Goat Milk Samples Research Articles

Determination of aflatoxin M1 (AFM1) in dairy sheep, goats and camel milk in Hail Region, Kingdom of Saudi Arabia and evaluation of different methods reducing its concentrations in milk

ABSTRACT This study aimed to determine aflatoxin M1 (AFM1) in dairy sheep, goats, and camel milk in Hail, Saudi Arabia, and evaluate methods for reducing AFM1. A total of 67 milk samples were collected from Ghazala and Al-Shweimis villages, Hail. AFM1 in milk samples was analyzed using enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC) with fluorescence detection. Results revealed concentration of AFM1 in goat and camel milk samples from Ghazala was higher than that in goat and camel milk samples from Al-Shweimis with a significant difference (p<0.05) using both ELISA and HPLC methods. The mean AFM1 concentration using ELISA for goat milk was (12.96 ± 2.23 ng/l), while the AFM1 concentration for camel milk was (1.54 ± 0.29 ng/l). Microwave heating and boiling are effective methods to reduce the AFM1 in milk. ‏‎‏‎‏The highest AFM1 removal percent was 42.96% by microwave and 12.32 % by boiling milk samples.

On-farm epidemiology, virulence profiling, and molecular characterization of methicillin-resistant Staphylococcus aureus at goat farms

Antimicrobial resistance (AMR) becomes a challenging issue that limits the therapeutic options for both veterinary and public health professionals. The current study aimed to investigate the on-farm epidemiology, antibiotics resisting profiling, virulence analysis, and molecular detection of methicillin-resistant Staphylococcus aureus (MRSA) at the caprine-human interface. A total of 768 goat milk samples and 94 skin swabs from farm personnel were collected from 30 goat flocks and processed for isolation of S. aureus. The study isolates were confirmed as MRSA based on the oxacillin and cefoxitin disc diffusion test and the presence of mecA gene. MRSA isolates of goats and human origin were characterized and further evaluated for the presence of virulence genes responsible for intramammary infections and public health hazards. The results revealed 26.82 % and 27.79 % goat milk samples and human samples positive for S. aureus, respectively. A higher MRSA prevalence of 35.92 % and 10.71 % was found in goat and human isolates respectively. The phylogenetic analysis revealed a lesser extent of homology in mecA gene of S. aureus isolates at the caprine-human interface. Moreover, this study revealed strong evolutionary connection between the study isolates and MRSA isolates of Pakistani cattle and buffalo while the in-silico protein analysis showed that all sequences have the same protein motifs resembling penicillin binding protein 2a. The risk factors analysis revealed that teat length, drainage system, hygienic measures during milking, use of teat dip, teat injury, and veterinary services were significantly associated with subclinical mastitis in goats. A total of 43.24 % of local MRSA isolates showed multi-drug resistance (MDR). The isolates showed higher resistance to oxytetracycline followed by gentamicin and vancomycin while moxifloxacin, and linezolid were among the susceptible antibiotics. Local MRSA isolates carried virulence markers (nuc and coag genes) and biofilm-associated icaA (43.24 %) and icaD (29.73 %) genes which are responsible for the intramammary infection. The local isolates also carried the virulence genes of public health concern including the enterotoxin C (sec) gene (24.3 %), enterotoxins B (seb) gene (5.41 %), and enterotoxin D (sed) gene (2.7 %). Enterotoxins A (sea) and E (see) genes were not detected in any isolate. The study concluded that MRSA is an emerging and prevailing pathogen in dairy goats with a high potential to transmit to associated human beings. The presence of a variety of virulence factors as well as the associated antibiotic resistance makes MRSA a potential threat at animal-human interface and thus demands further research.

Genetic variations of α-casein and K-casein genes associated with milk composition in goats

The quality of animal milk varies between individuals of the same breed. The present study aimed to detect the favorable SNPs for α-casein (CSN1S1) and k-casein (CSN3) genes associated with high-quality milk traits. Blood and milk samples of Zaraibi and Damascus goats were collected from Sakha farm in Kafr El-Shiekh. The solid non-fat, lactose, protein, and fat contents, were determined in milk using the biochemical method, and amino acids were determined using HPLC. To identify genotypes and nucleotide variations (SNPs), single-strand conformation polymorphism (SSCP) and sequencing methods were used. One-way ANOVA test was used to determine the effect of different genotypes on milk traits. The SSCP-PCR results in Zaraibi and Damascus goats showed that the CSN1S1 gene has 3 genotypes (AA, AB, and BB), and also the CSN3 gene has 3 genotypes (AA, AG, and GG). The results of sequencing showed three SNPs at positions 41G˂T, 69A˂G, and 80C˂T in the CSN1S1 gene, and three SNPs at positions 49C˂T, 111A˂G, and 340C˂T in the CSN3 gene. The milk results showed that the high protein, fat, and lactose content were associated with the AB genotype in the CSN1S1 gene while they were associated with the AG genotype in the CSN3 gene. Likewise, essential and branched-chain amino acids were increased in goat milk with the AB and AG genotypes of CSN1S1 and CSN3 genes, respectively. The essential amino acids for protein synthase were higher in Zaraibi than in Damascus goats. Therefore, the Zaraibi goats may more possess genotypes in the CSN1S1 and CSN3 genes, which affect the fat and protein level in milk.

Metagenomic analysis of the microbial community in kefir grains from different milk sources

Abstract. Sumarmono J, Kusuma RJ, Rahayu N, Sukarno AS, Wulansari PD. 2023. Metagenomic analysis of the microbial community in kefir grains from different milk sources. Biodiversitas 24: 5302-5308. Kefir is a type of traditional fermented milk made from kefir grains. The quality of kefir grain depends on the milk medium, which impacts microbial diversity and population. This study uses metagenomic analysis to assess the microbial populations of kefir grains prepared from cow's milk and goat milk using the 16s rRNA method. The results revealed that &gt;99% Relative Abundance (RA) of the sample's total bacteria belonged to the phylum Firmicutes and the phylum Bacteroidota, respectively. However, most of the phylum Firmicutes was found in the sample of goat milk kefir. Further investigation revealed that goat milk samples had Lactobacillus, Streptococcus, and Staphylococcus genera, while the cow milk samples contained &gt;99% RA of Lactobacillus, Bacteroides, and Muribaculaceae. Regarding yeast, the family Saccharomycetaceae predominated in cow's milk, while goat milk had 2% of the family Saccharomycetaceae and 97% of unassigned microorganisms. The functional analysis revealed that kefir grains from the two sources had a variety of amino acid metabolisms, secondary metabolite metabolisms, and vitamin production. This metagenomic analysis shows that the type of milk affects the diversity of the population of both bacteria and yeast. This study opens up opportunities to further investigate the potential of kefir as a functional food beverage, a source of probiotics, and an antibacterial agent property.

Development and validation of a versatile analytical method for absolute quantification of seven oligosaccharides in human, bovine, and goat milk

Oligosaccharides are significant in mammalian milk, where they serve as prebiotics that promote the growth of beneficial gut bacteria in infants. Comprehensive research of milk oligosaccharides requires precise and validated analytical methods for compositional studies. To address this need, the focus of our study was to develop and validate an analytical method using UPLC-MS/MS to quantify seven specific oligosaccharides found in mammalian milk. The developed and optimized method has adequate linearity, accuracy, and precision parameters. The detection (LOD) and quantification (LOQ) limits for the seven compounds ranged from 0.0018 to 0.0030 μg/mL and 0.0054–0.0063 μg/mL, respectively. The sample preparation method yielded recovery rates above 90.5 %. Furthermore, no significant matrix effect was observed. The validated method was successfully applied to human, goat, and bovine milk samples, demonstrating its proficiency in identifying variances in the concentration of oligosaccharides across different mammals. This versatile method will allow future research about factors affecting oligosaccharide composition.

Coxiella burnetii occurrence in dairy herds in Gabrovo Region, Bulgaria, evaluated by serological and molecular analyses of bulk-tank milk samples

This study investigated the occurrence of Coxiella burnetii in dairy cattle, goat herds and sheep flocks in the Gabrovo Region, central Bulgaria, to identify the potential sources of Coxiella burnetii infection diagnosed in veterinarians and farm workers in this region. To detect infection on livestock farms, we tested bulk-tank milk (BTM) for the presence of antibodies and/or the Coxiella burnetiid genome using ELISA and PCR, respectively. A total of 81 herds were tested, including 23 dairy cattle herds, 43 sheep herds, 9 goat flocks, and 6 mixed flocks (sheep and goats). By ELISA, antibodies against Coxiella burnetii were detected in 30.4% of the BTM tested samples from cattle farms, 60.4% of the sheep farms, and 11.1% of the goat BTM samples. The results were inconclusive in 6.98% of the tested sheep milk samples and 11.1% of the goat milk samples. There was a statistically significant correlation between the herd size and the ELISA S/P % values on the dairy cattle farms. Excretion of the pathogen in milk was detected by PCR in 9 out of 67 BTM samples, including 5 out of 19 cattle BTM samples, 3 out of 39 sheep BTM samples and 1 out of 5 goat BTM ones. The results indicate that C. burnetii infection is widely prevalent in the region, which calls for adequate control and prophylactic measures to reduce the health risks from the transmission of this zoonosis to humans.

Quantitative Determination of Casein and Lactose in Processed and Unprocessed Milk Samples from Ogwashi-Uku, Delta State

Milk is one of the most important nutritional constituent of our diet because it is largely composed of proteins and along with vitamins and minerals. This present study was based on determining the amount of casein and lactose present in processed (Dano cool cow and Peak milk) and unprocessed milk (Cow and Goat milk) samples collected from Ogwashi-uku, Delta State. The casein content was analyzed using Kjeldahl method and lactose content was analyzed using Benedict’s Method. Results from this study shows that cow milk sample; an unprocessed form of milk has more lactose content (40.298%) than other forms of milk while Dano cool cow milk, a processed milk has more casein (23.93%) as compared to all other milk. High concentration of casein is more beneficial to health and high percentage of lactose do not poses no threat as it can be digested easily.

Detection of Brucella melitensis in milk and serum samples of goats by serological and molecular techniques

The present investigation was planned for the detection of brucellosis in goats using serological and molecular techniques. A total of 500 clinical samples (250 milk and 250 serum) of goats were collected. All the milk samples were screened by Milk Ring Test and Enzyme-Linked Immunosorbent Assay and serum samples with i-ELISA. Further, the positive milk and serum samples were subjected to 16SrRNA and OMP-31 PCR assays. Results showed the seropositivity of brucellosis was 34.8% and 16% from milk and serum samples of goats by ELISA, respectively and 2.8% by MRT. The results of 16SrRNA PCR detected B. abortusS19, in 32 (36.78%) milk samples and 10 (25%) serum samples by showing an amplicon of 1412 bp. Similarly, the OMP-31 PCR assay tested positive for B. melitensis Rev1, in 22 (25.28%) milk and 05 (12.5%) serum samples by showing an amplicon of 720 bp. Hence, this study is helpful for the detection of brucellosis in goats by using milk and serum samples. The study has generated evidence on the distribution of Brucella melitensis in milk and demonstrated the need to aware people about the importance of boiling milk before consumption in household and thus reduce the risk of infection in human beings.

Analysis of CSN2 Exon 7 gene diversity and its association with Sapera goat milk composition

Sapera goats, a crossbreed between Saanen and Etawa Grade goats, are known for their milk pro-duction and adaptability to the Indonesian climate. Genetic selection is necessary to improve the Sa-pera goat's milk quality and quantity. CSN2 gene is one of the genes that can affect the composition of goat milk. Therefore, this study aimed to identify the mutation points (SNPs) at the CSN2 exon 7 gene and its association with Sapera goat's milk composition. This study used sixty-six blood and milk sam-ples of Sapera goats collected from the Livestock Research Center, Ciawi. This study found two muta-tion points (SNPs) at g.8946C&gt;T and g.8956G&gt;A. The association analysis showed that SNP g.8946C&gt;T was significantly associated with the lactose and salt content of Sapera goat's milk. In con-clusion, SNP g.8946C&gt;T can be used as a genetic marker to improve the composition of Sapera goat milk with high lactose and salt content.

Improving the physicochemical and antioxidative properties of fermented goat milk using carob molasses and some probiotic strains

Fermented goat milk samples, processed by adding 0, 2, and 4% carob molasses, and Bifidobacterium bifidum DSMZ or Lactobacillus helveticus CH5, were evaluated for their physicochemical, antioxidative, and sensory properties along with probiotic viability during storage. pH and viscosity gradually decreased over the storage period whereas their values increased with the increased amount of carob molasses. Bifidobacterium bifidum DSMZ or Lactobacillus helveticus CH5 kept higher viable numbers. Lactobacillus helveticus CH5 strain recorded higher viability. Increasing the added amount of carob molasses increased the total phenolic content, which in turn is reflected in the increase in antioxidant activity. Adding carob molasses participated in the partial masking of the goaty flavor and had no significant effect on the product’s acceptability, which was strongly influenced by the progress of cold storage. Therefore, fermented goat milk described by its enhanced physicochemical and antioxidative properties could be obtained by adding carob molasses and probiotics.

Characterization and profiling of the microRNA in small extracellular vesicles isolated from goat milk samples collected during the first week postpartum

Colostrum contains nutrients, immunoglobulins, and various bioactive compounds such as microRNA (miRNA). Less is known about the temporal changes in miRNA profiles in ruminant milk samples during the first week postpartum. In this study, we characterized and compared the profiles of miRNA in the small extracellular vesicles (sEV) isolated from colostrum (CM, collected immediately after parturition, n = 8) and transition milk (TM, collected 7 d postpartum, n = 8) from eight 1-yr-old Guanzhong dairy goats with a milk yield of approximately 500 kg/year. A total of 192 unique sEV-associated miRNA (transcripts per million >1 at least 4 samples in either CM or TM) were identified in all samples. There were 29 miRNA uniquely identified in the TM samples while no miRNA was uniquely identified in the CM samples. The abundance of the top 10 miRNA accounted for 82.4% ± 4.0% (± SD) of the total abundance, with let-7 families (e.g., let-7a/b/c-5p) being predominant in all samples. The top 10 miRNA were predicted to target 1,008 unique genes that may regulate pathways such as focal adhesion, TGF-β signaling, and axon guidance. The expression patterns of EV miRNA were similar between the 2 sample groups, although the abundance of let-7c-5p and miR-30a-3p was higher, whereas that of let-7i-5p and miR-103–3p was lower in CM than in TM. In conclusion, the core miRNAome identified in the samples from CM and TM may play an important role in cell proliferation, bone homeostasis, and neuronal network formation in newborn goat kids. The lack of differential miRNA expression between the CM and TM samples may be due to a relatively short sampling interval in which diet composition, intake and health status of ewes, and environment were relatively stable.

Quantification of cow milk in adulterated goat milk by HPLC-MS/MS using N-acetylglucosamine as a reliable biomarker of cow milk

This study aimed to develop a non-protein-based method for quantify cow milk in adulterated goat milk. The raw cow milk and raw goat milk samples were mixed separately with the same volume of cold acetone and centrifuged to remove their proteins. The supernatants were evaporated, and the residues were derivatized by silylation followed by GC-MS analysis. N-acetylglucosamine was identified as a thermostable non-protein biomarker of cow milk. Its concentration in the raw cow milk (146.7 mg/L) was 32 times higher than that in the raw goat milk. On this basis, a HPLC-MS/MS method using positive-ion electrospray ionization in parallel reaction monitoring mode was developed for quantifying cow milk in adulterated goat milk by determining peak area of the biomarker. The method showed good linearity over cow milk concentrations of 1–100% and could detect as low as 0.3% cow milk in adulterated goat milk. Besides, the method was characterized by a simple sample pretreatment process, rapid detection, high accuracy, and high precision. With this method, a sample could be analyzed in 10 min. The present study demonstrated the feasibility of quantifying cow milk in adulterated goat milk using N-acetylglucosamine as a biomarker of cow milk.

Chemometric tools applied to silver nanoparticles electrodeposition in 3D-printed disposable device for the determination of sulfamethoxazole in different samples by voltammetry

In this paper, a disposable electrode, of low cost (US$ 0.06), easy production, and adequate properties was developed using composite material (CM) modified with silver nanoparticles, immobilized on 3D acrylonitrile butadiene styrene (ABS) support (3Ds-CME/AgNP) for the determination of sulfamethoxazole (SMX) in tap water, synthetic urine, drugs samples, cow milk, goat milk, breast milk, and honey samples. The silver nanoparticles electrodeposition was optimized using 33 Box-Behnken design with triplicate in the central point. The electrode had its surface data characterized by the scanning electron microscopy technique. The bare and modified sensor was compared for the electrochemical response for SMX, where a 30% increase in current signal response was observed. Then, the determination of SMX by differential pulse voltammetry (DPV) using a multivariate calibration optimized method by central composite design (CCD) model 22 was optimized. The results by DPV using 3Ds-CME/AgNP showed a good linear range from 10 to 50 µmol/L, adequate detectability (0.96 µmol/L), good precision (relative standard deviation (RSD) < 5.8 %), and satisfactory recovery ranging from 93 to 115 %. The 3Ds-CME/AgNP device has been shown to be effective for the determination of SMX in different samples using a simple dilution of the sample.

Relation between αS1-casein, genotype, and quality traits of milk from Swedish dairy goats

Locally produced food is becoming popular among Swedish consumers. One product that has increased in popularity is artisan-manufactured goat cheese, and although the dairy goat industry in Sweden is small-scale, production is gradually increasing. In goats, the CSN1S1 gene regulates expression of the protein αS1-casein (αS1-CN), which has been found to be important for cheese yield. Over the years, breeding animals have been imported to Sweden from Norway. Historically, a high frequency of the Norwegian goat population carried a polymorphism at the CSN1S1 gene. This polymorphism, called the Norwegian null allele (D), leads to zero or significantly reduced expression of αS1-CN. Using milk samples from 75 goats, this study investigated associations between expression of αS1-CN and genotype at the CSN1S1 gene on milk quality traits from Swedish Landrace goats. Milk samples were grouped according to relative level of αS1-CN (low: 0-6.9% of total protein; medium-high: 7-25% of total protein) and genotype (DD, DG, DA/AG/AA). While the D allele leads to extremely low expression of αS1-CN, the G allele is low expressing and the A allele is highly expressing for this protein. Principal component analysis was used to explore the total variation in milk quality traits. To evaluate the effect of different allele groups on milk quality attributes, 1-way ANOVA and Tukey pairwise comparison tests were used. The majority (72%) of all goat milk samples investigated showed relative αS1-CN content of 0% to 6.82% of total protein. The frequency of individuals homozygous for the Norwegian null allele (DD) was 59% in the population of sampled goats, and only 15% carried at least one A allele. A low relative concentration of αS1-CN was associated with lower total protein, higher pH, and higher relative concentration of β-casein and levels of free fatty acids. Milk from goats homozygous for the null allele (DD) showed a similar pattern as milk with low relative concentration of αS1-CN, but total protein was only numerically lower, and somatic cell count and αS2-CN were higher than for the other genotypes. The associations between levels of αS1-CN and the investigated genotype at the CSN1S1 gene indicate a need for a national breeding program for Swedish dairy goats.

Content of Metals in Cow, Sheep and Goat Milk Samples

Milk is an excellent source of many essential nutrients, including Ca, proteins and vitamin D. Nine metals (Ca, Cd, Cu, Fe, Mg, Mn, Zn, Ni and Pb) in raw and pasteurized milk of cow, sheep and goat were determined by atomic absorption spectrometry, flame technique. The levels of Cd, Fe, Mn, Ni and Pb were below the detection limit of the used method. The concentration ranges for Ca, Mg, Zn and Cu, in all milk samples, were as follows: 459.8-992.8, 59.5-206.8, &lt;LOD-22.31 and &lt;LOD-3.20 mg/L, respectively. The order of the metal levels in regards to concentration was Ca&gt;Mg&gt;Zn&gt;Cu. The highest content of Ca and Mg was found in goat milk. In the case of cow's milk, the content of Ca, Mg and Zn increased with increasing amount of milk fat in processed milk. Matrix correlation analysis showed that there is a significant correlation for the following pairs: Ca-Mg (r = 0.830), Zn-Cu (r = 0.799) and Ca-Zn (r = 0.624). Also, a strong correlation was found between milk fat and Ca, Mg and Zn (Pearson factor, r &gt; 0.600). Based on daily consumption of 200 mL of milk, the milk consumption does not meet the daily requirements for determined elements. Most significant intake was in case of Ca.

Nutritional Parameters of Goat Milk and Its Consumption in Rural Communities

A survey was conducted using a pretested, semi-structured questionnaire in Mutoko district to determine the extent of goat milk consumption and reasons for the possible low-to-non-consumption of goat milk. A total of 120 respondents were randomly selected. Fresh goat milk samples were also collected from Mashona and Matabele goat breeds and analysed using a Milko-scan FT 6000 (FOSS, HillerOD, Denmark) to determine nutrient composition. Results from the study indicated that goat milk is lowly utilized – with only 14% of the surveyed households consuming goat milk. The respondents cited that goat milk was lowly utilised because goat milk consumption is traditionally uncommon in the area (57.70%) and has an undesirable strong smell (17.06%). Consuming goat milk was associated with reduced social status (10.66%). Respondents that had access to sufficient cow milk (13.96%) do not consume goat milk. Estimated mean milk yield per goat per milking, as reported in the study was 310.0±114.02 mL. High levels of education were associated with increased tendency to consume goat milk (χ2=246; df=40, p=0.000). Mashona goat milk had higher lactose (4.36%) and protein (4.77%) but lower fat content (3.45%) than Matabele goat milk. While goat milk is less popular in the study area, the milk from these indigenous goat genotypes is characterised by good nutritional value comparable to the accepted values of good quality milk. The quality of the milk, coupled with feeding and breed selection interventions to increase yield, has potential to be a rich nutrient source for small-holder communities threatened by malnutrition.

A rapid and simple multi-residue methodology for quantification of anthelmintic macrocyclic lactones in cow, sheep and goat milk by HPLC: development, validation and application for the real samples

Anthelmintic macrocyclic lactones (MLs) [ivermectin (IVM), abamectin (ABA), doramectin (DRM), eprinomectin (EPR) and moxidectin (MXD)] are used worldwide for the treatment of parasitic infections in large and small ruminants because of their low mammalian toxicity and higher efficacy against internal and external parasites at low dose levels. A rapid, simple and sensitive HPLC and a modified QuEChERS extraction method were developed and validated for the analysis of five anthelmintic MLs residues in cow, sheep and goat milk. The analytes were extracted from milk samples by acetonitrile deproteinization, followed by the addition of sodium sulphate and sodium chloride to generate a phase partition. HPLC separation was conducted at 50⁰C using a C18 analytical column (Zorbax, Eclipse Plus, 250 mm × 4,6 mm, 5µ). The mobile phase consisted of a mixture of acetonitrile: methanol: water (58:38:4, v/v/v), delivered by an isocratic program at the flow rate of 1.3 ml/min. The elution of five analytes was completed within 11 min. The fluorescence detector (FLD) was set at an excitation wavelength of 375 nm and an emission wavelength of 470 nm. Recoveries ranged between 78.44% and 92.66%. The quantification limits (LOQ) of anthelmintic MLs in the milk samples from 3 different ruminant species ranged between 2.01 and 3.10 ng/g. The developed method was validated in accordance with the criteria of Commission Decision 2002/657/EC. Linearity, decision limit, detection and quantification limits, recovery, accuracy, precision, sensitivity and selectivity were determined, and satisfactory results were obtained. This developed and validated method is rapid, simple, sensitive and environmentally friendly, and can be used for multiple residue analyses of anthelmintic MLs in cow, sheep and goat milk for human consumption. The quantification limits for all drugs were below the maximum residue limits (MRLs), making the method appropriate for routine testing. Finally, the application of this method was assessed using real samples of cow, sheep and goat milk. The presence of MLs was confirmed in 8 out of 70 tested milk samples, which shows the method can be successfully used to determine the residue of anthelmintic MLs in three types of milk.

Investigation of the presence of some antibiotics in Raw Goat milk collected from Ankara, Kırıkkale and Çankırı provinces

Antibiotics used in food producing-animals may cause residual problems in food in terms of public health. This situation can lead to serious problems in terms of human health. Raw milk is one of the foods that are likely to contain antibiotics, even in trace amounts. This study aimed to determine the residue levels of commonly used antibiotics of raw goat's milk samples offered for sale in Ankara, Çankırı and Kırıkkale. One active ingredient was selected from the five most commonly used antibiotic groups in animals and it determined the residue levels of these substances in milk. For this purpose, within one year and in two different periods, 150 raw goat milks analyzed in terms of antibiotics using HPLC method. The values for enrofloxacin, sulfamethoxazole, tylosin, penicillin G and oxytetracycline were 7.9, 9.7, 11.5, 5.4 and 7.3 minutes for retention times, 1.47, 0.8; 7.51; 2.69 and 8.89 µg/L for limit of detection (LOD) and 4.47, 2.44, 22.78, 8.16 and 26.96 µg/L for limit of quantification (LOQ), respectively. No antibiotic residues were detected in the goat milk samples. It is predicted that the higher resistance of goats to diseases compared to other milk-producing animals, and therefore the lower use of antibiotics in these animals, leads to this result. The findings obtained as a result of this study are valuable in terms of public health. It is important that no antibiotic residues are found in the analyzes.

Traceability, virulence and antimicrobial resistance of Yersinia enterocolitica in two industrial cheese-making plants

Between 2018 and 2019, 309 environmental and food samples were collected from two industrial cheese-making plants located in Sardinia, in order to investigate Y. enterocolitica presence and to characterize the isolates. Y. enterocolitica isolates were further compared with isolates detected during a previous investigation from sheep and goat raw milk samples. Y. enterocolitica was detected in 7.4 % of the samples and the prevalence was higher, even if not significantly (P > 0.05) higher in non-food contact surface samples (10.2 %) than in food contact surface samples (3.8 %). The highest prevalence was detected in floor samples (13.5 %), followed by drain samples (7.2 %), which might serve as main harborage sites for further contamination. Y. enterocolitica was also detected in food contact surfaces, namely shelves of the Ricotta cooling room and packaging room, one cheese cutting machine surface and one raw milk filter sample. The biotype 1A isolates identified in this study were classified into six different serotypes. Additionally, a bioserotype 2/O:5,27 isolate was identified in one goat milk sample. All 1A isolates possessed the virulence genes invA and ystB while the 2/O:5,27 isolate showed the presence of ail, ystA, invA and yadA genes, thus confirming a pathogenic potential. The isolates showed intrinsic resistance to amoxicillin-clavulanic acid, ticarcillin and cefoxitin due to the presence of the blaA gene. Whole genome sequencing allowed to identify seven different sequence types among the 1A isolates, thus showing a high genetic diversity. The same Y. enterocolitica sequence type (ST3) was detected from three different areas of the same cheese-making plant, indicating a possible transfer of the microorganism along the processing lines. Y. enterocolitica contamination in cheese-making plants can pose a risk to human health. Preventive measures include the hygienic design of the plant layout and equipment, in association with proper cleaning and disinfection programmes.

A Systematic Review and Meta-Analysis on Hepatitis E Virus Detection in Farmed Ruminants.

Swine are widely recognized as the main reservoir of zoonotic HEV; however, a growing body of data on the HEV prevalence in farmed ruminants of different species also points to a potential route for HEV transmission through ruminants and ruminant products and by-products. Definite information on the zoonotic potential of ruminants is still absent or unclear, compelling the necessity for increasing knowledge on this. The aim of the current study was to analyze the state-of-the-art in this research topic and provide a summary of HEV detection and characterization in farmed ruminants. A total of 1567 papers were retrieved from four search databases that resulted in 35 eligible papers after application of exclusion/inclusion criteria. Studies on HEV in farmed ruminants were mainly based on the detection of HEV RNA and were reported in Africa (n = 1), America (n = 3), Asia (n = 18) and Europe (n = 13), and focused on a variety of ruminants species, namely cow, goat, sheep, deer, buffalo and yak. The overall pooled prevalence of HEV was 0.02% (0.01-0.03, 95% CI). The subgroup pooled prevalence of HEV RNA was 0.01% (0.00-0.02, 95% CI) in cow milk, stool, serum, liver, intestinal, bile, blood, spleen and rectal swab samples; 0.09% (0.02-0.18, 95% CI) in goat serum, bile, stool, milk, liver, rectal swab and blood samples; 0.01% (0.00-0.04, 95% CI) in sheep stool, serum, milk, blood and liver samples. Most of the HEV genotypes found in farmed ruminants belonged to the zoonotic HEV-3 (subtypes 3a, 3c) and HEV-4 (subtype 4d, 4h), with Rocahepevirus also found. The wide HEV circulation observed in different farmed ruminants raises concerns for the possibility of HEV transmission through products from infected ruminants and alerts for the potential zoonotic route for HEV in ruminant products, such as meat and dairy products. Also, contact exposure to infected farmed animals could be a risk factor. Further research should be conducted in order to understand the circulation of HEV in these animals and its zoonotic potential, as there is currently a lack of data on this topic.