Bulk Milk Samples Research Articles

A Study on Milk and Caciocavallo Cheese from Podolica Breed in Basilicata, Italy

A study was undertaken on milk and caciocavallo cheese from Podolica cattle in the Basilicata Region (Southern Italy), with a view of the possible identification of specific traits useful to protect them from imitations. More than 800 individual milk samples and 29 bulk milk samples were taken in spring–early summer from cows registered in the genealogical book of the breed; moreover, 18 samples of caciocavallo cheese were taken in the same geographical area, 9 of which had been manufactured from Podolica milk. The obtained results confirmed the high aptitude of Podolica milk to cheesemaking, even though the exceptional dry weather in the period of sampling decreased the fat content with respect to the literature data. The presence of the variant A of α-lactalbumin, a characteristic trait of Podolica milk, was ascertained in only 14% of the animals considered in the study, indicating that this feature is disappearing in the population under study. The results on caciocavallo gave useful indications, because some possible peculiar characteristics were identified, such as the lower protein to fat ratio and some aroma descriptors. More research is needed to assess if these characteristics can be used for developing a multi-functional protocol, to be extended to all Italian Podolica populations, able to discriminate the cheese from imitations. In this perspective, the application of selection strategies for increasing the frequency of the variant A of α-lactalbumin should be carefully evaluated.

Comprehensive Investigation of Humic-Mineral Substances from Oxyhumolite: Effects on Fatty Acid Composition and Health Lipid Indices in Milk and Cheese from Holstein-Friesian Cows

The objective of this study was to determine the effect of the oxyhumolite supplementation in the feed of cows on the profile and the nutritional indices of fatty acids (FA) in milk and cheese. To the diet of 30 cows, a 100 g/per cow/per day humic-mineral supplement with 65% humic acids was included. Milk was sampled three times: control (0 day, before the dietary modification) and on days 30 and 60 after the introduction of the supplement. For chemical analyses, samples from each cow and for cheese manufacture samples of bulk milk were taken. Fat content in the milk and the cheese, and partial sums of fatty acids profile, nutritional fatty acid ratios and indices were determined. The indicated changes in milk fat quality are difficult to unequivocally assess from a dietary point of view. Negative changes were found in the increase in the proportion of hypercholesterolemic acids (HSFA), atherogenic (AI) and thrombogenic (TI) indices, and a decrease in the hypocholesterolemic/hypercholesterolemic (h/H) ratio, the proportion of desired (DFA) and monounsaturated (MUFA) FA over time of supplementation. Positive changes were also found: the increase in polyunsaturated (PUFA), branched-chain (BCFA), short- and medium-chain (SCSFA) and long-chain (LCSFA) FA percentages, and also content was reported. The cheese (30 and 60 d) showed an increase in the content (mg/100 g) of SFA (including SCFA and LCSFA), OCFA (odd-chain FA), BCFA, MUFA, and DFA. Adverse changes were observed with an increase in PUFA n6, the n6/n3 ratio, and HSFA and TI. No significant differences were found for the AI index. The preliminary results obtained are promising, although further research is needed.

Comparison of quantitative real-time PCR targeting <i>nuc</i> gene and culture-based plate count methods for quantification of <i>Staphylococcus aureus</i> in raw cow milk

Staphylococcal food poisoning (SFP) is caused by ingestion of enterotoxins produced by enterotoxigenic Staphylococcus aureus when the cell population exceeds 5 Log CFU per gram/ml of food. The Objectives of this study were to evaluate the performance of SYBR Green 1-based quantitative real-time PCR (qPCR) targeting the nuc gene for the quantification of S. aureus in milk and to compare the assay with the plate count method. The qPCR and the plate count were applied for the quantification of S. aureus in 92 naturally contaminated and artificially spiked bulk milk samples. Optimized standard curves were generated as the qPCR employed the absolute quantification method. The qPCR assay discriminates S. aureus from other Staphylococcus species with a large difference in quantification cycle (Cq) (Mean S. aureus Cq = 13.83± 0.93; other staphylococci Cq= 30.34 ± 2.65). The standard curve showed 91 % amplification efficiency and 0.98 coefficients of correlation (R2 ). The detection and quantification limit of the assay was 18 copies of the nuc gene. The precision of the assay as expressed by standard deviation was 0.12 – 0.3 for intra-assay and 0.29 – 0.5 for inter-assay variability. In artificially contaminated milk, the R2 between CFU ml-1 and S. aureus cell equivalent (SCE) ml-1 was 0.95, which implies, the estimation of CFU ml-1 in raw milk by qPCR is possible. A statistically significant (p< 0.05) difference in S. aureus count was documented between qPCR and plate count. The average SCE (5.59 ±1.55 Log SCE ml-1) estimated by qPCR was one Log higher than CFU (4.46 ± 1.06 Log CFU ml-1) estimated by plate count. Furthermore, 28% of the samples with < 5 Log ml-1 S. aureus by plate count had > 5 Log ml-1 by qPCR. Hence, the qPCR is recommended for routine and research work for its advantage of rapid, sensitivity, and reliability. Further study on validation of the qPCR protocol in different food matrixes for quantification of foodborne pathogens and cost-benefit analysis of the assay is required.

Macroelement Seasonal Variations in Latvian Organic Milk

Abstract Consumer perception of organic milk is associated with the assumption that organic milk differs from conventionally produced milk. The aim of the present study was to analyse calcium, magnesium, and phosphorus concentration in organic milk in the context of the season. The study was conducted from November 2019 to the end of October 2020. Over a year, raw bulk milk samples were collected and analysed. The milk for the study was supplied by two organic farms located in Latvia. Cows received a total mixed ration consisting of high moisture maize silage, grass silage, etc. The chemical composition of the total mixed rations was analysed, as well as fat, protein, lactose, milk solids non-fat, and total solids, calcium, phosphorus, and magnesium content in organic milk were determined. Seasonal variation in milk composition was observed. The average calcium concentration in our study was 107.96 ± 9.61 mg·100 g−1 with a lower average concentration 97 mg·100 g−1 in organic milk in March. The concentration of calcium, phosphorus, and magnesium was higher in organic milk during the spring–summer season. The sale of organic milk is growing in Latvia, and the presence of a favourable level of calcium in organic milk during the whole year should be reached, providing calcium concentration in cow’s milk around 120 mg·100 g−1 throughout the lactation period. Milk and milk products are an important part of daily nutrition, recommended to every consumer due to their wholesomeness and calcium concentration. Evaluating the bone health data of the Latvian population, 100 ml of milk consumption should provide at least 15% of the recommended daily intake of calcium.

Changes in Chemical Composition and Fatty Acid Profile of Milk and Cheese and Sensory Profile of Milk via Supplementation of Goats' Diet with Marine Algae.

The aim of the present study was to assess the effects of the low level of Schizochytrium limacinum marine algae (daily 5 g per animal) on the milk, cheese, and whey composition; fatty acid profile of milk and cheese; and the sensory profile of goat milk using an e-nose device. Thirty Alpine goats were randomly divided into two groups: the control group (C, n = 15)-fed grass with daily 600 g concentrate and the experimental group (MA, n = 15) who received the same forage and concentrate supplemented with 5 g/head/day marine algae. Animals were kept indoors and the investigation period lasted 52 days, including the first six weeks as the period of adaptation and the last 10 days as the treatment period. During the adaptation period, bulk milk samples from each group were collected once a week (0, 7, 14, 21, 28, 35, and 42 d), while during the treatment period (10 days), bulk milk samples from each group were taken every day, and cheese samples were processed from bulk milk each day from both groups. Marine algae supplementation had no negative effect on milk composition. In contrast, the marine algae inclusion significantly elevated the fat and protein content of whey and the protein content of cheese, as well as the recovery of fat and protein in the curd, while increasing the cheeses' moisture content on a fat-free basis. The marine algae supplementation significantly increased the docosahexaenoic acid (DHA) and the rumenic acid (CLA c9t11) concentrations and decreased the n-6/n-3 ratio in the milk and cheese. There were no significant differences between the C and the MA group with regard to the sensory profiles of the milk. It can be concluded that the milk obtained from goats given daily supplementation of 5g of MA has a fatty acid profile more beneficial to human health, without any negative effects on the milk's aromatic components.

A scoping review of the testing of bulk tank milk to detect nonbacterial pathogens or herd exposure to nonbacterial pathogens in dairy cattle

In this scoping review, we characterized the literature reporting on the testing of bulk milk samples to detect microorganisms other than bacteria that can cause diseases in dairy cattle, including viruses, helminths, algae, and protozoa. A search strategy was completed by screening databases, conference proceedings, animal health agency websites, disease surveillance program websites, and handbooks of cattle-related diagnostic tests for potentially relevant articles. Two reviewers independently screened articles in English, Portuguese, or Spanish; original studies reporting on the testing of farm-level, unprocessed bulk milk samples for presence of pathogens or specific antibodies against agents other than bacteria that can cause diseases in cows were retained. From all studies, we used spreadsheets to extract relevant information, including pathogen screened, test used, and country of origin of bulk milk samples. Additionally, for studies reporting sufficient data to estimate test characteristics, we extracted detailed information about herd eligibility, testing protocol, and herd-level infection definition. A total of 8,829 records were identified, from which 1,592 were retained and assessed for eligibility, and 306 were included. Bovine viral diarrhea virus, Fasciola hepatica, Ostertagia ostertagi, and bovine herpesvirus 1 were the most frequently screened agents, reported from 107, 45, 45, and 33 studies, respectively. Sensitivity of bulk milk ELISA to detect herds with animals infected by bovine herpesvirus 1 ranged from 2 to 100%, and was affected mostly by antigen selection, cut-off adopted, herd vaccination status, and seroprevalence of lactating cows. Bulk milk ELISA had very high specificity to detect herds free of bovine leukemia virus, and varying sensitivity to detect herds with infected animals, which depended on the within-herd seroprevalence of lactating cattle. As for bovine viral diarrhea virus, in general, the sensitivity of bulk milk ELISA was moderate to high (>80%) when infection status was defined based on presence of persistently infected cattle or a high proportion of seropositive lactating cattle. Nevertheless, bulk milk ELISA was not able to distinguish infected and noninfected herds based on presence of seropositive unvaccinated weanlings. The PCR or quantitative PCR protocols employed had very low sensitivities (<40%) and very high specificities (>95%) to classify bovine viral diarrhea virus infection status of dairy herds. Sensitivity and specificity of bulk milk ELISA to classify herds with regards to presence of F. hepatica- or O. ostertagi-parasitized cattle were generally high and driven mostly by the definition of herd infection status. Conversely, bulk milk ELISA demonstrated varying characteristics to detect herds with or without Dictyocaulus viviparus-parasitized cattle, depending primarily on the antigen selected and presence of cattle with clinical signs of lungworm infection.

Effectiveness of mid-infrared spectroscopy for the prediction of cow milk metabolites

Proton nuclear magnetic resonance (1H NMR) spectroscopy is acknowledged as one of the most powerful analytical methods with cross-cutting applications in dairy foods. To date, the use of 1H NMR spectroscopy for the collection of milk metabolic profile is hindered by costly and time-consuming sample preparation and analysis. The present study aimed at evaluating the accuracy of mid-infrared spectroscopy (MIRS) as a rapid method for the prediction of cow milk metabolites determined through 1H NMR spectroscopy. Bulk milk (n = 72) and individual milk samples (n = 482) were analyzed through one-dimensional 1H NMR spectroscopy and MIRS. Nuclear magnetic resonance spectroscopy identified 35 milk metabolites, which were quantified in terms of relative abundance, and MIRS prediction models were developed on the same 35 milk metabolites, using partial least squares regression analysis. The best MIRS prediction models were developed for galactose-1-phosphate, glycerophosphocholine, orotate, choline, galactose, lecithin, glutamate, and lactose, with coefficient of determination in external validation from 0.58 to 0.85, and ratio of performance to deviation in external validation from 1.50 to 2.64. The remaining 27 metabolites were poorly predicted. This study represents a first attempt to predict milk metabolome. Further research is needed to specifically address whether developed prediction models may find practical application in the dairy sector, with particular regard to the screening of dairy cows' metabolic status, the quality control of dairy foods, and the identification of processed milk or incorrectly stored milk.

Structure and milk hygiene of dairy cooperative value chains in an intensive production area of Uganda—A bottleneck of intervention

In Uganda, informal raw milk sales dominate for domestic dairy consumption. This study was implemented to identify the structure of the dairy value chain starting from farms that participated in the Japan International Cooperation Agency Safe Milk Promotion in Mbarara project conducted between 2016 and 2019, to assess the hygiene conditions along the chain, and thereby identify the bottleneck of dairy hygiene intervention. A longitudinal study was conducted in 30 dairy farms in Mbarara District to compare the practice, prevalence of sub-clinical mastitis, and level of milk hygiene in 2016–2017 and 2019, before and after the milking hygiene intervention in 2018. California Mastitis Test was used for diagnosis with sub-clinical mastitis. Bulk milk samples were collected and a checklist was used to examine hygiene practices by observation. A cross-sectional study was conducted in 15 milk collecting centers using a structured questionnaire to quantify the dairy value chain, and to sample milk from cooler tanks in 2020. Microbiological examinations of bulk milk from farms and collection centers were conducted using six-point blood agar scoring and 3M Petri film, respectively. Participatory online appraisals with farmers and dairy cooperatives union were conducted to better understand the overall dairy value chains. The cooperatives sold milk to both formal and informal chains, but the sale of raw milk to Kampala was conducted by independent private traders. Within-herd prevalence of sub-clinical mastitis significantly decreased from 72.3% before the intervention to 25.8% after (p &amp;lt; 0.001). However, the farm bulk milk score did not change (3.3 vs. 3.2, p = 0.418). A significant increase in the total bacterial count was observed in the milk from collection centers (mean: 6.50 log10 CFU/ml) when compared to farm bulk milk (mean: 3.79 log10 CFU/ml; p &amp;lt; 0.001). Only 13.3% of the samples from the centers met the microbiological criteria for processing for human consumption. Our findings suggest that intervention targeted only at mastitis does not lead to better public health due to the low level of hygiene in transportation and milk handling in milk collection centers. Systematic interventions are needed to improve post-harvest dairy hygiene in Uganda.

The prevalence and risk factors of subclinical mastitis in water buffalo (Bubalis bubalis) in Bangladesh

Subclinical mastitis (SCM) in water buffalo is responsible for reduced milk yield and quality. This cross-sectional study was carried out to a) estimate the prevalence of SCM, b) identify risk factors associated with SCM, and c) identify farm-level risk factors associated with bulk milk somatic cell count (BMSCC).The buffalo farms included in this study represented five rearing systems: free-range, semi-free-range, household, semi-intensive, and intensive, providing a total of 3491 functional quarters of 880 lactating buffalo on 248 farms. The California mastitis test score was used to identify SCM. Bulk milk samples (n = 242) were used for farm-level BMSCC. Quarter and buffalo-level risk factors for SCM were measured using questionnaires and observations.The overall SCM prevalence was high at 27.9% at the quarter-level (25th and 75th percentiles: 8.3% and 41.7%) and 51.5% at buffalo-level (25th and 75th percentiles: 33.3% and 66.7%). The geometric mean BMSCC was 217,000 cells/mL of milk (ranging from 36,000-1,213,000 cells/mL), which is low on average, but some farms could improve substantially. The buffalo rearing system, udder location (left versus right), teat shape, udder asymmetry, number of milkers, and having a quarantine facility were associated with buffalo udder health. Our findings suggest that mainly using free-range rearing systems may help decrease the prevalence of SCM primarily by employing buffalo breeding and better farm biosecurity, and udder health control strategies can be designed based on our findings.

A scoping review of the testing of bulk milk to detect infectious diseases of dairy cattle: Diseases caused by bacteria

Testing of bulk milk (BM) samples is a convenient, cost-effective strategy that can easily be implemented as part of disease surveillance programs on dairy farms. Here, we performed a scoping review to summarize the literature reporting on the testing of BM samples to detect infectious diseases of dairy cattle caused by bacteria. We also provide a non-exhaustive, albeit significant, list of diagnostic tests that are marketed for BM samples, as well as a list of disease surveillance activities that included testing of BM samples. A literature search was carried out in 5 databases, yielding 8,829 records from which 474 were retained. Overall, 575 eligible bacterial pathogens were screened for using BM samples, ranging from 1 to 6 individual pathogens per study. Staphylococcus aureus, including methicillin-resistant Staph. aureus, were the most studied bacteria (n = 179 studies), followed by Streptococcus agalactiae (86), Mycobacterium avium ssp. paratuberculosis (79), Coxiella burnetii (79), and Mycoplasma spp. (67). Overall, culture-based protocols, ELISA, real-time PCR, and PCR were the most commonly adopted methodologies to screen BM samples. Sensitivity of BM testing for bovine paratuberculosis was generally low and varied greatly according to the ELISA cut-offs adopted and herd-level definition of disease. In general, protocols had low to moderate sensitivities (<50%), which increased for herds with high within-herd seroprevalence. Specificity of BM testing for paratuberculosis was generally high. With respect to mastitis pathogens, BM testing demonstrated high sensitivity and specificity for Strep. agalactiae, in general. However, we observed inconsistency among studies with respect to the sensitivity of BM culture to detect infected herds, which was notably higher if enrolled herds were heavily infected or had history of clinical disease. Among Salmonella spp. pathogens, Salmonella Dublin was the most frequently studied bacterium for which BM testing has been validated. Specificity of BM ELISA was high, ranging from 89.0 to 99.4. In contrast, sensitivity varied greatly among studies, ranging from 50.6% to 100%. Our findings support that one of most important factors affecting sensitivity of BM ELISA for Salmonella Dublin is whether nonlactating cattle are considered in the definition of herd infection status. In general, protocols analyzed in this review suffered from very low sensitivities, which hardly justifies their use as part of disease surveillance as single testing. Nevertheless, test sensitivity can be increased by the adoption of more inclusive definitions of disease-free herds. Further, low-sensitivity and high-specificity methods can be valuable tools for surveillance when used repeatedly over time.

Intralaboratory Validation of a Kinetic Turbidimetric Assay Based on Limulus Amebocyte Lysate (LAL) for Assessing Endotoxin Activity in Cow Milk.

Mastitis, one of the most common diseases in dairy cattle, causes severe losses in the dairy sector worldwide and affects animal welfare. The disease is characterized by an inflammatory reaction of the mammary gland and is mainly caused by bacterial infections, including both Gram-negative and Gram-positive bacteria. The release of endotoxins associated to bacterial lysis is a weighty factor in the clinical course of Gram-negative associated mastitis and should be taken into consideration when using antibiotics in the treatment of these infections. Therefore, endotoxin detection in milk samples would be of help in the management of bovine mastitis. With this aim, we have validated a kinetic turbidimetric assay based on Limulus amebocyte lysate (LAL) for the quantification of endotoxins in milk samples. The assay was adapted to this particular matrix by incorporating filtration and dilution of the milk samples in the procedure. Our results demonstrate the robustness and usefulness of the assay, which allows the identification of coliform mastitis in milk samples from affected cows and the quantification of endotoxin activity in bulk and commercial milk samples. Further studies are required to evaluate the performance of the assay in mastitis milk samples associated to Gram-negative bacteria other than Escherichia coli as well as during the clinical course of these Gram-negative mastitis or after their treatment with antibiotics.

Variation of six bioactive milk proteins from milk from Chinese commercial dairy farms: Effect of season, farm, breed and udder health status

The study investigated potential changes in bioactive milk proteins in relation to the season, breed, farm and udder health status. Nine hundred and sixty bulk milk samples from 12 commercial farms in northwest China were collected during 2020–2021. Six bioactive proteins including fraction of β‐casein proteins, α‐lactalbumin, β‐lactoglobulin, lactoferrin (Lf) and osteopontin were evaluated. It was found that most proteins (with exception of β‐casein A1) of Jersey cows are significantly higher than Holstein cows. Most bioactive proteins demonstrated seasonal variation, and some exhibited geographical variation (with exception of whey albumins). The milk somatic cell count showed a positive correlation with immune proteins such as Lf.

Loss of Caprine Arthritis Encephalitis Virus (CAEV) Herd Accreditation: Characteristics, Diagnostic Approach, and Specific Follow-Up Scenarios on Large Dairy Goat Farms.

The retrovirus causing caprine arthritis encephalitis (CAE), a slowly progressive inflammatory disease in goats, belongs to the group of small ruminant lentiviruses (SRLVs) which cause lifelong infections that ought to be avoided for animal welfare as well as economic reasons. SRLV accreditation has been in place for forty years in The Netherlands and is based on the screening of small ruminant sera for specific antibodies. This paper evaluates 38 dairy goat herds that lost CAEV accreditation between 2012 and 2022. The characteristics of these herds are discussed, and specific follow-up scenarios, depending on desired goals, are introduced. The herd size of the participating herds varies from approximately 400 to 4600 adult dairy goats. The larger herds tended to be more prone to lose herd accreditation and had more difficulties regaining accreditation. Possible routes of introduction are lined up. The Royal GD's tailor-made approach and advice to support livestock farmers with herds that have lost CAE accreditation are discussed in detail. Specific emphasis is placed on the strategic deployment of various diagnostic tests (such as antibody ELISAs and PCR) in different media, such as (pooled) sera, (bulk)milk and tissue samples. Special attention is paid to the added value of retrospective bulk milk testing or the specific testing of groups based on housing and management, which enables the investigation of the moment of viral introduction and route of transmission into a herd. Furthermore, the prospective implementation of bulk milk and strategic pooled milk sample testing in the Dutch SRLV accreditation programs intensifies surveillance and enables the taking of swift action to prevent further transmission within and between herds. An appeal is made to share experiences to improve programs collectively, and to start research into the underlying mechanisms.

Impacts of production conditions on goat milk vitamin, carotenoid contents and colour indices

The content, composition and variation of vitamin compounds in goat milk have been little studied. An experimental design was based on 28 commercial farms, selected considering the main feeding system (based on main forage and especially pasture access), goat breed (Alpine vs Saanen) and reproductive management (seasonal reproduction), in the main French goat milk production area. Each farm received two visits (spring and autumn) that included a survey on milk production conditions and bulk milk sampling. Milk vitamins (A, E, B2, B6, B9, B12) and carotenoid concentrations plus colour indices were evaluated. A stepwise approach determined the variables of milk production conditions that significantly altered milk indicators. The main forage in the diet was the major factor altering goat milk vitamin and carotenoid concentrations and colour indices. Bulk milk from goats eating fresh grass as forage was richer in α-tocopherol (+64%), pyridoxal (+35%) and total vitamin B6 (+31%), and b* index (characterising milk yellowness in the CIELAB colour space) was also higher (+12%) than in milk from goats eating conserved forages. In milk from goats eating fresh grass, concentrations of pyridoxamine, lutein and total carotenoids were higher than in milk of goats fed corn silage (+24, +118 and +101%, respectively), and retinol and α-tocopherol concentrations were higher than in milk of goats fed partially dehydrated grass (+45 and +55%). Vitamin B2 concentration was higher in milk of goats eating fresh grass than in milk of goats fed hay or corn silage as forage (+10%). However, bulk milk when goats had access to fresh grass was significantly poorer in vitamin B12 than when fed corn silage (−46%) and in γ-tocopherol (−31%) than when fed conserved forage. Alpine goats produced milk with higher vitamin B2 and folate concentrations than Saanen goats (+18 and +14%, respectively). Additionally, the milk colour index that discriminates milks based on their yellow pigment contents was 7% higher in milk from Alpine than Saanen herds, but milk from Saanen goats was richer in lutein (+46%). Goat milks were richer in vitamins B2 and B12 and folates, but poorer in vitamin B6 in autumn than in spring (+12, +133, +15 and −13%, respectively). This work highlights that goat milk vitamin and carotenoid concentrations and colour indices vary mainly according to the main forage of the diet and secondly according to the breed and season.

Prevalence of Neospora caninum and Toxoplasma gondii Antibodies and DNA in Raw Milk of Various Ruminants in Egypt.

The prevalence of Neospora caninum and Toxoplasma gondii antibodies in raw milk samples was estimated in different ruminants and Egyptian governorates. Of 13 bulk milk samples tested by ELISA, five (38.5%) were positive for antibodies to N. caninum, and two samples were additionally positive for antibodies to T. gondii, resulting in a seroprevalence of 15.4% for both T. gondii and co-infection. In individual milk samples (n = 171) from the same bulks, antibodies to N. caninum were detected in 25.7%, to T. gondii in 14%, and 3.5% had antibodies to both parasites. A strong correlation between the OD values of the bulk samples and of the relevant individual milk samples was found for T. gondii (Pearson r = 0.9759) and moderately strong for N. caninum (Pearson r = 0.5801). Risk factor assessment for individual milk samples revealed that antibodies to T. gondii were significantly influenced by animal species, while no risk factors were detected for N. caninum antibodies. Additionally, DNA of N. caninum was detected in a bulk milk sample of cattle for the first time in Egypt, and DNA of T. gondii was found in bulk milk samples of cattle, sheep and goats. This is the first study in Egypt in which bulk milk samples of different ruminants were tested for the presence of N. caninum and T. gondii antibodies and DNA. Both individual and bulk milk samples are useful tools for monitoring antibody response to N. caninum and T. gondii infections in different ruminants in Egypt.

Microbiological and physicochemical properties of farm bulk tank milk and antimicrobial resistance of its dominant bacteria

AbstractThis study determined the antibiotic resistance of the dominant bacteria in the 85 farm BTMs according to the guidelines recommended by the epidemiological cutoff values in the EUCAST. In addition, some physicochemical and microbiological properties of farm BTMs were investigated. The milk samples were divided into two groups according to their SCC values. The milk samples with higher SCC than 400,000 cells mL−1 were further examined bacteriologically, and the antibiotic resistance of isolates was determined. The average TAMB value was 6.34 log CFU/mL in farm BTM. It was found that high‐SCC values did not affect other physicochemical properties of BTM samples, such as fat, protein and total solids, except for lactose content. Seventy‐two strains were isolated from 45 bulk milk samples. The most prevalent bacteria were Enterococcus spp. (23.61%). The other isolates were Citrobacter spp. (12.5%), Staphylococcus spp. (12.51%), Serratia spp. (11.12%), Klebsiella spp. (9.72%), Bacillus spp. (9.72%), and Enterobacter spp. (8.33%). In antibiotic resistance analysis, 52.6% of Enterobacterales isolates showed cefoxitin resistance, and nine Enterobacterales isolates were determined as the presumptive ESBL producers. None of them was confirmed as ESBL producers. Moreover, MDR was detected in 83.3% of Enterobacter spp. isolates and all Bacillus spp. isolates. The over and inappropriate use of antibiotics in mastitis treatment may cause antibiotic‐resistant microorganisms in milk. It was found that 52.7% of the isolated bacteria were MDR, which could pose a risk to public health and food safety, with the consumer's increasing interest in consuming raw milk.

Ingested versus inhaled limonene in sheep: A pilot study to explore potential different transfer to the mammary gland and effects on milk and Caciotta cheese aroma.

Concentration is a key determinant in the overall positive impact of terpenes on milk and cheese aroma; additionally, route of intake may affect the achievable concentrations of dietary terpenes in milk and cheese. In this study, we explored the possibility that the amount of the monoterpene limonene transferred to sheep milk and its corresponding cheese could differ depending on the route of intake and that the aroma profile of these products could also differ. To this aim, 12 lactating dairy ewes were repeatedly exposed to limonene by the oral or respiratory route during a 48-h test period, according to a 3 × 3 Latin square experimental design. Limonene content was measured in individual and bulk milk samples, in 1-d-old and 15-d-old Caciotta cheese obtained from that milk, in the related whey and curd, and in the air inhaled by the ewes in the respiratory treatment group (to obtain an estimate of the dose actually supplied by this route). Bulk milk and fresh (1-d-old) cheese underwent sensory analysis by ortho-olfactory evaluation. Both intake routes demonstrated transfer of limonene to milk, but the respiratory route transferred limonene with greater efficiency than the oral route. Moreover, according to the protocol used in this study, a short period of respiratory exposure induced a slightly higher limonene content in milk compared with oral exposure. As to the fate of limonene during cheesemaking, an important part of it was lost into the whey, perhaps through volatilization. The differences between milk and cheese tended to dissipate in curd and fresh cheese and disappeared completely after 15 d of ripening. Finally, it was possible to distinguish between the 2 routes of limonene intake using sensory analysis, even though no direct relationship was identified between the different aroma profiles of milks and cheeses from the oral and respiratory groups and their respective limonene contents. Overall, our results expand current knowledge on the biological pathways of terpene transfer from feed to sheep milk and cheese, as well as on the role played by terpenes in the formation of aroma in these products. Our observations may contribute to future development of strategies for external control and better standardization of the presence of odor compounds in milk and cheese from dairy ruminants.

Effects of preservative, storage time, and temperature of analysis on detailed milk protein composition determined by reversed-phase high-performance liquid chromatography.

Milk preservative and freezing are used as strategies to prevent microbial growth and milk degradation, especially when immediate analytical processing is not feasible. The effects of the addition of preservative and freezing procedures have been investigated mainly in relation to milk gross chemical composition predicted through mid-infrared spectroscopy. This study aimed to determine whether different preservatives (i.e., no preservative, hydrogen peroxide, Bronopol, and Azidiol), freezing times (i.e., 0, 7, and 30 d), and temperatures of analysis (i.e., 5 and 21°C) influence the composition of milk protein fractions determined through reversed-phase HPLC. Bulk milk samples for the analysis of protein profile were collected from 5 commercial dairy farms. Data were analyzed with a linear mixed model, which included type of preservative, time of storage, temperature of analysis, and the interaction between type of preservative and time of storage as fixed effects, with the farm and the residual as random effects. Samples with no preservative had the greatest amount of all protein fractions, whereas Bronopol-preserved milk had the lowest amount. Increasing storage time under freezing conditions had a nonlinear detrimental effect on milk protein fractions. The temperature of analysis significantly contributed to the variation of κ-casein, β-casein, αS1-casein, β-lactoglobulin, and α-lactalbumin fractions. The z-scores were calculated to evaluate the similarity between detailed protein profile of fresh milk without preservative analyzed at 5°C and detailed protein profile of milk treated according to the tested conditions. Overall results suggested a good agreement between different analytical conditions. Still, short storage time under freezing conditions is recommended to avoid degradation of milk protein fractions and consequent analytical underestimation.

Seroprevalence of Cattle Brucellosis in Al Gadarif State – Eastern Sudan

Aims: This study was conducted to determine the seroprevalence of bovine brucellosis in Al Gadarif state -Eastern Sudan- and to evaluate the sensitivity of RBPT, mRBPT, and milk ring test for serodiagnosis of bovine brucellosis.&#x0D; Study Design: Collect serum and milk samples and apply the recommended tests for diagnosis.&#x0D; Place and Duration of Study: This study was carried out in Al Gadarif state regional laboratory and Central Veterinary Research Laboratory (CVRL) in 2015.&#x0D; Methodology: A total of 367 serum samples were collected from 12 localities which include: Al Fao, Fashaga, Baldiat Al Gadarif, Wasat Gadarif, West Gadarif, Basonda, Al Gorisha, Al rhad,Mafaza , Butana, East Galapat and Gla nahl. Also, 100 bulk milk samples have been collected from Baldiat Al Gadarif, West Gadarif, Wasat Gadarif, and Fashaga and subjected to the milk ring test. All collected sera samples were tested for Brucella antibodies using the following serological tests: Rose Bengal Plate Test (RBPT), modified Rose Bengal Plate test (mRBT 1:2 and 1:3) and, c.ELISA test, the last test was done for 143 serum samples only.&#x0D; Results: The overall seroprevalence was 35.7%, 38.4%, 42.2% and 8.4% using RBPT, mRBPT (1:2), mRBPT (1:3) and c.ELISA tests respectively. According to this study the lowest seroprevalence was observed in Al Fao locality (11.1%), and the highest seroprevalence was in Al Gorisha Locality (71.4%).There was similarity in seroprevalence rate results using RBPT (1:2) and RBPT (1:3) in Al rahd (43.6%), Al Gorisha (85.7%) and Mafaza (50%) localities. Seroprevalence rate showed 10.9% and 9.1% in males and females respectively. There was no association between sex-as risk factor- and cattle brucellosis. Using the milk ring test the overall prevalence of positive milk samples was 39% (39/100). The highest prevalence was in Fashaga (60%), followed by Wasat Gadarif (46.7%). Baldiat Al Gadarif showed the lowest prevalence (22.9%).&#x0D; Conclusion: The serological investigation proved the occurrence of bovine brucellosis in Al Gadarif state -Eastern Sudan - using the recommended tests.

Evaluation of an ELISA for the diagnosis of bovine tuberculosis using milk samples from dairy cows in China

Bovine tuberculosis (bTB) is an important zoonotic disease in developing countries including China. Lack of rapid and simple detection methods for surveillance affects efficient control and eradication of this disease. The objective of this study was to determine the feasibility of using an individual and bulk milk sample ELISA based on the fusion protein of four specific antigens (CFP10/ESAT-6/MPB70/MPB83) of Mycobacterium bovis for the rapid detection and surveillance of bTB in dairy cattle herds and to identify individual animal factors that affect its results. The study population consisted of 388 dairy cows from four herds in Henan province, China. The serum sample ELISA (cut-off value 30%) and milk sample ELISA (cut-off value 10%) were shown to have good agreement, while, there was fair agreement between a blood sample IFN-γ in vitro release assay and the milk sample ELISA (cut-off value 10%) (Cohen’s kappa statistic of 0.492 and 0.306, respectively). The sensitivity and specificity for the milk sample ELISA using a S/P% cut-off value of 10%, as estimated using a Bayesian latent class analysis model, was 48.4% (95%CI: 31.0 – 85.2) and 97.1% (95%CI: 92.2 – 99.7), respectively. Although both ELISAs had comparable sensitivities and specificities, the milk sample ELISA had a greater discriminatory ability, as measured by the area under the curve (ROC), than the serum sample ELISA with the difference of their AUCs being − 0.069 (95%PCI: −0.121 to −0.021). Further, it was estimated that the lower limit of detection at an animal level lacto-prevalence might be 1.1% with this milk ELISA using bulk milk samples. Additionally, a mixed linear regression model, incorporating herd as a random effect variable, was constructed to investigate the association between natural log-transformed bTB sample-to-positive ratio (LnS/P%) and milk data. Across the model, natural log-transformed Somatic Cell Count (SCC) and parity had a positive effect on the LnS/P% of bTB antibody response, and milk urea nitrogen had a curvilinear association with LnS/P%. In conclusion, a milk ELISA for bTB antibodies, especially bulk tank milk antibodies, could be used as an efficient tool for rapid screening in surveillance, which might be followed by confirmatory testing with IFN-γ assay in dairy cattle, during the implementation of bTB control programmes. Relevant milk factors should be considered to adjust the S/P% with the aim of classifying the infection status of animals and herds as accurately as possible.