Caprine Milk Samples Research Articles

The Detection of Bacterial Pathogens, including Emerging Klebsiella pneumoniae, Associated with Mastitis in the Milk of Ruminant Species

Milk is an excellent medium for the growth of several bacteria and other microorganisms and thus, it has been extensively studied. An always current issue in the dairy industry is mastitis, which causes losses in milk volume and profits. In many cases, milk is used raw or treated at low temperatures for further dairy processes while there are quite a few cases in which foodborne-related outbreaks have occurred. Both culture-based methods and PCR were used to assess the presence of certain pathogens related to both contagious and environmental pathogens, especially the emerging pathogenic bacterium Klebsiella pneumoniae, as well as Staphyloccocus aureus and Enterobacter spp., which are associated with mastitis in milk samples from different lactating ruminant species (cows, goats, and sheep) and to further evaluate the significance of the isolated pathogens to public health. Even though significant mastitis contagious pathogens such as Staphylococcus aureus and Staphylococcus epidermidis were not detected, environmental pathogens related to poor hygiene conditions at the farm level (K. pneumoniae, Staphylococcus saprophyticus, and Enterococcus spp.) were detected. In particular, K. pneumoniae and Staphylococcus saprophyticus were present in ovine milk samples while bovine and caprine milk samples were contaminated with Enterococcus spp. The presence of these bacteria underlines the significant role of environmental hygiene especially since Staphylococcus saprophyticus and Enterococcus spp. are related to urinary tract infections and all of the tested pathogens may carry antibiotic resistance genes. More specifically, 20% of the isolated Klebsiella pneumoniae strains were found resistant to carbapenem antibiotics. The presence of emerging K. pneumoniae in ovine milk samples also indicates the need for new policies in terms of safety testing. Suggestions of monitoring processes carried out by the relevant authorities are discussed.

Phenotypic Analysis of Fourier-Transform Infrared Milk Spectra in Dairy Goats.

The infrared spectrum of bovine milk is used to predict many interesting traits, whereas there have been few studies on goat milk in this regard. The objective of this study was to characterize the major sources of variation in the absorbance of the infrared spectrum in caprine milk samples. A total of 657 goats belonging to 6 breeds and reared on 20 farms under traditional and modern dairy systems were milk-sampled once. Fourier-transform infrared (FTIR) spectra were taken (2 replicates per sample, 1314 spectra), and each spectrum contained absorbance values at 1060 different wavenumbers (5000 to 930 × cm-1), which were treated as a response variable and analyzed one at a time (i.e., 1060 runs). A mixed model, including the random effects of sample/goat, breed, flock, parity, stage of lactation, and the residual, was used. The pattern and variability of the FTIR spectrum of caprine milk was similar to those of bovine milk. The major sources of variation in the entire spectrum were as follows: sample/goat (33% of the total variance); flock (21%); breed (15%); lactation stage (11%); parity (9%); and the residual unexplained variation (10%). The entire spectrum was segmented into five relatively homogeneous regions. Two of them exhibited very large variations, especially the residual variation. These regions are known to be affected by the absorbance of water, although they also exhibited wide variations in the other sources of variation. The average repeatability of these two regions were 45% and 75%, whereas for the other three regions it was about 99%. The FTIR spectrum of caprine milk could probably be used to predict several traits and to authenticate the origin of goat milk.

Occurrence and congener profiles of dioxins (PCDDs), furans (PCDFs) and polychlorinated biphenyls (PCBs) in ovine and caprine milk samples collected in a very polluted site in Central Italy

Concentrations of 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs) and 18 polychlorinated biphenyls (PCBs), including 12 dioxin-like (DL-PCBs) and 6 non-dioxin-like PCBs (NDL-PCBs) were measured in 16 ovine and caprine milk samples collected in the territory of Bussi sul Tirino, central Italy, a Site of National Interest (SNI) due to its high and widespread environmental pollution. All the analyzed samples were compliant with the maximum levels fixed by Commission Regulation (EU) 1259/2011 for the content of PCDD/Fs and the sum of PCDD/Fs and DL-PCBs. In two cases, contamination levels of the sum of PCDD/Fs and DL-PCBs were higher than the action levels fixed by EU Recommendation 663/2014. The statistical analysis, performed by Principal Component Analysis (PCA), revealed that the differences in contamination profiles of the different milk samples were independent of the distance of the farms from the Bussi illegal landfill but likely related to local emission sources influencing the exposure to POPs of studied animals.

Chemical signatures of new pesticides in the bovine and caprine milk samples collected from western Uttar Pradesh (India) mples collected from western Uttar Pradsh

Raw buffalo, cow and goat milk collected from different locations of Northern India has been analyzed for suspected pesticides viz. azimsulfuron, cypermethrin, thiabendazole, crotonolactone, fluoxastrobin, aldicarb and carbofuran. Buffalo milk tested positive for azimsulfuron (4.51 ng/ml), cypermethrin (7.21 ng/ml) and thiabendazole (4.57 ng/ml). Cow’s milk did not show the presence of cypermethrin and thiabendazole, however, azimsulfuron (0.86 ng/ml), crotonolactone (4.73 ng/ml) and fluoxastrobin (0.54 ng/ml) were determined. Milk of the goats registered the presence of carbafuron (7.69 ng/ ml), fluoxastrobin (5.41 ng/ml) and azimsulfuron (5.28 ng/ml). Since all the milching cattle are herbivorous, these pesticides entered animal through food chain. The consumption of milk containing these pesticides even in traces may be hazardous to human population of Northern India. Concurrent presence of these pesticides may be more hazardous due to their synergistic manifestations. New synthetic molecules like azimsulfuron, fluoxastrobin and crotonolactone may pose severe public health problems.

Heat-Treatments Affect Protease Activities and Peptide Profiles of Ruminants' Milk.

Proteases present in milk are heat-sensitive, and their activities increase or decrease depending on the intensity of the thermal treatment applied. The thermal effects on the protease activity are well-known for bovine milk but poorly understood for ovine and caprine milk. This study aimed to determine the non-specific and specific protease activities in casein and whey fractions isolated from raw bovine, ovine, and caprine milk collected in early lactation, and to determine the effects of low-temperature, long-time (63°C for 30 min) and high-temperature, short-time (85°C for 5 min) treatments on protease activities within each milk fraction. The non-specific protease activities in raw and heat-treated milk samples were determined using the substrate azocasein. Plasmin (the main protease in milk) and plasminogen-derived activities were determined using the chromogenic substrate S-2251 (D-Val-Leu-Lys-pNA dihydrochloride). Peptides were characterized using high-resolution liquid chromatography coupled with tandem mass spectrometry. The activity of all native proteases, shown as non-specific proteases, was similar between raw bovine and caprine milk samples, but lower (P < 0.05) than raw ovine milk in the whey fraction. There was no difference (P > 0.05) between the non-specific protease activity of the casein fraction of raw bovine and caprine milk samples; both had higher activity than ovine milk. After 63°C/30 min, the non-specific protease activity decreased (44%; P > 0.05) for the bovine casein fraction only. In contrast, the protease activity of the milk heated at 85°C/5 min changed depending on the species and fraction. For instance, the activity decreased by 49% for ovine whey fraction, but it increased by 68% for ovine casein fraction. Plasmin and plasminogen were in general inactivated (P > 0.05) when all milk fractions were heated at 85°C/5 min. Most of the peptides present in heat-treated milk were derived from β-casein and αS1-casein, and they matched the hydrolysis profile of cathepsin D and plasmin. Identified peptides in ruminant milk samples had purported immunomodulatory and inhibitory functions. These findings indicate that the non-specific protease activity in whey and casein fractions differed between ruminant milk species, and specific thermal treatments could be used to retain better protease activity for all ruminant milk species.

Evidence from Neonatal Piglets Shows How Infant Formula and Other Mammalian Milk Shape Lipid Metabolism

We tested the hypothesis that the consumption of different milk lipids is one of the factors affecting metabolic response to lipid in the early life of infants. Neonatal piglets, as animal models, were stratified by the feeding mode (formula-fed, bovine-, caprine-, and human milk-fed). Lipidomic profiles of plasma and liver samples were detected using liquid chromatography-mass spectrometry (LC-MS). The results indicate that 31, 54, and 28 differential lipid species could be used as potential biomarkers for bovine milk, caprine milk, and infant formula-fed samples, respectively, and the main lipid classes screened in plasma were SM, PC, and PE, including PC(14:1/P-20:0) as the isoform of PC(34:1), which regulates the lipid metabolism gene peroxisome proliferator-activated receptor α, PPAR-α. SM(d15:1/22:0) was the common potential biomarker screened from all of the groups. The amounts of biomarkers screened from the caprine milk-fed liver samples were the highest, which had a significant effect on the distribution of SM, PI, and PA. Infant formula, bovine-, and caprine milk-fed samples had an obvious effect on the metabolism of glycerophospholipid and glycerol ester, especially TG (16:0/18:0/18:2).

Occurrence of quantitative genetic polymorphism at the caprine β-CN locus, as determined by a proteomic approach

Genetic screening of caseins in caprine milk samples enabled the identification of two novel β-casein (β-CN) phenotypes, C2 and F1, expressed at lower levels (3.3 and 2.7 g L−1 per allele, respectively) than reference β-CN C (4.7 g L−1 per allele), and another lacking in αS-complex. The β-CN C2 and F1 primary structures, determined by MS analysis, corresponded to β-CN C and F, respectively. The reasonable hypothesis supporting the low expression of both variants considers the C2 and F1 alleles as deriving from β-CN C1 and β-CN A1 precursors, respectively, and characterised by a genic transition C→T negatively affecting the mRNA stability. Further, phosphorylation of Thr41 responsible for the 7P β-CN component was determined by a proteomic approach for the first time. Caprine milk containing low levels of antigenic αS1-, αS2- and β-CN can be used for infant formula production and drinking milk for people with cows' milk protein allergy.

Evaluation of the presence of Aflatoxin-M1 in milk samples sold in the region of Campinas-SP

Abstract Milk and its derivatives are fundamental foods in the human diet. However, milk is highly susceptible to microbial contamination, among which is Aflatoxin M1 (AFM1), presenting a risk to public health. Aflatoxin M1 is the main hydroxylated metabolite of aflatoxin B1 present in the milk of animals that have ingested feed contaminated with B1. These toxins have carcinogenic and genotoxic potential and similar toxicities. According to Resolution RDC 07/2011, published by the National Health Surveillance Agency (ANVISA), the level of tolerance for AFM1 is 0.5 µg / Kg in Brazil. The present study aimed to evaluate qualitatively and quantitatively Aflatoxin M1 in raw milk samples, being 2 samples of bovine milk and one sample of goat milk. The raw, bovine and goat milk samples were purchased from local stores and were kept at approximately 5 ºC for 8 hours and subsequently frozen at 6 ºC for conservation purposes. The tests were carried out at the premises of Hexis Científica, Av. Antonieta Piva Barranqueiros, 385 - Distrito Industial - Jundiaí-SP, which provided training and use of the laboratory. The Scientific Charm Kits, Test SLAFMQ-EZ-20K were used. It is a quantitative test that uses ROSA immunoreceptors (Rapid Assay Step One) lateral flow technology. The milk sample interacts with colored spheres and the intensity of the color in the test area and is read as ppt (parts per trillion) by the reader. According to the analyzes, all the samples studied presented Aflatoxin M1, with a concentration of 2,507 ppb; 2,410 ppb; 2,627 ppb, respectively for bovine and caprine milk samples, which characterizes a concentration five times above the allowed by the current legislation, according to RDC 07/2011, published by the National Health Surveillance Agency (ANVISA). Key messages According to studies, most of the negative results obtained on the incidence of aflatoxin M1 can be attributed to the low sensitivity of the analytical methods employed. The presence of Aflatoxins M1, represents a public health issue, since milk is among the products most consumed by man and, constituting the basis of infant feeding.

Mcr-1 encoding colistin resistance in CTX-M-1/CTX-M-15- producing Escherichia coli isolates of bovine and caprine origins in Tunisia. First report of CTX-M-15-ST394/D E. coli from goats

The objective of this study was to isolate and characterize ESBL-producing Escherichia coli (ESBL-EC) from raw bovine and caprine milk samples, as well as from bovine faeces in Tunisia. Therefore, 120 bovine faecal samples and 9 caprine raw milk samples were collected from 2 extensive dairy-cow-farms and 5 ovine farms, respectively. In addition, 94 raw bovine milk samples, from containers and holding tanks from 50 small public-markets in the North of Tunisia, were processed for the isolation of cefotaxime-resistant E. coli (CTXR). Antimicrobial susceptibility testing was carried out by disc-diffusion/broth-microdilution methods. The presence of genes encoding ESBL, as well as those encoding colistin (mcr-1 to 5 genes)- sulfonamide-, tetracycline-, gentamicin-, quinolone and chloramphenicol-resistance and class 1 integrons were tested by PCR (and sequencing in some cases). ESBL-EC isolates were further characterized by phylogrouping and MLST/PFGE typing. Eight samples (3.6%) contained ESBL-EC isolates (3/2 from raw bovine/goat milk and 3 from cattle faeces) and one isolate/sample was characterized. Four ESBL-EC isolates, all of bovine origin (3 faeces/1 milk), were resistant to colistin (MIC: 8–16 μg/ml), harboured the mcr-1 gene and carried IncP- and IncFIB-type plasmids. The 8 ESBL-EC strains had the following characteristics: a) bovine faeces: mcr-1/CTX-M-1/D-ST1642 (3 strains); b) raw milk: mcr-1/CTX-M-1/A-ST10 (1 strain); CTX-M-15/B1-ST394 (3 strains), and CTX-M-15/A-ST46 (1 strain). Most of bovine ESBL-EC isolates were multidrug-resistant (4/5). Our results showed that ESBL-EC were detected in bovine and caprine samples (CTX-M-1/CTX-M-15 producers), being some of them colistin-resistant (associated with mcr-1 gene), and they belonged to international clonal lineages.

A comparative study of the fatty acid and terpene profiles of ovine and caprine milk from Greek mountain sheep breeds and a local goat breed raised under a semi-extensive production system.

The objective of this study was to compare the fatty acid and terpene profile of ovine and caprine milk from animals raised under a semi-extensive production system in commercial farms located in Northwest Greece. Regarding fatty acid profile, ovine milk had a higher percentage of conjugated linoleic acid (CLAcis-9, trans-11) as well as higher percentages of both n-6 and n-3 fatty acids in relation to caprine milk. Terpene profile analysis showed a high frequency of appearance for α-pinene, d-limonene, β-pinene in both types of milk. β-Caryophyllene was detected in the majority of the examined ovine and caprine milk samples suggesting that its presence could be used as a potential biomarker of grass feeding. The relative frequency of appearance was higher in caprine milk for the majority of identified terpenes. Ovine milk had better nutritional value in comparison to caprine milk that had an enriched terpene profile than ovine milk.

Toxoplasma gondii Antibodies in Bulk Tank Milk Samples of Caprine Dairy Herds.

A major public health issue, Toxoplasma gondii infection can affect humans mainly via the consumption of animal products from certain species, including small ruminants. Therefore, a regular monitoring of the infection in ovine and caprine populations is advisable for the control of human and animal toxoplasmosis. Antibody detection in individual and bulk tank milk (BTM) may represent a valid alternative to serological analysis, in that its collection is easy and does not affect animal welfare. Many serological tools for milk analysis have already been validated for several parasites, including Apicomplexa. Thus, the aim of the present study was to obtain epidemiological data on T. gondii infection through the detection of antibodies in BTM of dairy goat herds from an important area for caprine dairy production (northern Italy). The performance of a commercial ELISA was first evaluated for analysis of caprine milk samples, using a panel of serum-milk pairs of goats naturally infected by T. gondii. The analysis of BTM confirmed the presence of anti- T. gondii antibodies in 59% of the samples. Toxoplasma gondii antibody positivity was more frequently found in goats reared on farms under extensive (64.9%) or semi-intensive systems (68.7%) in comparison with intensive farms (51.1%). Analysis of milk was a valid alternative to serological tests, being easily applied in large-scale epidemiological surveys and for continuous monitoring of T. gondii infection.

Use of MALDI-TOF to characterize staphylococcal intramammary infections in dairy goats

The most common pathogens causing intramammary infections (IMI) in dairy goats are staphylococci. Gene sequencing has been the reference method for identification of staphylococcal species, but MALDI-TOF mass spectrometry could represent a rapid and cost-effective alternative method. The objectives were to evaluate the typeability and accuracy of partial gene sequencing and MALDI-TOF for identifying staphylococci isolated from caprine milk samples, and to evaluate the relationship between staphylococcal species IMI, milk somatic cell score (SCS), and milk yield (MY). A composite (goat-level) milk sample was collected from all 940 lactating goats in a single herd. Dairy Herd Information Association test-day data for parity, days in milk, SCS, and MY were retrieved from Dairy Herd Information Association records. Milk samples were cultured on Columbia blood agar, and isolates from samples that yielded a single colony type of a presumptively identified Staphylococcus spp. were identified by PCR amplification and partial sequencing of rpoB, tuf, or 16S-rRNA, and MALDI-TOF. Mixed linear models were used to evaluate the relationship between staphylococcal IMI, SCS, and MY. The goat-level prevalence of staphylococcal IMI based on isolation of a single colony type was 24.4% (213/874). Seventeen goats had a contaminated sample. Among the remaining goats (n = 857), the most common species causing single colony-type IMI were Staphylococcus simulans (7.9%), Staphylococcus xylosus (3.5%), Staphylococcus caprae (3.6%), Staphylococcus chromogenes (2.9%), and Staphylococcus epidermidis (2.2%). The typeability of staphylococcal isolates with partial housekeeping gene sequence analysis (rpoB, complemented by tuf and 16S as needed) was 97.7%. The typeability and accuracy of MALDI-TOF were 84 and 100%, respectively. Overall, only Staphylococcus chromogenes IMI was associated with a higher SCS than goats with no growth. After adjusting for parity and stage of lactation, staphylococcal IMI status was not significantly associated with MY. For the staphylococci isolated from goats in this herd, MALDI-TOF proved an accurate method of speciation with a relatively high typeability. An association between staphylococcal IMI, SCS, and MY was not defined using goat-level data with the exception of S. chromogenes IMI, which was associated with a higher SCS than goats with no growth.

DETECTION OF CRYPTOSPORIDIUM OOCYSTS IN OVINE AND CAPRINE RAW MILK IN RELATION TO REARING MANAGEMENT

During the present study an investigation was made for the assessment of the availability of oocysts of Cryptosporidium spp. in 100 samples of raw milk of sheep and goats reared in various places (Baasheqa, Hamdania and Tilkaif) in Ninevah, Iraq. Results revealed that the incidence rate of Cryptosporidium spp. oocysts in raw ovine and caprine milk samples were 32% and 46%, respectively. The type of rearing management has an effect on the incidence of oocysts in raw milk of these animals. Results showed that the contamination with Cryptosporidium oocysts in mixed (sheep and goats) rearing management of there animals was higher (p < 0.05) than separate rearing management.

Authentication of caprine milk and cheese by commercial qPCR assay

The objective of the study was to investigate potential adulteration of commercial caprine milks and cheeses with bovine milk using commercial qPCR assay. The assay comprised of bovine-, ovine- and caprine-specific primers and TaqMan probe and mammalian internal control. Specificity, sensitivity, linearity, reproducibility and efficiency of the bovine assay were tested as well. Specificity was verified by running reaction on the DNA of other milk-producing species (caprine and ovine) and made-up bovine-caprine (v/v) milk mixes. In both experiments, a bovine DNA fragment was amplified whereas no amplification was obtained from the other species. Sensitivity, linearity, reproducibility and efficiency were tested on 10-fold dilution series of 10 ng bovine DNA. The assay has shown good linearity (R2 = 0.983) within whole range, with efficiency of 86% and excellent reproducibility (SD around the CT for the technical replicates &lt;0.5). The sensitivity was adequate, as calculated LOD and LOQ were 1.44 pg and 2.94 pg of bovine DNA, respectively. Finally, the assay was used to authenticate 5 caprine milk samples and 5 caprine cheese samples, purchased from local supermarkets. Totally, 1 milk sample has shown the fluorescence signal, which exceeded baseline in cycle 39.01 ±0.69. However, the signal was above LOD and LOQ suggesting that there could not be unambiguously declared any adulteration with bovine milk. Amplification of bovine-specific DNA was not observed in the other samples indicating products were not adulterated. The commercial qPCR assay has proved that real-time PCR assays, as well as DNA-based techniques in a general, are the excellent and reliable tools for fighting with frauds in the food industry and protecting the public health.

A comparison of the kinetics of the thermal denaturation of the immunoglobulins in caprine and bovine skim milk samples

The irreversible thermal denaturation of the immunoglobulins in bovine and caprine milk samples was determined over a wide temperature and time range so that kinetic and thermodynamic parameters could be determined. The immunoglobulins in the bovine milk were more heat labile than those in the caprine milk. For both milk samples, the denaturation followed second order reaction kinetics. The activation energies and thermodynamic parameters (ΔH#, ΔG# and ΔS#) were similar for both bovine caprine milk samples, and these parameters were in the range expected for unfolding reactions as the rate determining step for the irreversible denaturation process.

Effect of stage of lactation on the immune competence of goat mammary gland

The present research was undertaken to evaluate the effect of stage of lactation on immune competence of the goat mammary gland. The prevalence and etiology of intramammary infections and cytokine pattern were studied in individual caprine milk during lactation. A total of 1,200 caprine milk samples were collected during early, mid, and late lactation (less than 40 d, from 110 to 130 d, and more than 200 d in lactation, respectively) and analyzed for milk quality, bacterial cell load, and cytokine pattern. Contagious and environmental pathogens associated with intramammary infection were isolated from caprine milk. Nutritional components of caprine milk were affected by stage of lactation; fat, protein, casein, and whey protein increased along with lactation due to the lowest milk yield. Lactose content showed an opposite trend, with a reduced percentage passing from early to late lactation. The impaired rheological properties detected in early and late lactation milk were associated with a modification of milk quality. An impairment of microbial quality was detected at the end of lactation as a consequence of a major susceptibility of mammary gland to infections. The percentage of bacteriologically positive caprine milk samples was 44% throughout lactation. The incidence of bacteria associated with intramammary infection was different according to the stage of lactation with a major prevalence of Staphylococcus aureus, Enterobacteriaceae, Staphylococcus hyicus, and Streptococcus uberis in early lactation milk, Staphylococcus chromogenes, Streptococcus bovis, and Staphylococcus epidermidis in mid lactation, and Pseudomonas aeruginosa and Staphylococcus caprae in late lactation milk. The higher values of IL-1β, tumor necrosis factor-α, and IL-6 were ascribed to the major prevalence of Staphylococcus aureus at the beginning of lactation, whereas a higher level of IL-10 was detected in mid-lactation caprine milk and correlated with Staphylococcus chromogenes. Monitoring the cytokine pattern in milk helps to understand the immune status of the mammary gland, its ability to cope with bacteria, and the evolution of infections.

Occurrence and antibiotic resistance of enterotoxigenic Staphylococcus aureus in raw ovine and caprine milk in Greece

Ovine (n = 140) and caprine (n = 35) raw bulk tank milk samples from farms in central Greece were examined for the occurrence of enterotoxigenic Staphylococcus aureus. The S. aureus isolates were screened for staphylococcal enterotoxin (SE) production, the presence of enterotoxin genes, antibiotic resistance (AR), and methicillin resistance. S. aureus was isolated from 24.3% and 31.4% of ovine and caprine milk samples, respectively. Among the S. aureus isolates of ovine milk (n = 34) and caprine (n = 11) milk, the enterotoxigenic (SEA-SED) isolates were 21 (61.8%) and 7 (63.6%) for the ovine and caprine milk, respectively. Most toxigenic isolates harbored more than one toxin gene and a total of 11 distinct toxinotypes were detected. The most frequent toxin-gene combinations were “sec, tst” (8 isolates), “seb, seg, sei, tst” (4), “seb, seg, sei” (3), and “seb” (3). Six isolates displayed multiple AR towards up to five antimicrobials. Among ovine milk isolates, the highest resistance frequency was observed towards erythromycin (11.8% of the isolates) and tetracycline (8.8%). Among caprine milk isolates, the most frequent resistance was observed towards erythromycin (18.2%). One methicillin-resistant S. aureus (MRSA) isolate was detected in an ovine milk sample and belonged to spa type t4038. This spa type has been isolated for the first time in Greece and, to our knowledge, has not been previously reported among MRSA isolates from raw milk or dairy products worldwide.

High prevalence and two dominant host-specific genotypes of Coxiella burnetii in U.S. milk

BackgroundCoxiella burnetii causes Q fever in humans and Coxiellosis in animals; symptoms range from general malaise to fever, pneumonia, endocarditis and death. Livestock are a significant source of human infection as they shed C. burnetii cells in birth tissues, milk, urine and feces. Although prevalence of C. burnetii is high, few Q fever cases are reported in the U.S. and we have a limited understanding of their connectedness due to difficulties in genotyping. Here, we develop canonical SNP genotyping assays to evaluate spatial and temporal relationships among C. burnetii environmental samples and compare them across studies. Given the genotypic diversity of historical collections, we hypothesized that the current enzootic of Coxiellosis is caused by multiple circulating genotypes. We collected A) 23 milk samples from a single bovine herd, B) 134 commercial bovine and caprine milk samples from across the U.S., and C) 400 bovine and caprine samples from six milk processing plants over three years.ResultsWe detected C. burnetii DNA in 96% of samples with no variance over time. We genotyped 88.5% of positive samples; bovine milk contained only a single genotype (ST20) and caprine milk was dominated by a second type (mostly ST8).ConclusionsThe high prevalence and lack of genotypic diversity is consistent with a model of rapid spread and persistence. The segregation of genotypes between host species is indicative of species-specific adaptations or dissemination barriers and may offer insights into the relative lack of human cases and characterizing genotypes.

Incidence of Listeria species in bovine, ovine, caprine, camel and water buffalo milk using cultural method and the PCR assay

ObjectiveTo determine the prevalence rate of Listeria species in bovine, ovine, caprine, camel and water buffalo milk in Iran. MethodsFrom September 2010 to December 2011 a total of 260 bulk milk samples including 85 bovine, 37 camel, 34 water buffalo, 56 ovine and 48 caprine bulk milk samples were collected from commercial dairy herds, in Fars and Khuzestan provinces, Iran and were evaluated for the presence of Listeria species using cultural method and the PCR assay. ResultsUsing cultural method, 19 samples (7.3%) were positive for Listeria spp. The highest prevalence of Listeria was found in raw water buffalo milk (11.8%), followed by raw bovine milk (10.6%), raw ovine milk (7.1%), and raw caprine milk (4.2%) samples. All 37 camel milk samples from 20 camel breeding farms were negative for Listeria spp. The overall prevalence of Listeria was 7.3%, in which Listeria innocua was the most recovered species (4.2%); the remaining isolates were Listeria monocytogenes (1.9%), Listeria ivanovii (0.08%) and Listeria seeligari (0.04%). The PCR assay could identify 8 Listeria-contaminated milk samples that were negative using the cultural method. ConclusionsThe results presented in this study indicate the potential risk of infection with Listeria in people consuming raw and unpasteurized milk.

A Survey of Aflatoxin M1 Contamination in Bulk Milk Samples from Dairy Bovine, Ovine, and Caprine Herds in Iran

A total of 150 bovine (60), ovine (42), and caprine (48) bulk milk samples were analyzed using a commercially available competitive ELISA kit. Overall, AFM1 was found in 46.7% of the analyzed samples by an average concentration of 40.3±22.2ng/L. The incidence rates of AFM1 contamination in bovine, ovine, and caprine bulk milk samples were 66.7, 31.0, and 35.4%, respectively. The concentration of AFM1 in 37.5% of AFM1-positive bovine milk samples and 5.9% of AFM1-positive caprine milk samples were higher than 50ng/L.