casein were screened and confirmed by protein software after analysis of high-resolution mass spectrometry. The multiple reaction monitoring method was established based on the qualitative results, and isotope-label peptides were used as internal standards. The linear correlation coefficients of this method were>0.99. The relative standard deviations of repeatability test were 0.2-3.6%. The recovery rate ranged from 93.3 to 114.4% with relative standard deviations<6% at three different spiking levels. The method was applied to analyze 45 milk samples from different species. The results showed that β-casein in Yak and Pien-niu milk was about 30% higher than that in cow milk. Furthermore, the β-casein in the Yak milk only contains A2-type β-casein. A1-type and A2-type β-casein coexist in most samples of Pien-niu and cow milk, a few samples contain only one type of β-casein. These results provide further understanding in nutritional value of milk from Yak and Pien-niu.

Molecular identification of blaCTX-M and blaTEM genes encoding extended-spectrum ß-lactamase (ESBL) producing Escherichia coli isolated from raw cow’s milk in East Java, Indonesia

Abstract. Ansharieta R, Ramandinianto SC, Effendi MH, Plumeriastuti H. 2021. Molecular identification of blaCTX-M and blaTEM genes encoding extended-spectrum ß-lactamase (ESBL) producing Escherichia coli isolated from raw cow’s milk in East Java, Indonesia. Biodiversitas 22: 1600-1605. The emergence of extended-spectrum ?-lactamase (ESBL) producing bacteria and its increasing level has become public health issue. The presence of these bacteria in food of animal origin is quite alarming. The objective of this study was to detect and characterize Escherichia coli producing ESBL encoding genes, isolated from 200 raw cow milk samples in East Java, Indonesia. The results of this study showed that 70.5% of isolates were confirmed as E. coli, based on the morphological growth of colonies on the EMB Agar and biochemical IMViC tests. In this study, the double-disc synergy test (DDST) method was used to confirm the ESBL, and previously sorted out presumptively by using Aztreonam antibiotic disc. The antibiotics used were amoxicillin-clavulanate, ceftazidime, and cefotaxime for DDST. In addition, ESBL confirmation with Multiplex PCR method for blaCTX-M and blaTEM genes were done. The presence of ESBL-producing by E. coli isolated from raw cow’s milk in East Java were 2.12% (3/141). The PCR results showed that the double blaCTX-M and blaTEM gene harbored by 2 ESBL isolates and one blaTEM gene as many as 1 ESBL isolate. Thus, the findings of our study indicate that milk can be a good reservoir of bacteria carrying blaCTX-M and blaTEM ESBL resistance genes with the potential to affect human health.

In vitro antimicrobial resistance profiles of Streptococcus uberis, Lactococcus spp., and Enterococcus spp. from quarter milk samples of cows between 2015 and 2019 in Southern Germany

The objective was to describe and compare antimicrobial resistance patters of esculin-hydrolyzing streptococci and streptococcal-like organisms (Streptococcus uberis, Enterococcus faecium, Enterococcus faecalis, Lactococcus garvieae, Lactococcus lactis) from routine diagnostic samples of the udder health laboratory of the Bavarian Animal Health Services between 2015 and 2019. All routine diagnostic samples of the udder health laboratory of the Bavarian Animal Health Services, that were tested with a standard microbroth dilution, were eligible to be included in this retrospective case series. A California Mastitis Test result was available for all samples. Most Strep. uberis and L. lactis were susceptible to all antibiotics tested. Enterococcus faecium had consistently the highest minimum inhibitory concentration required to inhibit the growth of 90% of tested isolates. The resistance patterns of Lactococcus garvieae were positioned between enterococci and L. lactis. The minimum inhibitory concentration for various antibiotics and pathogens tended to decrease over the 5-yr period. Regardless of the pathogen, isolates of clinical cases were less likely to express in vitro resistance than isolates of healthy or subclinical cases. Streptococcus uberis or L. lactis showed hardly any in vitro resistance to tested antibiotic groups. Penicillin should remain the first-choice antimicrobial for the therapy of Strep. uberis and Lactococcus spp. However, a success of any antimicrobial treatment of enterococcal infections seems questionable.

Phagomagnetic separation-quantitative PCR: A rapid, sensitive and specific surveillance tool for viable Mycobacterium avium ssp. paratuberculosis in bulk tank and individual cow milk samples

Bulk tank milk samples from 392 Northern Ireland dairy farms and individual milk from animals (n = 293) on 4 of these farms were tested by a novel phagomagnetic separation (PhMS)-quantitative (q)PCR assay able to detect and quantify viable Mycobacterium avium ssp. paratuberculosis (MAP), to demonstrate its potential utility as a milk surveillance tool. Viable MAP were detected in 26.5% of the bulk tank milks, with MAP contamination levels ranging from 1 to 8,432 MAP/50 mL of milk; less than 2% of farms had MAP contamination levels >100 MAP/50 mL in their bulk tank milk. Follow-up PhMS-qPCR testing of milk from individual animals on 4 farms that had the highest numbers of MAP in their bulk tank milks indicated that 17 to 24% of animals in each herd were shedding viable MAP in their milk. Mean MAP numbers detected ranged between 6.7 and 42.1 MAP/50 mL of milk. No significant correlation was observed between the detection of viable MAP in bulk or individual milks by PhMS-qPCR and parallel milk ELISA results, or between PhMS-qPCR results and any other milk recording results (somatic cell count, total bacterial count, % butterfat, or % protein). Viable MAP was detected by IS900 qPCR in 52 (85.2%) Pozzato broth cultures of 61 PhMS-qPCR-positive individual milks after 12 wk of incubation, suggesting few PhMS-qPCR results were false positives. The mean sensitivities of the PhMS-qPCR assay and milk ELISA applied to individual milks were estimated by Bayesian latent class analysis to be 0.7096 and 0.2665, respectively, and mean specificities were similar (0.9626 and 0.9509). Our findings clearly demonstrate that the novel PhMS-qPCR assay could be a useful milk surveillance tool for dairy processors, or a milk monitoring tool for Johne's disease control or milk quality assurance programs.

ANTIMICROBIAL RESISTANCE AND BIOFILM FORMATION PATTERNS OF Escherichia coli ISOLATED FROM MARKET RAW MILK AT ZAGAZIG CITY

In the present study, one hundred samples of raw cow milk were collected randomlyfrom different dairy shops and markets in Zagazig city for isolation and identification of Escherichiacoli which is considered a reliable indicator for fecal contamination and an important cause of foodpoisoning. Identification was done microscopically, biochemically by different biochemical tests(IMVIC) and serologically. The incidence of E. coli in raw milk samples was 47%. Also, theserological identification of E. coli isolates revealed that O26 is the most predominant serogroup bypercentage of 21.3%. E. coli pose the greatest threat to human health because of its growing resistanceto antibiotics. Antimicrobial susceptibility testing (AST) was done by disc diffusion method against 10antimicrobials and the results revealed that E. coli isolates were highly resistant to amoxicillinclavulanate,ampicillin, cefotaxime and ceftazidime with percentages of 89.4%, 89.4%, 100.0% and100.0%, respectively. However, they were highly sensitive to chloramphenicol, ciprofloxacin andtetracycline with percentage of 100.0%, 100.0% and 93.6% respectively. In addition, 89.4% of E. coliisolates showed multi drug resistance (MDR). The ability of bacteria for adherence to food surfacesand biofilm formation is a source of food contamination that affect food safety and industry. Microtiter plate assay used for testing biofilm formation and represented that 78.7% of E. coli isolates werenon-biofilm producers, 6.4% were weak biofilm producers, 14.9% were moderate biofilm producersand none of isolates was strong biofilm producers

Prevalence, antimicrobial resistance, and biofilm formation of Klebsiella pneumoniae isolated from human and cows

Klebsiella pneumoniae (K. pneumoniae) is an important multidrug-resistant (MDR) and biofilm producing pathogen that causes diverse infections in human and animals. This study aimed to evaluate the prevalence, antimicrobial resistance, and biofilm forming ability of K. pneumoniae isolates from diseased humans sputum and urine samples and mastitic cows milk samples in Zagazig city, Sharkia Governorate, Egypt. A total of 100 human and animal samples were collected and examined for the presence of Klebsiella species. The recovered isolates were identified by conventional bacteriological procedures and confirmed by the traditional PCR at the genus and species levels using gyrA, 16S-23S ITS and pehX genes, respectively. The confirmed K. pneumoniae isolates were subjected for testing their antimicrobial susceptibility and biofilm formation ability. The results revealed that 10 out of 50 human samples were positive for K. pneumoniae (20%); 28% (7/25) from sputum samples and 12% (3/25) from urine samples. Additionally, the prevalence rate of K. pneumoniae in milk samples from mastitic cows was 4% (2/50). PCR assays confirmed the 12 isolates as K. pneumoniae. The antimicrobial susceptibility results showed that K. pneumoniae isolates had high resistance rates to ampicillin and ampicillin/clavulanate (100% each) with multiple antibiotic resistance (MAR) index of 0.083, followed by azithromycin, cefepime, and trimethoprim/sulphamethoxazole (91.7% each). Meanwhile, these isolates revealed high sensitivity levels to chloramphenicol (83.3%) with MAR index of 0.014. Furthermore, 91.7% of K. pneumoniae isolates were able to produce the biofilm, where 8.3% was a non-biofilm producer. Out of 11 K. pneumoniae isolates, 6 (54.5%), 3 (27.3%) and 2 (18.2%) were moderate, strong and weak biofilm producers, respectively. The present study emphasized the high prevalence of MDR and biofilm producing K. pneumoniae isolates in human sputum and urine samples. Therefore, more attentions should be taken against antimicrobials usage and for providing new antibiofilm approaches against Klebsiella species biofilms.

English

Milk adulteration is a common phenomenon in many countries, which draws extensive attention from humans due to health hazards that might result in some fatal diseases. In this study, a portable near-infrared (NIR) spectrometer combined with multivariate analysis was used to detect and quantify milk adulteration. Fresh cow milk samples were collected from eight dairy farms in Beijing and Hebei province of China. Water, urea, starch and goat milk were used to adulterate milk at 11 different concentrations. The data driven soft independent modeling of class analogy (DD-SIMCA) method was employed for qualitative analysis. Partial least squares regression (PLSR) was applied for statistical analysis of the obtained NIR spectral data. The results showed that the DD-SIMCA approach achieved satisfactory classification. By the PLSR model, standard error of prediction (SEP) values of 4.35, 0.34, 4.74 and 5.56 g/L were obtained for water, urea, starch and goat milk, respectively. These results demonstrated the feasibility and reliability of NIR spectroscopy combined with multivariate analysis in the prediction of the total contents of the investigated adulterants in cow milk. Key words: Portable near-infrared (NIR)-spectroscopy, milk adulteration, DD-SIMCA, Partial least squares (PLS) regression.

Preparation and application of lysozyme aptamer fibre for specific recognition of lysozyme in food samples

A novel aptamer solid-phase microextraction (SPME) fibre-based on poly (methacrylic acid-co-ethylene glycol dimethacrylate) for lysozyme-specific recognition has been successfully prepared. The prepared SPME fibres were characterised by various instrumental methods, including scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectrometry. The results showed that the SPME fibre exhibited a porous structure, which is beneficial for the enrichment of the aptamer. The solid-phase microextraction-high-performance liquid chromatography-fluorescence detection (SPME-HPLC-FLD) with the superior selectivity and sensitivity responded linearly to the concentration of lysozyme over the 0.025–10 mg/L range, and the limit of detection was low at 6.8 μg/L, with a linearity of 0.9995. The method showed excellent reproducibility, and the relative standard deviations (RSDs) were less than 5.5%, which facilitated the analysis. The method was applied for the analysis of lysozyme in cow milk and papaya samples, and the recoveries ranged from 86.7–93.5% with RSDs of 4.3–6.1%, which clearly state that the proposed lysozyme aptamer SPME-HPLC-FLD method is a promising analytical tool for the analysis of lysozyme in food samples.

Combination of temperature-assisted ternary phase homogenous liquid-liquid extraction with deep eutectic solvent-based dispersive liquid-liquid microextraction for the extraction of phytosterols from cow milk and cream samples.

A three-phase homogenous liquid-liquid extraction method followed by deep eutectic solvent-based dispersive liquid-liquid microextraction has been used for the extraction and preconcentration of some phytosterols from cow milk and cream samples. In this method, cow milk or melted cream was transferred into a glass test tube and a mixture of sodium hydroxide solution (as fatty acids saponification agent) and acetonitrile (as extraction/dispersive solvent) was added to the solution. The mixture was shaken manually and placed in a water bath. After dissolving sodium chloride and centrifugation, the obtained supernatant phase (acetonitrile) was removed and mixed with ethyl methyl ammonium chloride: phenyl acetic acid deep eutectic solvent at microliter level. Under optimum conditions, low limits of detection (1.6-4.1μg/L) and quantification (5.3-13.1μg/L), high enrichment factors (138-207), and extraction recoveries (55-83%), and good precision (relative standard deviations ≤ 6.8%) can be obtained. The method was done on different milk and cream samples and the results showed that total phytosterols level in all samples were in the permitted level established by the National Standard Organization Guidelines, except for three cream samples.

How multiple farming conditions correlate with the composition of the raw cow's milk lactic microbiome.

Questionnaires on farming conditions were retrieved from 2129 dairy farms and clustered, resulting in 106 representative raw cow's milk samples analysed in winter and summer. Substantiating the efficiency of our survey, some farming conditions affected the milk physicochemical composition. Culturing identified several species of lactic acid bacteria (LAB) per milk, whose number increased through 16S ribosomal RNA (rRNA) gene sequencing and shotgun metagenome analyses. Season, indoor versus outdoor housing, cow numbers, milk substitutes, ratio cattle/rest area, house care system during lactation, and urea and medium-chain fatty acids correlated with the overall microbiome composition and the LAB diversity within it. Shotgun metagenome detected variations in gene numbers and uniqueness per milk. LAB functional pathways differed among milk samples. Focusing on amino acid metabolisms and matching the retrieved annotated genes versus non-starter lactic acid bacteria (NSLAB) references from KEGG and corresponding to those identified, all samples had the same gene spectrum for each pathway. Conversely, gene redundancy varied among samples and agreed with NSLAB diversity. Milk samples with higher numbers of NSLAB species harboured higher number of copies per pathway, which would enable steady-state towards perturbations. Some farming conditions, which affected the microbiome richness, also correlated with the NSLAB composition and functionality.

Fabric Phase Sorptive Extraction of Selected Steroid Hormone Residues in Commercial Raw Milk Followed by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

Hormones in edible matrices, such as milk, are a subject of concern because of their adverse effects on the endocrine system and cell signaling and the consequent disruption of homeostasis in human consumers. Therefore, the assessment of the presence of hormones in milk as potential endocrine-disrupting compounds is warranted. However, the complexity of milk as a sample matrix and the ultra-low concentration of hormones pose significant analytical challenges. Fabric phase sorptive extraction (FPSE) has emerged as a powerful analytical technique for the extraction of emerging pollutants from complex aqueous matrices. FPSE allows for substantially simplified sample handling and short extraction and desorption times, as well as the decreased use of organic solvents. It is considered a green alternative to traditional extraction methodologies. In this work, the FPSE technique was evaluated to perform the simultaneous extraction of 15 steroid hormones from raw milk without employing any sample pretreatment steps. Clean and preconcentrated hormone solutions obtained from FPSE of raw milk were analyzed using ultra-high-performance liquid chromatography–tandem mass spectrometry to achieve low detection limits, which ranged from 0.047 to 1.242 ng·mL−1. Because of the presence of many interferents in milk, such as proteins, lipids, and sugar, the effect of fat content on the extraction procedure was also thoroughly studied. Additionally, for the first time, the effect of lactose on the extraction of steroid hormones was evaluated, and the results showed that the extraction efficiencies were enhanced in lactose-free samples. Finally, the optimized methodology was applied to commercial samples of cow and goat milk, and no measurable concentrations of the studied hormones were detected in these samples.

Variations in N-linked glycosylation of glycosylation-dependent cell adhesion molecule 1 (GlyCAM-1) whey protein: Intercow differences and dietary effects

In bovine milk serum, the whey proteins with the highest N-glycan contribution are lactoferrin, IgG, and glycosylation-dependent cellular adhesion molecule 1 (GlyCAM-1); GlyCAM-1 is the dominant N-linked glycoprotein in bovine whey protein products. Whey proteins are base ingredients in a range of food products, including infant formulas. Glycan monosaccharide composition and variation thereof may affect functionality, such as the interaction of glycans with the immune system via recognition receptors. It is therefore highly relevant to understand whether and how the glycosylation of whey proteins (and their functionality) can be modulated. We recently showed that the glycoprofile of GlyCAM-1 varies between cows and during early lactation, whereas the glycoprofile of lactoferrin was highly constant. In the current study, we evaluated intercow differences and the effects of macronutrient supply on the N-linked glycosylation profiles of the major whey proteins in milk samples of Holstein-Friesian cows. Overall, approximately 60% of the N-glycan pool in milk protein was sialylated, or fucosylated, or both; GlyCAM-1 contributed approximately 78% of the total number of glycans in the overall whey protein N-linked glycan pool. The degree of fucosylation ranged from 44.8 to 73.3% between cows, and this variation was mainly attributed to the glycans of GlyCAM-1. Dietary supplementation with fat or protein did not influence the overall milk serum glycoprofile. Postruminal infusion of palm olein, glucose, and essential AA resulted in shifts in the degree of GlyCAM-1 fucosylation within individual cows, ranging in some cases from 50 to 71% difference in degree of fucosylation, regardless of treatment. Overall, these data demonstrate that the glycosylation, and particularly fucosylation, of GlyCAM-1 was variable, although these shifts appear to be related more to individual cow variation than to nutrient supply. To our knowledge, this is the first report of variation in glycosylation of a milk glycoprotein in mature, noncolostral milk. The functional implications of variable GlyCAM-1 fucosylation remain to be investigated.

Detection of CTX-M gene in extended spectrum β-lactamases producing Enterobacteriaceae isolated from bovine milk

Extended spectrum β-lactamases producing Enterobacteriaceae (ESBL-E) have emerged recently as the main cause that facilitates the spreading of antibiotic resistance worldwide. Due to its composition and nutritive values, raw cow milk is vulnerable to bacterial contamination from different sources, especially ESBL-E. Accordingly, present study aimed to detect the ESBL-E in the raw milk of healthy cows. 80 raw cow milk samples were collected from unorganized farms and cows belong to individual owners and investigated for the presence of ESBL-E with the main focusing on CTX-M type. The bacterial isolation was performed using selective MacConkey agar plus cefotaxime (MC+), while PCR was used to confirm the species of the isolated bacteria and presence of CTX-M gene. The results showed that 28.75%(23/80) samples were ESBL-E positive and distributed as following, 82.61%(19/23) were pure E. coli isolates, 4.35%(1/23) was pure K. pneumoniae isolate and finally, 13.04%(3/23) were mixed of both E. coli and K. pneumoniae isolates. Moreover, the total number of positive ESBL-E was 26 isolates with the majority of them were belong to E. coli and recorded 84.61%(22/26), while K. pneumoniae was recorded less 15.39%(4/26). Additionally, the CTX-M gene was successfully identified in all ESBL-E positive isolates by using PCR, including E. coli and K. pneumoniae isolates. The results of this study assert the importance of raw cow milk as a potential source of ESBL-E that might be transmitted to humans.

Concentrations of toxic elements (As, Cd, Hg and Pb) in cow milk: A review of the recent scientific literature

A continued intake of milk with certain contents of environmental pollutants/toxicants can mean health risks for the consumers. This paper is mainly focused on reviewing recent studies on the concentrations of As, Cd, Hg and Pb in cow milk of different countries. As expected, notable differences in the metal levels in cow milk samples, depending on the countries and the specific areas of collection, have been found. In general terms, based on the studies here reviewed, human exposure to As, Cd, Hg and Pb by frequent consumption of cow milk should not mean significant health risks for the consumers.