Search Results (15)

Terasi is a traditional Indonesian fermented condiment made from rebon shrimp and salt. This study investigated the effects of Tetragenococcus halophilus inoculation and varying salt concentrations (6%, 12%, and 18%) on the physicochemical and sensory properties of terasi, compared to a non-inoculated control (25% salt), after 7, 14, and 21 days of fermentation. Inoculation decreased pH, soluble protein, and texture while increasing N-amino acid content, moisture, lactic acid bacteria (LAB), and color darkening. Higher salt levels raised pH, soluble protein, and texture but reduced N-amino acids, moisture, and LAB, resulting in a lighter color. LAB activity peaked on day 7, with moisture and texture increasing over time. Sensory analysis favored inoculated samples, and TOPSIS identified terasi with T. halophilus, 6% salt, and 7 days of fermentation as optimal in quality and preference. This formulation also demonstrated strong bioactivity, including antioxidant activity (3.90 mg AEAC/g sample by DPPH assay and 8.76 ± 0.22 mg AEAC/g sample by FRAP assay), antidiabetic potential via α-amylase and α-glucosidase inhibition (IC₅₀ of 1.95 and 7.24 mg/mL), and antimicrobial effects against E. coli (32.78 mm) and S. aureus (30.85 mm). These results suggest that T. halophilus-inoculated terasi offers enhanced quality and functional properties, supporting its potential as a health-promoting fermented food product. Full article

Sixteen long-ripened, high-quality Cabrales cheeses from independent producers underwent a comprehensive biochemical and microbiological characterisation. Significant variations in total microbial counts and specific microbial groups were observed among the cheeses. A metataxonomic analysis identified 249 prokaryotic amplicon sequence variants (ASVs) and 99 eukaryotic ASVs, respectively, which were classified into 52 prokaryotic and 43 eukaryotic species. The predominant species included bacteria of the genera Tetragenococcus, Lactococcus (of which Lactococcus lactis was used as a starter), and Staphylococcus, followed by Brevibacterium and Corynebacterium species. The starter mould Penicillium roqueforti was highly abundant in all cheeses; Debaryomyces hansenii, Geotrichum candidum, and Kluyveromyces spp. constituted the subdominant fungal populations. Glutamic acid (≈20 mg g⁻¹) was the most abundant free amino acid in all samples, followed by lysine, leucine, and valine (≈10–13 mg g⁻¹). Moderate-to-high amounts of the biogenic amines tyramine and ornithine were detected. A large variation between cheeses of the main organic acids (lactic, acetic, or butyric) was detected. Differences between samples were also observed for the majority volatile compounds, which included organic acids, alcohols, esters, and ketones. Positive and negative correlations between bacterial and fungal species were detected, as well as between microbial populations and key biochemical markers. Among the latter, Tetragenococcus halophilus correlated positively with ethyl caprylate and hexanoic acid, and Loigolactobacillus rennini correlated positively with γ-aminobutyric acid. Conversely, Staphylococcus equorum showed a strong negative correlation with ethyl caprylate and capric acid. These microbial and biochemical insights enabled us to propose a microbiota-based starter culture comprising prokaryotic and eukaryotic components to enhance Cabrales cheese quality. Full article

Freshwater fish processing produces 30–70% nutrient-rich by-products, often discarded or undervalued. Grass carp by-products, rich in protein, offer potential as raw materials for fermented seasonings. This study explores the use of these by-products—specifically, minced fish and fish skin—in soybean fermentation to evaluate their effects on the quality of the resulting seasonings. Tetragenococcus halophilus was used as a starter culture alongside food-grade protease to assess their combined impact on the safety and flavor of soy fish paste and soy fish skin paste. The findings revealed that natural fermentation resulted in higher protein hydrolysis in soy fish skin paste compared to soy fish paste. Across all fermentation conditions, amino acid nitrogen levels increased, while total volatile basic nitrogen levels decreased in both pastes, indicating improved quality. Additionally, microbial fermentation significantly reduced biogenic amine content in soy fish paste, enhancing safety. Enzymatic fermentation further enriched the flavor of both pastes by boosting key compounds such as 2-methylbutanal and ethyl acetate. Notably, enzyme-microbe co-fermentation harnessed the strengths of both methods, achieving improved safety and enhanced flavor profiles while elevating overall product quality. These findings suggest a promising way to transform freshwater fish by-products into high-value condiments, advancing sustainable food processing. Full article

Ulcerative colitis (UC) is a persistent inflammatory intestinal disease that consistently affects the colon and rectum. Its exact cause remains unknown. UC causes a considerable challenge in healthcare, prompting research for novel therapeutic strategies. Although probiotics have gained popularity as possible candidates for managing UC, studies are still ongoing to identify the best probiotics or probiotic mixtures for clinical applications. This study aimed to determine the efficacy of a multi-strain probiotic mixture in mitigating intestinal inflammation in a colitis mouse model induced by dextran sulfate sodium. Specifically, a multi-strain probiotic mixture consisting of Tetragenococcus halophilus and Eubacterium rectale was used to study its impact on colitis symptoms. Anti-inflammatory effects were evaluated using ELISA and flow cytometry. The configuration of gut microbial communities was determined using 16S rRNA metagenomic analysis. According to this study, colitis mice treated with the probiotic mixture experienced reduced weight loss and significantly less colonic shortening compared to untreated mice. Additionally, the treated mice exhibited increased levels of forkhead box P3 (Foxp3) and interleukin 10, along with decreased expression of dendritic cell activation markers, such as CD40+, CD80+, and CD83+, in peripheral blood leukocytes and intraepithelial lymphocytes. Furthermore, there was a significant decrease in the frequencies of CD8+N.K1.1+ cells and CD11b+Ly6G+ cells. In terms of the gut microbiota, probiotic-mixture treatment of colitis mice significantly increased the abundance of the phyla Actinobacteria and Verrucomicrobia (p < 0.05). These results provide valuable insights into the therapeutic promise of multi-strain probiotics, shedding light on their potential to alleviate colitis symptoms. This research contributes to the ongoing exploration of effective probiotic interventions for managing inflammatory bowel disease. Full article

In this study, we analyzed the microbial community of traditional fermented foods of Jeju Island to identify the distribution of useful microorganisms and confirm their anti-inflammatory and anti-melanogenic effects to determine their potential use as cosmetic ingredients. Firstly, we examined the microbial communities of Omphalius rusticus Jeotgal (OR), Spratelloides gracilis Jeotgal (SG), Chromis notata Jeotgal (CN), Turbo cornutus Jeotgal (TC), Trichiurus lepturus intestine Jeotgal (TL), Branchiostegus japonicus Sweet Rice Punch (BJ), Salted Anchovy Sauce (SA), Jeju Soy Sauce (JSS), and Jeju Soybean Paste (JSP). We found that Latilactobacillus sakei (87.2%), Tetragenococcus halophilus (37.7%), T. halophilus (96.8%), Bacillus subtilis (23.4%), T. halophilus (71.3%), L. sakei (53.7%), Lentibacillus sp. (42.9%), Enterococcus durans (14.6%), and E. durans (32.8%) were the dominant species. Secondly, to study the nine Jeju fermented foods’ anti-inflammatory and anti-melanogenic effects, we employed RAW 264.7 and B16F10 cells, classic cell models for inflammation and melanogenesis studies. Ethyl acetate extracts of the nine Jeju fermented foods all inhibited nitric oxide (NO) and melanin production in a concentration-dependent manner. Thirdly, to test the applicability of the nine Jeju fermented foods to human skin, we used the MTT assay to assess their cytotoxic effects on human keratinocytes (HaCaT cells). Finally, the topical applicability of the nine Jeju fermented foods was tested through primary skin irritation, and it was found that they did not cause any adverse effects. Therefore, extracts from the nine Jeju fermented foods have potential applications as ingredients in anti-inflammatory and anti-melanogenic products and can be used in the cosmetic industry. Full article

Sfela is a white brined Greek cheese of protected designation of origin (PDO) produced in the Peloponnese region from ovine, caprine milk, or a mixture of the two. Despite the PDO status of Sfela, very few studies have addressed its properties, including its microbiology. For this reason, we decided to investigate the microbiome of two PDO industrial Sfela cheese samples along with two non-PDO variants, namely Sfela touloumotiri and Xerosfeli. Matrix-assisted laser desorption/ionization–time of flight mass spectrometry (MALDI-TOF MS), 16S rDNA amplicon sequencing and shotgun metagenomics analysis were used to identify the microbiome of these traditional cheeses. Cultured-based analysis showed that the most frequent species that could be isolated from Sfela cheese were Enterococcus faecium, Lactiplantibacillus plantarum, Levilactobacillus brevis, Pediococcus pentosaceus and Streptococcus thermophilus. Shotgun analysis suggested that in industrial Sfela 1, Str. thermophilus dominated, while industrial Sfela 2 contained high levels of Lactococcus lactis. The two artisanal samples, Sfela touloumotiri and Xerosfeli, were dominated by Tetragenococcus halophilus and Str. thermophilus, respectively. Debaryomyces hansenii was the only yeast species with abundance > 1% present exclusively in the Sfela touloumotiri sample. Identifying additional yeast species in the shotgun data was challenging, possibly due to their low abundance. Sfela cheese appears to contain a rather complex microbial ecosystem and thus needs to be further studied and understood. This might be crucial for improving and standardizing both its production and safety measures. Full article

The effects of fermentation with lactic acid bacteria (LAB) and yeast on the aroma of samples were analyzed in this work. The volatile features of different soybean hydrolysates were investigated using both GC-MS and GC-IMS. Only 47 volatile flavor compounds (VFCs) were detected when using GC-IMS, while a combination of GC-MS and GC-IMS resulted in the identification of 150 compounds. LAB-yeast fermentation could significantly increase the diversity and concentrations of VFCs (p < 0.05), including alcohols, acids, esters, and sulfurs, while reduce the contents of aldehydes and ketones. Hierarchical clustering and orthogonal partial least squares analyses confirmed the impact of fermentation on the VFCs of the hydrolysates. Seven compounds were identified as significant compounds distinguishing the aromas of different groups. The partial least squares regression analysis of the 25 key VFCs (ROAV > 1) and sensory results revealed that the treatment groups positively correlated with aromatic, caramel, sour, overall aroma, and most of the key VFCs. In summary, fermentation effectively reduced the fatty and bean-like flavors of soybean hydrolysates, enhancing the overall flavor quality, with sequential inoculation proving to be more effective than simultaneous inoculation. These findings provided a theoretical basis for improving and assessing the flavor of soybean protein hydrolysates. Full article

Microbial inoculation in moromi fermentation has a great influence on the physicochemical and flavour properties of soy sauces. This work investigated the effect of inoculating Tetragenococcus halophilus and Wickerhamomyces anomalus on the flavour formation of early-stage moromi (30 days) fermented at a lower temperature (22 °C) by determining their physicochemical and aroma changes. The results showed that single yeast or LAB inoculation increased the production of amino nitrogen, lactic acid and acetic acid, as well as free amino acids and key flavour components. Particularly, the sequential inoculation of T. halophilus and W. anomalus produced more free amino acids and aromatic compounds, and there might be synergistic effects between these two strains. More characteristic soy sauce flavour compounds, such as benzaldehyde, HEMF, guaiacol and methyl maltol were detected in the sequentially inoculated moromi, and this sample showed higher scores in savoury, roasted and caramel intensities. These results confirmed that sequential inoculation of T. halophilus and W. anomalus could be a choice for the future production of moromi with good flavour and quality under a lower temperature. Full article

Gamma-aminobutyric acid (GABA) has several health-promoting qualities, leading to a growing demand for natural GABA production via microbial fermentation. The GABA-producing abilities of the new Tetragenococcus halophilus (THSK) isolated from a commercial soy sauce moromi were proven in this investigation. Under aerobic conditions, the isolate produced 293.43 mg/L of GABA after 5 days of cultivation, compared to 217.13 mg/L under anaerobic conditions. Critical parameters such as pH, monosodium glutamate (MSG), and sodium chloride (NaCl) concentrations were examined to improve GABA yield. MSG had the most significant impact on GABA and GABA synthesis was not suppressed even at high NaCl concentrations. Data showed that a pH of 8, MSG content of 5 g/L, and 20% NaCl were the best culture conditions. The ultimate yield was improved to 653.101 mg/L, a 2.22-fold increase (293.43 mg/L). This design shows that the bacteria THSK has industrial GABA production capability and can be incorporated into functional food. Full article

Tetragenococcus halophilus strains are the halophilic lactic acid bacteria (LAB) that are present in microbial communities during soy sauce or other hyperosmotic foods’ fermentation. This species contributes to the formation of volatiles in fermented foods but may experience harsh conditions such as oxidative stress and osmotic stress during fermentation. The characterization of the oxygen tolerance of T. halophilus and elaboration of its antioxidant mechanism are important for the selection of suitable LAB for food fermentation. In this work, the growth of T. halophilus strains isolated from soy sauce moromi under both aerobic and anaerobic conditions was compared, and the function of their antioxidant enzymes was investigated. These strains showed differences in oxidation resistance, and they all produce antioxidant enzymes including superoxide dismutase, peroxidase and glutathione reductase. Interestingly, genes encoding catalase (CAT) are present in the genome of T. halophilus strains, though some of them are pseudogenes. Catalase produced by T. halophilus belongs to the heme-dependent CAT, and its activity could only be detected in the presence of heme under aerobic condition. The CAT from T. halophilus conditionally contributes to resistance to hydrogen peroxide and oxidative stress. These results elucidated the possible antioxidant mechanism of T. halophilus and revealed the differences in the oxidative stress tolerance of T. halophilus strains. Full article

The effect of temperature (32–50 °C) on bacterial dynamics and taxonomic structure was evaluated during spontaneous whey fermentation for lactic acid production. Bacterial plate count in fresh whey (5 log CFU/mL) increased in two orders of magnitude after 60 h of fermentation (7 log CFU/mL), followed by one log reduction after 120 h (6 log CFU/mL) at 37 and 42 °C. Streptococcus and Lactobacillus counts ranged between 5–9 and 5–8 log CFU/mL, respectively. High-throughput sequencing of the 16S rRNA gene (V3-V4 region) used as a taxonomic marker revealed thirteen different bacterial phyla. Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria were detected in all fermentation treatments (32–50 °C, 0–120 h), where Firmicutes was the predominant phylum. Bacterial diversity included more than 150 bacterial genera with predominant lactic acid bacteria (belonging to Firmicutes) such as Lactobacillus, Lactococcus, Streptococcus, and Tetragenococcus. At the species level, fresh whey presented 61 predominant species (relative abundance > 0.05%); however, only 57.4% of these resisted the fermentation conditions (most of them belonging to lactic acid bacteria genera). Tetragenococcus halophilus, Lactococcus lactis, and Enterococcus casseliflavus were the predominant bacteria found in all treatments. Temperatures between 37–42 °C were more favorable for lactic acid production and could be considered appropriate conditions for fermented whey production and for the standardization of some artisanal cheese-making processes requiring acid whey addition for milk coagulation. The diversity of native beneficial bacteria found in fresh whey offers attractive technological characteristics, and their fermentative capacity would represent a biotechnological option to add value to cheese whey. Full article

Background: Ethyl carbamate (EC), a byproduct that naturally forms in fermented foods, can cause tumors and cell death and is classified as a probable human carcinogen (Group 2A). EC is naturally formed through the alcoholysis reaction between ethanol and carbamyl compounds. The major precursors and dominantly emerging stages of EC differ with disparate food types, including soy sauce. This work aimed to clarify the formation of EC and its influence factors throughout the soy sauce production process with or without high-pressure process (HPP) treatment. Methods: Tetragenococcus halophilus, Pediococcus acidilactici, Zygosaccharomyces rouxii, and Candida versatilis were added to soy sauce. The levels of citrulline and EC were measured, and a 16S and ITS assay investigated the microbiota. Results: L-citrulline production was found in each group after fermentation for one month. In addition, L-citrulline levels were generated the most in group D (500 MPa treated raw soy sauce with 12% saltwater and mixed fermentation bacteria, including T. halophilus,P. acidilactici,Z. rouxii, and C. versatilis) and group E (soy sauce fermentation with 12% saltwater without HPP treatment) compared to group F (soy sauce fermentation with 18% saltwater without HPP treatment). Conclusions: These results indicated that salt concentration and mixed fermentation bacteria (T. halophilus,P. acidilactici,Z. rouxii,C. versatilis) might not be major factors for L-citrulline production. Full article

Ulcerative colitis (UC) is one of the major subtypes of inflammatory bowel disease with unknown etiology. Probiotics have recently been introduced as a treatment for UC. Tetragenococcus halophilus (T. halophilus) is a lactic acid-producing bacterium that survives in environments with high salt concentrations, though little is known about its immunomodulatory function as a probiotic. The purpose of this study is to determine whether T. halophilus exerts an anti-inflammatory effect on intestinal inflammation in mice. Colitis was induced in C57BL/6J mice by feeding 4% DSS in drinking water for 7 days. T. halophilus was orally administered with DSS. Anti-inflammatory functions were subsequently evaluated by flow cytometry, qRT-PCT, and ELISA. Gut microbial composition was analyzed by 16S rRNA metagenomic analysis. DSS-induced colitis mice treated with T. halophilus showed less weight loss and significantly suppressed colonic shortening compared to DSS-induced colitis mice. T. halophilus significantly reduced the frequency of the dendritic cell activation molecule CD83 in peripheral blood leukocytes and intestinal epithelial lymphocytes. Frequencies of CD8+NK1.1+ cells decreased in mice with colitis after T. halophilus treatment and IL-1β levels were also reduced. Alteration of gut microbiota was observed in mice with colitis after administration of T. halophilus. These results suggest T. halophilus is effective in alleviating DSS-induced colitis in mice by altering immune regulation and gut microbiome compositions. Full article

Producers of soy sauce are constantly making efforts to improve the sensory quality and nutritional value of their products. In this study, radishes, apples, and pears were used to prepare a distinctly flavored soy sauce, and the lactic acid bacteria, volatile compound content, and nutritional and functional qualities of the product were compared with two commercial flavored soy sauce products. Comparable physiochemical properties, antioxidant activities (in vitro and cellular), and higher prevalence of lactic acid bacteria (7.74 ± 0.55 log CFU mL⁻¹) were observed in the prepared flavored soy sauce than in commercial flavored soy sauce. The comprehensive enzyme activity profile of the isolated lactic acid bacteria, Tetragenococcus halophilus (NCBI GenBank Accession no. MN270899), revealed the absence of any harmful enzymes such as β-glucuronidase. Moreover, the cell-free extract of T. halophilus showed xanthine oxidase inhibitory activity (half maximal inhibitory concentration (IC₅₀) = 0.79 mg mL⁻¹), suggesting that the product possessed functionality against xanthine oxidase-induced oxidative stress. Additionally, the prepared flavored soy sauce had higher amounts of total free amino acids (48.68 mg mL⁻¹) and organic acids (7.77 mg mL⁻¹). These results suggest that radishes, apples, and pears at a defined ratio are suitable for the large scale production of a flavored soy sauce with improved nutritional and functional qualities. Full article

We assessed the prevalence of antibiotic resistant and antibiotic resistance genes for 49 Tetragenococcus halophilus (T. halophilus) strains isolated from Xuawei ham in China. The antibiotic resistance phenotype was detected by the Bauer–Kirby (K–B) method and the results showed that 49 isolates can be considered completely susceptible to penicillin, ampicillin, amoxicillin, cefradine, cefotaxime, tetracyclines, minocycline, doxycycline, and vancomycin, but resistant to gentamicin, streptomycin, neomycin, polymyxinB, cotrimoxazole. This resistance was sufficiently high to consider the potential for acquisition of transmissible determinants. A total of 32 isolates were resistant to ofloxacin, 4 isolates were resistant to ciprofloxacin and chloramphenicol, and 2 isolates were resistant to ceftazidime and ticarcillin. The antibiotic resistance genes were detected by routine polymerase chain reaction (PCR). Among the 26 antibiotic resistance genes, 5 varieties of antibiotic resistance genes, including acrB, blaTEM, AAda1, SulII, and GyrB were detected and the detection rates were 89.79%, 47.7%, 16.33%, 77.55%, and 75.51%, respectively. The potential acquisition of transmissible determinants for antibiotic resistance and antibiotic resistance genes identified in this study necessitate the need for a thorough antibiotic resistance safety assessment of T. halophilus before it can be considered for use in food fermentation processes. Full article