Search Results (259)

Kargı Tulum cheese differs from other Tulum cheeses with its unique production and ripening method. No systematic study has yet explored the change in the volatile compounds and fatty acids during the ripening process of Kargı Tulum cheese. The objective of this study was to monitor the change in the fatty acids and volatile compounds of Kargı Tulum cheese at different time points during the production and ripening stages. Fatty acid profile, lipid quality parameters and volatile compound profiles were determined. A principal component analysis (PCA) was performed to determine how the volatile profiles differed across production and ripening stages. During the ripening, short- and medium-chain fatty acids (FAs) increased with notably high levels of butyric acid. Lipid quality parameters, including total saturated FAs (SFAs), atherogenicity index (AI), and thrombogenicity index (TI), remained unchanged throughout ripening. A total of 62 volatile compounds (VOC) were detected. Esters and ketones were the most abundant groups in fresh curds, while carboxylic acids became the dominant group by the end of the ripening process. The total concentration of most VOC increased over time. Butyric acid, hexanoic acid, ethyl hexanoate and acetic acid were the dominant compounds contributing the flavor of the Kargı Tulum cheese. This study presents data on what flavor compounds form and how they change during ripening and can be useful for comparative purposes in future studies on ripened raw milk cheeses. Full article

Using raw milk in cheesemaking poses several risks and often requires higher salt levels. Gel brine is a promising brining method to reduce salt and to prevent excessive softening, yet it was not employed to raw milk cheese before. In this study, the impact of ripening in gel brine—prepared by adding selected thickeners (gelatin and carrageenan) to a 12% salt brine—on the composition, proteolysis, texture, and microbiological properties of raw milk cheese was examined over 120 days. The aim was to assess the potential of gel brine to shorten the ripening time of raw milk cheese at a relatively low salt concentration while maintaining acceptable quality parameters. Response surface methodology was used to determine the optimum ripening time and thickener concentrations required to achieve target microbial counts, proteolysis, and moisture levels. The addition of stabilizers did not significantly influence the overall composition of the cheese, except for salt in dry matter. Stabilizers also limited the increase in trichloroacetic acid-soluble nitrogen (TCA-SN) during storage and led to a marked reduction in Escherichia coli counts. Texture profile analysis results were significantly affected (p < 0.05). The optimum conditions were estimated as 0.9% carrageenan, 0.8% gelatin, and 35 days of ripening. Full article

This paper illustrates the results of a case study conducted in the Madonie Regional Park (Sicily, Italy) focusing on Prangos ferulacea (L.) Lindl. This species spontaneously grows in the area and plays an important role as forage plant, contributing to the production of traditional dairy products. A multidisciplinary approach was adopted to investigate the ecological characteristics and the chemical composition of the species, and to assess its effects on chemical and microbiological properties of raw milk and ricotta from grazing animals. Indices of bioindication were used to analyse the ecological features of the study area, and a change in the landscape has been observed. Samples of P. ferulacea were collected in the wild in specific plot areas. Chemical analyses were carried out to determine the main nutritional parameters of the species. Chemical and microbiological analyses were performed on raw milk and ricotta samples to evaluate their nutritional composition and quantify the main microbial groups. Raw milk showed no significant microbial differences between samples, with low levels of lactic acid bacteria (LAB) and some Enterobacteriaceae and Escherichia coli (~10² CFU/mL), while pathogens like Listeria monocytogenes and Salmonella spp., as well as spoilage yeasts were undetectable. Ricotta cheese showed a high hygienic profile, with LAB around 10⁴ CFU/g and no spoilage or pathogenic microbes detected, including STEC-negative E. coli. Additionally, SPME-GC/MS and LC/MS analyses were carried out to identify the phenolic compounds of the species with those of dairy products and showed how the contribution of P. ferulacea to ricotta was effective for the aromatic profile and negligible for the polyphenolic component. Full article

Toxic Shock Syndrome Toxin-1 (TSST-1) is produced by Staphylococcus aureus strains encoded by the tst gene. Toxic shock syndrome (TSS) is a severe disease caused by TSST-1 toxin and associated with staphylococcal food poisoning (SFP). The aim of the present review was to present data on the occurrence of S. aureus TSST-1 in foods published in various countries. PCR-based assays are most frequently used for the detection of S. aureus TSST-1 in foods. S. aureus TSST-1 is predominantly detected in foods of animal origin. The highest occurrence has been observed in mastitic ruminants’ milk, indicating that mastitis is a risk of milk contamination with the pathogen. High occurrence rates of S. aureus TSST-1 have also been identified in raw milk and artisanal cheeses. Various occurrence levels have also been reported in beef, pork, lamb, and chicken meat. Low occurrence levels have also been reported for fish or other seafood products. The tst gene was also found in combination with other toxigenic genes in S. aureus TSST-1 isolates (e.g., MRSA or Panton-Valentine Leukocidin, PVL). Monitoring S. aureus TSST-1 in food is important for public health because food can be a vehicle for transmitting the antibiotic-resistant pathogen to humans. Full article

Traditional raw milk cheeses are valued for their distinctive sensory properties and microbial richness but may pose microbiological safety risks. The objective of this research was to investigate the bacterial communities present in cheeses sourced from dairies from different regions of one voivodeship using culture-based methods and 16S rRNA amplicon sequencing. Artisanal Polish “twarog”-type cheeses produced from raw cow’s milk were obtained from four small local dairies in the Łódź Voivodeship. Microbial diversity and safety were assessed by culture-based enumeration following ISO standards and 16S rRNA amplicon sequencing targeting the V3–V4 region. Microbial counts included total viable microorganisms, lactic acid bacteria (LAB), Enterobacteriaceae, coagulase-positive staphylococci, yeasts, molds, and pathogens (Salmonella spp., Listeria monocytogenes). Significant differences (p < 0.05) were observed among cheeses, with samples ZJ-473 and ZJ-505 showing the highest LAB and total counts, while Salmonella spp. and L. monocytogenes were undetected. 16S rRNA amplicon sequencing revealed dominance of Firmicutes and Proteobacteria, mainly Lactococcus lactis, Leuconostoc pseudomesenteroides, and Lactobacillus delbrueckii. Alpha diversity and co-occurrence analyses indicated higher microbial complexity in samples ZJ-473 and ZJ-505. The integration of culture-based and sequencing data provided a comprehensive view of cheese microbiota and safety, confirming the protective role of LAB and emphasizing the need for strict hygiene in artisanal cheese production. Full article

Whey, a by-product of cheese and casein manufacture, represents a major output in dairy processing and a valuable resource for the production of functional foods. This review examines the technological, environmental, and nutritional aspects of whey valorization, emphasizing its transformation from an ecological burden to a raw material with high economic potential. Over time, whey has evolved from being regarded as waste product to becoming a strategic ingredient in the formulation of modern functional foods and bio-based materials. Data from January 2015 to October 2025 were collected from PubMed, Web of Science, and Scopus to outline global whey production, utilization rates, and emerging processing methods. Modern membrane, enzymatic, and non-thermal technologies enable the recovery of valuable components, including proteins, lactose, and bioactive compounds. The use of these techniques reduces the biochemical and chemical oxygen demand in wastewater The review highlights the use of whey in functional beverages, milk and meat processing, edible films, bioplastics, and biofuels, as well as its microbiological and biotechnological potential. Results indicate that only about half of the 180–200 million tonnes of whey produced annually is effectively valorized, underscoring the need for integrated circular-economy approaches. Overall, whey valorization contributes to sustainable food production, environmental protection, and the development of innovative, health-promoting products that align with global strategies for waste reduction and the development of functional foods. Full article

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. Full article

Ewe’s milk cheese produced from raw milk holds cultural and economic importance in Southern European countries; however, it poses microbiological challenges. Among spoilage microorganisms, Pseudomonas fluorescens is particularly concerning due to thermostable enzymes that impair the texture, aroma, and stability of cheese, even under refrigeration and salinity. This study evaluated the influence of sodium chloride concentration on Pseudomonas fluorescens given the pivotal role of salt in ensuring cheese stability and safety. Cheeses inoculated with Pseudomonas fluorescens were produced under an experimental design that combined three ripening temperatures with four salt concentrations. Physicochemical composition and microbiological stability were assessed at the end of ripening (20 days). Results showed that the ripening temperature emerged as the most determinant factor, influencing microbial viability and increasing solid retention, proteolysis, and dehydration, leading to harder cheeses. Low temperatures without salt favoured surface colour defects, whereas, although high salt levels contributed to partial control of Pseudomonas spp., they also delayed ripening, resulting in cheeses with a pale, uncharacteristic appearance. Conversely, moderate salinity (2%) combined with higher ripening temperatures promoted uniform maturation, resulting in a stable texture and appearance free of defects. These findings highlight the need to balance salt and ripening conditions to optimise quality and safety in traditional raw ewe’s milk cheeses. Full article

A freeze-dried natural starter culture (NSC) was developed and assessed for its suitability in producing a semi-cooked, 60-day-ripened cheese resembling the protected designation of origin (PDO) Pecorino Sardo. The culture, derived from raw ewe’s milk from a dairy farm involved in the study, without thermal decontamination to preserve indigenous microbiota, was enriched with two strain-level-characterised, biodiverse mixtures of Streptococcus thermophilus (Str-mix) and Lactobacillus delbrueckii (Lb-mix). This study evaluated the technological robustness and adaptability of NSC enriched with biodiverse Str-mix and Lb-mix across three different artisanal dairy-processing environments with varying milk compositions and equipment levels at plants located in different geographic areas. During cheesemaking, technological, physico-chemical, and compositional parameters were monitored, along with microbial characterisation of milks and 1-day cheeses. After 60 days of ripening, cheeses were characterised from the microbiological, physico-chemical, and compositional perspectives. Furthermore, nutritional labelling was established, and consumer acceptance was determined. Results showed that the starter (NSC + Str-mix + Lb-mix) demonstrated strong and reproducible technological performance in all dairies, regardless of the milk’s chemical and microbial composition variability. Sensory quality was preserved in cheeses ripened for up to 180 days. These preliminary findings seem to support the use of freeze-dried, raw-milk-derived natural cultures in artisanal cheesemaking as a way to preserve microbial diversity and to reconnect with traditional practices that enhance both the tangible and intangible assets of modern society. Full article

The detection of H5N1 highly pathogenic avian influenza virus (HPAIV) in lactating dairy cattle in the United States, with high viral titers in raw milk, has raised concerns about zoonotic transmission through unpasteurized milk and dairy products. While viral inactivation during pasteurization is documented, data on persistence in raw-milk cheeses remain limited. This study evaluated the survival of avian influenza viruses (AIVs), both low pathogenic (LPAIV, H1N1) and highly pathogenic (HPAIV, H5N1), during the production and ripening of Grana-type hard cheeses from raw cow’s milk. Experimental cheesemaking was carried out with milk artificially contaminated with A/duck/Italy/281904-2/06 (H1N1; 10^7.75 EID₅₀/mL) or A/duck/Italy/326224-2/22 (H5N1 clade 2.3.4.4b; 10^6.75 EID₅₀/mL). Cheeses were manufactured under Parmigiano-Reggiano standards and ripened 30 days at 5–6 °C. Viral detection in finished cheeses was performed using inoculation in specific-pathogen-free embryonated chicken eggs (SPF-ECEs), hemagglutination (HA) assay, and monoclonal antibody-based ELISA. No infectious virus was detected in cheese samples after two blind passages in SPF-ECEs. Both HA and ELISA tests were negative, indicating complete viral inactivation. These results demonstrate that Grana-type cheese processing, including cooking, acidification, and ripening, effectively inactivates LPAIV and HPAIV. Findings support the microbiological safety of raw-milk hard cheeses regarding AIV, contributing to risk assessment and food safety policies. Full article

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. Full article

Dairy products harbor complex and dynamic microbial communities that contribute to their sensory properties, safety, and cultural distinctiveness. Raw milk contains a diverse microbiota shaped by seasonality, storage conditions, lactation stage, animal health, farm management, and genetics, serving as a variable starting point for further processing. Fermentation, whether spontaneous or starter driven, selects for subsets of lactic acid bacteria (LAB), yeasts, and molds, resulting in microbial succession that underpins both artisanal and industrial products such as kefir and cheese. Kefir represents a balanced LAB–yeast symbiosis, with species composition influenced by grain origin, milk type, and processing parameters, whereas the cheese microbiota reflects the interplay of starter and non-starter LAB, coagulants, ripening conditions, and “house microbiota”. Methodological factors—including DNA extraction, sequencing platform, and bioinformatic pipelines—further impact the reported microbial profiles, highlighting the need for standardization across studies. This review synthesizes current knowledge on raw milk, kefir, and cheese microbiomes, emphasizing the biological, technological, environmental, and methodological factors shaping microbial diversity. A holistic understanding of these drivers is essential to preserve product authenticity, ensure safety, and harness microbial resources for innovation in dairy biotechnology. Full article

In this study, the contents of minerals, free amino acids (FAAs), biogenic amines (BAs), γ-aminobutyric acid (GABA), and spermidine (SPD) were analyzed in selected white mold-ripened and blue-veined cheeses, including their spatial distribution between rind and core. Blue-veined cheeses contained higher levels of sodium, calcium, phosphorus, FAAs, and SPD. The BAs content was higher in cheeses produced from raw milk. Compared to the cores, the rinds of the analyzed cheeses contained more calcium (up to 66-fold), phosphate (up to 4.4-fold), zinc (up to 9.9-fold), and GABA (up to 17-fold). In white mold-ripened cheeses, where molds do not grow in the core, the rinds also contained more FAAs (up to 15-fold) and SPD (up to 127-fold). Our results confirm previous observations that the rinds of mold-ripened cheeses contain higher amounts of nutritionally valuable cations that form poorly soluble phosphate salts. To our knowledge, this study provides the first demonstration that the rinds of white mold-ripened cheeses are enriched in GABA and SPD, bioactive compounds associated with beneficial health effects. This highlights the high nutritional value of the outer layers of cheese produced with food-grade molds. Full article

This study provides a comprehensive characterization of the microbiological, chemical, and sensory profiles of Sicilian Canestrato Fresco (SCF) cheese, a traditional agri-food product (TAP) made from raw cow’s milk using artisanal methods and typically consumed after 20 d of ripening. Plate count analyses confirmed high levels of mesophilic lactic acid bacteria (LAB) exceeding 10⁸ CFU/g. Both rod- and coccus-shaped LAB populations were present at these elevated levels. Pathogens such as Listeria monocytogenes and Salmonella spp. were not detected, although potential contaminants including Enterobacteriaceae, total coliforms, and Escherichia coli were detected at levels of 1.0–3.5 log CFU/g. High-throughput sequencing confirmed LAB as the dominant taxa, comprising the majority of the bacterial community, which accounted for 78.12% to 99.63% of the total relative abundance (RA) across all cheese samples. The fatty acid profile was typical of cow’s milk cheeses, with long-chain fatty acids (C15–C18) representing ~75% of the total, followed by medium- (~17%) and short-chain (<8%) fatty acids. Volatile organic compound analysis showed free fatty acids as the most abundant class, followed by esters, alcohols, ketones, and aldehydes. These findings highlight the role of traditional practices in preserving the sensory and chemical identity of SCF cheese. However, the presence of hygiene indicators suggests a need for improving sanitary measures along the production chain. Future research should explore the impact of targeted microbial management and packaging conditions to enhance both safety and product standardization without compromising artisanal traits. Full article

The objective of this work was to deliver a comprehensive genetic characterization of a collection of E. coli strains isolated from raw sheep milk. To complete our purpose, the technique of whole-genome sequencing, coupled with bioinformatics and phenotypic characterization of antimicrobial resistance, was performed. These Gram-negative, facultative anaerobic bacteria belong to the family Enterobacteriaceae, together with other intestinal pathogens, such as Shigella spp. and Salmonella spp. Genetic analysis was carried out on all strains (phylogram, sequence types, VFs, AMR genes, and pangenome). The results showed the presence of various genetic traits that are related to virulence factors contributing to their pathogenic potential. In addition, genes conferring resistance to antibiotics were also detected and confirmed using phenotypic tests. Finally, the genome of the E. coli strains was characterized by the presence of several mobile genetic elements, thus facilitating the exchange of various genetic elements, associated with virulence and antimicrobial resistance, within and beyond the species, through horizontal gene transfer. Contaminated raw sheep milk with pathogenic E. coli strains is particularly alarming for cheese production in artisan dairies. Full article