Search Results (180)

Traditional cheese products harbor complex microbial communities that influence their quality and safety. However, the effects of processing scale and manufacturing stage on the microbial profile of hurood, a traditional Mongolian cheese, remain poorly understood. This study examined microbial indicators, community composition, and succession dynamics across four manufacturing stages (raw milk, yogurt, whey, and hurood) and three processing scales (pastoral household, workshop, and factory) using plate counting and 16S rRNA gene amplicon sequencing. Twenty-four samples were collected from Xilin Gol, Inner Mongolia. Total aerobic plate counts and coliform counts decreased significantly from raw milk (7.30 and 4.49 log CFU/g, respectively) to hurood (2.02 and 0.34 log CFU/g, respectively; p < 0.05), reflecting progressive microbial reduction through acidification and thermal treatment, whereas yeast counts remained stable across stages. Firmicutes dominated the fermented stages, with Lactococcus and Lactobacillus as the predominant genera. Whey harbored an exceptionally high abundance of Acetobacter (21.6%), highlighting its valorization potential. Factory-scale production yielded the lowest mold and coliform counts in finished products despite higher initial coliform levels in industrial raw milk, reflecting the effectiveness of standardized hygiene management. In contrast, workshop-scale samples exhibited a higher relative abundance of environmental indicator bacteria, suggesting a comparatively elevated contamination risk this intermediate production scale. PICRUSt2-based functional predictions indicated stage-specific metabolic potential, including predicted enrichment of pyruvate and fatty acid metabolism in yogurt, amino acid metabolism in whey, and vitamin B6 metabolism in hurood. These findings provide a systematic microbial baseline for hurood, identify scale-specific microbiological risk profiles, and offer a foundation for targeted hygiene control and standardized production strategies. Full article

In Mexico, cheese whey (CW) is commonly treated as a dairy wastewater despite its high lactose and nutrient content. This study evaluated cheese whey (CW) and ultrafiltered cheese whey (UF-CW) as low-cost substrates for the cultivation of the probiotic strains Lactobacillus acidophilus and Lactococcus lactis. The proposed bioprocess simultaneously enables the production of probiotic biomass and lactic acid, a high-value platform chemical with broad applications in the food, pharmaceutical, and biopolymer industries. In the first experimental trials, in which CW and UF-CW were used solely as media, fermentations lasted 36 h at 30 and 37 °C, with initial pH levels of 5 and 7. CW demonstrated a greater capacity to support the growth of lactic acid bacteria. Thus, to increase the fermentative capability of UF-CW, it was supplemented with yeast extract (YE) or corn steep liquor (CSL), and CaCO₃ was added to stabilize pH, as low pH values inhibit growth and lactic acid production. The proposed strategy notably improved microbial growth in UF-CW, increasing Lc. lactis and L. acidophilus populations from 8.3 and 8.2 Log₁₀ CFU/mL to 9.3 Log₁₀ CFU/mL, respectively. The findings suggest that dairy wastewater can be effectively repurposed as a low-cost cultivation medium for these bacteria. ASPEN simulation analyses demonstrated that lactose conversion efficiency and final product concentration were key factors affecting process performance and economic feasibility. Among the evaluated scenarios, a 45% lactose-to-lactic acid conversion yielded the most economically favorable process performance compared with conversions of 10% and 25%. Future research should focus on enhancing fermentation yields and adopting more efficient downstream recovery techniques. Full article

This study investigated the chemical composition, fermentation dynamics, fatty-acid profile, and polyphenolic evolution of two mixed silages designed to valorize agro-industrial by-products for ruminant feeding. Silages were produced by co-ensiling wheat straw, cheese-whey, and molasses with grape pomace (SIL-1) or olive mill wastewater (SIL-2), and were monitored over a 150-day ensiling period. The two formulations exhibited distinct compositional characteristics and fermentation kinetics. SIL-1 showed higher crude protein content and a more favorable fatty-acid profile, with greater levels of selected long-chain fatty acids, whereas SIL-2 had higher dry matter and structural fiber fractions. Both silages achieved effective fermentation, reaching stable acidic conditions (pH < 4.0), although SIL-1 consistently maintained lower pH and higher buffering capacity. Fermentation end-products differed between silages, with higher concentrations of short-chain fatty acids in SIL-1 and greater lactic acid accumulation in SIL-2, under significant treatment × time interactions. Bioactive compound analysis revealed higher total phenolic content and antioxidant capacity in SIL-1, whereas SIL-2 showed marked degradation of phenolic compounds, including the loss of characteristic secoiridoids. Polyphenolic profiles displayed compound-specific temporal dynamics during ensiling. Overall, both silages were well preserved; however, SIL-1 demonstrated superior nutritional quality and bioactive stability, supporting its potential as a functional feed ingredient for ruminant nutrition. Full article

Making 1 $\mathrm{k}$$\mathrm{t}$ of cheese produces 9 $\mathrm{k}$$\mathrm{t}$ of cheese whey permeate, a waste with 5% lactose, which is either discarded or dried for animal feed. One pathway to add value to this waste is to convert it to lactic acid (LA), a monomer for polylactic acid, the largest bioplastic produced in the world. Lactose hydrolyses to glucose and galactose. While Brønsted acidity enhances lactose hydrolysis, Lewis acidity favours the formation of lactic acid. For the first time, we tested both industrial whey permeate and purified lactose as feedstocks for LA over a heterogeneous catalyst–Er₂O₃/Al₂O₃. LA Yield from whey permeate reached 14%, while the maximum yield with purified lactose was 22%. LA yield was invariant with respect to mixing speed while increasing temperature accelerates the time it takes to reach quasi-equilibrium. Yield was also independent of pressure with either air, He, N₂, or H₂ in the vapour space above the liquid phase in the autoclave. LA yield over spent catalyst with fresh lactose was only 11%, which indicates that the catalyst deactivates. Based on XRF analyses, the Er₂O₃ mass fraction dropped from 15% to 5%, with 6.4% leaching into the aqueous phase after the first step but only 0.8% after the second test. Full article

Podliveni cheese is a traditional fresh cheese produced in Serbia, typically made from fresh cow’s milk. Donkey milk is recognized for its nutritional benefits, particularly its hypoallergenic properties; however, its use in cheese production is partially limited due to its specific protein composition and low casein content. In addition, information in the scientific literature regarding its application in cheese production remains limited. In this study, Podliveni cheese was produced from raw cow’s milk, while in a second experimental group, 30% milk from autochthonous Balkan and Banat donkey breeds was added to obtain a value-added Podliveni cheese. The selected proportion (30%) was based on previous studies using lower inclusion levels (10% and 20%), which demonstrated measurable but limited effects on cheese properties. The technological production process was identical in both groups and is described for each type of cheese. Microbiological parameters analyzed included total lactic acid bacteria (LAB), Enterobacteriaceae, Escherichia coli, coagulase-positive staphylococci (CPS), Salmonella spp., and Listeria monocytogenes. Sensory analysis was conducted using a five-point hedonic scale with a panel of 21 participants (male and female, aged 20–60 years). The following chemical composition parameters were also evaluated: dry matter, fat content, fat in dry matter, fat-free dry matter, protein, ash, pH, and salt. The content of essential minerals and trace elements was determined, including Ca, P, Na, K, Mg, Zn, Cu, Fe, and the Ca/P ratio. The addition of donkey milk significantly affected curd formation, which required six times longer compared to cheese produced exclusively from raw cow’s milk. Furthermore, the inclusion of donkey milk reduced cheese yield and resulted in increased whey separation during storage, indicating reduced water-holding capacity. No statistically significant differences were observed in microbiological parameters, and pathogenic bacteria (Salmonella spp. and Listeria monocytogenes) were not detected in either cheese. No significant differences were observed in most sensory attributes, except for texture. Conversely, the inclusion of donkey milk significantly affected the majority of chemical parameters and the mineral composition of the cheese. The addition of donkey milk resulted in a significant decrease (p < 0.05) in fat, fat in dry matter, fat-free dry matter, Ca, P, K, Zn, Cu content and the Ca/P ratio, while a significant increase (p < 0.05) was observed in dry matter, protein, salt, Na, Mg, and Fe content. The incorporation of donkey milk represents an innovative approach that expands the range of traditional cheeses without compromising the absence of tested pathogenic bacteria and preserving traditional production practices, simultaneously offering new value-added products. Further research is required to better understand the health benefits associated with the inclusion of donkey milk in cheese production. This study contributes to expanding knowledge on the use of donkey milk and supports the conservation of autochthonous breeds and the improvement of human health. Full article

The aim of the research was to assess changes in the bioactive status of organic yoghurts produced in the spring/summer season from Simmental cows’ bulk milk during 28-day refrigerated storage, including whey proteins, lipophilic vitamins, and free fatty acids, and to interpret these changes not only in terms of compositional stability but also regarding their nutritional significance, as evaluated using the IYQ (Index of Yoghurt Quality) for vitamins. Raw milk was found to be a significantly richer source of biologically active compounds compared with milk subjected to heat treatment. During the 28-day refrigerated storage of the yoghurts, unfavourable alterations were observed in the levels of selected bioactive components belonging to both the protein and lipid fractions. A reduction in the concentration of the analyzed proteins and vitamins was observed, ranging from 2% for vitamin D₃ to 38% for lactoferrin, while the content of free fatty acids increased, from 8% for monounsaturated free fatty acids (MUFFAs) to 39% for short-chain free fatty acids (SCFFAs). The most pronounced changes were observed in lactoferrin content (p ≤ 0.01), whereas vitamin D₃ exhibited the highest stability throughout the storage period. The stability of vitamin D₃ was further confirmed using the Index of Yoghurt Quality (IYQ). Despite the significant changes observed in the bioactive profile, the yoghurts retained high sensory quality throughout the entire storage period. This indicates that alterations in bioactive status did not compromise the sensory quality of the product, even after 28 days of storage (i.e., at the end of the shelf life). The obtained results indicate the feasibility of developing organic milk processing directly at the farm level while preserving the nutritional value of the products. The possibility of processing organic milk not only into cheese but also into fermented dairy beverages, particularly yoghurts, is of key importance for farmers aiming to diversify production, increase added value, and improve the economic sustainability of small-scale organic farms. Full article

This study presents the first comprehensive assessment of a bacteriophage P100-activated edible whey-protein solution (WPS) applied to the rind of Sicilian Canestrato Fresco (SCF) cheese. Beyond evaluating its anti-Listeria efficacy in pre- and post-packaging contamination contexts, the work investigates the coating’s effects on chemical composition, volatilome, sensory properties, and consumer responses, including willingness to pay. To assess anti-Listeria activity, all samples were stored at 4 °C for 30 days. Contamination was carried out either before or after coating application, depending on the specific treatment. Listeria monocytogenes was monitored at 0, 1, 3, 7, 15, and 30 days of refrigerated storage. The active coating reduced the pathogen from approximately 3 log CFU/g to undetectable levels (0 log CFU/g) within 3 days, whereas the untreated controls reached about 5 log CFU/g after 30 days. WPS-coated cheeses showed no significant changes in chemical composition (moisture ~33%, protein ~29%, fat ~33%) or fatty acid profile compared to traditional SCF. The volatilome was dominated by hexanoic and butanoic acids and ethyl esters, without significant differences between coated and control samples, as confirmed by Smart Nose^® analysis. Sensory evaluation by trained assessors demonstrated that the bioactive coating did not alter the traditional sensory profile of SCF cheese. A consumer survey conducted with 240 participants from two retail formats revealed significant differences in product familiarity and perceived food safety, while openness to innovation and willingness to pay were similar. More than 90% of respondents were willing to pay a 10% price premium. Overall, phage-based edible coatings appear to be edible, renewable, and biodegradable packaging alternative to improve cheese safety without compromising quality. Full article

This study investigated the diversity and functional potential of lactic acid bacteria isolated from traditional lamb rennet, cheese, and whey collected from seven artisanal sheep farms in southern Romania. A total of 31 samples were analyzed, yielding 118 Gram-positive, catalase-negative isolates. Following dereplication by rep-PCR and 16S rRNA gene sequencing, 63 unique strains were identified across nine genera, with Lactiplantibacillus, Lactococcus, and Leuconostoc being the most prevalent. Strain distribution varied by sample type and manufacturer, with rennet and whey showing greater species diversity than cheese. Technological characterization showed strain-dependent differences in acidification and growth in cow’s and goat’s milk. Genetic screening revealed a high prevalence of functional genes such as ribA, gad, and α-amy, while genes associated with bacteriocin (nisA, pln) and folate (folK) production were less common. Most strains carried multiple functional genes, indicating a genetic potential for diverse functional traits. Antibacterial activity assays demonstrated that nearly all strains inhibited at least three indicator pathogens, with ten strains, particularly Lactiplantibacillus plantarum and Lactococcus lactis strains, exhibiting strong inhibitory effects. Bacteriocin production was confirmed for three Lact. lactis strains. Exopolysaccharide (EPS) production was confirmed in two strains, with yields varying by growth medium and sucrose supplementation. Overall, the results underscore the rich microbial diversity and promising biotechnological potential of LAB from traditional Romanian dairy ecosystems, supporting their use in food fermentation and functional product development. Full article

The purpose of this study was to examine how hydraulic retention time (HRT) influences biohydrogen generation and the formation of end-products during the co-digestion of olive mill wastewater (OMW), cheese whey (CW), and sewage sludge (SS) mixed in a 40:40:20 (v/v/v) ratio. The relationship between the substrates, resulting metabolites, and microbial communities was also explored. Continuous fermentation trials were carried out under both mesophilic (37 °C) and thermophilic conditions using HRTs of 12, 24 and 48 h. Acetic, propionic, and butyric acids were identified as the main end-products. The highest hydrogen production rate (4.4 ± 0.5 L H₂/L_reactor/day) occurred under thermophilic conditions at an HRT of 24 h, whereas under mesophilic operation at the same HRT the hydrogen production reached 3.0 ± 0.3 L H₂/L_reactor/day. In contrast, the greatest accumulation of volatile fatty acids (VFAs) was observed under mesophilic conditions (10.02 g/L), while thermophilic operation at 24 h HRT resulted in 5.54 g/L of total VFAs. The improved performance under thermophilic fermentation is likely linked to the suppression of hydrogen-consuming bacteria at elevated temperatures, which favors rapid hydrogen producers. Microbial community analysis indicated dominance of Firmicutes and persistent Lactobacillus prevalence across conditions. Shorter HRT at 37 °C promoted community diversification with genera such as Olsenella, Dialister, and Prevotella increasing in relative contribution. Under thermophilic operation, consortia remained Lactobacillus-dominant but showed significant temporal restructuring. The predominance of acetic acid (~2.80 g/L) and butyric acid (~2.60 g/L) indicates that hydrogen generation mainly followed the acetic and butyric pathways. This study reveals how targeted control of HRT and temperature can steer microbial communities toward highly hydrogen-productive consortia in the continuous dark fermentation of mixed agro-industrial wastes. Full article

Large amounts of agro-industrial residues—such as grape pomace, olive mill wastewater, wheat straw, and cheese whey—pose disposal challenges and generate substantial environmental and economic burdens. Incorporating these by-products into ruminant diets may reduce feeding costs while supporting sustainability within a circular bioeconomy. Two experiments were conducted to evaluate: (i) the characteristics of a mixed raw agro-industrial by-product silage (BPS) in cylindrical bale silos (50 kg) and (ii) its effects as dietary supplementation on metabolic profile, oxidative status, milk yield, and milk quality in lactating goats. The BPS was formulated from raw wheat straw, grape pomace, olive mill wastewater, and cheese whey and tested at a 30% inclusion level (dry-matter basis). The combined by-products produced in 50 kg cylindrical bale silos were positively characterized and exhibited a nutritionally suitable silage with relevant antioxidant potential. Dietary BPS improved oxidative status, as evidenced by increased TAS and vitamin E and reduced ROMs, and positively influenced lipid and immunological blood markers of goats. Milk yield was higher in goats receiving the BPS. Moreover, milk quality was improved through a more favorable fatty acid profile, higher vitamin E content, reduced cholesterol levels, and enhanced oxidative stability, as evidenced by lower TBARS values. Overall, BPS supplementation enhanced animal health indicators and milk nutritional properties, demonstrating that this silage can contribute to more sustainable dairy goat production while offering potential benefits for human nutrition. Full article

The aim of this study was to assess the influence of milk’s rennet coagulation properties (RCPs) on cheese yield and cheese-making losses in the production of Parmigiano Reggiano PDO cheese. Higher contents of citric acid (181.10 vs. 172.13 vs. 166.47 mg/100 g) and phosphorus (95.02 vs. 91.14 vs. 88.78 mg/100 g) in milk with optimal and sub-optimal RCPs, compared to milk with poor RCPs, respectively, positively affect the acidity of the milk, lowering the pH values (6.68 vs. 6.70 vs. 6.72, respectively), which results in a faster reaction between chymosin and casein and consequently a reduced time of milk coagulation. The lower values of curd firming time and the higher values of curd firmness, strength to cut (68.97 vs. 64.43 vs. 44.38 g), and strength to compression (31.48 vs. 30.49 vs. 25.70 g) for milk with optimal and sub-optimal coagulation, compared to milk with poor coagulation, result in a higher stress resistance across the technological steps of the cheese-making process, leading to lower fat losses (14.23 vs. 15.48 vs. 16.72%) in the whey and a higher cheese yield (8.79 vs. 8.56 vs. 8.08 kg/100 kg). Full article

Cheese whey, the major by-product of the dairy industry, poses an environmental challenge due to its high organic load but simultaneously represents a nutrient-dense matrix suitable for biotechnological valorization. This review synthesizes recent advances positioning whey as (i) a fermentation substrate for lactic acid bacteria, yeasts/fungi, and microalgae, enabling the production of functional biomass, organic acids, bioethanol, exopolysaccharides, enzymes, and wastewater bioremediation; (ii) a platform for postbiotic generation, supporting cell-free preparations with functional activities; and (iii) a food-grade encapsulating material, particularly through whey proteins (β-lactoglobulin, α-lactalbumin), which can form emulsions, gels, and films that protect biotics and bioactive compounds during processing, storage, and gastrointestinal transit. We analyze key operational variables (whey type and pretreatment, supplementation strategies, batch and continuous cultivation modes), encapsulation routes (spray drying, freeze-drying, and hybrid protein–polysaccharide systems), and performance trade-offs relevant to industrial scale-up. Finally, we outline future directions, including precision fermentation, mixed-culture processes with in situ lactase activity, microfluidics-enabled encapsulation, and life-cycle assessment, to integrate product yields with environmental performance. Collectively, these strategies reframe whey from a high-impact waste into a circular bioeconomy resource for the food, nutraceutical, and environmental sectors. Full article

Lactic acid bacteria (LAB) have attracted scientific attention as potential producers of biosurfactants (BS); however, there is limited knowledge on the structure of the produced molecules. The aim of this study was to elucidate the individual components comprising the crude BS produced by Limosilactobacillus fermentum ACA-DC 0183. Initially, batch fermentations using substrate recycling were employed, leading to the production of 0.76 g/L of crude BS from cheese whey as the sole carbon and nutrient source. The produced BS maintained their properties under various temperatures, pH values, and salinity levels, signifying their potential uses in food applications. Additionally, the structural components were analyzed after hydrolysis. The lipoic part was mainly composed of palmitic acid, oleic acid, and stearic acid, while 17 amino acids were identified as part of the protein moiety of the molecule. Acid hydrolysis of the carbohydrate moiety revealed that this part consisted of glucose, galactose, and glycerol. Partial purification with column chromatography and characterization using FTIR demonstrated the presence of a glycoprotein and a glycolipid as surface-active molecules. Revealing the structure and specific properties of microbially produced BS can expand their utilization in target applications, while their production from renewable sources contributes towards the sustainable production of LAB-based BS. Full article

Natural whey starter (NWS) cultures are microbial consortia characterized by high microbial diversity in terms of genus and species, as well as strains, accounting for the variety of different characteristics and quality of the artisanal fermented food. By means of a combined approach, using plate counts, bacterial isolation, molecular identification, and genotyping, we analyzed 41 colonies isolated from NWS of cow milk used in the production of caciocavallo, a typical pasta filata Italian cheese. Results revealed that 27 of them were lactic acid bacteria (LAB), including Lactococcus lactis as the dominant species, followed by Streptococcus thermophilus, Enterococcus faecium, Limosilactobacillus fermentum, Lactobacillus helveticus, and Lacticaseibacillus rhamnosus. The remaining isolates were taxonomically identified as non-LAB, probably due to environmental contamination. These results were mostly confirmed by metagenomic analysis, with the exception of only three species. Finally, small-scale fermentation experiments were performed in both standard media and skimmed milk to further characterize the newly isolated LAB strains. Overall, our results show that, except for four of the Lactococcus isolates and one Streptococcus, which show multi-drug resistance, the isolated strains under study exhibit levels of acidifying, metabolic properties, and safety parameters, suggesting their potential as starter cultures in cheese production. Full article

Background/Objectives: Metabolites are low-molecular-weight organic compounds (<1 kDa) that act as intermediates and end products of cellular metabolism. Their characterization provides valuable information on the nutritional quality, functionality, and potential health impacts of food products. In the dairy sector, proton nuclear magnetic resonance (¹H NMR) spectroscopy has emerged as a powerful tool for metabolite profiling, enabling the simultaneous identification and quantification of diverse compounds. In this study, ¹H NMR was applied to characterize and compare the metabolic composition of whey, a major by-product of cheese and yogurt production, and whey protein concentrate (WPC-80), a whey derivative containing approximately 80% protein by weight and rich in essential amino acids. Methods: Five whey and four WPC-80 samples from a single Parmigiano Reggiano dairy plant were collected, each representing a biologically independent sample. Statistical evaluation was performed using Mann–Whitney U tests to identify significantly different metabolites between groups, while principal component analysis and partial least squares discriminant analysis were employed to assess group separation and determine discriminant metabolites. Results: The results revealed marked compositional differences: whey was higher in dimethyl sulfone, succinate, orotate, fumarate, and lactose (p < 0.05), whereas WPC-80 contained significantly higher levels of histidine, formate, glucose + glucose-6-phosphate, acetate, and choline (p < 0.05). Moreover, metabolites such as hippurate, valine, lactate + threonine, and uracil were exclusively found on whey and not in WPC-80, likely due to processing steps such as ultrafiltration. Conclusions: These findings highlight the metabolic distinctions introduced by WPC-80 processing from Parmigiano Reggiano whey and provide insights into the nutritional and functional characteristics of whey-derived products. Such knowledge can inform the design of innovative dairy ingredients and functional foods, with potential benefits for both industry applications and consumer health. Full article