This study evaluated the microbiological quality, presence of virulence genes, and antimicrobial resistance of Staphylococcus aureus and Escherichia coli in sheep and goat milk and traditional Romanian dairy products (Telemea and Burduf cheeses). Raw milk contained high levels of coagulase-positive staphylococci (CPS; 5.2 log CFU/mL) and E. coli (4.3 log CFU/mL), with several samples exceeding legal limits. Sour cream exhibited moderate CPS (1.2–1.9 log CFU/g) and E. coli (0.4–3.12 log CFU/g) counts, with occasional non-compliance. Cheeses had low CPS (0.52–0.84 log CFU/g) and E. coli (0.37–0.89 log CFU/g) levels, all within permissible limits. Molecular analysis detected the nuc gene in 21 sheep milk samples, of which 85.7% also carried the sea gene and 14.3% carried seb. Additionally, two goat milk samples tested positive for both nuc and sea. Three Telemea cheese samples were also sea-positive. Among raw milk samples, 10 E. coli isolates carried stx1, and two additionally harbored hly, while dairy products were negative for E. coli virulence genes. Antimicrobial susceptibility testing showed high resistance of S. aureus to penicillin (90.5%) and ampicillin (85.7%), with multidrug resistance among sea- and seb-positive isolates. STEC isolates showed resistance to ampicillin (70%), tetracycline (50%), and trimethoprim–sulfamethoxazole (40%), but remained susceptible to amoxicillin–clavulanic acid.

Antihypertensive and antioxidant peptide identification and storage stability assessment of novel probiotic fermented sheep milk: A comparative study with bovine milk

Autochthonous enterococci surviving mild thermization of raw milk (RM) before traditional Greek cheese processing may simultaneously comprise safe and virulent thermoduric strains with multiple antibiotic resistances (ARs). Therefore, this study biotyped and then compared the ARs of 60 Enterococcus isolates from two antilisterial sheep milks of native Epirus breeds before (RM) and after (TM) thermization at 65 °C for 30 s; the RM isolates were previously genotyped and evaluated for primary safety traits, namely, hemolytic activity, vanA/vanB, cytolysin, and virulence genes, by molecular methods. Biochemically typical and atypical strains of Enterococcus faecium (six biotypes), E. durans (five biotypes), E. faecalis (two biotypes), and E. hirae (one biotype), which were subdominant to other LAB species in RM (19 isolates), prevailed in TM (41 isolates). E. faecium biotypes 1A, 1D, and 1H included multiple-Ent+ (entA/entB/entP or entA/entB) strains with strong antilisterial CFS activity, whereas E. faecium 1X (entA), E. durans 2A, 2B, 2C, and 2X (entA/entP or entP), E. faecalis 3B, and E. hirae 4A (entA) biotypes displayed direct in vitro antilisterial activity only. Biotypes 1D, 1X, and 2A were selected in TM. All E. faecium/durans isolates were susceptible to vancomycin, but the m-Ent + E. faecium biotype 1A and 1D strains were resistant to penicillin, erythromycin, ciprofloxacin, and ampicillin. In contrast, all biotype 1X isolates were susceptible to all antibiotics tested. All E. faecalis and most E. durans isolates were resistant to penicillin but susceptible to erythromycin and ciprofloxacin. Biotype 2X isolates and one virulent (ace; gelE) E. faecalis isolate from RM were tetracycline-resistant. A sporadic RM isolate of E. hirae that was resistant to penicillin and vancomycin was not retrieved from the counterpart TM, but the inclusion of three vancomycin-resistant isolates from TM in the primary biotype 3B of E. faecalis was a cause for concern. In conclusion, based on the results, antibiotic-susceptible representatives of all strain biotypes of the E. faecium/durans group, as well as antagonistic m-Ent+ E. faecium strains from sheep milk that were susceptible to vancomycin and ampicillin and lacking virulence genes, can be included in safe complex natural starters to be developed for onsite use in traditional Greek hard cheese technologies.

This article presents the results of experimental studies on the cheese suitability of sheep's milk of local and other breeds and the improvement of the technology for the production of a new type of national homemade soft cheese from a mixture of sheep and goat milk.At the first stage of research, a review of scientific, technical and patent literature on the problems of trends in the development of technology for the production of National Dairy and protein products, including national types of soft cheese, was carried out. Further, experimental studies were conducted on the suitability of milk of local and other breeds of goats and sheep for cheese.Goat milk of thе «gornoaltai» breed and sheep of the Aboriginal breed of the «Kazakh Northern Merino» were chosen as the main raw materials for the production of a new type of National soft homemade cheese «Kereku» from a mixture of goat and sheep milk. To obtain a new type of National soft homemade cheese «Kereku» from a mixture of goat and sheep milk, the process of coagulation of milk suitable for cheese using various yeasts and enzymes was studied.The clotting process was carried out at a temperature of 37-38 0C 40-60 min. The results showed that such an enzyme «lactoferm ECO yeast» Natural rennet has a very high milk clotting activity. Soy paste made from dry soy milk was also used as a functional additive for the National soft homemade cheese «Kereku» from a mixture of goat and sheep milk, and its concentration in the cheese mixture of the product was determined. In this case, samples of soft cheese with 8-10% soy paste were chosen. It was found that exceeding 10% of the amount of soy puree leads to a deterioration in organoleptic indicators, that is, an excessively pronounced taste of the soy component.The recipe and technological process for the production of a new type of National soft homemade cheese «Kereku» from a mixture of goat and sheep milk in two versions has been developed, determining the quality indicators of the finished product.

ABSTRACT This study aims to evaluate the rheological behavior of cow, goat, buffalo, and sheep milk over a wide temperature range (1°C–90°C), considering their chemical composition. The milk from the different species showed Newtonian behavior, and the Newton model was the most suitable ( R adj 2 ≥ 0.9979; P (%) ≤ 2.6817; RQME ≤ 0.0333) to predict the rheological behavior of milk over the wide temperature range studied (1°C–90°C). Despite the statistically significant differences in the viscosity of goat and cow milk, the effect size is small in practical terms (on average, less than 4% difference), indicating that the necessary operating conditions are close to those found for a process designed for cow milk. In contrast, buffalo and sheep milk presented, on average, viscosity up to 24%–26% higher than cow and goat milk, which was attributed to the higher content of lipids, ash, and total solids, in addition to structural factors such as fat crystallization, protein interactions, and micellar structure. The Newtonian viscosity of milk from different species decreased with increasing temperature, and the Arrhenius equation described its thermal dependence well. These findings help better understand the rheological properties of milk from different species, supporting the development and improvement of dairy processes and products.

Comparative study of the outcome of yogurt-type fermentation of lactose-containing and lactose-free cow and sheep milk

The variation patterns of microorganisms in sheep milk under different heat treatments and storage times

Uncovering milk quality in local sheep breeds: From bioactive constituents to genetics.

DNA metabarcoding for the identification and relative abundance assessment of general and potentially pathogenic bacteria in Sardinian sheep cheese processing environments.

Fermented dairy products such as yogurt, kefir, and traditional cheeses are increasingly consumed worldwide for their nutritional and probiotic properties. Lipidomic profiling provides valuable insights into microbial-driven biochemical changes during fermentation. In this study, we performed a comprehensive untargeted lipidomic analysis of sheep milk and Gioddu, a traditional Sardinian fermented dairy product. Using UHPLC-QTOF-MS platform, we observed that fermentation significantly reshaped the lipidome. Gioddu samples showed higher levels of phosphatidylethanolamines (PE) and lysophosphatidylethanolamines (LPE), together with a pronounced reduction in sphingolipids (glucosylceramides, ceramides, sphingomyelins) and glycerophospholipids (phosphatidylinositols, phosphatidylserines, phosphatidylcholines) compared to sheep milk. These findings align with known enzymatic activities of lactic acid bacteria (LAB), including phospholipases A1 and A2, phosphatidylinositol-specific phospholipase C (PI-PLC), and sphingomyelinase. Fermentation also affected triglycerides, with reduced levels of FA 18:1-containing species, suggesting the selective lipolysis of monounsaturated fatty acids by microbial lipases. Complementary metabolomic profiling revealed reduced levels of simple sugars such as galactose and inositol in Gioddu samples, consistent with their use as primary carbon sources during early fermentation. Conversely, a marked accumulation of carboxylic acids (succinic, malic, hydroxyisovaleric, hydroxyglutaric, glyceric) was revealed, reflecting enhanced microbial fermentative activity. Increased levels of amino acids, including alanine, serine, proline, and ethanolamine, further highlighted active proteolysis and membrane remodeling driven by LAB metabolism. These findings show that LAB enzymes play a key role in modifying the lipidome of fermented dairy products, highlighting their metabolic flexibility and potential impact on nutritional and health properties. This integrated approach sheds new light on the metabolic plasticity of fermentative processes and underscores the value of omics-based tools in understanding traditional food systems.

White brine cheese is a widely consumed and recognized product that is produced in almost all regions of North Macedonia. Traditional white brined cheeses in North Macedonia are typically produced with raw untreated milk and no addition of starter cultures. White brined cheeses are rindless, with soft to semi-hard consistency and more often produced from cow's and sheep's milk than from buffalo or goat milk. Specific sensory attributes such as: flavor, aroma, and texture are fundamental to defining the identity, quality, and consumer acceptability of goat cheese. This study presents a comparative sensory evaluation of spring and autumn-produced goat cheese with the aim of identifying seasonal impacts on sensory quality attributes. Cheese samples from both seasons were assessed by a panel according to a structured scoring system for appearance, consistency, odor, and taste. Spring cheese achieved consistently high scores in all parameters, with mean values approaching the maximum for taste (19.85 ± 0.48), odor (29.37 ± 0.90), consistency (33.75 ± 2.19), and appearance (19.37 ± 0.92), resulting in an overall sensory score of 102.35 ± 2.74 out of 105 (97.48%). In contrast, autumn cheese showed greater variability and generally lower sensory performance, particularly in odor (23.15 ± 3.10) and taste (16.85 ± 1.07), with an overall mean score of 90.92 ± 7.87 (86.59%). The results suggest that seasonality significantly influences the sensory characteristics of cheese, with spring conditions yielding a cheese of higher sensory quality.

Background: The variation in sheep milk composition is closely related to the sheep’s metabolic status. This study aimed to analyze the milk composition and serum metabolic characteristics of Xinggao sheep during different lactation periods and to evaluate the association between milk quality traits and body metabolism. Methods: Eighteen intensively reared ewes were divided into three groups: an early lactation group (MA), a mid-lactation group (MB), and a late lactation group (MC). Milk components were detected by infrared spectroscopy, and the ewes’ serum metabolomic characteristics were detected by liquid chromatography–mass spectrometry (LC-MS). K-means correlation analysis revealed that the milk fat percentage was positively correlated with L-aspartic acid and negatively correlated with citrulline levels. Random forest analysis for metabolite importance ranking showed that methionine sulfoxide and methionine exhibited high mean decrease accuracy and mean decrease Gini index values. Results: The milk composition results showed that, compared with MA, the milk fat content and total solids in MB and MC were significantly higher, while the freezing point in the MC was significantly lower. Metabolomic studies showed that 207, 210, and 238 differential metabolites were identified in the comparisons of MA vs. MB MA vs. MC, and MB vs. MC, respectively, and these metabolites were mainly enriched in the pyrimidine metabolism, arachidonic acid metabolism, and arginine biosynthesis pathways. Evaluation of metabolite importance using random forest models revealed that 27 metabolites, including 2-Arachidonyl glycerol ether, methionine, and methionine sulfoxide, showed a high mean decrease accuracy and mean decrease Gini index. Correlation analysis revealed that milk fat percentage and total solids were positively correlated with 11 metabolites, including citrulline, phenylalanine, and octadecylamine, and negatively correlated with isoproterenol, cortisol, and kynurenic acid. The freezing point was positively correlated with cortisol, isoproterenol, and kynurenic acid and negatively correlated with aldosterone, dehydroepiandrosterone, and betaine. Conclusions: This study showed that there were significant differences in the milk composition and metabolites of Xinggao sheep during different lactation periods, highlighting the impact of lactation stage on milk composition and production performance. We recommend developing targeted nutritional strategies based on the specific metabolic profiles of different lactation periods to optimize the feeding management and nutritional regulation of Xinggao sheep.

This study was conducted to determine the effects of potassium sorbate, nisin and lysozyme on the microbiological, chemical and sensory quality of pickled white cheeses during their shelf life. For this purpose, Şavak pickled white cheese, experimentally produced from a mixture of 50% sheep milk and 50% cow milk, was sliced (4×4×4 cm in size) and stored in 16% salt brine containing potassium sorbate (1 g·mL-1), nisin (12.5 mg·L-1) and lysozyme (200 mg·L-1) singly or in combination at 4°C for a shelf life of 90 days. At the end of storage, statistically significant differences were found between the combination group using potassium sorbate 1 g·L-1 + nisin 12.5 mg·L-1 and the control group in terms of antimicrobial effect levels on coliform, Enterobacteriaceae, fecal streptococci, lipolytic, proteolytic and E. coli microorganisms (P≤0.05). No statistically significant differences were found between the groups in terms of sensory evaluation (P>0.05). However, according to the numerical scores given, group 4 (potassium sorbate 1 g·L-1 + nisin 12.5 mg·L-1) and group 7 (potassium sorbate 1 g·L-1 + nisin 12.5 mg·L-1 + lysozyme 200 mg·L-1) became the two most appreciated groups in terms of sensory evaluation with equal scores (95.55). It was concluded that the combination of potassium sorbate 1 g·L-1 + nisin 12.5 mg·L-1, which is an additive with the Generally Recognized as Safe status and is in compliance with the legislation for use in cheeses ripened in brine and offered for sale, can be used safely as an alternative method to heat treatment to improve the quality of pickled white cheeses and that it contains data that can form the basis for new studies to investigate how these additives can also have effects on some pathogenic bacteria.

Abstract The effects of gastrointestinal nematodes (GIN) in lactating ewes have been studied throughout the sheep dairy industry. Not much is known about the impacts of GIN in the milk of meat sheep. Gastrointestinal nematodes sequester nutrients from the GI tract of the ewe, leading to changes in milk components. Milk Fatty acids (FAs) are taken by the udder from blood circulation or are newly synthesized in the mammary tissue. Essential fatty acids (EFAs) can only be obtained from the diet and are important for lamb development. The objective of this study was to investigate the relationship between fecal egg count (FEC), as a representation of the GIN load and milk fat percentage and fatty acid profile in lactating ewes. Twenty-four primiparous Katahdin ewes were selected. Milk, feces, and blood were collected seven days post parturition. The body weight (BW) and body conditioning scores (BCS) were recorded. Blood serum was used to measure levels of β-hydroxybutyric acid. Feces were used for FEC. Milk fat percentage was measured by crematocrit analysis. Finally, a fatty acid extraction was performed using Folch extraction and the FAs were analyzed using FAME gas chromatography. The cause-effect relationship between the FEC to the fatty acid profiles and milk fat percentage was evaluated by using the Theil-Sen Siegel regression analysis. Ewes were divided between high and low GIN loads based on the FEC median (1950 eggs/g of feces) for the correlation analysis. Spearman’s correlation coefficient (ρ) was used to perform the correlation. Statistical significance was considered at p < 0.05, and coefficients ρ > 0.70 were deemed strong and biologically relevant. The regression analysis found that FEC was negatively associated (p < 0.05) with BW, caprylic (C8:0), capric (C10:0), lauric (C12:0), myristic (C14:0), palmitic (C16:0) and linoleic (C18:2) acids. In the high FEC animals, FEC was negatively correlated to capric (ρ = -0.629) and lauric acids (ρ = -0.650). In low FEC animals, FEC was negatively correlated to total fat percentage (ρ = -0.729). Linoleic acid and BW were also negatively correlated to FEC. In both groups, short and medium chain FAs (C8 – C16) were positively correlated (ρ > 0.6) and long chain FAs (>C18) were positively correlated (ρ > 0.6) between them. These results suggest that ewes with a higher GIN load have milk containing less de novo FAs, linoleic acid, and EFAs, supporting the idea that GIN infections have repercussions on the milk nutritional quality, which can lead to poor lamb development.

Investigating the variance components pattern and the genetic basis of repeated Fourier-transform infrared spectra in sheep milk.

Organic Acid-Treated Ensiled Date Palm Leaves Improve Texture and Sensory Quality of White Soft Cheese from Farafra Sheep Milk

Lipidomics revealed the geographical origin and breed variability of sheep milk

ABSTRACTDairy products are essential components of human and animal nutrition, providing vital nutrients such as proteins, vitamins and minerals. However, their susceptibility to microbial contamination, particularly by pathogens like Proteus mirabilis, poses significant risks to both animal and public health. This study investigated the prevalence, antibiotic resistance patterns and biofilm‐forming ability of P. mirabilis in various dairy products, with a focus on raw milk, in Shahrekord, Iran. A total of 480 samples, including raw cow, goat and sheep milk, as well as cheese, yogurt, cream, curd and a traditional Iranian fermented yogurt‐based beverage (doogh), were analysed under controlled laboratory conditions. The findings revealed a 12.29% prevalence rate of P. mirabilis, with raw cow's milk showing the highest contamination rate (21.66%). Among the isolates, 88.12% were capable of forming biofilms, and 71.15% exhibited strong biofilm production. Antibiotic susceptibility testing identified a high prevalence of multidrug‐resistant strains, with the highest resistance rates observed for cotrimoxazole (59.32%) and gentamicin (50.84%). In addition, 25.42% of the isolates were identified as extended‐spectrum beta‐lactamase (ESBL) producers, with blaCTX‐M being the most prevalent resistance gene.A significant correlation was found between biofilm‐forming ability and the presence of antibiotic resistance genes, highlighting the dual challenges of microbial persistence and antimicrobial resistance. These findings emphasize the need for improved hygiene practices in dairy production, targeted biofilm‐disrupting strategies and enhanced surveillance programs to mitigate risks to both animal and public health. This study provides critical insights for veterinary professionals and policymakers to develop effective interventions aimed at reducing contamination and combating antimicrobial resistance in dairy products.

Remimazolam is a short-acting sedative/anesthetic. For safe breastfeeding, infor-mation on the extent and possible risks of remimazolam passing through a mother´s milk to the infant is needed. The objective of this work was to study the transfer of remimazolam from maternal to infant circula-tion by mother´s milk in an animal model. Three lactating British milk sheep received intravenous remimazolam (0.4 mg/kg bolus plus 4-hr-infusion at 1 or 2 mg/kg/hour). Drug profiles were recorded in plasma and milk. Six suckling lambs were administered remimazolam by intravenous and oral gavage administration for a comparison of plasma con-centration profiles of remimazolam and its primary metabolite, CNS7054. Treatment of lactating sheep induced dose-dependent sedation and loss of consciousness. At the end of infusion, the concentration of remimazolam was higher in milk than in plasma. The subsequent elimination of remimazolam from milk was rapid, although somewhat slower than from plasma. In lambs, intravenous, but not oral, remimazolam (2 mg) caused different grades of sedation/an-esthesia (fully reversible within 8 to 15 min). Mean plasma Cmax was 278.3 ng/mL after intravenous and 1.3 ng/mL after oral administration. Oral gavage resulted in a sizable plasma concentration of CNS7054 (Cmax around 100 ng/mL), indicating efficient intestinal absorption of the parent drug, followed by extensive first-pass metabolic elimination, leading to negligible bioavailability of oral remimazolam. In mother´s milk, remimazolam reaches higher concentrations than in plasma and is cleared by redistribution to the central compartment for final hepatic elimination. In lambs, oral remimazolam results in minimal plasma concentrations, suggesting that safety concerns regarding breast-fed infants would be minor and could be completely alleviated by a short nursing interruption.

Identification of lipids and proteins associated with different heat treatments in sheep milk based on lipidomics and proteomics