Streptococcus Thermophilus Research Articles

Evaluation of the effectiveness of probiotic bacteria Bifidobacterium BB-12 and Streptococcus thermophilus TH-4 in the prevention of microecological and gastrointestinal disorders in children born by cesarean section

The clinical and laboratory effectiveness of a biocomplex of probiotic bacteria (Bifidobacterium BB-12, Streptococcus thermophilus TH-4) in preventing the development of microecological and gastrointestinal disorders in children born by cesarean section has been studied. A prospective open comparative study was conducted. The main group consisted of 16 healthy newborns born by cesarean section who were treated with a probiotic (Bifidobacterium BB-12, Streptococcus thermophilus TH-4) at 1 dose once a day. Oral administration of the probiotics began immediately after delivery and continued for 14 days. A control group of 21 healthy babies born by caesarian section who did not receive the probiotics during the study period was also included. Bacteriological analysis of fecal samples and assessment of the health status were performed at the ages of 4–5 days, 1 month, and 3 months. In children receiving probiotics, the incidence of infantile intestinal colic was lower at the age of 1 month, opportunistic microflora were less frequently isolated (p<0.01), and signs of inflammation in the intestines were less often detected during the follow-up period, as shown by a coprological study.Conclusion. The effectiveness of using probiotics (Bifidobacterium BB-12 and S. thermophilus TH-4) to prevent microecological and gastrointestinal problems in children born by cesarean section has been demonstrated.

Optimizing Probiotic Low‐Fat Yogurt: The Benefits of Incorporating Defatted Rice Bran for Enhanced Quality and Functionality

ABSTRACTThis study investigated the effects of incorporating defatted rice bran (DRB) at different concentrations (0.5%, 1%, 1.5%, and 2%) on the quality, microbiological, and sensory characteristics of probiotic low‐fat yogurt (LFY) during a 21‐day storage period at 4°C. DRB is rich in dietary fiber, essential amino acids, vitamins, and bioactive compounds, and its addition aimed to enhance the nutritional and functional properties of LFY. LFY samples were evaluated for proximate composition, hardness, viscosity, syneresis, color characteristics, rheology, and sensory evaluation. Also, microbiological analysis includes total bacterial counts (TBC), Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus thermophilus, Bifidobacterium bifidum counts. Results indicated that DRB addition significantly (p < 0.05) increased probiotic counts, especially at 1% and 1.5% concentrations, with these samples maintaining higher bacterial stability over the storage period. DRB‐added LFY also showed improved nutritional profiles, with increased TS, protein, ash, fiber, and antioxidant activity. Additionally, hardness, viscosity, and rheology (G′ and G″) values significantly (p < 0.05) increased with the addition of DRB, while syneresis significantly (p < 0.05) decreased. However, higher DRB concentrations negatively affected the color, with lightness decreasing and the browning index increasing. This also impacted sensory characteristics, resulting in lower scores for color, flavor, and overall acceptability, particularly in LFY with 2% DRB. To conclude, moderate DRB addition (up to 1.5%) optimally balances the enhancement of probiotic and nutritional properties with acceptable sensory quality offering a viable strategy for producing functional low‐fat yogurt.

Features of the oropharyngeal microbiota of healthy children and those with acute respiratory infections. A prospective single-center randomized study

Background. The oropharyngeal microbiota is involved in the development of colonization resistance, affecting viral adhesion and metabolism. Any deviations in the stability of the environmental microbial niches of the oropharynx alter the local immune response and can trigger severe chronic somatic disorders. Aim. To compare the composition of the microbiota of children during an episode of respiratory infection and healthy volunteers examined in different periods of convalescence. The obtained data can be used to predict the course of the disease, analyze the risk of complications, and assess the frequency of the diseases in the future. Materials and methods. From 20.01.2022 to 23.12.2022, an open-label prospective single-center randomized comparative study was conducted, which included 120 children aged 5-10 who presented with symptoms of acute respiratory infection. The control group consisted of 15 asymptomatic children examined at different periods of convalescence. The study compared changes in the oral microbiota composition of patients and healthy children. The evaluation was performed using complete 16S rRNA gene sequencing on the Oxford Nanopore platform. Taxonometric analysis at the species and genera level was performed using the Knomics-Biota platform. The R programming language was used for statistical processing. In addition, the parameters of α- and β-diversity of the microbiota were assessed. The Chao1 and Shannon indices were calculated to assess α-diversity (diversity within one community). The Chao1 index is based on the number of species found in the sample and also rare species that are found only 1 or 2 times, thus preventing underestimation of diversity. The Shannon index includes both the number of species and their uniformity in the community. A change in the index indicates the dominance of one or more species. The following indicators were used to assess the β-diversity describing the differences between two microbiota samples at the species and genera level: Bray–Curtis dissimilarity (characterizing the ratios of common and different microorganisms between the samples) and the Aitchison distance (reflecting the differences in the proportions of microorganisms). In addition, the balance between the two groups of microorganisms was evaluated using the NearesBalance method, which characterizes the differences between the microbiota of the main and control groups. Results. The results of our study show that during respiratory infection, the state of the oropharyngeal microbiota is characterized by an increase in α-diversity, which is associated with an increase in the proportion of species of Streptococcus salivarius, Streptococcus pneumoniae, Streptococcus pseudopneumoniae, Streptococcus pyogenes, Streptococcus thermophilus and A12 versus the proportion of Streptococcus mitis, Streptococcus oralis, Streptococcus gwangjuense, Streptococcus sanguinis, Streptococcus gordonii and FDAARGOS_192. In the control group, the oropharyngeal microbiota was divided into two clusters. The dominance of streptococci was observed in the first group (control), while the second group had a more uniform representation. Analysis of the changes in microbial communities in the main and control groups can show the stages of oral microbiota recovery after an acute respiratory infection episode. Conclusion. More research is needed in the field of the oropharyngeal microbiome on a larger sample of healthy children, to standardize the communities of the oropharyngeal microbiota, to study the interaction within communities and with the body as a whole. Analysis of the impact of the microbiota on the frequency and course of respiratory infections and the rate of complications opens up new prospects in treating, rehabilitating, and preventing diseases. These research areas can contribute to improving children's health and quality of life and introducing new approaches into clinical practice.

Longitudinal Fecal Microbiota Profiles in A Cohort of Non-Hospitalized Adolescents and Young Adults with COVID-19: Associations with SARS-CoV-2 Status and Long-Term Fatigue

Adolescents most often experience mild acute COVID-19, but may still face fatigue and persistent symptoms such as post-COVID-19 condition (PCC) and post-infective fatigue syndrome (PIFS). We explored the fecal microbiota of SARS-CoV-2 positive and negative non-hospitalized adolescents and young adults (12–25 years of age) in the “Long-Term Effects of COVID-19 in Adolescents” (LoTECA) project, a longitudinal observational cohort study. With a targeted qPCR approach, the quantities of 100 fecal bacterial taxa were measured at baseline (early convalescent stage) in 145 SARS-CoV-2-positive and 32 SARS-CoV-2 negative participants and after six months in 107 of the SARS-CoV-2-positive and 19 of the SARS-CoV-2 negative participants. Results: Faecalibacterium prausnitzii M21.2 and Gemmiger formicilis (both p < 0.001) were enriched in the SARS-CoV-2-positive participants compared to negative controls at baseline. In SARS-CoV-2-positive participants, lower baseline abundance of Faecalibacterium prausnitzii M21/2 (p = 0.013) and higher abundance of Clostridium spiroforme (p = 0.006), Sutterella wadsworthensis (p < 0.001), and Streptococcus thermophilus (p = 0.039) were associated with six-month fatigue. Sutterella wadsworthensis and Streptococcus thermophilus enrichment was additionally associated with PCC in the SARS-CoV-2-positive group (p < 0.001 and 0.042 respectively). Conclusions: Adolescents and young adults with mild acute COVID-19 infection had increased fecal abundance of the beneficial Faecalibacterium prausnitzii M21/2 and Gemmiger formicilis compared to SARS-CoV-2 negative controls in the early convalescent stage. Additionally, the abundance of both known (Faecalibacterium prausnitzii, Streptococcus thermophilus) and new (Clostridium spiroforme, Sutterella wadsworthensis) bacteria were associated with persistent symptoms such as fatigue in the COVID-19 infected group, warranting further exploration of the role of these bacteria in COVID-19 disease and PCC pathophysiology.

Development of plant-based yogurt from munguba (Pachira aquatica) seeds: Stability and predictive growth of lactic acid cultures

Lactic fermentation is employed to enhance the nutritional quality of plant-based milks, and exploring underutilized plant matrices like munguba (Pachira aquatica) can bring innovation to the plant-based beverage market. This study aimed to develop a yogurt from munguba seeds and investigate the fermentation kinetics of lactic acid bacteria (LAB), as well as the product's stability during storage. Munguba seed milk was prepared through cleaning, peeling, blanching, blending, filtering, and storing at 5 °C. Fermentation was conducted with Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, and Lactobacillus fermentum at 36 °C, and microbial growth was monitored to construct a LAB growth curve. Ultra High Temperature (UHT) whole cow's milk was used for comparison. Munguba seed milk fermented for 9 h showed LAB growth from 3.89 to 8.22 log CFU/mL, while UHT cow's milk fermented for 6 h showed LAB growth from 4.55 to 6.33 log CFU/mL. The Baranyi model showed good fits for both data sets (R2 of 0.9528 for munguba milk and 0.9340 for UHT milk). Specific growth rates, doubling times, and multiplication rates were higher for munguba milk (μ of 1.10 h^-1, td of 0.66 h, MR of 1.59 h^-1) compared to UHT milk (μ of 0.85 h^-1, td of 0.84 h, MR of 1.22 h^-1). LAB, mold, and yeast counts, pH, and lactic acid content remained stable over 31 days of refrigerated storage of munguba seed yogurt. These results indicate that munguba seed milk is a promising substrate for fermented beverages and beneficial microorganisms.

Effects of novel autochthonous starter cultures on quality characteristics of yoghurt

Abstract In the study, in order to develop novel starter cultures, three types of yoghurt were produced with different combinations of autochthonous yoghurt bacteria and the samples were investigated in terms of fermentation, microbiological quality, physicochemical properties (pH, acidity, water-holding capacity, apparent viscosities, and rheological properties), organic and benzoic acid contents, and sensory properties during 28 days. Lactobacillus delbrueckii subsp. bulgaricus content of all samples was between 7.29 and 8.58, and Streptococcus thermophilus content was between 8.03 and 9.02 log CFU/g during storage. Yoghurt type and storage time statistically affected pH, acidity, water-holding capacity, apparent viscosity, rheological properties, organic and benzoic acid content, and some sensory parameters. The general acceptability scores of the probiotic, traditional, exopolysaccharide, and control samples during storage were 8.27, 7.82, 7.53, and 7.47 respectively. Moreover, the results revealed that the strain combinations for probiotic, traditional, and exopolysaccharide yoghurt samples can be used as novel starter cultures for yoghurt production.

The Impact of Fermented Milk Products Containing Bifidobacterium longum BB536 on the Gut Environment: A Randomized Double-Blind Placebo-Controlled Trial.

Probiotics, particularly those native to the gut microbiota, have a profound influence on the gut environment. In this study, we conducted a randomized placebo-controlled, double-blind, parallel-group comparison trial to investigate the effects of Bifidobacterium longum BB536 (B. longum BB536) on the fecal microbiota and metabolite compositions in healthy individuals. We compared the effects of fermented milk produced solely with Streptococcus thermophiles and Lactobacillus bulgaricus (placebo group) and fermented milk supplemented with B. longum BB536 (BY group). Our findings revealed a significantly greater relative abundance of Faecalibacterium in the BY group than in the placebo group by the 3rd day, a trend that persisted until the end of the trial on the 17th day. Additionally, the BY group presented significantly increased concentrations of tryptophan (Trp), Indole-3-lactic acid, and Indole-3-aldehyde on the 17th day. A significant positive correlation was observed between the relative abundance of Faecalibacterium and the number of viable B. longum BB536 bacteria in the feces. The concentrations of Trp and Indole-3-acetic acid were also significantly correlated with the number of viable B. longum BB536 bacteria in the feces. Our results suggest that B. longum BB536 intake can modulate the gut microbiota and metabolite profiles, which are general indicators for monitoring the gut environment, potentially conferring health benefits to the host.

Impact of synbiotics on disease activity in systemic lupus erythematosus: Results from a randomized clinical trial.

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects various organs in the body. In SLE, inflammatory cytokines play a crucial role in initiating and sustaining the inflammatory process. Synbiotics may help modulate these inflammatory cytokines. This randomized, double-blind, placebo-controlled clinical trial aimed to assess the impact of synbiotics intervention on interleukin-17A (IL-17A) levels, disease activity, and inflammatory factors in patients with SLE. Fifty SLE patients were randomly assigned to receive either standard therapy plus synbiotics (consisting of Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus salivarius, Lactobacillus reuteri, Bifidobacterium lactis, Bifidobacterium longum, Bifidobacterium bifidum, and the prebiotic fructooligosaccharides) or standard therapy alone for 2 months. The results demonstrated a significant reduction in both protein and mRNA levels of IL-17A, as well as in the Systemic Lupus Erythematosus Disease Activity Index 2000 score, within the synbiotics group after the intervention compared to baseline. In contrast, the placebo group did not experience significant changes in IL-17A levels or disease activity. Synbiotic supplementation shows potential as an adjunctive therapeutic approach for SLE management; however, further research is needed to elucidate its underlying mechanisms. PRACTICAL APPLICATION: This study explores the use of synbiotics as a supplementary treatment for systemic lupus erythematosus, which is typically managed with immunosuppressive therapies.

Eco-friendly production and probiotic purification of agarose degradation products: Oligosaccharides and 3,6-anhydro-L-galactose

Algal biomass offers a solution to global resource scarcity, with agarose, a key component of Gelidium amansii, containing valuable products like oligosaccharides and 3,6-anhydro-L-galactose. However, current purification methods limit their commercial viability. In this study, we utilized gel filtration chromatography to purify agaro-oligosaccharides and neoagaro-oligosaccharides with varying degrees of polymerization, achieving a novel purification of odd-numbered neoagaro-oligosaccharides. Additionally, by fermenting a mixture of 3,6-anhydro L-galactose and D-galactose with six probiotics, our results demonstrate that five probiotics—Lactobacillus plantarum, Bifidobacterium adolescentis, Streptococcus thermophilus, Lactobacillus acidophilus, and Lactobacillus rhamnosus effectively utilize D-galactose in mixed carbon sources while retaining 3,6-anhydro L-galactose. This approach enables efficient, low-cost, and eco-friendly purification of 3,6-anhydro L-galactose, opening avenues for its widespread utilization.

Fermented buttermilk drinks fortified by plant raw materials

The research featured fortified fermented drinks from pasteurized buttermilk with such natural additives as Jerusalem artichoke syrup and beetroot dietary fiber. The optimal symbiotic culture included Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus: it provided rapid fermentation and a creamy, homogeneous structure with delta pH time = 3.5 h. Jerusalem artichoke syrup was added in amounts of 3, 6, and 9%. Its optimal share proved to be 6% by the weight of the finished product. Beet dietary fiber was added in amounts of 2, 4, and 6%, where the optimal amount was 4%. A higher percentage affected the consistency of the finished product but not its clotting or taste. The experimental drinks were produced by the tank method and fermented at 42 ± 2°C until dense clotting and titratable acidity = 72 ± 2°T. The finished product was stored at 4 ± 2°C. The shelf-life was 12 days for the sample with Jerusalem artichoke syrup and 14 days for the drink fortified with beetroot fiber. The physical and chemical indicators showed that the energy value of the fortified fermented buttermilk drinks was on average 45.3% lower compared to conventional fermented dairy drinks. As a result of research, it has been established that the use of plant components, namely Jerusalem artichoke syrup and beet dietary fiber in the production technology of fermented milk drink from buttermilk makes it possible to obtain a finished product with improved consumer properties.

Predicting Lactobacillus delbrueckii subsp. bulgaricus-Streptococcus thermophilus interactions based on a highly accurate semi-supervised learning method.

Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) and Streptococcus thermophilus (S. thermophilus) are commonly used starters in milk fermentation. Fermentation experiments revealed that L. bulgaricus-S. thermophilus interactions (LbStI) substantially impact dairy product quality and production. Traditional biological humidity experiments are time-consuming and labor-intensive in screening interaction combinations, an artificial intelligence-based method for screening interactive starter combinations is necessary. However, in the current research on artificial intelligence based interaction prediction in the field of bioinformatics, most successful models adopt supervised learning methods, and there is a lack of research on interaction prediction with only a small number of labeled samples. Hence, this study aimed to develop a semi-supervised learning framework for predicting LbStI using genomic data from 362 isolates (181 per species). The framework consisted of a two-part model: a co-clustering prediction model (based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) dataset) and a Laplacian regularized least squares prediction model (based on K-mer analysis and gene composition of all isolates datasets). To enhance accuracy, we integrated the separate outcomes produced by each component of the two-part model to generate the ultimate LbStI prediction results, which were verified through milk fermentation experiments. Validation through milk fermentation experiments confirmed a high precision rate of 85% (17/20; validated with 20 randomly selected combinations of expected interacting isolates). Our data suggest that the biosynthetic pathways of cysteine, riboflavin, teichoic acid, and exopolysaccharides, as well as the ATP-binding cassette transport systems, contribute to the mutualistic relationship between these starter bacteria during milk fermentation. However, this finding requires further experimental verification. The presented model and data are valuable resources for academics and industry professionals interested in screening dairy starter cultures and understanding their interactions.

Studies on the Probiotic, Adhesion, and Induction Properties of Artisanal Lactic Acid Bacteria: to Customize a Gastrointestinal Niche to Trigger Anti-obesity Functions.

The primary goals of this work are to explore the potential of probiotic lactic acid bacteria's (LAB) mucin/mucus layer thickening properties and to identify anti-obesity candidate strains that improve appropriate habitat for use with the Akkermansia group population in the future. The HT-29 cell binding, antimicrobial properties, adhesion to the mucin/mucus layer, growth in the presence of mucin, stability during in vitro gastrointestinal (GI) conditions, biofilm formation, and mucin/mucus thickness increment abilities were all assessed for artisanal LAB strains. Sixteen LAB strains out of 40 were chosen for further analysis based on their ability to withstand GI conditions. Thirteen strains remained viable in simulated intestinal fluid, while most showed high viability in gastric juice simulation. Furthermore, 35.9-65.4% of those 16 bacteria adhered to the mucin layer. Besides, different lactate levels were produced, and Streptococcus thermophilus UIN9 exhibited the highest biofilm development. In the HT-29 cell culture, the highest mucin levels were 333.87µg/mL with O. AK8 at 50mM lactate, 313.38µg/mL with Lactobacillus acidophilus NRRL-B 1910 with initial mucin, and 311.41µg/mL with Lacticaseibacillus casei NRRL-B 441 with initial mucin and 50mM lactate. Nine LAB strains have been proposed as anti-obesity candidates, with olive isolates of Lactiplantibacillus plantarum being particularly important due to their ability to avoid mucin sugar consumption. Probiotic LAB's attachment to the colonic mucosa and its ability to stimulate HT-29 cells to secrete mucus are critical mechanisms that may support the development of Akkermansia.

Effect of a Novel Food Rich in Miraculin on the Oral Microbiome of Malnourished Oncologic Patients with Dysgeusia

Background/Objectives: Dysgeusia contributes to the derangement of nutritional status in patients with cancer as well as worsening the quality of life. There has been a lack of effective treatments for taste disorders provided by the pharmaceutical industry. Methods: This was a pilot randomized, parallel, triple-blind, and placebo-controlled intervention clinical trial in which 31 malnourished patients with cancer and dysgeusia receiving antineoplastic treatment were randomized into three arms [standard dose of DMB (150 mg DMB/tablet), high dose of DMB (300 mg DMB/tablet) or placebo (300 mg freeze-dried strawberry)] for three months. Patients consumed a DMB or placebo tablet before each main meal. Using the nanopore methodology, we analyzed the oral microbiome of patients with cancer using saliva samples. Results: All patients with cancer and dysgeusia had dysbiosis in terms of lower bacterial diversity and richness. DMB consumption was associated with changes in oral microbiome composition. Neither selected bacteria nor taste perception, type of diet, and cytokine levels were associated with mucositis. Likewise, alcohol and tobacco consumption as well as general and digestive toxicity due to systemic therapy were not associated with specific changes of the oral microbiome, according to logistic binary regression. The standard dose of DMB resulted in a lower abundance of Veillonella compared with the high DMB dose and placebo at 3 months after intervention with DMB. In particular, some species such as Streptococcus parasanguinis, Veillonella parvula, and Streptococcus mutans were less abundant in the DMB standard-dose group. Additionally, the consumption of a standard dose of DMB revealed a negative association between the concentrations of TNF-α and the abundance of species such as Streptococcus thermophilus, Streptococcus pneumoniae, Streptococcus dysgalactiae and Streptococcus agalactiae. Conclusions: Accordingly, regular DMB consumption could modify the oral microbiome in patients with cancer and dysgeusia, which may contribute to maintaining an appropriate immune response. However, as the present pilot study involved a small number of participants, further studies are necessary to draw robust conclusions from the data.

Selective degradation of phage RNAs by the Csm6 ribonuclease provides robust type III CRISPR immunity in Streptococcus thermophilus.

Type III CRISPR immune systems bind viral or plasmid RNA transcripts and activate Csm3/Cmr4 and Cas10 nucleases to uniquely cleave both invader RNA and DNA, respectively. Additionally, type III effector complexes generate cyclic oligoadenylate (cOA) signaling molecules to activate trans-acting, auxiliary Csm6/Csx1 ribonucleases, previously proposed to be non-specific in their in vivo RNA cleavage preference. Despite extensive in vitro studies, the nuclease requirements of type III systems in their native contexts remain poorly understood. Here we systematically investigated the in vivo roles for immunity of each of the three Streptococcus thermophilus (Sth) type III-A Cas nucleases and cOA signaling by challenging nuclease defective mutant strains with plasmid and phage infections. Our results reveal that RNA cleavage by Csm6 is both sufficient and essential for maintaining wild-type levels of immunity. Importantly, Csm6 RNase activity leads to immunity against even high levels of phage challenge without causing host cell dormancy or death. Transcriptomic analyses during phage infection indicated Csm6-mediated and crRNA-directed preferential cleavage of phage transcripts. Our findings highlight the critical role of Csm6 RNase activity in type III immunity and demonstrate specificity for invader RNA transcripts by Csm6 to ensure host cell survival upon phage infection.

Use of rice flour to produce plant-based yogurt alternatives.

Plant-based yogurt alternatives (YAs) are in demand due to the societal prevalence of milk sensitivities and allergies and some consumers abstaining from animal-derived products. Producing rice flour YAs has considerable potential because rice flour is hypoallergenic, more economical compared to plant milks, and there are no commercial rice-based YAs. A new higher protein variety of rice was developed, Frontière, which is sold as both brown and white rice. Therefore, the overall goals of this study were (1) to compare physicochemical properties of YAs from Frontière brown (Frontière brown rice flour [FBRF]) and white (Frontière white rice flour [FWRF]) high-protein rice flours to regular protein level rice flours and (2) to evaluate the sensory quality of Frontière YAs compared to commercial plant-based oat yogurt. Rice flours were fermented with Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, and Lacticaseibacillus rhamnosus (a probiotic) to produce FBRF- and FWRF-YAs. A consumer study was conducted to compare FBRF- and FWRF-YAs to a commercially available oat-based YA. Consumers rated the YAs using 9-point hedonic and just-about-right (JAR) scales. Protein, fat, and ash levels were greater, whereas starch levels and peak viscosities were lower for BRFs than for WRFs. The use of BRF resulted in longer fermentation times but higher bacteria counts for YAs. FWRF-YA was preferred in terms of overall flavor and liking, sweetness, and tartness. Purchase intent (PI) for FWRF-YA increased 2.6 times after providing a health claim. This research showed that rice flour can be used to produce YAs with probiotic counts above the minimum recommended, which provides added health benefits for consumers. PRACTICAL APPLICATION: This research provides a possible new use of Frontière high-protein rice flour to produce plant-based yogurts. This will help the rice industry by adding value, and those who are vegan, allergic to casein, or lactose-intolerant will have another option for a plant-based yogurt. Moreover, the greater levels of probiotic bacteria found in the brown rice flour YAs can potentially provide greater health benefits, making brown rice flour a better choice for making rice-based YAs.

Use of plant raw materials in the production of dairy products

Abstract Today, the development of the food industry is aimed at creating balanced products that have beneficial properties for the human body in the long term. As one of these approaches, the use of sprouted plant raw materials (barley grains) in fermented milk products – yoghurts – can be proposed. The proposed plant raw materials have a number of useful properties: total antioxidant activity (136 ± 4) DPPH%, flavonoid content (96 ± 5) %, polyphenols (125 ± 4) %, and also contains a large amount of dietary fiber and minerals. The most effective way is to add the vegetable raw ingredient after the fermentation process and the formation of a product clot. The addition of the plant ingredient was carried out in quantities of 1, 2 and 3%. A direct relationship was noted between the amount of added additive and the degree of syneresis; application in larger quantities partially worsens the syneresis properties of the fermented milk product, and the viscosity of yogurt also slightly decreases. At the same time, a positive effect on the development of microflora of fermented milk products was noted, the presence of Streptococcus thermophilus in the form of mono-, diplo- and streptococcal forms was revealed.

Isolation and Preliminary Characterization of Probiotic Isolates from Healthy Thai Adult Feces

Probiotics are known for health-promoting microorganisms, for examples, assisting gastrointestinal digestion and short chain fatty acid producers. Several current oral human probiotics were derived from human samples; yet, of various ethnic (genetics) and dietary patterns. As probiotics from similar ethnic (genetics) and dietary pattern might confer certain advantages (e.g., more compatibility with hosts), this study isolated and characterized probiotics from healthy Thai adults. To screen for potential probiotic isolates from healthy Thai adult feces, and preliminary characterize these probiotic isolates by biochemical tests and 16S rRNA gene sequencing, following the established Thailand’s Food and Drug Administration (FDA) and National Center for Genetic Engineering and Biotechnology (BIOTEC) guidelines. Twenty fecal samples with clinically verified healthy Thai males and females aged 22-42 years were cultivated on MRS (or M17) media along the broad probiotic screenings (pH 4.0 and 0.1% oxgall) for bacterial probiotic propagation. All derived colonies of different morphologies were continued colony PCR using universal probiotic primers (specific for genera Bifidobacterium, Enterococcus, Lactobacillus, Pediococcus and Streptococcus thermophilus), and only PCR-positive colonies from any of these probiotic primer pair were further cultivation for isolates. Then, these isolates were screened and characterized general probiotic properties that included acid tolerance (pH 2.0), bile salt tolerance (0.3% bile salt), hydrophobicity, antibiotic (ampicillin, ciprofloxacin, erythromycin and vancomycin) susceptibility, no hemolysis activity, catalase, and potassium hydroxide (KOH). The final passing isolates represented potential probiotic isolates that could perhaps maintain in gastrointestinal tract with safety, and were full-length 16S rRNA gene sequenced to identify the genus and species by BLASTN against non-redundant GenBank database. A total of 295 bacterial isolates were obtained from the cultivated on MRS (or M17) media along the broad probiotic screenings from 20 fecal samples. Then, following the general probiotic property characterizations and the full-length 16S rRNA gene sequence analysis, 7 potential isolates were finally derived: 2 Bifidobacterium animalis subsp. lactis, 1 Lactobacillus (new genus name as Limosilactobacillus) reuteri, 1 L. reuteri or L. vaginalis, and 3 Pediococcus pentosaceus. These isolates exhibited strong acid and bile salt tolerances, and relatively high cell surface hydrophobicity. These isolates were susceptible to ampicillin and erythromycin, similar to a reference probiotic control Lactobacillus casei strain Shirota; and the CU13-450 and CU13-451 were also susceptible to vancomycin, similar to a reference control Bifidobacterium breve. Catalase-negative consistent with these bacteria in intestinal tract as anaerobes or facultative anaerobes, and KOH-negative result inferred the Gram-positive bacteria consistent with the full-length 16S rRNA gene sequence identification (Bifidobacterium, Lactobacillus, and Pediococcus are Gram-positive bacteria). No hemolysis activity was observed for these isolates. These 7 probiotic isolates had general probiotic properties and with confirmed the 16S rRNA gene sequences, that follow the Thailand’s FDA and BIOTEC guidelines. However, additional beneficial function investigations, such as in vitro epithelial cell adhesion and in vivo animal model, and whole genome sequencing, should be performed to better validate their possible human health benefits and safety.

Comparative Genome Analysis and Assessment of the Functional Properties of <i>Streptococcus thermophilus</i> Strains

Streptococcus thermophilus are commonly used as starter cultures. Search for new safe strains with desired industrial and probiotic properties is an important issue. Complete genome sequencing was carried out, and the main genome characteristics of two new strains, S. thermophilus 16t (Str16t) and 159 (Str159), were determined. In silico analysis of the genomes revealed the absence of transmissible antibiotic resistance genes, virulence genes associated with pathogenicity, and integrated plasmids; gene clusters encoding class I and class II bacteriocin were found. In vitro tests showed phosphatase, peptidase, β-galactosidase, and esterase activity of both strains, as well as their ability to ferment glucose, lactose, sucrose, and ribose. Strain Str16t metabolized mannose as well. Str16t and Str159 are promising strains for application as starter and probiotic cultures.

A comprehensive study on the autochthonous microbiota, volatilome, physico-chemical, and morpho-textural features of Montenegrin Njeguški cheese

The present study aims to deepen the knowledge of the microbiota, gross composition, physico-chemical and morpho-textural features, biogenic amines content and volatilome of Njeguški cheese, one of the most popular indigenous cheeses produced in Montenegro. Cheese samples were collected in duplicate from three different batches produced by three Montenegrin artisan producers. For the first time, the microbiota of Njeguški cheese was investigated using both culture-dependent techniques and metagenomic analysis. Coagulase positive staphylococci viable counts were below the detection limit of the analysis (<1 log cfu g−1). Salmonella spp., Listeria monocytogenes and staphylococcal enterotoxins were absent. However, relatively high viable counts of Enterobacteriaceae, Escherichia coli, Pseudomonadaceae and eumycetes were detected. Metataxonomic analysis revealed a core microbiome composed of Lactococcus lactis, Streptococcus thermophilus, Debaryomyces hansenii, and Kluyveromyces marxianus. Furthermore, the detection of opportunistic pathogenic yeasts such as Magnusiomyces capitatus and Wickerhamiella pararugosa, along with the variable content of biogenic amines, suggests the need for increased attention to hygienic conditions during Njeguški cheese production. Significant variability was observed in humidity (ranging from 38.37 to 45.58 %), salt content (ranging from 0.70 to 1.78 %), proteins content (ranging from 21.42 to 25.08 %), ash content (ranging from 2.97 to 4.05 %), hardness, springiness, and color among samples from different producers. Gas chromatography-mass spectrometry analysis showed a well-defined and complex volatilome profile of the Njeguški cheese, with alcohols (ethanol, isoamyl alcohol, phenetyl alcol), esters and acetates (ethyl acetate, ethyl butanoate, isoamyl acetate), ketones (acetoin, 2-butanone), and acids (acetic, butanoic, hexanoic acids) being the main chemical groups involved in aroma formation. This research will provide new insights into the still poorly explored identity of Njeguški cheese, thus serving as a first baseline for future studies aimed at protecting its tradition.

The Involvement of Lactic Acid Bacteria in Modulating the Levels of Biogenic Amino Acids within Fermented Tarasas Products

Combining turnip roots and leaves with cooked wheat grits and salt makes Tarasas, a fermented dish from Iraqi Kurdistan. The fermentation process takes 15 days, to produce a ready-to-eat dish. This study aims to identify the bacteria responsible and the role of wheat grits during the 0, 5, 10, and 15 days of fermentation for forming biogenic amines in Tarasas. The results demonstrate that pH levels during the fermentation periods decreased gradually. Microbial analysis showed an increased lactic acid bacteria count during Tarasas fermentation. The study also investigates how adding Lactobacillus plantarum, and yogurt starters (Lactobacillus bulgaricus and Streptococcus thermophilus) affects the process. The current study shows that adding yogurt starters at 3% increased biogenic amine levels, On the other side, using Lactobacillus plantarum as a starter at 3% reduced biogenic amine levels compared with treatments that ferment spontaneously. Additionally, decreasing the wheat grit content to 50% (of the total weight of wheat grits) was associated with a decrease in biogenic amines in the Tarasas. The sensory evaluation results also revealed that the treatments containing Lactobacillus plantarum were more acceptable to the consumer than the traditional treatment or the one with added yogurt.