Search Results (369)

This study investigated the effects of Lactococcus lactis subsp. 1.2472 (L)-, Streptococcus thermophilus 1.2718 (S)-, and thermostable Lactobacillus rhamnosus HCUL 1.1901-1912 (T)-fermented rice flour with inoculum levels of 3–11% (w/w) on rice bread staling. Optimal staling resistance was achieved, as follows: 9% L-fermented rice bread (LRB), 7% T-fermented rice bread (TRB), and 5% S-fermented rice bread (SRB). Lactic acid bacteria-fermented rice flour significantly enhanced hydration properties. LF-NMR analysis revealed that T₂₁ (strongly bound water) and T₂₂ (weakly bound water) relaxation times decreased, while T₂₃ (free water) increased with prolonged storage. Fermented-rice-flour groups had significantly more strongly bound water than the control group on 7 d. The optimized formulations exhibited exceptional volumetric stability with specific volume change rates of 17.63% (LRB), 17.60% (TRB), and 19.58% (SRB), coupled with maximal porosities of 10.34%, 9.05%, and 9.41%, respectively. This study provides a theoretical foundation for improving rice bread’s anti-staling properties. Full article

Background/Objectives: Lactobacillus kefiranofaciens HL1, isolated from kefir, exhibits antioxidant and anti-aging activities, defined here as improved cognitive function and reductions in oxidative stress and inflammatory markers. However, its poor milk viability limits application. This study developed a novel fermented milk by co-culturing HL1 with Lactococcus lactis subsp. cremoris APL015 (APL15) to enhance fermentation and health benefits. Methods: HL1 and APL15 were co-cultured to produce fermented milk (FM), and fermentation performance, microbial viability, texture, and syneresis were evaluated. A D-galactose-induced aging BALB/c mouse model was used to assess cognitive function, oxidative stress, inflammation, antioxidant enzyme activity, and gut microbiota after 8 weeks of oral administration. Results: FM reached pH 4.6 within 16 h, with high viable counts (~10⁹ CFU/mL) for both strains. HL1 viability and texture were maintained, with smooth consistency and low syneresis. In vivo, FM improved cognitive behavior (Y-maze, Morris water maze), reduced oxidative damage (MDA), lowered IL-1β and TNF-α, and enhanced brain SOD levels. FM-fed mice exhibited increased short-chain fatty acid producers, higher cecal butyrate, and reduced Clostridium perfringens. Conclusions: The co-cultured fermented milk effectively delivers HL1 and provides antioxidant, anti-inflammatory, and anti-aging effects in vivo, likely via gut–brain axis modulation. It shows promise as a functional food for healthy aging. Full article

Lactococcus lactis (L. lactis) is a pathogenic Gram-positive, catalase-negative coccobacillus (GPCN) associated with bovine mastitis. In this study, nine strains of L. lactis were successfully isolated and characterized from 457 milk samples from cows with clinical mastitis in China. All isolates exhibited a high degree of susceptibility to marbofloxacin and vancomycin. A series of molecular and cell biological techniques were used to explore the biological characteristics and pathogenicity of these isolates. The virulence gene profiles of the isolates were analyzed using whole genome resequencing combined with polymerase chain reaction (PCR) to elucidate the differences in virulence gene expression between isolates. To provide a more visual demonstration of the pathogenic effect of L. lactis on bovine mammary epithelial cells, an in vitro infection model was established using MAC-T cells. The results showed that L. lactis rapidly adhered to the surface of bovine mammary epithelial cells and significantly induced the release of lactate dehydrogenase, suggesting that the cell membranes might be damaged. Ultrastructural observations showed that L. lactis not only adhered to MAC-T cells, but also invaded the cells through a perforation mechanism, leading to a cascade of organelle damage, including mitochondrial swelling and ribosome detachment from the endoplasmic reticulum. The objective of this study was to provide strong evidence for the cytotoxic effects of L. lactis on bovine mammary epithelial cells. Based on this research, a prevention and treatment strategy for L. lactis as well as major pathogenic mastitis bacteria should be established, and there is a need for continuous monitoring. Full article

The production of fermented sausages from poultry meat using traditional technologies and natural maturation conditions is a major challenge. The aim of this study was to identify indigenous microbiota with antilisterial activity from an innovative, additive-free, traditionally fermented chicken sausage. Isolates (n = 88) of lactic acid bacteria (LAB) were collected during maturation and subjected to MALDI-TOF mass spectrometry identification. The capacity to combat Listeria was screened against five strains using the agar well diffusion method in 63 selected LAB isolates. MALDI-TOF mass spectrometry identified four different LAB genera, namely Enterococcus, Lactococcus, Leuconostoc and Lactobacillus, the proportions of which differed significantly during the production phases (p < 0.001). Enterococcus faecalis was the most prevalent LAB species in the initial sausage dough. The presence of lactococci (Lactococcus lactis) and enterococci was detected during the 14- and 30-day ripening period and was gradually displaced by leuconostocs and lactobacilli. Lactobacilli appeared to be abundant during the central and late maturation phases, and consisted of only two species—Latilactobacillus sakei and Latilactobacillus curvatus. In total, 38 LAB isolates (60%) showed antilisterial activity toward at least one Listeria indicator strain. The proportions of antilisterial LAB differed significantly during sausage maturation. Inhibitory activity against all indicator Listeria was detected in the neutralized cell-free supernatants of five strains of Enterococcus faecalis, two L. sakei strains and one Leuconostoc mesenteroides strain. The antilisterial activity observed in the indigenous LAB revealed the possible role of L. sakei as a bioprotective culture, as well as the role of Ln. mesenteroides and E. faecalis as bacteriocin producers, for practical applications. Full article

Wine vinegar and wine are traditional Spanish products, obtained from grape must by alcoholic fermentation (wine) and subsequent acetification (vinegar). Although these are established products, there is great interest in the development of new products, particularly new vinegars, and among these, the possibility of vinegars containing gluconic acid stands out. Gluconic acid in vinegar, mainly produced by acetic acid bacteria (AAB), is positively valued by consumers. Its content depends on the availability of glucose in the base wine; however, this hexose is preferentially consumed by the indigenous yeast population which conducts the previous alcoholic fermentation. For this reason, the use of non-conventional fructophilic yeasts, which consume fructose rather than glucose, is required. In this work, we isolated, screened, and identified osmophilic and fructophilic non-Saccharomyces yeasts from sun-dried grape must and tested them under different fermentation conditions in synthetic and natural grape musts, in order to obtain a base wine with ethanol and glucose content for the development of new vinegars containing gluconic acid. The isolate of the species Starmerella lactis-condensi was found to be an ideal candidate due to its fructophilic and osmophilic features, which allowed for the production of a base wine with high ethanol (11% v/v) and glucose (up to 200 g/L) content from a natural concentrated must. In fresh must, inoculation with Starmerella lactis-condensi resulted in faster and preferential fructose consumption over glucose compared to the control. However, both sugars were completely consumed at the end of the alcoholic fermentation; therefore, new fermentation strategies should be tested in this type of must. Furthermore, this strain could be of interest in oenology due to its high glycerol yield and low volatile acid production during alcoholic fermentation. The use of this strain could allow for the production of new wines with unique metabolic profiles suitable for further vinegar production. Full article

Background/Objectives: Lactobacillus delbrueckii subsp. lactis CKDB001 (LL) has demonstrated anti-inflammatory, antioxidant, and lipid-regulatory effects in vitro and in vivo, including attenuation of hepatic steatosis and modulation of lipid metabolism. Given the known interactions between host metabolism and gut microbiota, these findings suggest a potential role for LL in modulating microbial composition under conditions of diet-induced obesity. This study aimed to investigate the microbiome-related effects of LL using an established murine model. To evaluate the effect of LL supplementation on gut microbial composition and predict microbial metabolic functions in mice with high-fat diet-induced obesity. Methods: Male C57BL/6J mice were fed a high-fat diet and administered LL orally for 12 weeks. Fecal samples were collected and analyzed using 16S rRNA gene sequencing. Microbial taxonomic profiles were assessed using linear discriminant analysis effect size, and functional predictions were performed using PICRUSt2. Results: LL supplementation significantly altered the gut microbiota by increasing the relative abundance of Lactobacillus and other commensal taxa while reducing the prevalence of pro-inflammatory genera such as Alistipes and Bilophila. Functional prediction analysis revealed a downregulation of lipopolysaccharide and ADP-L-glycero-β-D-manno-heptose biosynthesis pathways. Microbial functions associated with carbohydrate metabolism and short-chain fatty acid production were enriched in the LL-treated group. Conclusions: LL modulated gut microbial composition and suppressed pro-inflammatory microbial pathways while enhancing beneficial metabolic functions in high-fat diet-fed mice. These findings support the potential of LL as a safe and effective microbiota-targeted probiotic for managing obesity-related metabolic disorders. Full article

Background/Objectives: Probiotics are increasingly recognized for their role in managing gastrointestinal disorders through modulation of gut microbiota. Restoring microbial balance remains a therapeutic challenge. Recent strategies combine probiotics, inulin, and sodium butyrate as synergistic agents for gut health. This study aimed to evaluate the effects of milk supplementation with inulin and sodium butyrate on physicochemical properties, sensory characteristics, and the survival of selected probiotic strains during in vitro simulated gastrointestinal digestion. Methods: Fermented milk samples were analyzed for color, pH, titratable acidity, and syneresis. A trained sensory panel evaluated aroma, texture, and acceptability. Samples underwent a standardized in vitro digestion simulating oral, gastric, and intestinal phases. Viable probiotic cells were counted before digestion and at each stage, and survival rates were calculated. Results: Physicochemical and sensory attributes varied depending on probiotic strain and supplementation. Inulin and the inulin–sodium butyrate combination influenced syneresis and acidity. Lacticaseibacillus casei 431 and Lactobacillus johnsonii LJ samples showed the highest viable counts before digestion. Two-way ANOVA confirmed that probiotic strain, supplementation type, and their interactions significantly affected bacterial survival during digestion (p < 0.05). Conclusions: The addition of inulin and sodium butyrate did not impair probiotic viability under simulated gastrointestinal conditions. The effects on product characteristics were strain-dependent (Bifidobacterium animalis subsp. lactis BB-12, L. casei 431, L. paracasei L26, L. acidophilus LA-5, L. johnsonii LJ). These findings support the use of inulin–butyrate fortification in dairy matrices to enhance the functional potential of probiotic foods targeting gut health. Full article

Accurate quantification of Bifidobacterium animalis subsp. lactis HN019, a clinically validated probiotic strain conferring immune modulation, gastrointestinal health, and gut barrier integrity benefits, is essential for diverse applications. To address the critical need for strain-specific detection, we developed a quantitative PCR (qPCR) assay targeting a unique single-nucleotide polymorphism (SNP) within the galK gene, identified through comparative whole-genome sequencing (WGS) analysis of 31 B. animalis subsp. lactis strains. The assay exhibited exceptional specificity, distinguishing HN019 from 19 other Bifidobacterium strains. Sensitivity tests indicated a detection limit of 0.5 pg of DNA and 10³ CFU/mL of bacterial cells, making it suitable for industrial-scale applications. Additionally, the method exhibited strong repeatability, reproducibility across different qPCR platforms, and resistance to interference from high cell density of B. animalis subsp. lactis DSMZ 10140. Successful quantification of HN019 in complex multi-strain probiotic powders confirmed its practical reliability. This work establishes a rapid, robust, and scalable tool for precise probiotic strain tracking, addressing critical quality control and regulatory compliance needs within the rapidly expanding probiotic industry. Full article

Raw goat milk-derived Lactococcus lactis MK1/3 (CCM 9209) was studied to show its potential for use in the dairy industry. Finding an innovative strain indicates having a new safe, original additive for functional food. The strain has been shown to be safe using a model experiment with Balb/c mice, when no mortality was noted. Its counts were increased continually during 120 days, with the highest value on day 90 (4.38 ± 1.24 colony-forming unit per gram (CFU/g, log 10). In vivo (in the experimental mice), anti-staphylococcal effect was noted with difference 1.82 log cycles. The safety of the strain MK1/3 has been also indicated by the fact that it did not produce damaging enzymes, it has been susceptible to antibiotics, and it has shown low-grade biofilm-forming ability (0.126 ± 0.35). This strain has tolerated bile, and low pH sufficiently. It produced a postbiotic active substance with inhibitory activity against cheese and milk contaminants (Enterococci), reaching antimicrobial activity up to 3200 AU/mL. The count of the strain MK1/3 was higher in yogurts from ewe goat milk (4.66 ± 0.30 CFU/g, log 10), in comparison with its count in yogurts from ewe milk (4.10 ± 0.10 CFU/g, log 10), with no influencing yogurt pH. Its use in 100% starter culture to process fresh cheese based on goat milk was revealed in the standard cheese quality with sufficient amount of lactic acid microbiota. To support the benefit of the strain MK1/3, additional human trials have been reinforced. Full article

The health benefits associated with microbial species inhabiting aquatic animals have garnered increasing attention, as it is expected that the colonization and efficacy of native probiotic bacteria adapted to the internal environment of the target species will be more active than non-native bacteria. In this study, six isolates were obtained from the intestinal tract of largemouth bass. Three of these isolates demonstrated higher growth ability compared to the others and were further characterized using in vitro assays. Lactococcus lactis LBM15 was found to exhibit antibacterial activity against common pathogens affecting largemouth bass; the adhesion inhibition capabilities of the isolates were systematically evaluated through competitive, repulsive, and substitutive adhesion assays. The strain inhibited adhesion to all six tested pathogen strains, with competitive adhesion inhibition rates ranging from 42% to 54%, the highest of which was observed against V. anguillarum. Repulsive adhesion inhibition rates ranged from 27% to 55%, with the highest rate noted for Edwardsiella tarda. Additionally, substitutive adhesion inhibition rates were found to range from 48% to 76%, with the highest inhibition observed against Aeromonas hydrophila. Furthermore, LBM15 exhibited favorable antimicrobial susceptibility profiles, showing sensitivity to 21 antibiotics tested. Notably, safety assessment trials were performed exposing fish to LBM15 at a concentration of 1 × 10⁹ CFU/mL by injection and at a concentration of 1 × 10⁸ CFU/mL by feed administration. No clinical abnormalities, behavioral alterations, or mortality were documented in either exposure group, confirming the safety of LBM15 for application in aquaculture. The results suggested that LBM15 isolates from largemouth bass have potential for further investigation and possible application as probiotic candidates. Full article

The increasing interest in fermented foods stems from their health benefits, mediated by foodborne microorganisms. This study aimed to characterize the fermentative microbiota of Pecorino di Picinisco, a traditional Italian cheese made from ovine raw milk, and to evaluate the probiotic and technological potential of selected lactic acid bacteria strains. Three strains representative of the different species found (Lactococcus lactis, Lactiplantibacillus plantarum and Latilactobacillus curvatus) were chosen and analyzed. All three strains were able to adhere to human intestinal Caco-2 cells, were resistant to simulated in vitro digestion and significantly prolonged the lifespan of Caenorhabditis elegans, used as a simplified in vivo model, with respect to the commercial probiotic strain Lacticaseibacillus rhamnosus GG. The L. plantarum Pic37.4 strain was particularly promising; therefore, its cell-free supernatant was employed to evaluate the antimicrobial activity against indicator strains of foodborne and intestinal pathogens or spoilage bacteria. The results demonstrated the effectiveness of the supernatant against all strains tested, with the strongest effect on the intestinal pathogen enterotoxigenic Escherichia coli K88. In addition, the inhibitory effect on pathogen adhesion to intestinal mucosa was investigated on Caco-2 cells, resulting in a significant reduction in adhesion mediated by the L. plantarum Pic37.4 supernatant. The antimicrobial properties of the L. plantarum strain were confirmed in vivo in C. elegans. These promising results lay the ground for further investigations aimed at substantiating the probiotic and technological potential of the L. plantarum Pic37.4 investigated in this work. 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

This study aimed to provide deeper insights into fermentation dynamics, aerobic stability, and bacterial community composition during the short-term ensiling of maize forage with lactic acid bacteria-based inoculants. A 50:50 combination of Lentilactobacillus buchneri DSM2250 and Lactococcus lactis DSM11037 (LBL target application: 150,000 CFU per 1 g forage) was tested alongside an untreated control (C) over fermentation periods of 2, 4, 8, 16, and 32 days. A total of 50 3 L mini-silos were filled with 2 kg of fresh maize each and stored at 20 °C. The pH, dry matter, nutrient profiles, volatile fatty acids, lactic acid, alcohols, ammonia-N, microbiological counts (yeast and mold), and aerobic stability of all samples were analyzed after seven days of air exposure. LBL silage showed higher average dry matter content (DMc) and crude protein (CP) levels by 1.5%, p < 0.001, and 10.8%, p < 0.001, respectively, as well as reduced average dry matter (DM) losses by half (p < 0.001) compared to pure silage. The beneficial effects of inoculation became more pronounced with prolonged storage, particularly by day 32 of fermentation. LBL silage showed increased production of lactic and acetic acids by an average of 55.5% and 5.0%, respectively, (p < 0.01) and significantly reduced butyric acid formation by approximately 14 times. Ethanol and ammonia-N concentrations were also reduced by 55.4% and 25.6%, respectively (p < 0.001), while the pH value remained 0.17 units lower (p < 0.001) compared to the control. The combination of the two strains improved silage aerobic stability by 2.4 days (p < 0.001) and extended shelf life by reducing yeast counts (8.02 vs. 7.35 log₁₀CFU g⁻¹ FM, p < 0.001), while maintaining the pH value close to its initial level. Therefore, compared to the untreated control, the inoculated silage exhibited higher nutritional value, reduced fermentation losses, and suppressed undesirable microbial activity. The positive effects of inoculation became increasingly evident over time, particularly by day 32, highlighting the synergistic benefits of using mixed-strain lactic acid bacteria. These findings support the use of LBL inoculants as an effective strategy to enhance short-term silage quality and stability. Full article

Probiotic microorganisms from sugary kefir were incorporated into Brazilian non-alcoholic beers to enhance their functional and nutritional properties through aerobic static fermentation over 24 h. Non-alcoholic beers inoculated with sugary kefir showed appropriate acidity (pH reduction from ~3.74 to ~3.52), color, and microbial balance, along with excellent sensory acceptance (scores of 6.9–8.4 on a 9-point hedonic scale). The kefir microbiota included Lacticaseibacillus paracasei, Lacticaseibacillus casei, Lacticaseibacillus paracasei subsp. paracasei, Lacticaseibacillus paracasei subsp. tolerans, Lactobacillus delbrueckii subsp. lactis, Lentilactobacillus parabuchneri, Lentilactobacillus kefiri, Lactococcus lactis, Leuconostoc citreum, Acetobacter lovaniensis, and yeasts such as Saccharomyces cerevisiae, Kluyveromyces lactis, Lachancea meyersii, and Kazachstania aerobia. Genetic analysis confirmed the absence of undesirable or pathogenic microorganisms. Fermentation led to reductions in sucrose (~0.35 to ~0.22 g/L) and °Brix (~5.55 to ~3.80), with increases in lactic acid (~0.55 to ~1.25 g/L) and acetic acid (~0.08 to ~0.14 g/L), confirming active microbial metabolism. Ethanol levels remained within legal limits for non-alcoholic beverages. The process preserved sensory attributes while enriching the beverage with well-documented kefir microorganisms. These findings highlight sugary kefir as a promising biotechnological tool to enhance the functional profile of non-alcoholic beers without compromising their sensory quality. Full article

Background: The disruption of the intestinal barrier and the imbalance of the gut microbiota (GM) seem to play a major role in the complex pathogenesis of irritable bowel syndrome (IBS). Specific microbial strains could improve the gut microenvironment, promoting anti-inflammatory pathways; similarly, vitamin D supplementation could play a role in enhancing the barrier integrity and modulating the immune response in the gut. This study aims to evaluate the efficacy of a new multistrain probiotic, combined with vitamin D, in improving gut barrier function in IBS without constipation. Methods: In this phase IIb double-blind randomized placebo-controlled, parallel-group, multicenter, clinical trial, 35 patients were treated for 12 weeks with OttaBac^®, a high concentration multistrain probiotic plus cholecalciferol, or placebo and were followed up until week 16. Symptoms, quality of life, intestinal permeability, fecal biomarkers, and microbiota composition were evaluated at 0, 12, and 16 weeks. Results: Mean zonulin values showed a significant progressive reduction in the active group (−10.2 ng/mL at week 12, p = 0.0375; −19.5 ng/mL at week 16, p = 0.0002), with a significant difference between groups at week 16 in the per-protocol population (−19.01, p = 0.0053). The active group showed a more stable trend toward improvement in stool frequency and consistency at both week 12 and 16, with a significant improvement compared to the baseline and to the placebo group (−23.2, p = 0.0265, and 5.57 vs. −23.2, p = 0.0492, respectively). No differences were found in regards to the lactulose/mannitol ratio, Irritable Bowel Syndrome Severity Scoring System (IBS-SSS) and Short Form Health Survey (SF-36) total scores, plasmalemmal vesicle associated protein-1 (PV-1), and citrulline levels. In the active group, Bifidobacterium animalis subsp. lactis and Streptococcus thermophilus levels were increased (p < 0.05), while those for Lachnospira were decreased (p < 0.05), and significant changes in Actinobacteria and Proteobacteria were observed (p < 0.05). Lactate (p < 0.01) and acetate (p < 0.05) levels increased post-treatment. Correlation analysis pointed out a significant association between the microbial biomarkers and the symptoms (p < 0.05). Conclusions: Probiotic plus vitamin D could improve IBS-associated symptoms through gut microbiota modulation and gut barrier enhancement, with persistent benefits after treatment discontinuation. Full article