Goat Milk Research Articles

Investigation of some probiotic and technological properties of lactic acid bacteria strains isolated from artisanal sheep milk cheese and their growth in goat milk

The objective of this study was to assess the probiotic and technological properties of lactic acid bacteria (LAB) isolated from artisanal sheep milk cheeses for potential use in dairy products made from goat milk. Strains studied were Lacticaseibacillus paracasei LC6, Lactiplantibacillus plantarum LP48, Lactococcus lactis subsp. hordniae LH69 and Leuconostoc mesenteroides LM99. The criteria studied were fermentative capacity, carbohydrate fermentation profile, β-galactosidase (lactase) activity, auto-aggregation capacity, hydrophobicity, antimicrobial activity, resistance to simulated gastric secretion, bile resistance, and resistance to different pH and salts concentrations, as well as growth and viability in goat milk. In general, the strains studied showed characteristics compatible with potential probiotic effects. However, according to criteria studied, L. plantarum LP498 best met the conditions; it was compatible with probiotic potential under all the conditions considered and showed noteworthy differences compared to the other micro-organisms studied, particularly in its capacity for self-aggregation and pH resistance. Therefore, L. plantarum LP48 could be adequate for the manufacture of artisanal goat milk products.

Chia Seed Mucilage as a Functional Ingredient to Improve Quality of Goat Milk Yoghurt: Effects on Rheology, Texture, Microstructure and Sensory Properties

Chia Seed Mucilage as a Functional Ingredient to Improve Quality of Goat Milk Yoghurt: Effects on Rheology, Texture, Microstructure and Sensory Properties

Preparation, characterisation and functional effects of goat milk whey protein isolate with low lactose after heat and non‐heat treatments

This study investigates the physicochemical and functional properties of goat milk whey with heat and non‐heat treatments (pasteurisation, high‐temperature heating, ultrasonic treatment and microwave heating) and lactose hydrolysis. The optimal lactose hydrolysis conditions were obtained through orthogonal test. The results revealed the lactose and glucose in low‐lactose goat milk whey remained largely unchanged through all four treatments, while high‐temperature and microwave treatments induced protein structure alteration. The foaming and emulsifying properties of low‐lactose whey powder were enhanced by heating and ultrasonic treatments, although foam stability decreased. Our findings provide valuable insights into exploiting more nutritional goat milk products.

Goat Milk Allergy and a Potential Role for Goat Milk in Cow's Milk Allergy.

In many parts of the world, goat milk has been part of the human diet for millennia. Allergy to goat's milk, not associated with allergy to cow's milk, is a rare disorder, although some cases have been described. Goat milk proteins have substantial homology with cow's milk proteins and even show cross-reactivity; therefore, they are not advised as an alternative to cow's milk for infants with IgE-mediated cow's milk allergies. However, there are indications that, due to the composition of the goat milk proteins, goat milk proteins show lower allergenicity than cow's milk due to a lower αS1-casein content. For this reason, goat milk might be a better choice over cow's milk as a first source of protein when breastfeeding is not possible or after the breastfeeding period. Additionally, some studies show that goat milk could play a role in specific types of non-IgE-mediated cow milk allergy or even in the prevention of sensitization to cow's milk proteins. This review discusses a possible role of goat milk in non-IgE mediated allergy and the prevention or oral tolerance induction of milk allergy.

Label-free quantitative proteomic analysis of functional changes of goat milk whey proteins subject to heat treatments of ultra-high-temperature and the common low-temperature

This work investigated the functional changes in whey proteins obtained from goat milk subject to various temperature treatments. Ultra-high temperature instantaneous sterilization (UHTIS) caused less damage than the common low-temperature, whereas spray-drying treatment had the opposite effect. A total of 426 proteins were identified in UHTIS and control treatment groups, including 386 common proteins and 16 and 14 unique proteins. The UHTIS treatment upregulated 55 whey proteins while down-regulated 98. The UHTIS-treated whey proteins may upregulate three metabolic pathways but downregulate one. Overall, UHTIS only slightly impacted the composition and functions of whey proteins from goat milk compared to the common low-temperature treatments.

Quality of native goat's milk from a multivariate perspective

The aim of this study was to assess the relationship between physical components and the fatty acid (FA) profile of goat's milk, compare the physical and chemical variables of the milk using canonical correlation, and verify the contribution of the physical variables in predicting the FAs in the milk, contributing to the selection of the FA profile by the correlated response based on the physical profile of the milk. A total of 24 native goats, weighing 42 ± 4 kg and 30 ± 3 days into lactation, were used. The data were subjected to canonical analysis to identify the variables that best discriminate. The main objective of this procedure is to find the best set of variables to compose the discriminant function. Four components were needed to explain 70.68% of the total variation in the physical variables and FA profile in the milk of native goats. The percentage of variance accumulated in the first two factors is 41%. The most important variables in the first factor were the short-chain FAs, namely, caproic (6C), caprylic (8C), capric (10C), and lauric (C12), which are responsible for giving the milk its characteristic and even unpleasant odor, depending on their concentration. New studies with a larger sample of data should be carried out to better understand the relationships between physical and chemical variables in the milk of native goats as well as other breeds of goats for comparison. In addition, the weak simple correlations between the variables studied contributed to the results obtained.

Socio-economic aspects and farming practices of goats in Southern Tunisia.

This study aims to describe socio-economic aspects, farming practices and production limitations of goats by surveying 53 farms holding 5507 head in the regions of Tataouine-Tunisia. It was revealed that goats represented a major source of income for most of the producers (66.1%). Approximately 35.8% of the farmers had not received formal education, with the majority (56.6%) having been engaged in goat breeding for over 10 years. Additionally, 50.9% of stockholders relied on technical knowledge for animal breeding. The investigated herds were mostly (97.4%) comprised of local goat breeds. The most common management system was semi-intensive (49.1%) based on grazing in communal rangelands and supplementation with agricultural by-products and concentrates. The fertility, fecundity and prolificacy rates were 91.3 ± 8.3, 109.8 ± 19.5 and 127.0 ± 15.4%, respectively. The main reasons for keeping goats were their major contribution to the income by the sale of male kids and the provision of milk for home consumption. Sale of male kids at an age of 7.7 months was practiced mostly via intermediaries (94.3%) and rarely directly to butchers and markets (5.7%). The total amount of milk produced on each farm was on average 15.1l/day, and more than half of farmers (54.7%) consumed goat milk as part of their daily diet. The majority (71.7%) of respondents locally processed milk into Leben, Rayeb and cheese because the goat milk market faced constraints in the Tataouine regions, mainly in terms insufficient milk production and low consumer acceptability. Goats contribute to the income source in rural zones of southern Tunisia, where their breeding is mainly for the purpose of meat sale and the provision of milk for home consumption. The development of goat milk market can represent an added value to this sector.

Screening of lactic acid bacteria with the ability to reduce goaty flavor related fatty acids in goat milk

In this study, we conducted sensory evaluation and gas chromatography–mass spectrometry analysis on fermented goat milk samples prepared by 12 strains of lactic acid bacteria (LAB) isolated from goat milk to screen for strains with the ability to reduce the goaty flavor. The bacterial counts of fermented goat milk was 7.07–9.01 log CFU/mL. The electronic nose distinguished fresh goat milk (FGM) and fermented goat milk, and the electronic tongue results showed that Leuconostoc citreum 1, 4, 20, 22, 32, and 57, Latilactobacillus curvatus 144 and 147 imparted fermented goat milk a taste different from FGM. Overall, Leuconostoc citreum 57, Leuconostoc citreum 126, Latilactobacillus curvatus 142, Latilactobacillus curvatus 143, and Latilactobacillus curvatus 147 were screened with the ability to improve the flavor of goat milk. They gave fermented goat milk a goat flavor score lower than or equal to FGM. And the fermented goat milk samples 57, 126, 142, 143, and 147 contained 25, 22, 15, 24, and 17 volatile flavor compounds, respectively, with a greater variety and content of ketones and aldehydes and lower levels of hexanoic acid, octanoic acid, and decanoic acid than FGM. However, the pH and WHC results indicated that the application of these strains as secondary cultures is necessary. Our finding provides basic research data to improve the flavor of goat milk products.

A Comparative Study on the Composition and Structure of Human Milk Phospholipids and its Natural Resources: Based on a Similarity Evaluation Model

Human milk phospholipids (HMPLs) play an indispensable role in the neurodevelopment and growth of infants. In this study, a total of 37 phospholipid fatty acid (PLFA) species and 139 phospholipid molecular species were detected from human milk and other natural phospholipid sources (including 5 animal-derived species and 2 plant species). Moreover, a similarity evaluation model for HMPLs was established, including phospholipid classes, PLFAs, and phospholipid molecular species, to evaluate their natural substitutes. The closest scores for HMPL substitute in these three dimensions was 0.89, 0.72, and 0.77, which belonged to mare milk, goat milk, and camel milk, respectively. The highest comprehensive similarity score was obtained by camel milk at 0.75, while the lowest score was observed in soybean phospholipid (0.22). Therefore, these results not only monitored the stereochemical structure of HMPLs and their substitutes, but also further provided new insights for the development of infant formulae.

Metabolite profiling of different Iranian traditional yogurts using an untargeted metabolomics approach

We used gas chromatography-mass spectrometry (GC-MS) with an untargeted metabolomics approach to look at the metabolite profiles of traditional Iranian yogurts made from cow, goat, buffalo, and sheep milk. Results showed that different animal milks significantly influenced physicochemical properties and fatty acid (FA) composition, resulting in diverse metabolites. Over 80 % of all the fatty acids in the yogurt samples were saturated. The main fatty acids found were myristic acid (C14:0), palmitic acid (C16:0), and oleic acid + petroselenic acid (cis-9 C18:1 + cis-6 C18:1). In total, 36 metabolites, including esters, aldehydes, alcohols, and acids, were detected. Some important metabolites that changed yogurt profiles were 2-heptanone, methyl acetate, 2-propanone, butyl formate, and 4-methyl benzal. Associations between metabolite profiles and milk compositional traits were also observed, with statistical models showing a strong correlation between metabolite profiles and FA content. This study is the first to explore the impact of different animal sources and regions in Iran on the metabolome profiles of traditional yogurts. These results give us useful information about how metabolites differ between species and can be used to make new dairy products based on milk compositions and metabolites, which will help with future formulations of autochthonous starters.

Detection and quantification of antibiotic residues in goat milk in Mahikeng Local Municipality.

Goat milk could be used to reduce malnutrition since it is highly nutritious, and many people in rural communities in South Africa rear small ruminants for survival. However, the risk of food contamination by antibiotic residues is one of the significant problems facing public health, and is a result of the irresponsible use of veterinary drugs. One hundred goat farmers were interviewed using a questionnaire, and raw milk samples from 266 goats were collected and analysed for the presence of antibiotic residues. Screening for amoxicillin, tetracycline, sulfamethazine, erythromycin, and streptomycin residues was done using the enzymelinked immunosorbent assay (ELISA) while high-performance liquid chromatography (HPLC) was carried out for confirmation. The questionnaire shows that all (100%) of the participants acknowledged the use of antibiotics on their goats and 99% of them were aware of the possibility of antibiotic residues in milk. ELISA results for residues of erythromycin, sulfamethazine and amoxicillin exceeded the Codex Alimentarius maximum residue levels (MRLs) in 94.7%, 82.3%, and 35.3% of analysed samples, respectively. Tetracycline was present in all (100%) analysed milk samples, and streptomycin was detected in 18.7% of samples; however, these results were below the recommended MRLs. The HPLC method confirmed the presence of streptomycin and tetracycline residues in 90% and 40% of the samples analysed. However, the concentrations were below the accepted MRL standards. Approximately 76.6% of samples exceeded the established MRL for sulfamethazine and 10% for erythromycin. Amoxicillin was not detected by the HPLC method. The results obtained in this study indicate a high level of contamination of goat milk with antibiotic residues, which may harm the health of the consumers.

Phytochemical characterization and quality evaluation of stirred goat milk yoghurt with added fruit and vegetable puree during storage

PurposeGoat milk yoghurt differs from cow milk yoghurt in that it has a different casein composition and content, which presents several technical challenges, including consistency with an appropriate flavor.Design/methodology/approachIn this study, the antioxidant potential and phytochemical profiling of the fruits (pineapple and papaya) and vegetable (carrot) extracts was evaluated and the effect of their purees on the quality and stability of stirred goat milk yoghurt (GMY) were investigated. The qualities of stirred GMY with carrot (CrY), pineapple (PaY) and papaya (PpY) purees were assessed against the product without puree (CY).FindingsThe carrot puree had the highest moisture, ash contents and pH value. The carrot extract had the highest DPPH radical scavenging activity, while the pineapple extract had the highest total phenolic value (1.59 µg GAE/g) and flavonoids content (0.203 µg CE/g). The scanning of all the puree extracts in GC-MS indicated that 5-hydroxymethylfurfural was a major component. The phytochemical quantification of the extracts through multiple reaction monitoring (MRM) against 16 compounds showed the presence of sinapic acid, cinnamic acid, pthalic acid, ferulic acid, 4-OH-benzoic acid, 3-OH-benzoic acid, p-coumaric acid, caffeic acid and vanillic acid in different quantities. The addition of purees and storage period had a significant (p < 0.05) effect on the moisture, pH, titratable acidity, syneresis, viscosity, color values and sensory properties of the products. In all the samples after 15 days of storage, Streptococcus thermophilus and Lactobacillus bulgaricus counts remained above the recommended level of 106CFU/g. Stirred GMY sample produced with pineapple puree showed a higher syneresis and viscosity, but the CrY sample demonstrated the highest antioxidant activity. The developed formulations remained stable with minimum changes in quality and sensory attribute during refrigerated storage for 10 days.Originality/valueThis study suggests that addition of fruit and vegetable improve the viscosity and sensory perception of the product with minimal use of synthetic flavor and preservatives.

Analysis of AMDAL aspects on Bangkalan Red Land Goat Farms in the Perspective of Business Feasibility Study

Goat farms in Indonesia are currently developing very rapidly because many results can be obtained. Some of the results include the sale of parent, child and milk. Another addition is the result of processing goat manure (inthil) into organic fertilizer. Good feed provision and sufficient quantities need to be done to improve the quality of goats, milk and tillers produced. In order to continue to provide quality feed, knowledge is needed for making good quality fermented goat feed and can last a long time. Various kinds of processed goat milk can be produced such as pure milk packed in bottles or milk powder. Waste goat manure, both in the form of solid waste (inthil) or liquid waste (urine) if managed properly will provide economic added value. In addition, it is also necessary to assume about management and good marketing techniques to get maximum profits. The use of information technology (e-commerce) will be able to expand the marketing range of goat products in Indonesia.

Analysis of Human Milk Microbiota in Northern Greece by Comparative 16S rRNA Sequencing vs. Local Dairy Animals.

Milk is a biological fluid with a dynamic composition of micronutrients and bioactive molecules that serves as a vital nutrient source for infants. Milk composition is affected by multiple factors, including genetics, geographical location, environmental conditions, lactation phase, and maternal nutrition, and plays a key role in dictating its microbiome. This study addresses a less-explored aspect, comparing the microbial communities in human breast milk with those in mature milk from species that are used for milk consumption. Since mature animal milk is used as a supplement for both the infant (formula) and the child/adolescent, our main aim was to identify shared microbial communities in colostrum and mature human milk. Using 16S rRNA metagenomic sequencing, we focused on characterizing the milk microbiota in the Northern Greek population by identifying shared microbial communities across samples and comparing the relative abundance of prevalent genera. We analyzed ten human milk samples (from five mothers), with five collected three days postpartum (colostrum) and five collected thirty to forty days postpartum (mature milk) from corresponding mothers. To perform an interspecies comparison of human milk microbiota, we analyzed five goat and five bovine milk samples from a local dairy industry, collected fifty to seventy days after birth. Alpha diversity analysis indicated moderate diversity and stability in bovine milk, high richness in goat milk, and constrained diversity in breast milk. Beta diversity analysis revealed significant distinctions among mammalian species, emphasizing both presence/absence and abundance-based clustering. Despite noticeable differences, shared microbial components underscore fundamental aspects across all mammalian species, highlighting the presence of a core microbiota predominantly comprising the Proteobacteria, Firmicutes, and Actinobacteriota phyla. At the genus level, Acinetobacter, Gemella, and Sphingobium exhibit significant higher abundance in human milk compared to bovine and goat milk, while Pseudomonas and Atopostipes are more prevalent in animal milk. Our comparative analysis revealed differences and commonalities in the microbial communities of various mammalian milks and unraveled the existence of a common fundamental milk core microbiome. We thus revealed both species-specific and conserved microbial communities in human, bovine, and goat milk. The existence of a common core microbiome with conserved differences between colostrum and mature human milk underscores fundamental similarities in the microbiota of milk across mammalian species, which could offer valuable implications for optimizing the nutritional quality and safety of dairy products as well as supplements for infant health.

Combined Metabolomic and NIRS Analyses Reveal Biochemical and Metabolite Changes in Goat Milk Kefir under Different Heat Treatments and Fermentation Times.

Dairy products are an important source of protein and other nutrients in the Mediterranean diet. In these countries, the most common sources of milk for producing dairy products are cow, goat, sheep, and buffalo. Andalusia is traditionally the largest producer of goat milk in Spain. Kefir is a fermented product made from bacteria and yeasts and has health benefits beyond its nutritional properties. There is a lack of knowledge about the molecular mechanisms and metabolites that bring about these benefits. In this work, the combination of analytical techniques (GC-FID, UHPLC-MS-QToF, GC-QqQ-MS, and GC-ToF-MS) resulted in the detection of 105 metabolites in kefir produced with goat milk from two different thermal treatments (raw and pasteurized) fermented at four time points (12, 24, 36, and 48 h, using 0 h as the control). Of these, 27 metabolites differed between kefir produced with raw and pasteurized milk. These changes could possibly be caused by the effect of pasteurization on the microbial population in the starting milk. Some interesting molecules were identified, such as shikimic acid, dehydroabietic acid, GABA, and tyramine, which could be related to antibacterial properties, strengthening of the immune system, and arterial pressure. Moreover, a viability assay of the NIRS technique was performed to evaluate its use in monitoring the fermentation and classification of samples, which resulted in a 90% accuracy in comparison to correctly classified samples according to their fermentation time. This study represents the most comprehensive metabolomic analysis of goat milk kefir so far, revealing the intricate changes in metabolites during fermentation and the impact of milk treatment.

Age-specific composition of milk microbiota in Tibetan sheep and goats

This study investigates the dynamic changes in milk nutritional composition and microbial communities in Tibetan sheep and goats during the first 56 days of lactation. Milk samples were systematically collected at five time points (D0, D7, D14, D28, D56) post-delivery. In Tibetan sheep, milk fat, protein, and casein contents were highest on D0, gradually decreased, and stabilized after D14, while lactose and galactose levels showed the opposite trend. Goat milk exhibited similar initial peaks, with significant changes particularly between D0, D7, D14, and D56. 16S rRNA gene sequencing revealed increasing microbial diversity in both species over the lactation period. Principal coordinates analysis identified distinct microbial clusters corresponding to early (D0–D7), transitional (D14–D28), and mature (D56) stages. Core phyla, including Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, dominated the milk microbiota, with significant temporal shifts. Core microbes like Lactobacillus, Leuconostoc, and Streptococcus were common in both species, with species-specific taxa observed (e.g., Pediococcus in sheep, Shewanella in goats). Furthermore, we observed a highly shared core microbiota in sheep and goat milk, including Lactobacillus, Leuconostoc, and Streptococcus. Spearman correlation analysis highlighted significant relationships between specific microbial genera and milk nutrients. For instance, Lactobacillus positively correlated with total solids, non-fat milk solids, protein, and casein, while Mannheimia negatively correlated with protein content. This study underscores the complex interplay between milk composition and microbial dynamics in Tibetan sheep and goats, informing strategies for livestock management and nutritional enhancement.Key points• The milk can be classified into three types based on the microbiota composition• The changes of milk microbiota are closely related to the variations in nutrition• Filter out microbiota with species specificity and age specificity in the milk

Use of crude glycerin in dairy goat feeding and its effects on milk and cheese performance and quality

This study aimed to assess the impact of stepwise dietary inclusion of crude glycerin (CG) on the productive traits of dairy goats and the quality of their milk and cheese. Sixteen Saanen goats, averaging 55 ± 6 kg live weight and 45 days in milk, were allocated into four simultaneous Latin squares (4×4) and fed on diets containing 0 (control), 50, 100, and 150 g/kg of CG in the dry matter (DM). A linear decrease (P < 0.05) was observed in DM, crude protein (CP), neutral detergent fiber (NDF), and non-fibrous carbohydrates intake with increasing CG levels in the diet, with a significant reduction (P < 0.05) noted at 100 and 150 g/kg of CG. Additionally, CP digestibility, nitrogen balance, and plasma urea nitrogen decreased (P < 0.05) with CG inclusion. Milk yield corrected for 3.5 % fat, total solids content, and total fatty acid (FA) amounts in goat milk decreased (P < 0.05) with 100 and 150 g/kg of CG. Furthermore, inclusion of 150 g/kg of CG decreased (P < 0.05) fat content in "coalho" cheese, although cheeses from goats fed up to 50 g/kg of CG showed superior (P < 0.05) appearance, global impression, and purchase intention. The CG inclusion increased (P < 0.05) short and odd-chain FA contents while decreasing (P < 0.05) long-chain and polyunsaturated FA levels in goat milk. Overall, we recommend incorporating up to 50 g/kg of CG in dairy goat diets as it does not affect milk and "coalho" cheese performance and quality.

Prevalence, antibiogram and molecular characterization of Listeria monocytogenes from ruminants and humans in New Valley and Beheira Governorates, Egypt

BackgroundListeriosis is a global health threat to both animals and humans, especially in developing countries. This study was designed to isolate Listeria monocytogenes from faeces; environmental samples; and cow, sheep and goat milk, as well as human stool, to study its molecular characteristics and antibiotic sensitivity in the New Valley and Beheira Governorates, Egypt. The isolation and identification of L. monocytogenes were carried out using traditional culture and biochemical methods, followed by antibiography, genus confirmation of some isolates and detection and sequencing of InlB genes via PCR.ResultsOut of 2097 examined samples, the prevalence of L. monocytogenes was 13.4% in animals; the prevalence was 9.2%, 2.4%, 25.4%, 4%, 42.4%, and 6.4% in cattle faeces, cattle milk, sheep faeces, sheep milk, goat faeces, and goat milk, respectively. However, the prevalence of L. monocytogenes was 8.3% in human samples. Both animal and human isolates showed 100% resistance to trimethoprim-sulfamethoxazole, and the isolates showed the highest sensitivity to flumequine (100%), amikacin (99.2%), gentamicin (97.6%), and levofloxacin (94.6%). Multidrug resistance (MDR) was detected in 86.9% of the tested isolates. The 16 S rRNA and inlB genes were detected in 100% of the randomly selected L. monocytogenes isolates. Phylogenetic analysis of three isolates based on the inlB gene showed 100% identity between faecal, milk and human stool isolates.ConclusionsFaeces and milk are major sources of listeriosis, and the high degree of genetic similarity between animal and human isolates suggests the possibility of zoonotic circulation. The high prevalence of MDR L. monocytogenes in both animal and human samples could negatively impact the success of prevention and treatments for animal and human diseases, thereby imposing serious risks to public health.

Draft genome sequences of Weissella cibaria GM93m3, a promising probiotic strain from raw goat milk.

The draft genome of a previously documented potential probiotic Weissella cibaria strain GM93m3 from raw goat milk in Nigeria is reported. The total genome size was 2,447,229 with 46 contigs and G+C content of 44.86%.

Label-free-based proteomics analysis reveals differential proteins of sheep, goat, and cow milk

Regarding the limited information on species protein differences between sheep, goat, and cow milk, we analyzed the differentially expressed proteins in sheep, goat, and cow milk and their functional differences using label-free proteomics technology to identify potential biomarkers. In all, 770 proteins and 2,914 peptide segments were identified. Statistical analysis showed significant differences in the relative abundances of the 74 proteins among sheep, goat, and cow milk. CSN3 and LALBA can be used as potential biomarkers for goat milk, XDH can be used as a potential biomarker for cow milk, and CTSB and BPIFB1 can be used as potential biomarkers for sheep milk. Functional analysis using Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes showed that these significantly different proteins were enriched by different pathways, including thyroid hormone synthesis and glycerol phospholipid metabolism. The data revealed differences in the amounts and physiological functions of the milk proteins of different species, which may provide an important basis for research on the nutritional composition of dairy products and adulteration identification technology.