Search Results (3,745)

Probiotic lactic acid bacteria are widely recognized for their health-promoting effects. However, the use of live microorganisms may pose safety concerns and stability limitations. Consequently, postbiotics, defined as inactivated microbial cells and/or their components, have emerged as a promising alternative. This study integrates genome-guided evaluation of probiotic potential, experimental validation of in silico predictions and process optimization for the production of inactivated Lactiplantibacillus plantarum DM1 and KK1 cells as postbiotics. Genome mining identified genes and gene clusters associated with metabolic versatility, antimicrobial activity, gastrointestinal stress tolerance, adhesion and prebiotic substrate utilization. Building on these findings, to generate postbiotics, the efficiency of thermal, enzymatic, mechanical and radiation-based inactivation methods was evaluated in bacterial suspensions prepared in three dairy by-product matrices: milk permeate, sweet whey and sour whey. Complete inactivation of both strain cells was achieved by thermal treatment (3 min pasteurization), γ-irradiation (3 kGy), and combined lysozyme–pasteurization treatment, whereas other treatments showed partial and matrix-dependent effects. Matrix composition significantly influenced treatment efficacy, suggesting a protective role of food components used. These findings highlight the importance of combining genome mining for potential probiotic strain characterization with robust, matrix-adapted inactivation strategies for the development of stable postbiotic formulations. Full article

To address the industrialization limitations of traditional sourdough and develop high-performance direct-vat-set (DVS) starters for steamed buns, this study screened superior lactic acid bacteria (LAB) and optimized the preparation technology of freeze-dried bacterial powder. The results demonstrated that the compound system of Lactiplantibacillus plantarum and Streptococcus thermophilus at a 1:1 ratio achieved favorable synergistic fermentation with sourdough, which effectively regulated dough acidification and improved the comprehensive sensory quality of steamed buns. The critical processing parameters, including centrifugation conditions and compound lyoprotectant composition containing trehalose, lactose and skim milk powder, were systematically optimized to significantly enhance the freeze-drying survival ability of compound LAB, and the high fitting degree of the established regression model confirmed the stability and reliability of the optimized formulation. The optimal dosage of freeze-dried DVS powder was verified to rationally modulate dough acidity and comprehensively promote the specific volume, structural characteristics and sensory performance of steamed buns. This systematic study provides robust theoretical and technical support for the industrial application of DVS LAB starters in high-quality steamed bun production, facilitating the modernization of traditional fermented wheat products. Full article

Lactic acid bacteria (LAB) have been widely utilized in the production of fermented foods worldwide due to their well-established health-promoting benefits for both humans and animals. In addition to their nutritional value, LAB exhibit antagonistic activity against foodborne pathogens, particularly Salmonella spp., which are commonly associated with livestock and animal production systems. LAB exert a range of biological effects that can inhibit the growth of Salmonella and modulate its virulence. In the present study, the antagonistic potential of Weissella confusa WM36 was evaluated based on its ability to inhibit S. Typhimurium growth, disrupt biofilm formation, and suppress the expression of virulence-associated genes. A preliminary safety assessment of W. confusa WM36 was conducted through hemolytic activity and antibiotic susceptibility profiling. In addition, the biofunctional properties of its cell-free supernatant (CFS), herein referred to as postbiotic metabolites, were investigated with a particular focus on antioxidant activity. Experimental results demonstrated that W. confusa WM36 and its CFS at 40% (v/v) achieved a complete reduction (100%) of S. Typhimurium cell counts within 6 to 12 h of treatment. Furthermore, CFS at 20% and 40% (v/v) significantly impaired biofilm formation, while treatment with 20% (v/v) CFS markedly downregulated the expression of key virulence genes. The strain WM36 exhibited α-hemolytic activity and showed susceptibility to most of the antibiotics tested, although resistance to ceftriaxone and trimethoprim–sulfamethoxazole was observed. These findings provide preliminary information regarding its safety characteristics; however, further molecular and in vivo investigations are required to comprehensively evaluate its safety for practical applications. Additionally, the CFS exhibited notable antioxidant activity, with DPPH radical scavenging capacity of 8.90 ± 0.06 mM Trolox equivalents and ABTS radical scavenging power of 13.10 ± 1.42 mM Trolox equivalents. Collectively, these findings highlight the potential of W. confusa WM36 and its postbiotic metabolites as promising biocontrol and functional agents against S. Typhimurium, while further safety validation remains necessary. Full article

Bamboo shoot dietary fiber (BSDF) is dominated by an insoluble fraction, which severely restricts its physicochemical performance and food application. In this study, the soluble dietary fiber (SDF) content of bamboo shoots was enhanced using three enzyme fermentation sequences: enzymatic hydrolysis followed by fermentation (EH), fermentation followed by enzymatic hydrolysis (F-EH), and integrated enzymatic hydrolysis and fermentation (IEHF). EH-F treatment resulted in the highest SDF content (17.27%). Variations in pH, biomass, enzyme activity, and short-chain fatty acids were assessed to understand the differences in the modification efficiency among the treatment sequences. Fourier transform infrared (FTIR) spectroscopy indicated that sequential enzymatic and fermentation treatments altered the chemical structure of bamboo shoot powder, consistent with the conversion of insoluble to soluble fractions. SDF from the EH-F treatment exhibited superior water-holding capacity (6.71 g/g), oil affinity (6.42 g/g), and DPPH radical scavenging rate (65.69% at 1.2 mg/mL). Moreover, SDF from the EH-F treatment achieved an 87.82% carbohydrate residue retention rate during simulated gastrointestinal digestion. These enhanced properties were associated with improved hydration properties resulting from the sequential tailoring process. This preliminary study explored the effects of different enzyme fermentation sequences on BSDF modification, providing a reference for the utilization of BSDF. Full article

Iodine deficiency remains a major nutritional concern worldwide, and fermented dairy products are considered promising vehicles for iodine fortification. However, the chemical form of iodine may influence the physicochemical and microbiological stability of fermented dairy systems. This study aimed to compare potassium iodide and iodocasein as iodine sources for the fortification of a fermented dairy product and to evaluate their effects on product quality and iodine retention during refrigerated storage. Three formulations were produced: a control sample without iodine fortification and samples fortified with potassium iodide or iodocasein at a level of 25 µg iodine per 100 g of product. Samples were stored at 4 ± 1 °C for 7 days. Changes in pH, titratable acidity, syneresis, viscosity, viable counts of starter lactic acid bacteria, iodine retention, and sensory properties were evaluated during storage. The results showed that the iodine source significantly affected product stability. The potassium iodide-fortified sample exhibited greater post-acidification, increased syneresis, lower viscosity, and a more pronounced reduction in viable lactic acid bacteria during storage. In contrast, the iodocasein-fortified sample maintained physicochemical and microbiological characteristics closer to the control and demonstrated higher iodine retention. Fortification at the studied level did not significantly affect the basic composition or amino acid profile of the product. The findings indicate that iodocasein can improve iodine stability while preserving the quality characteristics of fermented dairy products, supporting its potential application in the development of iodine-enriched functional dairy foods. 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 aimed to evaluate the technological, functional and nutritional effects of exopolysaccharide-producing lactic acid bacteria (LAB) strains, isolated from artisanal Tulum cheese as type II sourdough starters. The objective of this study was to improve bread quality, delay staling, and enhance bioactive properties, such as antioxidant capacity and estimated glycaemic index (eGI). Six LAB strains (Loigolactobacillus coryniformis, Lactiplantibacillus plantarum, Levilactobacillus brevis, Lacticaseibacillus paracasei, Lactobacillus helveticus, and Lacticaseibacillus rhamnosus) were individually used for sourdough fermentation. Bread samples were analyzed for pH, titratable acidity (TA), LAB counts, specific volume, colour, total phenolic content (TPC), antioxidant activity (DPPH and ABTS), starch digestibility, eGI, staling kinetics (Avrami model) and amylopectin retrogradation (DSC). Strain-dependent improvements in bread functionality were observed. L. brevis and L. coryniformis strains increased sourdough acidity to a greater extent, and resulting in lower pH values. Accordingly, bread produced with sourdough fermented by these strains exhibited higher specific volume than the control. Although higher ABTS radical scavenging activity and TPC were detected in sourdough bread compared to the control bread, no significant differences were observed among the breads in terms of total antioxidant activity measured by DPPH. L. rhamnosus significantly improved antioxidant activity and reduced the eGI. L. coryniformis, L. plantarum and L. brevis were the most effective at retarding staling, reducing the increase in hardness and limiting amylopectin retrogradation. This study is the first to demonstrate the functional potential of LAB strains from artisanal Tulum cheese as sourdough starters. These findings reveal the potential for developing clean-label bakery products with an extended shelf life and improved health-related functionality. Full article

Traditional fermented dairy products represent an important source of autochthonous microorganisms with potential applications in food biotechnology. This study aimed to isolate and characterize microorganisms from the traditional Kazakh fermented product kurt collected from different regions of the Abai area (Kazakhstan) and to evaluate their suitability for biotechnological applications in meat processing. Microbial isolation was performed using MRS medium under anaerobic conditions, followed by morphological and physiological characterization. Accurate identification was carried out using MALDI-TOF MS and 16S rRNA gene sequencing. The results showed that microbial counts ranged from 10⁶ to 10⁸ CFU/g, confirming high microbial diversity of kurt. MALDI-TOF MS analysis revealed the presence of Pichia fermentans, Enterococcus faecalis, Leuconostoc mesenteroides, and Lactobacillus helveticus, indicating that MRS medium supports the growth of both lactic acid bacteria and accompanying microbiota. Subsequent molecular analysis confirmed Leuconostoc mesenteroides and Lactobacillus helveticus as the most promising strains. These isolates demonstrated tolerance to salt, acidic conditions, and mesophilic temperatures, which are essential for meat fermentation processes. In contrast, Enterococcus faecalis was excluded from further application due to potential safety concerns. Overall, the study demonstrates that kurt is a valuable source of technologically important microorganisms and that the identified strains (Leuconostoc mesenteroides and Lactobacillus helveticus) are promising candidates for the development of starter cultures for fermented goat meat processing. Full article

Lemon processing by-products are rich in flavonoids, limonoids, and phenolic acids, but their direct utilization is limited by glycoside-dominant flavonoid profiles, bitterness-associated limonoids, and insufficiently defined valorization strategies. This study compared eight food-relevant microorganisms, including lactic acid bacteria, Bacillus, yeast, and filamentous fungi, using a common aerobic submerged fermentation framework for lemon by-products. Rather than evaluating fermentation as a single uniform process, the study aimed to determine whether different microbial groups could redirect the same substrate toward distinct functional remodeling profiles. Targeted HPLC analysis of flavonoids, limonoids, and phenolic acids, together with DPPH and ABTS radical-scavenging assays, revealed clear strain-dependent differences in metabolite remodeling and antioxidant outcomes. L. plantarum showed the most consistent antioxidant enhancement profile, characterized by increased hesperetin and phenolic acid responses together with low DPPH and ABTS IC₅₀ values. L. pentosus promoted flavonoid remodeling but showed a more timing-sensitive antioxidant response. S. cerevisiae tended to preserve glycosylated flavonoids and showed a release-oriented phenolic acid profile with strong early ABTS activity. R. stolonifer exhibited the most pronounced limonoid remodeling, including marked limonin reduction and obacunone accumulation, suggesting potential relevance for bitterness-oriented applications. These findings demonstrate that different microorganisms can be functionally classified according to their dominant remodeling tendencies, including antioxidant enhancement, flavonoid conversion, glycosylated flavonoid preservation, phenolic acid release, and limonoid-associated debittering. This functional classification provides a practical basis for selecting microorganisms according to the intended application of lemon by-product valorization. Full article

Dairy cows are frequently affected by postpartum uterine infections, such as metritis and endometritis, which negatively impact fertility and cause significant economic losses. The extensive use of antibiotics may alter the reproductive microbiota and contribute to the emergence of antibiotic resistance. This study aimed to isolate lactic acid bacteria (LAB) from healthy vaginal samples of cows and evaluate their antimicrobial activity against uterine pathogens such as Escherichia coli and Salmonella spp. Phenotypic characterization and antibiotic susceptibility testing were performed, along with antagonistic assays using both overlay and well diffusion methods. The results demonstrated strain-dependent inhibitory activity against E. coli, with inhibition zones ranging from 2 to 4 mm depending on the LAB strain and the method used, whereas no inhibitory activity was observed against Salmonella. These findings support the potential application of selected LAB strains in bovine reproductive health management. However, further in vitro and in vivo studies are required to confirm their efficacy, safety, and stability under physiological conditions. Full article

This review examines the functional role of lactic acid bacteria (LAB) and Bifidobacteria in modulating host physiology through interconnected metabolic, immune, and neuroendocrine pathways. These effects are particularly relevant in gastrointestinal diseases, where dysbiosis is associated not only with local intestinal dysfunction but also with systemic conditions, including metabolic syndrome, infections and complications in immunocompromised individuals. LAB and Bifidobacteria play key roles through the production of short-chain fatty acids, which contribute to maintaining intestinal barrier integrity, regulating lipid and glucose metabolism, improving insulin sensitivity, and exerting anti-inflammatory effects that may reduce the risk of metabolic disorders. Beyond metabolic regulation, the review explores the emerging concept of psychobiotics, focusing on how probiotic bacteria modulate host physiology through integrated metabolic, immune and neuroendocrine mechanisms. Current evidence suggests that these effects are highly strain-specific and influenced by dosage and study design, and host-related factors, often arising indirectly through complex host-microbe interactions rather than direct neurotransmitter activity. Although increasing evidence links these microorganisms to stress regulation, mood, and cognitive function, findings from human studies remain inconsistent. Therefore, well-designed clinical trials, combined with multi-omics approaches, are needed to clarify underlying mechanisms and substantiate clinical efficacy. Overall, probiotics-based strategies offer a promising and practical approach to supporting metabolic health and general psychological well-being through functional foods. Full article

Growing demand for natural and functional foods has increased interest in fermentation-based technologies. This study aimed to develop and characterize fermented and freeze-dried vegetable snacks from beetroot, potato, zucchini, and cucumber. The evaluation included physicochemical properties (pH, titratable acidity, and color), microbiological quality, antioxidant potential using TEAC, ABTS and FRAP assays, along with determination of total phenolic content (TPC), vitamin C, sensory acceptability and attributes. Fermentation resulted in a significant decrease in pH and an increase in titratable acidity of samples, confirming active growth of lactic acid bacteria (LAB), with counts exceeding 6 log₁₀ CFU/g after five days. Freeze-drying preserved the acidic profile and influenced color parameters. Antioxidant capacity varied depending on the raw material, with beetroot showing the strongest potential to scavenge the ABTS^•+, while cucumber was characterized by the highest vitamin C content (175.24 mg/100 g dry matter. Zucchini exhibited moderate antioxidant capacity, whereas potato showed the lowest values. Sensory analysis indicated high acceptance of beetroot and potato snacks, associated with balanced flavor and texture, while cucumber and zucchini samples were rated lower due to softer texture and higher acidity. The combination of lactic fermentation and freeze-drying enables the production of vegetable snacks with desirable sensory properties and enhanced functional potential. Full article

The aim of this study was to characterize the toxicokinetics of dietary Hg and to identify lactic acid bacteria (LAB) strains capable of reducing methylmercury (MeHg) accumulation in organs. BALB/c mice and Wistar rats were exposed via drinking water [Hg(II) MeHg] and feed (swordfish, mushrooms). The data showed that the feed matrix did not modify MeHg accumulation, though it reduced Hg(II) accumulation compared to the data observed with drinking water. Two in vitro LAB strains (L. intestinalis LE1 and L. johnsonii LE2) were selected to determine their efficacy in reducing tissue accumulation in mice exposed for 40 days to dietary MeHg. Daily dosing of both strains produced a relevant reduction in Hg content in the organs of animals exposed through drinking water (18–64%). The LE1 strain also reduced Hg content in animals exposed via feed (13–40%). LAB could be a useful strategy in populations which are chronically exposed to Hg through their diet. Full article

This study investigated the behavior of Salmonella Typhimurium ATCC 14028, Escherichia coli O157:H7 and Listeria monocytogenes ATCC 13932 during the ripening of ‘Nduja, a traditional spreadable fermented sausage for which quantitative microbiological data remain limited. An experimental challenge test was conducted under pilot-plant conditions simulating artisanal production, with products inoculated with the three pathogens and monitored over a 28-day ripening period. Microbiological analyses were performed at defined time points, alongside pH and water activity measurements, and inactivation kinetics were modelled using linear and non-linear approaches. The results showed a pathogen-dependent response to the combined antimicrobial hurdles of the process. Salmonella Typhimurium was declined to levels below the detection limit by day 28 (–7.10 log CFU/g), while E. coli O157:H7 showed a progressive reduction (–3.61 log CFU/g) but persisted at detectable levels. L. monocytogenes exhibited the highest resistance, with only a limited reduction (–1.32 log CFU/g); however, no net growth was observed throughout the ripening period, indicating that the product environment did not support its growth. The ripening process was characterized by decreasing pH and water activity, driven by lactic acid bacteria growth, with no differences between inoculated and control samples. Non-linear models provided the best fit to the survival data, highlighting the presence of resistant subpopulations. Overall, the results suggest that ‘Nduja ripening creates conditions unfavorable for sustained pathogen proliferation, although the extent of microbial reduction differed among the investigated microorganisms. These findings provide useful data for the microbiological characterization of this traditional product and may support future risk assessment and process validation studies. Full article

To screen high-quality porcine-derived lactic acid bacteria for swine production, this study compared growth performance, acid production, acid and bile salt tolerance, and genome characteristics of Lactobacillus plantarum (MRS002), Lactobacillus amylovorus (MRS003), and Lactobacillus salivarius (MRS004). All experiments were performed with three biological replicates, and data were analyzed using the GraphPad Prism software 8.4.3 by one-way analysis of variance (one-way ANOVA) followed by Tukey’s multiple comparison test (significance level p < 0.05). All three strains showed typical anaerobic growth. L. amylovorus MRS003 had a longer growth cycle and higher biomass, while L. plantarum MRS002 and L. salivarius MRS004 grew faster and produced more acid, with pH values reaching 4.2 and 4.3 at 24 h, respectively. L. plantarum MRS002 and L. salivarius MRS004 also exhibited higher survival rates under 0.3% bile salt and pH 2.0 stress. Genome annotation revealed that more than 50% of genes were related to metabolism in all strains. L. plantarum MRS002 possessed the most comprehensive metabolic and stress-resistance gene networks; L. amylovorus MRS003 shows genomic enrichment in starch-degradation pathways and appears promising for high-starch feed fermentation; and L. salivarius MRS004 showed unique advantages in aromatic amino acid metabolism (e.g., phenylalanine, tyrosine, and tryptophan biosynthesis). In summary, based on the evaluated in vitro indicators, L. salivarius MRS004 has more favorable phenotypic characteristics, L. plantarum MRS002 has broad adaptability, and L. amylovorus MRS003 is suitable for high-starch feed fermentation. This study provides a theoretical basis for the research and development of probiotic products. Full article