Sakei Research Articles

Isolation, identification and evaluation of Lactic acid synthesis of bacteria in traditional fermented products in Vietnam

Nowadays, many food products are promoted as being particularly healthy due to the characteristics of certain strains of lactic acid bacteria. Lactic acid bacteria (LAB) play a vital role in different fields, including food, pharmacy due to their benefit for young children, pregnant women and the elderly. LAB is one of the most significant groups of microorganisms used in food fermentations. They improve the flavour and texture of fermented foods. Moreover, LAB kills food spoilage bacteria by developing growth-inhibiting compounds. In this study, seven strains of LAB were isolated from traditional fermented products in VietNamm including fermented rice, kimchi, and yoghurt. Moreover, LAB isolated was identified by amplification and sequencing of 16s rDNA gene. The isolated strains were Lactobacillus plantarum (M2 and M7), Lactobacillus paracasei (M4), Lactobacillus sakei (M10), Leuconostoc mesenteroides (M15), Lactobacillus curvatus (M17), Lactobacillus delbruekii sub sp. (M19). Cultural characteristics of M1 and M7 surface colony are 2mm wide, raised, smooth and white on MRS agar. The morphology of the colonies M4 and M10 is rounded, smooth, light yellow. Nevertheless, M4 and M10 are quite different in colour, white and light yellow, respectively. Moreover, M15 colonies are convex, with flat edges, smooth, semitransparent. M17 and M19 are small, normally rough and non-pigment. Acid lactic content produced by the isolated strains determined by spectral absorbance at 390 nm with FeCl3 (0.2%), was highest in M2 strain (37.814g/l), followed by M17 (32.357g/l), M19 (27.336g/l), M4 (20.853g/l), M10 (9.408g/l), M7 (8.864g/l), and M15 (6.645g/l). In this study, the highest lactic acid content produced was M2 stain (Lactobacillus plantarum) and the lowest was M15 (Leuconostoc mesenteroides).

From cheese whey permeate to Sakacin-A/bacterial cellulose nanocrystal conjugates for antimicrobial food packaging applications: a circular economy case study

Applying a circular economy approach, this research explores the use of cheese whey permeate (CWP), by-product of whey ultrafiltration, as cheap substrate for the production of bacterial cellulose (BC) and Sakacin-A, to be used in an antimicrobial packaging material. BC from the acetic acid bacterium Komagataeibacter xylinus was boosted up to 6.77 g/L by supplementing CWP with β-galactosidase. BC was then reduced to nanocrystals (BCNCs, 70% conversion yield), which were then conjugated with Sakacin-A, an anti-Listeria bacteriocin produced by Lactobacillus sakei in a CWP based broth. Active conjugates (75 Activity Units (AU)/mg), an innovative solution for bacteriocin delivery, were then included in a coating mixture applied onto paper sheets at 25 AU/cm2. The obtained antimicrobial food package was found effective in reducing Listeria population in storage trials carried out on a fresh Italian soft cheese (named “stracchino”) intentionally inoculated with Listeria. Production costs of the active material have been mainly found to be associated (90%) to the purification steps. Setting a maximum prudential 50% cost reduction during process up-scaling, conjugates coating formulation would cost around 0.89 €/A4 sheet. Results represent a practical example of a circular economy production procedure by using a food industry by-product to produce antimicrobials for food preservation.

Lactobacillus sakei ADM14 Induces Anti-Obesity Effects and Changes in Gut Microbiome in High-Fat Diet-Induced Obese Mice.

The aim of our study was to evaluate the anti-obesity effects of Lactobacillus sakei (L. sakei) ADM14 administration in a high-fat diet-induced obese mouse model and the resulting changes in the intestinal microbiota. Prior to in vivo testing, L. sakei ADM14 was shown to inhibit adipogenesis through in vitro test and genetic analysis. Subsequently, mice were orally administered 0.85% saline supplemented or not with L. sakei ADM14 to high-fat diet group and normal diet group daily. The results showed that administration of L. sakei ADM14 reduced weight gain, epididymal fat expansion, and total blood cholesterol and glucose levels, and significantly decreased expression of lipid-related genes in the epididymal fat pad. Administration of L. sakei ADM14 showed improvement in terms of energy harvesting while restoring the Firmicutes to Bacteroidetes ratio and also increased the relative abundance of specific microbial taxa such as Bacteroides faecichinchillae and Alistipes, which are abundant in non-obese people. L. sakei ADM14 affected the modulation of gut microbiota, altered the strain profile of short-chain fatty acid production in the cecum and enhanced the stimulation of butyrate production. Overall, L. sakei ADM14 showed potential as a therapeutic probiotic supplement for metabolic disorders, confirming the positive changes of in vivo indicators and controlling gut microbiota in a high-fat diet-induced obese mouse model.

Avaliação da qualidade sensorial, instrumental e microbiológica de salames tipo Italiano, adicionados de culturas starters

Objetivou-se com esse estudo, produzir salames com e sem a adição de culturas starters e avaliar o efeito das mesmas sobre as características sensoriais, físicas e microbiológicas dos produtos. Foram elaborados 3 tratamentos de salames tipo italiano: T1 (controle - sem adição de cultura starter); T2, produto com adição de culturas starters Lyocarni RHM-33 (Pediococcus pentosaceus e Staphylococcus xylosus) e T3 com adição de culturas starters Lyocarni SBM-11 (Staphylococcus xylosus, Staphylococcus carnosus, e Lactobacillus sakei). A contagem de bactérias láticas nos produtos inoculados ao final do 21º dia de processamento, foi de 2,9 x 106 UFC/g, e 3,2 x 105 UFC/g, para os tratamentos 2 e 3 respectivamente. A contagem de coliformes totais e termotolerantes não foi afetada (P>0,05) pela interação entre tratamentos. A presença de culturas starters nos tratamentos não afetou os índices de luminosidade (L*) e Índice de amarelo (b*) em relação ao tratamento controle (p>0,05). Para índice de vermelho e saturação, o Tratamento 2 apresentou maiores valores (P<0,05). Apenas os parâmetros de dureza e mastigabilidade foram afetados (p<0,05) pela adição das culturas starters. Os dados obtidos com a análise sensorial mostraram que o tratamento T2, apresentou-se como o melhor aceito entre os salames produzidos, para os atributos de sabor, textura e impressão global. Com isso, este trabalho mostrou que devem ser estudados profundamente os aspectos físicos, microbiológicos e sensoriais para a escolha de culturas starters, pois a interação dos microrganismos interferem nos aspectos tecnológicos dos produtos.

Probiotics-Derived Peptides and Their Immunomodulatory Molecules Can Play a Preventive Role Against Viral Diseases Including COVID-19.

As of recent, the pandemic episode of COVID-19, a severe acute respiratory syndrome brought about by a novel coronavirus (SARS-CoV-2) expanding the pace of mortality, has affected the disease rate profoundly. Invulnerability is the fundamental choice to prevent the ruining event of COVID-19, as the drugs and antibodies are in the phase of preliminary clinical trials. Within this brief period, a few strains of SARS-CoV-2 have been recognized by the vaccine manufacturers, which could be an incorrect guess about the strain that will end up spreading. Since the circulating SARS-CoV-2 strains continue to mutate, immunizations, if at all works, might be for a restricted time. We have not put sufficient time in research to understand the immune responses that correlate with protection as this could help refine vaccines. Here, we have summed up the adequacy of the immunomodulatory component of probiotics for the prevention against viral infections. Furthermore, an in silico data have been provided in support of the “probiotics-derived lipopeptides” role in inactivating spike (S) glycoprotein of SARS-CoV-2 and its host receptor molecule, ACE2. Among well characterized lipopeptides derived from different probiotic strains, subtilisin (Bacillus amyloliquefaciens), curvacin A (Lactobacillus curvatus), sakacin P (Lactobacillus sakei), lactococcin Gb (Lactococcus lactis) was utilized in this study to demonstrate a higher binding proclivity to S-protein of SARS-CoV-2 and human ACE2. The outcome revealed noteworthy capabilities of the lipopeptides, due to their amphiphilic nature, to bind spike protein and receptor molecule, which may act to competitively inhibit the mandatory interaction of SARS-CoV-2 with the host epithelial cell expressing ACE2 for its entry into the cell for reproduction. In the current situation, probiotic treatment alongside chemotherapy may assist in bringing about substantial improvement of the health of COVID-19 patients. At the same time, probiotics may aid towards building up the immune defenses in people to evade COVID-19.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12602-020-09727-7.

Immunostimulatory Effects of Live Lactobacillus sakei K040706 on the CYP-Induced Immunosuppression Mouse Model

Our previous studies have shown that heat-killed Lactobacillus sakei K040706 exerts immunostimulatory and anti-inflammatory activities in macrophages, cyclophosphamide (CYP)-treated mice, and dextran sulfate sodium–induced colitis mice. However, the immunostimulatory effects of live Lactobacillus sakei K040706 (live K040706) against CYP-induced immunosuppression and its underlying molecular mechanisms remain unknown. Therefore, we investigated the immunostimulatory effects of live K040706 (108 or 109 colony forming unit (CFU)/day, p.o.) in CYP-induced immunosuppressed mice. Oral administration of live K040706 prevented the CYP-induced decreases in body weight, thymus index, natural killer (NK) cell activity, T and B cell proliferation, and cytokine (interferon (IFN)-γ, interleukin (IL)-2, and IL-12) production. The administration of live K040706 also exerted positive effects on the gut microbiota of CYP-induced mice, resulting in a microbiota composition similar to that of normal mice. Moreover, live K040706 significantly enhanced IL-6 and granulocyte-macrophage colony-stimulating factor (GM-CSF) production in the splenocytes and Peyer’s patch (PP) cells of mice and increased bone marrow (BM) cell proliferation. Taken together, our data indicate that live K040706 may effectively accelerate recovery from CYP-induced immunosuppression, leading to activation of the immune system. Therefore, live K040706 may serve as a potential immunomodulatory agent against immunosuppression.

Effect of a Lactobacillus sakei and Staphylococcus xylosus protective culture on Listeria monocytogenes growth and quality traits of Italian fresh sausage (salsiccia) stored at abusive temperature

Fresh sausages are not always thoroughly cooked before consumption and can support the growth of pathogenic microorganisms, especially when stored at incorrect temperatures. The aim of this study was to verify the growth of Listeria monocytogenes in Italian salsiccia stored at 2 °C, 7 °C and 12 °C for 9 days (t9) with (PC+) and without (PC–) a commercial protective culture (Lactobacillus sakei and Staphylococcus xylosus). L. monocytogenes PC + counts were statistically different from PC–, after 7 days (t7) at 7 °C and at 12 °C. At 2 °C, they increased in PC + by 0.03 and 0.36 log CFU/g vs. 0.25 and 0.91 in PC–, at t7 and t9. Moreover, quality characteristics (total aerobic counts, colour parameters, TBARS values, pH, sensory attributes) were assessed in fresh sausages stored at 7 °C. Significant differences were obtained in PC + samples at t7 for Pseudomonadaceae and Enterobacteriaceae (about 2 log CFU/g). Yeasts and moulds and Brochothrix thermosphacta were also significantly lower in PC + samples. PC + samples were more acidic than PC–, with statistically different colour parameters values particularly at the external surface; raw sausages resulted sensorially discernible at t7, whereas PC + and PC– cooked samples did not show any significant sensory difference. The studied protective culture proved to be a useful tool to increase safety and microbiological quality of salsiccia at abusive storage temperature, effectively limiting the growth of L. monocytogenes and Gram negative spoilage microorganisms, with some sensory drawbacks, especially at the end of the shelf life. HIGHLIGHTS The tested culture improves the microbial safety of salsiccia. It reduces the growth of spoilage microorganisms, especially Pseudomonadaceae and Enterobacteriaceae. It mainly influences colour and acidity evolution of the raw product with no sensory drawbacks in the cooked product.

Lactic acid bacteria isolated from traditional Italian dairy products: activity against Listeria monocytogenes and modelling of microbial competition in soft cheese

Several studies showed that lactic acid bacteria isolated from traditional cheeses produced in Calabria (Italy) inhibited in vitro the growth of different spoilage and/or pathogenic microorganisms. However, the activity of these autochthonous strains against Listeria monocytogenes has never been investigated. One hundred and fifteen lactic acid bacteria isolated from traditional Calabrian cheeses were screened for their technological characteristics and inhibiting action against Listeria monocytogenes in laboratory media. The anti-Listeria activity of representative strains was evaluated also in soft cheese during chilled storage. Bacterial interaction was studied using a competitive modelling approach based on Lotka-Volterra equations. Strains 29 (Lactobacillus sakei), 31 (Lactobacillus plantarum group), and 76 (Lactobacillus plantarum group) showed the best performances both in vitro and in soft cheese reducing the loads of Listeria monocytogenes from 0.5 to almost 1 Log CFU/g. Also considering their technological features, these strains could be used as adjunct cultures to improve the safety of finished products. The proposed competition model returned good predictions, especially after the application of the interspecific competition parameter β. This approach may be useful to understand the mechanisms of microbial competition in food.

Probiotic potential of lactic acid bacteria obtained from fermented curly kale juice

The aim of the paper was to analyse changes in lactic acid bacteria (LAB) populations during spontaneous fermentation of green curly kale juice (Brasicca oleracea L. var. acephala L.) and to determine the probiotic potential of LAB isolates. The analyses revealed that changes in LAB populations were specific for spontaneously fermented vegetable juices. The initial microbiota, composed mostly of Leuconostoc mesenteroides bacteria, was gradually replaced by Lactobacillus species, mainly Lactobacillus plantarum, Lactobacillus sakei, and Lactobacillus coryniformis. Screening tests for the antimicrobial properties and antibiotic susceptibility of isolates allowed for the selection of 12 strains with desirable characteristics. L. plantarum isolates were characterized by the widest spectrum of antimicrobial interactions, both towards Gram-positive and Gram-negative bacteria. Also, L. plantarum strains exhibited the best growth abilities under low pH conditions, and at different NaCl and bile salt concentrations. All strains showed different levels of antibiotic sensitivity, although they were resistant to vancomycin and kanamycin. The present study has shown that bacterial isolates obtained from spontaneously fermented kale juice could constitute valuable probiotic starter cultures, which may be used in fermentation industry.

Isolation and Identification of Potentially Pathogenic Microorganisms Associated with Dental Caries in Human Teeth Biofilms.

Dental caries is attributed to the predominance of cariogenic microorganisms. Cariogenic microorganisms are pathological factors leading to acidification of the oral microenvironment, which is related to the initiation and progression of caries. The accepted cariogenic microorganism is Streptococcus mutans (S. mutans). However, studies have found that caries could occur in the absence of S. mutans. This study aimed to assess the presence of potentially cariogenic microorganisms in human teeth biofilm. The microorganisms were isolated from human mouth and freshly extracted human maxillary incisors extracted for reasons of caries. The isolates were sorted based on their acidogenic and aciduric properties, and the S. mutans was used as the reference strain. Four potentially cariogenic strains were selected. The selected strains were identified as Streptococcus salivarius (S. salivarius), Streptococcus anginosus (S. anginosus), Leuconostoc mesenteroides (L. mesenteroides), and Lactobacillus sakei (L. sakei) through morphological analysis followed by 16S rRNA gene sequence analysis. The cariogenicity of isolates was analyzed. We show, for the first time, an association between L. sakei (present in fermented food) and dental caries. The data provide useful information on the role of lactic acid bacteria from fermented foods and oral commensal streptococci in dental caries.

Metabolic Profiling of Xylooligosaccharides by Lactobacilli.

Three lactic acid bacteria (LAB) strains identified as Lactobacillus plantarum, Lactobacillus brevis, and Lactobacillus sakei isolated from meat products were tested for their ability to utilize and grow on xylooligosaccharides (XOSs). The extent of carbohydrate utilization by the studied strains was analyzed by HPLC. All three strains showed preferences for the degree of polymerization (DP). The added oligosaccharides induced the LAB to form end-products of typical mixed-acid fermentation. The utilization of XOSs by the microorganisms requires the action of three important enzymes: β-xylosidase (EC 3.2.1.37) exo-oligoxylanase (EC 3.2.1.156) and α-L-arabinofuranosidase (EC 3.2.1.55). The presence of intracellular β-D-xylosidase in Lb. brevis, Lb. plantarum, and Lb. sakei suggest that XOSs might be the first imported into the cell by oligosaccharide transporters, followed by their degradation to xylose. The studies on the influence of XOS intake on the lipids of rat liver plasma membranes showed that oligosaccharides display various beneficial effects for the host organism, which are probably specific for each type of prebiotic used. The utilization of different types of oligosaccharides may help to explain the ability of Lactobacillus strains to compete with other bacteria in the ecosystem of the human gastrointestinal tract.

Encapsulation of two fermentation agents, Lactobacillus sakei and calcium ions in microspheres

Alginate microspheres loaded with two fermentation active agents, calcium cations and strain LS0296 identified as Lactobacillus sakei, have been prepared and characterized. The role of calcium cation is twofold, it acts as gelling cation and as fermentation active agent. Encapsulation and the presence of calcium ions in the same compartment do not inhibit the activity of LS0296. Molecular interactions in microspheres are complex, including mainly hydrogen bonds and electrostatic interactions.In vitro calcium cations and strain LS0296 release profiles were fitted to the Korsmeyer–Peppas empirical model. The calcium cation release process is driven at first by Fickian diffusion through microspheres and then by anomalous transport kinetics. The in vitro LS0296 release process is driven by Fickian diffusion through microspheres showing a much slower releasing rate than calcium cations. The release of LS0296 strain is followed by a decrease in the pH value.Results obtained give us a new insight into complex interactions between bacterial cultures and microsphere constituents. Prepared formulations of calcium alginate microspheres loaded with LS0296 could be used as a new promising tool and a model for different starter cultures encapsulation and use in the production of fermented foods.

Inhibition of Anabaena sp. and Oscillatoria sp. Using Probiotic Lactic Acid Bacteria

Water blooms are a serious environmental problem affecting fresh and marine ecosystem. Application of probiotic bacteria has been introduced as an emerging and eco-friendly tool to regulate or inhibit cyanobacterial blooms. In the present study, we have isolated and morphologically identified cyanobacteria from El Manzala Lake. Afterward, we examined the use of probiotic lactic acid bacteria MT2 (Lactobacillus sakei) isolated from Nile Tilapia (Oreochromis niloticus) intestine in controlling Anabaena sp. and Oscillatoria sp., isolated from El Manzala Lake. Measuring chlorophyll, phycocyanin and biomass concentration were conducted in a co-culture experiment between the selected cyanobacterial isolates and probiotic lactic acid bacteria (MT2). Chlorophyll content, phycocyanin content and biomass concentration of Anabaena sp., and Oscillatoria sp., were decreased significantly in the co-culture experiment with MT2 bacteria. Also, the microscopic examinations showed that MT2 bacterium was able to lysis and degrade the selected cyanobacterial cells under microscope. We concluded that the use of MT2 (Lactobacillus sakei) is potentially effective against some cyanobacteria especially Anabaena sp. and Oscillatoria sp.

Effects of tyrosine decarboxylase negative strains from Harbin dry sausage on the growth and tyramine production of foodborne pathogens

The effect of tyrosine decarboxylase negative strains from Harbin dry sausage on the growth and tyramine production of foodborne pathogens (FBP) was evaluated. Lactobacillus paraplantarum, Lactobacillus curvatus, Lactobacillus sakei, Lactobacillus paracasei, Lactobacillus plantarum and Staphylococcus epidermidis were screened as tyrosine decarboxylase negative strains by thin layer chromatography, HPLC, and PCR. High tyramine degradation rates were observed in S. epidermidis (21.73%), L. sakei (20.02%), and L. curvatus (17.66%) (P < 0.05). In particular, S. epidermidis exhibited significant inhibition on the growth of L. monocytogenes, E. coli, and S. paratyphi B, and production of tyramine by FBP (P < 0.05). Consequently, S. epidermidis, L. sakei, and L. curvatus could be used in downstream research to ferment Harbin dry sausage and control tyramine production.

Heme Uptake in Lactobacillus sakei Evidenced by a New Energy Coupling Factor (ECF)-Like Transport System.

Lactobacillus sakei is a nonpathogenic lactic acid bacterium and a natural inhabitant of meat ecosystems. Although red meat is a heme-rich environment, L. sakei does not need iron or heme for growth, although it possesses a heme-dependent catalase. Iron incorporation into L. sakei from myoglobin and hemoglobin was previously shown by microscopy and the L. sakei genome reveals the complete equipment for iron and heme transport. Here, we report the characterization of a five-gene cluster (from lsa1836 to lsa1840 [lsa1836-1840]) encoding a putative metal iron ABC transporter. Interestingly, this cluster, together with a heme-dependent catalase gene, is also conserved in other species from the meat ecosystem. Our bioinformatic analyses revealed that the locus might correspond to a complete machinery of an energy coupling factor (ECF) transport system. We quantified in vitro the intracellular heme in the wild type (WT) and in our Δlsa1836-1840 deletion mutant using an intracellular heme sensor and inductively coupled plasma mass spectrometry for quantifying incorporated 57Fe heme. We showed that in the WT L. sakei, heme accumulation occurs rapidly and massively in the presence of hemin, while the deletion mutant was impaired in heme uptake; this ability was restored by in trans complementation. Our results establish the main role of the L. sakei Lsa1836-1840 ECF-like system in heme uptake. Therefore, this research outcome sheds new light on other possible functions of ECF-like systems.IMPORTANCELactobacillus sakei is a nonpathogenic bacterial species exhibiting high fitness in heme-rich environments such as meat products, although it does not need iron or heme for growth. Heme capture and utilization capacities are often associated with pathogenic species and are considered virulence-associated factors in the infected hosts. For these reasons, iron acquisition systems have been deeply studied in such species, while for nonpathogenic bacteria the information is scarce. Genomic data revealed that several putative iron transporters are present in the genome of the lactic acid bacterium L. sakei In this study, we demonstrate that one of them is an ECF-like ABC transporter with a functional role in heme transport. Such evidence has not yet been brought for an ECF; therefore, our study reveals a new class of heme transport system.

Screening and identification of bacteriocin-like inhibitory substances producing lactic acid bacteria from fermented products

Abstract A total of 544 isolates of lactic acid bacteria isolated from fermented products: 451 isolates from fermented products from Thailand and 93 isolated from French fermented products were screened for bacteriocin production. 10 isolates showed antimicrobial activities. Identification of the selected strains by random amplification of polymorphic DNA-polymerase change reaction using the primers E1, E2 and M13 showed three different RAPD patterns. One of the isolates from each product was chosen and good antimicrobial activity were displayed by 3 strains including MP6/2, PKS2-1 and OV1-1 producing in MRS broth bacteriocin-like substance (BLIS) inhibiting Candida albicans ATCC 90028, Carnobacterium maltraromaticum NCDO 2760, Lactobacillus sakei subsp. sakei JCM 1157, Listeria innocula CIP 80.11, Listeria ivanovii SLCC 2379, Pseudomonasc aeruginosa ATCC 27853, Staphylococcus aureus CIP 76.25 and Streptococcus mutans used as indicator strains. However, inhibitory activities of MP6/2 and PKS2-1 were related to the production of either organic acid, while OV2-1 was not affected by heating. The inhibitory activities of these three isolates were sensitive to proteolytic enzymes. 16S rDNA gene sequencing allowed to identify the MP6/2 as Pediococcus pentosaceus while PKS2-1 and OV1-1 were identified as Enterococcus faecium. It was concluded that the obtained isolates may be used as bio-preservative cultures to produce fermented foods.

Lactobacillus sakei suppresses collagen-induced arthritis and modulates the differentiation of T helper 17 cells and regulatory B cells

BackgroundTo evaluate the immunomodulatory effect of Lactobacillus sakei in a mouse model of rheumatoid arthritis (RA) and in human immune cells.MethodsWe evaluated whether L. sakei reduced the severity of collagen-induced arthritis (CIA) and modulated interleukin (IL)-17 and IL-10 levels, as well as whether it affected the differentiation of CD4+ T cells and regulatory B cells. We evaluated osteoclastogenesis after culturing bone marrow-derived mononuclear cells with L. sakei.ResultsThe differentiation of T helper 17 cells and the serum level of IL-17 were suppressed by L. sakei in both human peripheral blood mononuclear cells and mouse splenocytes. The serum level of IL-10 was significantly increased in the L. sakei-treated group, whereas the regulatory T cell population was unchanged. The population of regulatory B cells significantly increased the in L. sakei-treated group. Oral administration of L. sakei reduced the arthritis incidence and score in mice with CIA. Finally, osteoclastogenesis and the mRNA levels of osteoclast-related genes were suppressed in the L. sakei-treated group.ConclusionL. sakei exerted an anti-inflammatory effect in an animal model of RA, regulated Th17 and regulatory B cell differentiation, and suppressed osteoclastogenesis. Our findings suggest that L. sakei has therapeutic potential for RA.

Physicochemical and microbiological characteristics of El-Guedid from meat of different animal species

El-Guedid is an Algerian traditional meat-based product that is prepared from red meats. It belongs to the wide diversity of salted/dried meat products. This study described the physicochemical and microbiological properties of different products from four animal origins and during all the conservation. Results indicated that these products were mainly characterized by a low moisture with an average decrease of water content between 15.6% and 16.3% for all the samples, and a decrease in water activity ranging from 0.66 to 0.68, while the salt content ranged from 8.8 to 19.3%. A decrease in pH values oscillated from (6.3-6.4) to reach (5.2-5.5) at T0 and T365 consecutively, in all the samples. Microbial analyses revealed the absence of pathogenic bacteria such as Listeria and Salmonella but the sporadic contamination by Staphylococcus aureus up to one month of ripening. Lactic acid bacteria and coagulase negative staphylococci were the dominant populations in El-Guedid with Leuconostoc mesenteroides, Lactobacillus sakei, and Staphylococcus saprophyticus as the main species identified. All these populations decreased along the process and reached low levels (2 log CFU/g) at the end of storage (365days). The drastic drying of El-Guedid led to safe traditional meat product that could promote its production.

Antibiotic resistance of microorganisms isolated from a Baikal seal

The article presents the results of microbiological studies of the material taken from the seals’ corpses. The authors studied the taxonomic characteristics of microorganisms, their virulence and antibiotic resistance. It has been established that the following types of microorganisms are found in the seal: Citrobacter braakii, S. warneri, S. aureus, Escherichia coli serotypes O2, O18 and O39, Lactobacillus sakei, Aguamicrobium lusatiense. All pathogens isolated from the gastrointestinal tract were sensitive to 52.6% of antibiotics (ampicillin, cefuroxime, cefixime, gentamicin, amikacin, ciprofloxacin, ofloxacin, furadonin, Ceftriaxone) and resistant to 15.8% of antibiotics, two representatives of cephalosporins (cefaclor and ceftazidim) and ticarcillin. Conditionally pathogenic enterobacteria (Citrobacter braakii and Escherichia coli) isolated from muscles and liver were sensitive to all antibiotics.

Effects of combining two lactic acid bacteria as a starter culture on model kimchi fermentation

This study aimed to establish a mixed starter culture to standardize the flavor of kimchi, a traditional Korean food. Leuconostoc mesenteroides and Lactobacillus sakei were selected for the culture based on their key roles in kimchi fermentation. The effects of various starter culture mixing ratios on the overall fermentation process were investigated. Fermentation was carried out at 15 °C for 72 h. In the microbial community analysis, a similar ratio to the initial mixed inoculated ratio was observed in the microbial environments. Treatment with high-rate L. mesenteroides inoculation, exhibiting hetero-fermentative characteristics, led to the production of mannitol (1393.11 mg/100 g), acetic acid (57.70 mg/kg), and lactic acid (1141.90 mg/kg), in addition to the induction of a rapid increase in the number of viable cells, thereby reducing the pH (pH 3.9). Conversely, treatment with high-rate L. sakei inoculation, exhibiting homo-fermentative characteristics, led to the production of less mannitol and acetic acid, with more lactic acid. Principal component analysis score plots showed a distinct difference in kimchi metabolites depending on the lactic acid bacteria (LAB) starter culture. Therefore, by using mixed LAB starter strains, this study demonstrated the value of various characteristics and standardized manufacturing of kimchi. LAB types and inoculation ratios greatly affected the types and concentration of metabolites in kimchi fermentation.