Search Results (307)

Buffalo mozzarella cheese whey (CW) and ricotta cheese exhausted whey (RCEW) are valuable by-products of the Mozzarella di Bufala Campana PDO production chain. This study characterized their microbial communities using an integrated culture-dependent and -independent approach. Metabarcoding analysis revealed that the dominance of lactic acid bacteria (LAB), including Streptococcus thermophilus, Lactobacillus delbrueckii, and Lactobacillus helveticus, alongside diverse heat-resistant yeasts such as Cyberlindnera jadinii. Culture-based isolation identified subdominant lactic acid bacteria strains, not detected by sequencing, belonging to Leuconostoc mesenteroides, Enterococcus faecalis, and Enterococcus durans. These strains were further assessed for their probiotic potential. E. faecalis CW1 and E. durans RCEW2 showed tolerance to acidic pH, bile salts, and lysozyme, as well as a strong biofilm-forming capacity and antimicrobial activity against Bacillus cereus and Staphylococcus aureus. Moreover, bile salt resistance suggests potential functionality in cholesterol metabolism. These findings support the potential use of CW and RCEW as reservoirs of novel, autochthonous probiotic strains and underscore the value of regional dairy by-products in food biotechnology and gut health applications. Full article

The role of Enterococcus spp. in food is debated since this group of lactic acid bacteria contains opportunistic pathogenic strains, some of which exhibit a multidrug-resistant profile. In livestock farms, the use of antibiotics is the most common practice to deal with mastitis-causing bacteria. However, the heavy usage and/or misuse of antibiotics has led to the emergence of antibiotic resistance. This study aimed to genetically and phenotypically characterize Enterococcus strains isolated from raw sheep milk. Samples were collected over one year from the bulk tank of a dairy sheep farm and cultured on selective media. Isolates were purified and analyzed by whole-genome sequencing and antimicrobial susceptibility testing. The isolates were divided into clusters and the corresponding species were identified along with their genes related to virulence and antibiotic resistance. The pan-, core- and accessory-genomes of the strains were determined. Finally, the antibiotic-resistant profile of selected strains was examined and associated with their genomic characterization. These findings contribute to a better understanding of Enterococci epidemiology, providing comprehensive profiles of their virulence and resistance genes. The presence of antibiotic-resistant bacteria in raw sheep milk destined for the production of cheese should raise awareness. Full article

This study aimed to verify, under real operating conditions, the effectiveness of protective lactic acid bacteria (LAB) culture in counteracting the development of late blowing defects in Valtellina Casera PDO cheese and its impact on product sensory characteristics. Thirty-four LAB isolated from Bitto and Valtellina Casera PDO cheeses were screened for anti-Clostridium activity. Lacticaseibacillus casei VC201 was able to inhibit all the indicator strains through organic acid production. Valtellina Casera PDO cheese-making was performed twice in three dairy farms using a commercial autochthonous starter culture with and without the addition of the protective culture VC201. Cheese was ripened both at 8 °C and 12 °C and analyzed after 70 and 180 days for LAB population, proteolysis, and lipolysis evolution as well as sensory impact. Cheeses with the addition of the VC201 strain showed higher contents of rod-shaped LAB throughout the ripening at both temperatures. The protective culture decreased the production of butyric acid at 70 days, especially at 8 °C (−15.4%), while butyric fermentation was occasionally lightly observed at 12 °C. The sensory profile was favorably impacted by the higher relative proportion of short-chain fatty acids (SCFFAs, C2–C8), which was especially pronounced at 8 °C and persisted for 180-day ripening (23.91% vs. 18.84% at 70 days and 23.84 vs. 21.71 at 180 days of ripening). The temperature and time of ripening had a significant effect on the free fatty acid content of the cheese samples in all three classes (SCFFA, MCFFA, and LCFFA). The cheese made with Lcb. casei VC201 was preferred, according to the sensory evaluation, being perceived as less acidic, less bitter, tastier, and with more intense flavor. Protective cultures can represent a practical way to reduce late blowing defects in Valtellina Casera cheese production while maintaining adherence to its PDO regulatory requirements. Full article

This study aimed to evaluate the microbiological quality of colostrum on three dairy farms with different colostrum management hygiene practices and to compare it with the current colostrum quality guidelines. On farm A, colostrum was fed raw, while on farms B and C it was heat treated. On farms A and B, the feeding equipment was cleaned manually, while on farm C, an automated cleaning system was used. Samples were collected from the calf-feeding equipment and submitted for microbial culture: total plate count (TPC); total coliform count (TCC); and E. coli, enterobacteria (ENTB), staphylococci (STAP), and lactic acid bacteria counts. In addition, pH, water activity (a_W), and Brix were analyzed. Colostrum quality was defined as follows: good quality (GQ)—TPC < 100,000, TCC < 10,000, STAP < 50,000 cfu/mL, and Brix ≥ 22%; excellent quality (EQ)—TPC < 20,000, TCC < 100, STAP < 5000 cfu/mL, and Brix ≥ 25%. Mean concentrations were as follows: TPC was 3.99 × 10⁵ cfu/mL (min: 40.00, max: 1.32 × 10⁷ cfu/mL); TCC was 1.17 × 10⁴ cfu/mL (min: <detection limit, max: 6.37 × 10⁵ cfu/mL); and STAP was 1.77 × 10⁴ cfu/mL (min: <detection limit, max: 3.50 × 10⁵ cfu/mL). Approximately 54% (GQ) and 32% (EQ) of samples met the defined criteria. Farm C consistently showed lower microbial counts across all culture types. Colostrum from farm B had lower TCC, LAB, and E. coli counts than farm A but not TPC, STAP, and ENTB. These results showed that a considerable proportion of calves were fed colostrum with suboptimal quality, especially when less rigorous hygiene practices were implemented. Full article

Consumer demand for natural, additive-free foods is increasing. Following the trend, this study evaluated the antifungal potential of lactic acid bacteria (LAB) against Penicillium species commonly found in cheese, using both LAB ferments and hydroxypropylmethylcellulose (HPMC) coatings. LAB strains were first screened with a dual-culture assay. Fermentations in Man–Rogosa–Sharpe (MRS) broth and milk whey were lyophilized and tested, with whey-based ferments showing greater antifungal activity. All whey ferments inhibited fungal growth, with KK₁₃, KB₂, KB₃, and KB₄ being the most effective based on MIC and MFC assays. KB₃-fermented whey had the highest levels of antifungal metabolites, such as phenyllactic acid. A coating containing 5% HPMC and 100 g/L of KB₃-fermented whey was applied to cheese slices, reducing the fungal counts of Penicillium commune by more than 1 Log₁₀ CFU per gram and extending shelf life by 12 days. In whole-cheese trials with natural contamination, this coating delayed visible fungal growth until day 60, extending shelf life by 45 days compared with uncoated samples and 33 days compared with coated controls. These findings support the use of LAB-fermented whey and HPMC coatings as natural preservation strategies, thereby contributing to the sustainable reuse of dairy by-products. Full article

Listeriosis, the disease caused by the bacterium L. monocytogenes, can take invasive forms, with severe complications such as septicemia or meningitis, mainly affecting vulnerable people, such as pregnant women, the elderly, and immunocompromised people. The main transmission is through the consumption of contaminated food, and unpasteurized dairy products are common sources of infection. Due to the high mortality and the difficulty in eliminating the bacterium from the production environment, rigorous hygiene and control measures are essential to prevent the spread of Listeria in the food chain, and research on biofilm formation and bacterial resistance is vital to improve food safety. Dairy products, raw milk, and soft cheeses are among the most vulnerable to contamination with L. monocytogenes, especially due to pH values and low-temperature storage conditions. This paper presents a synthesis of the specialized literature on methods to reduce the incidence of L. monocytogenes in milk and dairy products. Conventional strategies, such as pasteurization and the use of chemical disinfectants, are effective but can affect food quality. Specialists have turned their attention to innovative and safer approaches, such as biocontrol and the use of nonthermal methods, such as pulsed electric fields, irradiation, and nanotechnology. Barrier technology, which combines several methods, has demonstrated superior efficiency in combating the bacterium without compromising product quality. Additionally, lactic acid bacteria (LAB) and bacteriocins are examples of biopreservation techniques that provide a future option while preserving food safety. Natural preservatives, especially those derived from plants and fruits, are promising alternatives to synthetic compounds. Future solutions should focus on developing commercial formulations that optimize these properties and meet consumer demands for healthy, environmentally friendly, and clean-label products. Full article

Lactic acid bacteria (LAB) have long been recognized for their versatility and historical significance, with a remarkable capability to produce a wide range of bioactive compounds that can be used across food, pharmaceuticals, nutrition, agriculture, and sustainable industrial sectors. This review aims to explore the current state of knowledge regarding LAB in beverages, emphasizing their diversity across dairy, non-dairy, and hybrid beverage matrices. Key aspects discussed include fermentation processes, associated challenges, and future perspectives. By examining a wide array of studies, this review offers a holistic perspective on the role of LAB in influencing sensory characteristics (both desirable and undesirable), promoting health benefits, extending shelf life, and enhancing their safety. Furthermore, emerging trends are highlighted, such as the use of LAB for the development of novel LAB-based beverages, their use for bioremediation of toxic compounds, genetic engineering of LAB strains to optimize and tailor their fermentation outcomes, and their use in drug delivery. Full article

Background/Objectives: Listeria monocytogenes is a major foodborne pathogen responsible for listeriosis, a serious illness with high morbidity and mortality, particularly in vulnerable populations. Its persistence in food processing environments and resistance to conventional preservation methods pose significant food safety challenges. Lactic acid bacteria (LAB) offer a promising natural alternative due to their antimicrobial properties, especially through the production of bacteriocins. This study investigates the competitive interactions between Lactococcus lactis and L. monocytogenes under co-culture conditions, with a focus on changes in their secretomes to better understand how LAB-derived bacteriocins can help mitigate the Listeria burden. Methods: Proteomic approaches, including Tricine-SDS-PAGE, two-dimensional electrophoresis, and shotgun proteomics, were employed to analyze the molecular adaptations of both species in response to bacterial competition. Results: Our results reveal a significant increase in the secretion of enolase by L. monocytogenes when in competition with L. lactis, suggesting its role as a stress-responsive moonlighting protein involved in adhesion, immune evasion, and biofilm formation. Concurrently, L. lactis exhibited a shift in the production of its bacteriocin, nisin, favoring the expression of Nisin Z—a variant with improved solubility and diffusion properties. This differential regulation indicates that bacteriocin production is modulated by bacterial competition, likely as a defensive response to the presence of pathogens. Conclusions: These findings highlight the dynamic interplay between LAB and L. monocytogenes, underscoring the potential of LAB-derived bacteriocins as natural biopreservatives. Understanding the molecular mechanisms underlying microbial competition could enhance food safety strategies, particularly in dairy products, by reducing reliance on chemical preservatives and mitigating the risk of L. monocytogenes contamination. Full article

Fermenting fruit and vegetable juices with probiotic bacteria is becoming a popular way to create functional drinks, offering an alternative to traditional dairy-based probiotic products. These plant-based juices are naturally rich in nutrients that help support the growth and activity of various probiotic strains. They also meet the rising demand for lactose-free, vegan, and clean-label options. This review looks at the key microbiological, nutritional, and sensory aspects of probiotic fermentation in juice. Common probiotic groups like Lactobacillus, Bifidobacterium, Lactococcus, Bacillus, and Streptococcus show different abilities to adapt to juice environments, affecting properties such as antioxidant levels, shelf life, and taste. The review also explores how factors like pH, sugar levels, heating, and storage can influence fermentation results. New non-thermal processing methods that help maintain probiotic survival are also discussed. Since fermented juices can sometimes develop off-flavors, this paper looks at ways to improve their taste and overall consumer appeal. Finally, future directions are suggested, including personalized nutrition, synbiotic products, and advanced encapsulation technologies. Overall, probiotic fermentation of fruit and vegetable juices shows strong potential for developing a new generation of healthy and appealing functional foods. Full article

Buffalo milk is a rich source of precursor fatty acids for bioactive compounds and provides an optimal environment for bacterial growth. This study aimed to isolate and select lactic acid bacteria strains with potential to conjugated linoleic acid (CLA) production for technological application in fermented buffalo milk. Fifty-eight strains were isolated from raw milk, kefir, artisanal cheese, kombucha, and jaboticaba juice and tested for CLA biosynthesis. In milk fermentation, selected strains with linoleic acid (LA) conversion rates ranging from 65.66% to 21.86% were L. paraplantarum, L. plantarum, P. pentosaceus, and L. fermentum. The highest viability average values between 11.85 and 11.15 Log CFU/mL were observed after 8 h of fermentation for the L. plantarum, control L. plantarum, and L. fermentum treatments, while it took 10 h of fermentation for L. paraplantarum and P. pentosaceus to reach a stationary phase, with pH stabilizing at 4.60 ± 0.1 after 30 h. Despite L. paraplantarum showing the highest in vitro CLA production (0.99 mg/mL), in buffalo milk, all strains similarly produced c9t11 CLA, with no detectable t11c12 CLA. P. pentosaceus and L. fermentum showed a fatty acid profile with higher PUFA content, especially in CLA and MUFA, related to a lower degree of atherogenicity (IA) and thrombogenicity index (ThI). These findings boost understanding of dairy (raw milk, artisanal cheese, and milk kefir) and non-dairy substrates (kombucha and jaboticaba juice) as reservoirs for functional bacteria and highlight buffalo milk as a matrix for diversification of naturally enriched fermented dairy products. Full article

Yogurt is a highly consumed dairy product valued for its nutritional and probiotic properties. Its production involves the use of lactic acid bacteria, which drive biochemical transformations during fermentation. Optimizing fermentation time without compromising yogurt quality is essential for improving processing efficiency. Pulsed electric fields (PEFs) constitute a promising technology that stimulates microbial activity. In this study, a yogurt starter inoculum suspended in milk (IM) with different fat content (0.5–2.8%) was treated with low-intensity PEFs (1 kV/cm, 800–1600 µs) to enhance fermentation kinetics. pH, soluble solids, lactose, lactic acid, and riboflavin concentrations were monitored during 6 h, comparing PEF-treated IM (PEF-IM) and untreated IM (C-IM). PEF-treatments applied to IM reduced the fermentation time of inoculated milk by 4.3–20.4 min compared to C-IM. The lowest fermentation time (5.1 ± 0.16 h) was observed in milk added with PEF-IM (2.8% fat) treated at 1 kV/cm for 1600 µs. Milk inoculated with PEF-IM exhibited enhanced lactose consumption (1.6–3.1%) and higher lactic acid production (7.2%) than milk with C-IM. Riboflavin concentration (0.9–7%) decreased between 2 and 4 h, but it stabilized at the end of fermentation. Obtained results suggest that PEFs promote reversible electroporation in microbial cells, facilitating nutrient uptake and acidification, making it a promising assisted-fermentation approach to improve yogurt production. Full article

Lactic acid bacteria (LAB) isolated from plant sources are gaining increasing attention due to their potential probiotic and postbiotic functionalities. In the present study, Limosilactobacillus fermentum isolated from Prunus padus (bird cherry) was evaluated for its physiological, functional, and technological attributes for application in fermented dairy products. The strain was isolated through anaerobic fermentation and identified using API 50 CHL and 16S rRNA sequencing. Its acid tolerance, antioxidant capacity, antibacterial effects, and hemolytic activity were assessed. The cell-free supernatant (CFS) was evaluated for thermal and pH stability. Fermentation trials were conducted using both mono- and co-culture combinations with the commercial yogurt starter strain YC-380. Physicochemical properties, viable cell counts, and viscosity were monitored throughout fermentation and refrigerated storage. The L. fermentum isolate exhibited strong acid resistance (48.28% viability at pH 2.0), non-hemolytic safety, and notable DPPH radical scavenging activity. Its CFS showed significant antibacterial activity against five Escherichia coli strains, which remained stable after heat treatment. Co-cultivation with YC-380 enhanced fermentation efficiency and improved yogurt viscosity (from 800 to 1200 CP) compared to YC-380 alone. During 24 days of cold storage, co-cultured samples maintained superior pH and microbial stability. Additionally, the moderate acidification profile and near-neutral pH of L. fermentum created favorable conditions for postbiotic compound production. These results indicate that L. fermentum derived from P. padus holds considerable promise as a functional adjunct culture in yogurt production. Its postbiotic potential, technological compatibility, and heat-stable bioactivity suggest valuable applications in the development of safe, stable, and health-promoting fermented dairy products. Full article

This study evaluated the effects of raspberry pomace addition on kefir’s chemical, microbiological, and sensory properties during a 14-day refrigerated storage. Kefir samples were prepared using 10% and 20% raspberry pomace, either retaining or straining out pomace after fermentation. Raspberry pomace notably enhanced antioxidant activity, peaking at 95.91% DPPH radical reduction on day 10, and increased total polyphenol content to 78.24 mg gallic acid/L. Pomace addition also improved microbiological stability, maintaining higher lactic acid bacteria (7.48 log CFU/mL) and stable yeast counts. Repeated measures ANOVA revealed a significant effect of storage duration on the concentrations of all analyzed parameters. Results showed that pomace-enriched samples, particularly those retaining pomace during storage, exhibited significantly higher levels of lactic, acetic, and citric acids, as well as ethanol and residual sugars. Sensory evaluations revealed kefir samples with strained raspberry pomace had the highest consumer acceptability, scoring 7.8 out of 9 for overall acceptance due to balanced flavor and improved texture. These results highlight raspberry pomace’s potential as a valuable ingredient for improvement in kefir, offering a promising approach to functional dairy innovation. Full article

Campylobacter jejuni (C. jejuni) is the primary Campylobacter species and a major cause of foodborne illness associated with poultry products. This review focuses on lactic acid bacteria (LAB), especially Lactobacillus species, and acid whey as a dairy by-product for C. jejuni control in poultry as a sustainable method. LAB strains L. crispatus exhibit a cecal colonization reduction of >90% by competitive exclusion and bacteriocin activity, while L. johnsonii FI9785 decrease bacterial load 4–5 log₁₀. Acid whey, which is abundant in organic acids (e.g., lactic acid) and bioactive peptides (e.g., lactoferrin), reduces C. jejuni viability, decreasing the food product contamination on the carcass for a short time by 40%. LAB antimicrobial function becomes more effective when used with acid whey, although specific farm-related variables require additional optimization. Some of the key strategies include co-encapsulating LAB with acid whey or plant-derived antimicrobials for improving survival, conducting in vivo trials in commercial farm conditions to evaluate scalability, and adding whey into feed (1–2% inclusion) or applying it as a pre-slaughter spray. These strategies enable the antibiotic-free production and circular economy goals through repurposing low-cost acid whey. Future studies should directly compare them with standard antimicrobials to confirm their scalability for poultry safety. Full article

The valorization of cheese whey, a rich by-product of the dairy industry that is rich in lactose (approx. 70%), proteins (14%), and minerals (9%), represents a promising approach for microbial fermentation. With global whey production exceeding 200 million tons annually, the high biochemical oxygen demand underlines the important need for sustainable processing alternatives. This review explores the biotechnological potential of whey as a fermentation medium by examining its chemical composition, microbial interactions, and ability to support the synthesis of valuable metabolites. Functional microorganisms such as lactic acid bacteria (Lactobacillus helveticus, L. acidophilus), yeasts (Kluyveromyces marxianus), actinobacteria, and filamentous fungi (Aspergillus oryzae) have demonstrated the ability to efficiently convert whey into a wide range of bioactive compounds, including organic acids, exopolysaccharides (EPSs), bacteriocins, enzymes, and peptides. To enhance microbial growth and metabolite production, whey fermentation can be carried out using various techniques, including batch, fed-batch, continuous and immobilized cell fermentation, and membrane bioreactors. These bioprocessing methods improve substrate utilization and metabolite yields, contributing to the efficient utilization of whey. These bioactive compounds have diverse applications in food, pharmaceuticals, agriculture, and biofuels and strengthen the role of whey as a sustainable biotechnological resource. Patents and clinical studies confirm the diverse bioactivities of whey-derived metabolites and their industrial potential. Whey peptides provide antihypertensive, antioxidant, immunomodulatory, and antimicrobial benefits, while bacteriocins and EPSs act as natural preservatives in foods and pharmaceuticals. Also, organic acids such as lactic acid and propionic acid act as biopreservatives that improve food safety and provide health-promoting formulations. These results emphasize whey’s significant industrial relevance as a sustainable, cost-efficient substrate for the production of high-quality bioactive compounds in the food, pharmaceutical, agricultural, and bioenergy sectors. Full article