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Screening of lactic acid bacteria isolated from fermented table olives with probiotic potential
... where CFU f denotes final counts, D required dilution, and V total volume by the end of the assay. Bautista-Gallego et al. [22] reported that overall survival data are more realistic than results obtained upon application of a separate test for each stage of digestion; when applied, the sequential simulated gastrointestinal and pancreatic digestions allowed monitoring of the independent behavior of strains in response to each of them. Although prone to lead to a good independent choice, it might unfold an inappropriate global selection. ...
... Despite the fact that not all such publications resort to analytical procedures directly comparable to the one selected for our study, it is generally considered that L. pentosus is a good probiotic candidate. Montoro et al. [27], Arroyo-Lopez et al. [28], Bautista-Gallego, Arroyo-López, Rantsiou, Jiménez-Díaz, Garrido-Fernández and Cocolin [22], and Guantario et al. [29] also developed work encompassing a number of strains of L. Pentosus and their results resemble our own data; such results on survival rate range between 40% and 80%, so they are consistent with those presented hereby. Considering L. paraplantarum isolated from Southern Portuguese table olives, Peres, Alves, Hernandez-Mendoza, Moreira, Silva, Bronze, Vilas-Boas, Peres and Malcata [9] reported survival rates up to 48%, a low figure compared to our results (between 29% and 67%); however, survival rates ranging from 40% to 60% for the strains of L. paraplantarum were reported elsewhere [30,31] pertaining to strains isolated from dairy products. ...
... Lopez et al. [28], Bautista-Gallego, Arroyo-López, Rantsiou, Jiménez-Díaz, Garrido-Fernández and Cocolin [22], and Guantario et al. [29] also developed work encompassing a number of strains of L. Pentosus and their results resemble our own data; such results on survival rate range between 40% and 80%, so they are consistent with those presented hereby. Considering L. paraplantarum isolated from Southern Portuguese table olives, Peres, Alves, Hernandez-Mendoza, Moreira, Silva, Bronze, Vilas-Boas, Peres and Malcata [9] reported survival rates up to 48%, a low figure compared to our results (between 29% and 67%); however, survival rates ranging from 40% to 60% for the strains of L. paraplantarum were reported elsewhere [30,31] pertaining to strains isolated from dairy products. ...
Current market trends point at increasing demand for functional foods, namely those carrying probiotics. In the case of table olives, presence of probiotics would convey a competitive advantage to Mediterranean-based diets, already established for their cultural heritage and gastronomic character. This work assessed the safety and resistance to gastrointestinal digestion of 19 native LAB strains from Cobrançosa table olives. Strains were identified via molecular sequencing (4 fingerprints/10 strains for Lactiplantibacillus pentosus, and 2 fingerprints/9 strains for L. paraplantarum), and exposed to simulated gastrointestinal fluids, as per the INFOGEST in vitro protocol with modifications. None of those strains proved dangerous for human consumption. Survivability to the gastrointestinal resistance test ranged from 29% to 70%, with strain-dependent variability. L. paraplantarum i18, i27, and i102, and L. pentosus i10 and i11 exhibited statistically lower survival rates (29–35%) than probiotic the Greek table olive reference strain L. pentosus B281 (53%). Among the other strains, L. paraplantarum i101 and L. pentosus i53 and i106 showed the highest survival rates but were not significantly different from the strain of Lacticaseibacillus casei isolated from commercial probiotic yoghurt (65–70%). In vitro results proved that strains retrieved from fermenting cultivar Cobrançosa possess the potential to be claimed as probiotics—thus deserving further attention toward the development of a specific starter culture.
... For all the aforementioned, last decade, the interest of the scientific community was focused on the isolation of autochthonous microbes, to study beyond their technological characteristics described above, their potential probiotic properties. Indeed, there are several studies dealing with the probiotic characterization of LAB Ghabbour et al., 2011;Abriouel et al., 2012;Argyri et al., 2013;Bautista-Gallego et al., 2013a;Bleve et al., 2014Bleve et al., , 2015Botta et al., 2014;Montoro et al., 2016;Anagnostopoulos et al., 2018;Guantario et al., 2018;Yalçınkaya and Kılıç, 2019;El Issaoui et al., 2021) and yeast/mold (Hernández et al., 2007;Bevilacqua et al., 2009Bevilacqua et al., , 2013Silva et al., 2011;Bonatsou et al., 2015Bonatsou et al., , 2018aBavaro et al., 2017;Oliveira et al., 2017;Porru et al., 2018;Mujdeci and Ozbas, 2020;Simões et al., 2021) strains, isolated from several olive varieties, in order to select and use those with the most promising features to produce table olives with potential health benefits. It is crucial to point out that in the majority of the studies, strain selection is based on the most combined range of both technological and probiotic features. ...
... It is crucial to point out that in the majority of the studies, strain selection is based on the most combined range of both technological and probiotic features. It is noteworthy that in some previous studies, the significant contribution of principal component analysis (PCA), to discriminate the strains with the best combination features, was highlighted and recommended as the most appropriate statistical tool to be applied for such kind of studies (Rodríguez-Gómez et al., 2012;Bautista-Gallego et al., 2013a;Oliveira et al., 2017;Anagnostopoulos et al., 2018). As a representative example, Bautista-Gallego et al. (2013a) used PCA for the discrimination of 111 LAB isolates, which were examined for several potential properties (autoaggregation, hydrophobicity, bacteriocin production, etc.). ...
... It is noteworthy that in some previous studies, the significant contribution of principal component analysis (PCA), to discriminate the strains with the best combination features, was highlighted and recommended as the most appropriate statistical tool to be applied for such kind of studies (Rodríguez-Gómez et al., 2012;Bautista-Gallego et al., 2013a;Oliveira et al., 2017;Anagnostopoulos et al., 2018). As a representative example, Bautista-Gallego et al. (2013a) used PCA for the discrimination of 111 LAB isolates, which were examined for several potential properties (autoaggregation, hydrophobicity, bacteriocin production, etc.). The analysis highlighted a unique profile of four L. pentosus isolates that contained the best combination features. ...
Table olives are among the most well-known fermented foods, being a vital part of the Mediterranean pyramid diet. They constitute a noteworthy economic factor for the producing countries since both their production and consumption are exponentially increasing year by year, worldwide. Despite its significance, olive’s processing is still craft based, not changed since antiquity, leading to the production of an unstable final product with potential risk concerns, especially related to deterioration. However, based on industrial needs and market demands for reproducible, safe, and healthy products, the modernization of olive fermentation processing is the most important challenge of the current decade. In this sense, the reduction of sodium content and more importantly the use of suitable starter cultures, exhibiting both technological and potential probiotic features, to drive the process may extremely contribute to this need. Prior, to achieve in this effort, the full understanding of table olive microbial ecology during fermentation, including an in-depth determination of microbiota presence and/or dominance and its functionality (genes responsible for metabolite production) that shape the sensorial characteristics of the final product, is a pre-requisite. The advent of meta-omics technology could provide a thorough study of this complex ecosystem, opening in parallel new insights in the field, such as the concept of microbial terroir. Herein, we provide an updated overview in the field of olive fermentation, pointing out some important challenges/perspectives that could be the key to the olive sector’s advancement and modernization.
... They hardly affect the gut microbes in this regard. Even though they do not stay in the environment or the body, target strains are less likely to encounter destroyed bacteriocin fragments, which might result in bacteriocin resistance (6). Bacteriocins have the potential to replace antibiotics as natural food preservatives. ...
... The organic acid and its pH lowering may prevent many dangerous bacteria (9). The undissociated molecule affects pH immediately and may collapse susceptible bacteria's electrochemical proton gradient, causing bacteriostasis and death (6). Lactic acid bacteria also produce trace quantities of acetic and propionic acids. ...
Background: Bacteriocins are proteins groups, produced by gram-positive bacteria having the potential to use as food preservatives and antibacterial agents. Objectives: This review is aim to provide a comprehensive information on bacteriocins and their application. Methodology: Different databases were searched to find relevant information. Results: The protein of bacteriocins is ribosomal synthesized peptides. These proteins are produced by protein synthesis mechanism within a cell with amino acid composition ranging from 30 to 60 amino acids. The peptides have a narrow to wide spectrum of antibacterial activity against gram-positive bacteria, and their antibacterial properties remain intact even when exposed to heat. Bacteriocins proteins can be used in hot environments, such as cooking and food preparation, without losing their effectiveness. Additionally, the producer strain of Bacteriocins can provide a degree of self-protection against its own antibacterial peptide. Other than bacteriocins, specific LAB may generate antimicrobial peptides aiding in the preservation and safety of food due to production of cyclic dipeptides. Nisin is non-toxic, produced by generally recognized as safe (GRAS) bacteria, and quickly eliminated in the digestive system. Bacteriocins does not adversely affect the gut microflora. Conclusion: The bacteriocins can provide immunity for foods, allowing processors to maintain their desired microbial balance even after manufacture is complete.
... The degradation of oleuropein was attributed to the β-glucosidase activity of the L. plantarum strain. However, some studies have shown that oleuropein degradation is not only associated with β-glucosidase and esterase but also polyphenol oxidase and peroxidase catalyze the conversion of oleuropein [31,32]. ...
... The degradation of oleuropein was attributed to the β-glucosidase activity of the L. plantarum strain. However, some studies have shown that oleuropein degradation is not only associated with -glucosidase and esterase but also polyphenol oxidase and peroxidase catalyze the conversion of oleuropein [31,32]. The sequential model sum of squares obtained for the hydroxytyrosol results of the sample extracts fermented with L. plantarum ATCC 14917 and ATCC-BAA 793 is given in Tables 4 and 5, respectively. ...
Olive leaves are important by-products for the recovery of phenolic compounds and extracts with high phenolic content using lactic acid bacteria during fermentation. Lactiplantibacillus plantarum (L. plantarum) strains as glucosidase-positive strains are starter cultures used to control the fermentation process. The main objective of the present work is to determine the most effective strain for the biodegradation of oleuropein to hydroxytyrosol using two L. plantarum strains for the fermentation of olive leaves. Box–Behnken experimental design was applied to determine the optimum ultrasound-assisted extraction (UAE) conditions to obtain hydroxytyrosol-rich extract using the brine of the fermented leaves. L. plantarum ATCC 14917 (hydroxytyrosol; 126.89 ± 1.59 mg/L) strain showed higher oleuropeinolytic activity than L. plantarum ATCC-BAA 793 (85.93 ± 0.70 mg/L) in olive leaf brine. When the UAE method was applied, it was seen that the hydroxytyrosol concentration of samples that were inoculated with L. plantarum ATCC 14917 (362.29 ± 2.31 mg/L) compared to L. plantarum ATCC-BAA 793 (248.79 ± 4.14) increased. The optimum UAE conditions were determined as 30% amplitude-5 min-30% ethanol for ATCC 14917 and 45% amplitude-9 min-10% ethanol for BAA 793 strain. This study showed that the brines of fermented olive leaves with oleuropeinolytic strains can be considered high added value products.
... They carry endogenous communities of Lactic Acid Bacteria (LAB) that become enriched during the fermentation process. For example, brined olives carry significant amounts of Lactobacillus suggesting a possible probiotic role in olives 19,20 . Another class of fermented foods is represented by cheeses and other dairy products. ...
... They have been recognized as an important food with respect to human health as they are rich in phenolic compounds, fatty acids, and antioxidant properties 58,59 . Moreover, during the pickling process, green olives are enriched by LAB, mainly Lactobacillus populations, many of which (i.e., L. plantarum, L. pentosaceus) have been recognized as probiotics due to their health benefits in humans 19,20 . By applying binning analysis, we were able to recover five near-complete MAGs that were closely related to L. buchneri and L. acetotolerans, 99.7% and 98.2% ANI respectively, as well as MAGs that might represent novel genera within the Lactobacillaceae family based on the ANI metrics for genus definition (> 80% ANI) (Supplementary Table 4). ...
Plant microbiomes have been extensively studied for their agricultural relevance on growth promotion and pathogenesis, but little is known about their role as part of the diet when fresh fruits and vegetables are consumed raw. Most studies describing these communities are based on 16S rRNA gene amplicon surveys, limiting our understanding of the taxonomic resolution at the species level and functional capabilities. In this study, we characterized microbes colonizing tomatoes, spinach, brined olives, and dried figs using shotgun metagenomics. We recovered metagenome-assembled genomes of novel lactic acid bacteria from green olives and identified high intra- and inter-specific diversity of Pseudomonas in tomatoes. All samples were colonized by Pseudomonas, consistent with other reports with distinct community structure. Functional characterization showed the presence of enzymes involved in vitamin and short chain fatty acid metabolism and degradation of diverse carbohydrate substrates including plant fibers. The dominant bacterial members were isolated, sequenced, and mapped to its metagenome confirming their identity and indicating the microbiota is culturable. Our results reveal high genetic diversity, previously uncultured genera, and specific functions reflecting a likely plant host association. This study highlights the potential that plant microbes can play when consumed as part of our diet and proposes these as transient contributors to the gut microbiome.
... This might present an abnormal texture and/or flavor in the fermented foods. To achieve this target, the selection of an appropriate strain of LAB is necessary, which the task requires characterization of LAB (Bautista-Gallego et al., 2013). ...
... Each bag was mixed at 250 rpm for 5 min and diluted to 10 -2 -10 -4 , then plated on MRS broth at anaerobic conditions (in a jar and along with gas pack) and incubated at 37 °C for 24 h. Then, streak culture was prepared from grown broth culture, then gram stain and catalase tests were performed (Bautista-Gallego et al., 2013). ...
... Autoaggregation assays were performed according to the methodology described by Bautista-Gallego et al. [19] with slight modifications. The strains were propagated in YPD broth at 30 °C/24 h, and the cells were recovered as indicated above; 6 log cfu/mL was subsequently resuspended in sterile saline solution and incubated at 37 °C for 30 min. ...
... Hydrophobicity assays were performed according to the methodology described by Bautista-Gallego et al. [19] with the modifications proposed by Fernández-Pacheco et al. [20]. A pellet of each strain was recovered by centrifugation (2240 × g/5 min) and washed with saline solution. ...
Yeast isolates from flowers and fruits from a Brazilian forest were studied. The yeasts were identified at species and strain level by PCR–RFLP and PCR-RAPD, respectively. The 46 isolated yeasts were classified into 11 different species belonging to the genera Candida, Diutina, Hanseniaspora, Meyerozyma, Pichia, Rhodotorula, and Torulaspora. A total of 20 different strains were found. In order to ascertain the probiotic potential, the resistance to gastrointestinal conditions, autoaggregation, and hydrophobicity assays were studied, along with the capacity to form biofilm. The results indicate that, although most of the strains presented better results than Saccharomyces boulardii (the only strain recognized as a probiotic yeast), four strains were the most promising, namely, Rhodotorula mucilaginosa 32, Meyerozyma caribbica 35, and Diutina rugosa 12 and 45, according to the Duncan test. Several biotechnological properties were evaluated. D. rugosa inhibited Dekkera bruxellensis. The assimilation or fermentation of seven sugars was tested, and only five of the yeasts did not show a capacity to assimilate any of the sugars under aerobic conditions. However, all strains were able to ferment at least one of the sugars under anaerobic conditions. As far as enzyme production is concerned, positive results were only found for the enzymes’ amylase, pectinase, and protease. D. rugosa 42 and Hanseniaspora opuntiae 18, followed of Pichia kluyveri 26, showed high values for the production of melatonin. In conclusion, the results of this study show that several non-Saccharomyces present probiotic characteristics, and these have good potential for industrial applications in the food or biotechnology industries.
... The fermented beverage of chickpea and coconut was subjected to gastric juice, pancreatic juice, and sequential exposure to gastric and pancreatic juice. The following controls were used in the experiment to evaluate the protective effect of fermented chickpea and coconut beverage in L. paracasei LBC 81 against gastrointestinal stress conditions: Gastric juice: Synthetic gastric juice was prepared according to the protocol of Bautista-Gallego et al. [37]. Gastric juice was prepared with NaCl (2.05 g/L), KH 2 PO 4 (0.60 g/L), CaCl 2 (0.11 g/L), and KCl (0.37 g/L). ...
... The suspensions of cells in saline (control 1) and in chickpea and coconut beverage (control 2) were submitted to the same conditions. Pancreatic juice: The synthetic pancreatic juice was prepared according to the protocol of Bautista-Gallego et al. [37]. The synthetic pancreatic juice was prepared with dibasic sodium phosphate heptahydrate (50.81 g/L) and NaCl (8.50 g/L). ...
The objective of this study was to evaluate in a static in vitro digestion model the survival of Lactobacillus paracasei subsp. paracasei LBC 81 in fermented chickpea and coconut beverage. The fermented beverage was stored for 1 and 8 days at 4 °C and then submitted to gastric juice, pancreatic juice, or sequential exposure to gastric and pancreatic juice. The experiment controls were (i) control 1—suspension of cells in 0.85% saline solution; (ii) control 2—cell suspension in chickpea and coconut beverage. The survival of L. paracasei was determined in log CFU/mL and expressed as a survival percentage. The survival of L. paracasei in the fermented beverage after exposure to gastric juice and sequential exposure to gastric and pancreatic juice was 99.47 + 2.05% and 93.21 + 0.43%, respectively. These values were higher than those found for controls 1 and 2. The storage condition of the fermented beverage for 1 or 8 days at 4 °C did not affect the survival after exposure to gastric juice, pancreatic juice, or sequential exposure. The results obtained in this study conclude that the fermented beverage of chickpeas and coconut is an excellent carrier for L. paracasei LBC 81, capable of enhancing survival to gastrointestinal conditions and ensuring a greater number of viable cells reaching the intestinal epithelium.
... Among these, the gram-positive Lactic acid bacteria (LAB) are a phylogenetically heterogenous and versatile group which comprise high probiotic potential [4]. Interestingly, LAB of vegetal origin represent a promising and attractive probiotic profile, including Lactiplantibacillus plantarum and Lactiplantibacillus pentosus (formerly known as Lactobacillus plantarum and Lactobacillus pentosus) isolated from raw and fermented vegetal foods such as table olives [5][6][7][8], cucumber [9], kimchi [10] and pickles [11] among others. The versatility of L. plantarum and L. pentosus is due to their genomic diversity, plasticity and functionality linked to their ecological niches which allow them to survive in harsh conditions such as gastrointestinal tracts and unstable environmental conditions [12][13][14]. ...
The probiotic potential of Lactiplantibacillus pentosus CF-6HA isolated from traditionally fermented Aloreña table olives was analyzed in vitro and in silico. Results obtained suggested that this strain can be catalogued as “talented” bacterium exhibiting bacteriocin production with antimicrobial activity against human/animal and plant pathogens, such as Pseudomonas syringae and Verticillium dahliae. The robustness, safety and probiotic potential of L. pentosus CF-6HA was confirmed by in silico analysis. In addition, a plethora of coding genes for defense and adaptability to different life styles besides functional properties were identified. In this sense, defense mechanisms of L. pentosus CF-6HA consist of 17 ISI elements, 98 transposases and 13 temperate phage regions as well as a CRISPR (clustered regularly interspaced short palindromic repeats)/cas system. Moreover, the functionality of this strain was confirmed by the presence of genes coding for secondary metabolites, exopolysaccharides and other bioactive molecules. Finally, we demonstrated the ability of L. pentosus CF-6HA to biotransform selenite to nanoparticles (SeNPs) highlighting its potential role in selenium bioremediation to be exploited in foods, agriculture and the environment; but also for the bio-enrichment of fermented foods with selenium.
... Processing methods often rely on local traditions, which affect the fruit's taste, color, and texture. Previous studies reported whether fermented olive fruits have probiotic effects, this could lead to improved digestive health (Hurtado et al., 2012;Bautista-Gallego et al., 2013). Different pickling processes of olive fruits promote quantitative and qualitative alterations in the phenolic compounds of olive fruits, thereby changing their nutritional and health properties (Marsilio et al., 2001). ...
... Processing methods often rely on local traditions, which affect the fruit's taste, color, and texture. Previous studies reported whether fermented olive fruits have probiotic effects, this could lead to improved digestive health (Hurtado et al., 2012;Bautista-Gallego et al., 2013). Different pickling processes of olive fruits promote quantitative and qualitative alterations in the phenolic compounds of olive fruits, thereby changing their nutritional and health properties (Marsilio et al., 2001). ...
Olive fruits (Olea europaea L) have several health and nutritional benefits due to their high content of antioxidant compounds. This study evaluated the hepato-renal toxic effects of pickled olive fruits that were treated with acid black nigrosine dye (ABND) in mice. Twenty male Swiss albino mice (CD-1) were used to determine the median lethal dose (LD50) of ABND. Then the other forty male mice were equally divided into 4 groups (N = 10) as follows: Group 1 (Gp1) was served as a control group. Gp2 was administered orally with a normal olive fruit extract (NOFE) of 150 mg/kg b.wt. Gp3 was administered with pickled olive fruit extract treated with KOH and ABND (POFE/B/KOH/ABND) at 150 mg/kg b.wt. The last group (Gp4) was administered with ABND alone at 60 mg/kg b.wt. The treatment of all the experimental groups was daily for 2 consecutive months. At the end of the experiment, percentages of body weight (% b.wt.) changes were calculated. Blood and sera samples were collected for determination of the hematological and biochemical parameters Liver and kidney tissues were collected for histopathological investigations. The results showed that the group of mice that were treated with POFE/B/KOH/ABND showed significant hepato-renal dysfunctions, as evidenced by altering some of the hematological, biochemical, and histopathological parameters.
... The microbial adhesion to hydrocarbons (MATH) method was used to determine the surface hydrophobicity of L. sakei MS103 in the hydrophobic organic solvent xylene, while surface charge characteristics were assessed using chloroform and ethyl acetate as the Lewis acid and Lewis base, respectively [28]. L. sakei MS103 was prepared using the abovementioned method. ...
Fermented vegetable-based foods, renowned for their unique flavors and human health benefits, contain probiotic organisms with reported in vitro antioxidative effects. This study investigates the probiotic properties of Latilactobacillus sakei MS103 (L. sakei MS103) and its antioxidant activities using an in vitro oxidative stress model based on the hydrogen peroxide (H2O2)-induced oxidative damage of RAW 264.7 cells. L. sakei MS103 exhibited tolerance to extreme conditions (bile salts, low pH, lysozyme, H2O2), antibiotic sensitivity, and auto-aggregation ability. Moreover, L. sakei MS103 co-aggregated with pathogenic Porphyromonas gingivalis cells, inhibited P. gingivalis-induced biofilm formation, and exhibited robust hydrophobic and electrostatic properties that enabled it to strongly bind to gingival epithelial cells and HT-29 cells for enhanced antioxidant effects. Additionally, L. sakei MS103 exhibited other antioxidant properties, including ion-chelating capability and the ability to effectively scavenge superoxide anion free radicals, hydroxyl, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid, and 2,2-diphenyl-1-picrylhydrazyl. Furthermore, the addition of live or heat-killed L. sakei MS103 cells to H2O2-exposed RAW 264.7 cells alleviated oxidative stress, as reflected by reduced malondialdehyde levels, increased glutathione levels, and the up-regulated expression of four antioxidant-related genes (gshR2, gshR4, Gpx, and npx). These findings highlight L. sakei MS103 as a potential probiotic capable of inhibiting activities of P. gingivalis pathogenic bacteria and mitigating oxidative stress.
... The ability to adhere to intestinal epithelial cells is a crucial requirement for the colonization of potentially probiotic strains in the gastrointestinal tract, as it helps them avoid immediate elimination through peristalsis and gives a competitive advantage within the gastrointestinal tract. Many authors suggest that strains with high hydrophobicity exhibit high adherence to intestinal cell lines [45,46]. All, except three strains: 36_Metsch_pulcherrima (54.63%), 32_Pich_kluyveri (59.42%) and 13_Metsch_ziziphicola (76.53%), showed hydrophobicity above 80% which may suggest their ability to quickly adhere to the mucosa. ...
One approach towards maintaining healthy microbiota in the human gastrointestinal tract is through the consumption of probiotics. Until now, the majority of probiotic research has focused on probiotic bacteria, but over the last few years more and more studies have demonstrated the probiotic properties of yeast, and also of species besides the well-studied Saccharomyces cerevisiae var. boulardii. Probiotic strains have to present the ability to survive in harsh conditions of the host body, like the digestive tract. Must fermentation might be an example of a similar harsh environment. In the presented study, we examined the probiotic potential of 44 yeast strains isolated from Polish wines. The tested isolates belonged to six species: Hanseniaspora uvarum, Pichia kluyveri, Metschnikowia pulcherrima, Metschnikowia ziziphicola, Saccharomyces cerevisiae and Starmerella bacillaris. The tested strains were subjected to an assessment of probiotic properties, their safety and their other properties, such as enzymatic activity or antioxidant properties, in order to assess their potential usefulness as probiotic yeast candidates. Within the most promising strains were representatives of three species: H. uvarum, M. pulcherrima and S. cerevisiae. H. uvarum strains 15 and 16, as well as S. cerevisiae strain 37, showed, among other features, survivability in gastrointestinal tract conditions exceeding 100%, high hydrophobicity and autoaggregation, had no hemolytic activity and did not produce biogenic amines. The obtained results show that Polish wines might be a source of potential probiotic yeast candidates with perspectives for further research.
... Bile salt tolerance is closely related to both BSH and osmotic stress tolerance. Because BSH activity is not common among bacteria isolated in non-bilious environments, such as cheese or fermented vegetables [43][44][45], it is not surprising that most of the isolates showed low BSH activity. We measured BSH activity in strains treated with simulated gastric juice for 2 h because LAB is in a state of acid stress that must resist exposure to bile secreted into the small intestine. ...
To understand the biological roles of Pediococcus pentosaceus strains as probiotics isolated from the traditional Korean fermented food, Jangajji, Pediococcus pentosaceus was selected based on its high cinnamoyl esterase (CE) and antioxidant activities. The acid and bile stability, intestinal adhesion, antagonistic activity against human pathogens, cholesterol-lowering effects, and immune system stimulation without inflammatory effects were evaluated. Nitric oxide (NO) levels were measured in co-culture with various bacterial stimulants. Fermentation ability was measured by using a broccoli matrix and the sulforaphane levels were measured. Resistance to acidic and bilious conditions and 8% adherence to Caco-2 cells were observed. Cholesterol levels were lowered by 51% by assimilation. Moreover, these strains exhibited immunomodulatory properties with induction of macrophage TNF-α and IL-6 and had microstatic effects on various pathogens. Co-culture with various bacterial stimulants resulted in increased NO production. Fermentation activity was increased with the strains, and higher sulforaphane levels were observed. Therefore, in the future, the applicability of the selected strain to broccoli matrix-based fermented functional foods should be confirmed.
... The ability of potential probiotic candidates to survive under low pH is crucial since probiotics are exposed to stomach acidity and pepsin after oral ingestion (Giles-Gómez et al., 2016). Bautista--Gallego et al. (2013) and Chen et al. (2014) also reported the survival ability of probiotics yeast and LAB at pH 2.5. Nonetheless, there was variable response in the tested strains' acid tolerance (p < 0.05), +Isolates that had recorded 0.8-1.0 ...
... They found that L. casei Zhang, which was isolated from soymilk and bovine milk, is a good tolerant to gastric and intestinal juice and maintain high viability (>10 CFU/g) during storage. Bautisa-Gallego et al. [27] found that 107 olives isolates were identified as L. plantarum, L. pentosus, and L. paraplantarum. Most of them showed lower survival to gastric than to pancreatic digestion. ...
Lactobacillus has a well known positive effect on human health. Therefore, this study aimed at applying the antimicrobial and antibiofilm effects of L. pentosus, L. plantarum and L. pentosus HG against 2 common pathogens, Bacillus cereus (food born pathogen) and Pseudomonas aeruginosa (plant pathogen). All lactic acid bacterial strains were identified by partial sequencing of the 16S rRNA gene and exerted tolerance to stress conditions such as bile salts, gastric juice and NaCl. The cell-free Lactobacillus supernatant CFLS showed a good antimicrobial activity against both pathogens. The MIC90 of L. pentosus and L. plantarum were 30 μl and more than 40 μl, respectively. On the other hand, the MIC90 of L. pentosus HG was 30 μl in case of P. aeruginosa and more than 40 μl in case of B. cereus. Both pathogens displayed remarkable reduction in biofilm formation in presence of 20 μl or more of CFLS. The antibiofilm dose of L. plantarum or L. pentosus HG was 20 μl against B. cereus. Besides, 20 μl of L. plantarum supernatant is the antibiofilm dose against both pathogens. In conclusion, the three Lactobacillus strains isolated from traditional fermented milk are strongly recommended as probiotics as well as biocontrole agents against B. cereus and P. aeruginosa by inhibition of their ability to form biofilm.
... Of course, potential probiotic strains with much higher auto-aggregation potential than the current strain have also been identified. For example, Bautista-Gallego et al. (2013) showed that four strains including GG1ST0-4, HM2T0-63, GM2FT1-129, and HG2T1-138 had the auto-aggregation ability of above 90% [31]. Table 3 shows the L. paracasei cholesterol assimilation capacity, about 74 ± 2.3%. ...
Previous studies documented that Lactobacillus paracasei has obvious in vitro cholesterol-lowering abilities. In this study, initially, L. paracasei was tested in terms of antibacterial properties as well as antibiogram profile. Then, the safety of the mentioned strain was evaluated in rats. Evaluation of antibiotic susceptibility revealed that the L. paracasei strain had high antibiotic resistance to several antibiotics as well as a great ability to autoaggregation. After identification of the probiotic aptitude, six groups of six rats from both sexes were used (three groups of each sex). L. paracasei was administered to the experimental groups via drinking water for 28 days (1 × 108 and 1 × 109, respectively). The negative control group received only tap water during this period. Hematological indicators, serum liver enzyme activity including (alanine transaminase (ALT), alkaline phosphatase (ALP), and aspartate transaminase (AST)) as well as serum creatinine and urea were evaluated at the end of 28 days. The blood and serum factors were not changed significantly during the 28 days. The only noticeable difference was the increase of blood urea in both sexes which was in a normal range. Furthermore, the evaluation of antagonistic properties revealed that L. paracasei had antibacterial aptitude against Escherichia coli and Staphylococcus aureus. In conclusion, this strain has good cholesterol-lowering and antibacterial properties and is a safe supplement in Wistar rats.
... Therefore, two traits are suitable criteria for examination and identification of potential probiotic strains. However, it should be noted that in vitro conditions can be different from those in vivo and cannot simply be interpreted explicitly by using these results [29]. ...
Abstract—Probiotic properties of 6 human and foodborne Lactobacillus strains were investigated in vitro with comparison to standard strains (Lactiplantibacillus plantarum ATCC 8014 and Lacticaseibacillus rhamnosus ATCC53103). They included viability in acidic environment (pH 2.5), survival in presence of bile salt and pepsin-pancreatin, autoaggregation, surface hydrophobicity (an indirect parameter of colonization of intestine cells), co-aggregation with pathogens (Escherichia coli O157:H7, Salmonella enterica ATCC 13076 and Listeria monocytogenes ATCC 7644) and antibiotic resistance. In addition, different groups of mice were fed by lactic acid bacteria for 7 days and viability of strains in mice feces were analyzed. All bacterial strains showed high survival at pH 2.5 (>98%), simulated pancreatic juice (>90%), simulated gastric condition (>77%) and also high resistance against bile salt (>89%). L. rhamnosus M1, isolated from cow milk, showed the greatest average surface hydrophobicity (63.7%), auto-aggregation (80.6%) and co-aggregation. Different
strains of L. plantarum had resistance to the tested antibiotics, except for M8, which was sensitive to kanamycin and chloramphenicol. Among L. rhamnosus strains, M1 and RHM were the most sensitive to antibiotics demonstrating susceptibility to erythromycin. Oral feeding of the isolated strains caused beneficial effect reducing microbial amount on Plate Count and MacConkey agars in mice feces during 7 days. L. rhamnosus M1 and L. plantarum M8 are considered to be the best suitable candidates for probiotic strains because they showed a wide range of antimicrobial properties, resistance to acid and bile and survival in gastric and intestinal colonization.
... Simulated gastric digestion (GD) was performed with minor modifications to the method of Bautista-Gallego et al. (2013). Simulated gastric fluid buffer without enzymes, pH 2.0 (adjusted with 1 M HCl) containing gastric solution, NaCl (2.05 g l −1 ), KH 2 PO 4 (0.60 g l −1 ), CaCl 2 (0.11 g l −1 ), and KCl (0.37 g l −1 ) was prepared and autoclaved at 121 • C for 15 min. ...
Aims:
This study aimed to evaluate the probiotic properties of Enterococcus strains isolated from Turkish traditional cheeses.
Methods and results:
Fifty-two Enterococcus spp. were taxonomically determined as follows: Enterococcus faecium (26), Enterococcus faecalis (18), Enterococcus durans (6), and Enterococcus italicus (2). The ability of isolates/strains to survive the harsh conditions (acidity and in-vitro gastric solution) of the gastrointestinal tract was established. They also showed auto-aggregation, hydrophobicity, and co-aggregation ability. Hydrophobicities of the strains were found between 0.8%-21%, 0.7%-56%, and 2%-63% for xylene, chloroform, and ethyl acetate, respectively. Autoaggregation values of the Enterococcus strains were 4%-20%, 7%-30%, and 36%-98% after 2, 4, and 24-h incubation, respectively. In this study, the Enterococcus strains tested showed co-aggregation ability with the Escherichia coli ATCC 25922, Salmonella Typhimurium ATCC 14028, and Staphylococcus aureus ATCC 25923. The results of PCR amplification revealed that only five strains possess virulence factor genes (gelE,asa1,cyl A,esp). We determined antibiotic resistance, biofilm forming abilities, and hemolytic activity for safety evaluation of strains.
Conclusions:
In this large and comprehensive study, we found that only few of Enterococcus strains have promising probiotic potential, among which E. faecalis ES1 and E. faecium EM1 showed the best probiotic properties (are the most promising probiotic candidates).
... Most studies have shown Lb. pentosus and Lb. plantarum as the dominant species in table olive fermentation (Bautista-Gallego et al., 2013;Doulgeraki et al., 2013). Benítez-Cabello et al. (2019) reported Lb. pentosus as the dominant species present on the surface of Gordal, Aloreña, and Manzanilla varieties, which were processed in a green Spanish style or directly pickled olives, whereas Abriouel et al. (2011) reported that Lb. plantarum and Lb. ...
In the present study, we aimed to isolate and biochemically identify tyramine-producing lactic acid bacteria (LAB) from black and green fermented olive samples produced by traditional methods and obtained from different provinces of Turkey. A total of 36 LABs, including Enterococcus spp. (2 isolates), Lactobacillus spp. (16 isolates), and Lactococcus spp. (18 isolates) were isolated from the fermented olive samples. Among them, 27 isolates could decarboxylate tyrosine amino acid; however, the decarboxylase enzyme activity of the remaining 9 isolates was negative. The ability of LAB isolates with positive enzyme activity to produce tyramine was evaluated using high-performance liquid chromatography (HPLC), and 6 isolates were found to be significant tyramine producers in vitro, producing tyramine at concentrations ranging from 107.251 to 207.618 mg L-1 .
... Fermented table olives represent a valuable Mediterranean healthy food, thanks to their high content of bioactive compounds, dietary fibers, fatty acids, and antioxidants (Boskou et al., 2015;Campus et al., 2018;Perpetuini et al., 2020). In addition to this, they have been recognized as a source or even a vehicle of probiotic microorganisms (Bautista-Gallego et al., 2013;Bevilacqua, Altieri, et al., 2010;Blana et al., 2014;De Bellis et al., 2010;Peres et al., 2014). Hence, they might represent an ideal ingredient for the development of innovative vegetable-based foods, characterized by health-beneficial traits, balanced nutritional content, and pleasant sensory traits (Galanakis, 2021). ...
Table olives (Olea europaea L.) are one of the most important fermented vegetables worldwide, whereas sea fennel (Crithmum maritimum L.) represents an emerging food crop, characterized by interesting nutritional and sensory qualities. Both are characterized by a high concentration of bioactive compounds with health beneficial effects. Thanks to these features, table olives and sea fennel undoubtedly represent two valuable ingredients for the manufacture of innovative vegetable preserves. Given these premises, the present study was aimed at exploring the co-fermentation of green olives and sea fennel to produce laboratory-scale prototypes of innovative high value preserves. To this end, the effects of two recipes, two standard methods for production of table olives, and two fermentation microbiota (resident or inoculated) were assessed. The prototypes were evaluated for their microbial dynamics as well as for key sensory traits by a panel of trained assessors. During the fermentation, all the prototypes showed a progressive pH reduction. Mesophilic lactobacilli, mesophilic lactococci, and yeasts were the main microbial groups at the end of the fermentation, while Enterobacteriaceae decreased during fermentation. Metataxonomic analysis revealed an evolution of the microbiota, with Lactiplantibacillus plantarum dominating in all the prototypes in the late stage of fermentation, irrespective of the recipe, processing method, and starter inoculation. A greater crunchiness and lower fibrousness were perceived in the Greek style prototypes, which were preferred than Spanish style prototypes by trained panelists.
... The surface hydrophobicity of L. mesenteroides LVBH107 was determined using the microbial adhesion to hydrocarbons (MATH) method with toluene and xylene serving as hydrophobic organic solvents. Chloroform was selected as Lewis acid and ethyl acetate as Lewis base in order to determine surface charge characteristics of L. mesenteroides LVBH107 [27]. The method used for L. mesenteroides LVBH107 preparation was the same method as described above except that the bacterial pellet was resuspended in 0.1 M KNO 3 buffer (pH 6.2) and adjusted to an OD 600 value of 0.60. ...
Probiotics, active microorganisms benefiting human health, currently serve as nutritional supplements and clinical treatments. Periodontitis, a chronic infectious oral disease caused by Porphyromonas gingivalis (P. gingivalis), activates the host immune response to release numerous proinflammatory cytokines. Here, we aimed to clarify Leuconostoc mesenterica (L. mesenteroides) LVBH107 probiotic effects based on the inhibition of P. gingivalis activities while also evaluating the effectiveness of an in vitro P. gingivalis lipopolysaccharide-stimulated RAW 264.7 cell-based inflammation mode. L. mesenteroides LVBH107 survived at acid, bile salts, lysozyme, and hydrogen peroxide conditions, auto-aggregated and co-aggregated with P. gingivalis, exhibited strong hydrophobicity and electrostatic action, and strongly adhered to gingival epithelial and HT-29 cells (thus exhibiting oral tissue adherence and colonization abilities). Moreover, L. mesenteroides LVBH107 exhibited sensitivity to antibiotics erythromycin, doxycycline, minocycline, ampicillin, and others (thus indicating it lacked antibiotic resistance plasmids), effectively inhibited P. gingivalis biofilm formation and inflammation (in vitro inflammation model), reduced the secretion of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β) and inflammatory mediators (NO and PGE2), and decreased the expression levels of inflammation related genes. Thus, L. mesenterica LVBH107 holds promise as a probiotic that can inhibit P. gingivalis biofilm formation and exert anti-inflammatory activity to maintain oral health.
... pentosus), and Lactiplantibacillus paraplantarum (L. paraplantarum) are responsible for the fermentation of olives (Hurtado et al. 2012;Bautista-Gallego et al. 2013). Kimchi is a traditional Korean food made by fermentation of vegetables under the action of various LAB belonging to the genera Latilactobacillus (formerly belonged to the genus Lactobacillus) Leuconostoc, and Weissella (Jung, Lee, and Jeon 2014). ...
Probiotic bacteria exhibit beneficial effects on human and/or animal health, and have been widely used in foods and fermented products for decades. Most probiotics consist of lactic acid bacteria (LAB), which are used in the production of various food products but have also been shown to have the ability to prevent certain diseases. With the expansion of applications for probiotic LAB, there is an increasing concern with regard to safety, as cases with adverse effects, i.e., severe infections, transfer of antimicrobial resistance genes, etc., can occur. Currently, in vitro assays remain the primary way to assess the properties of LAB. However, such methodologies are not meeting the needs of strain risk assessment on a high-throughput scale, in the context of the evolving concept of food safety. Analyzing the complete genetic information, including potential virulence genes and other determinants with a negative impact on health, allows for assessing the safe use of the product, for which whole-genome sequencing (WGS) of individual LAB strains can be employed. Genomic data can also be used to understand subtle differences in the strain level important for beneficial effects, or protect patents. Here, we propose that WGS-based bioinformatics analyses are an ideal and cost-effective approach for the initial in silico microbial risk evaluation, while the technique may also increase our understanding of LAB strains for food safety and probiotic property evaluation.
... Lacticaseibacillus paracasei showed in situ antagonistic activity against pathogens. Recently, LAB have been isolated from different products, such as water kefir grains (23), different curd samples (34), cooked meat products (37), fermented table olives (5), Slovak Bryndza cheese (6), buffalo mozzarella cheese (8), raw milk, artisanal ewe's cheese (32), goat's milk (13), Brazilian kefir grains (25), and feta-type cheese (33). ...
The objectives of this investigation were (i) to isolate bacteria from various foods (dairy products, fruits, and vegetables) and evaluate their probiotic potential and (ii) to select, identify, and characterize the bacterial strain(s) with the highest probiotic potential. From 14 food samples, 117 bacterial strains were isolated; however, only 42 (T1 to T42) had the correct characteristics (gram positive, coccoid, and bacilliform) and were catalase and oxidase negative to be considered presumptive lactic acid bacteria (LAB). The antagonistic activity of the 42 strains was evaluated against Escherichia coli (O157:H7E09), Listeria monocytogenes (ATCC 19115), Staphylococcus aureus (ATCC 25923), and Salmonella enterica serotype Typhimurium (ATCC 14028). The nine strains with the highest antagonistic activity were recovered from the following foods: pulque (T1), sprouted beans (T26), Ranchero cheese (T30, T31, T32, T33, T35, and T36), and Tenate cheese (T40). The inhibition zones on culture and sensitivity plates were 17.0 ± 1.2 to 19.3 ± 2.8 mm in diameter. Based on the antagonistic activity against pathogenic bacteria and resistance to low pH and bile salts, strain T40 had the highest probiotic potential. A 16S rRNA technique was used to identify strain T40 as Lacticaseibacillus paracasei (renamed from Lactobacillus paracasei in April 2020). This strain had no resistance to ampicillin, gentamicin, erythromycin, and tetracycline. The antagonistic activity was evaluated in situ (fresh cheese) against pathogenic bacteria, supporting the probiotic potential of L. paracasei. Isolates of this LAB recovered from Tenate cheese had characteristics of a probiotic microorganism with high potential for use in food technology.
Highlights:
... The resistance of isolates against simulated gastric juice was evaluated using a bacterial suspension after 3 h of incubation at 37 • C in sterile M17 broth adjusted to pH levels of 2.5 by the addition of HCl as defined by Bautista-Gallego et al. (2013). Besides, the ability of the isolates to survive for 2 h of incubation at 37 • C using M17 broth containing of 0.06%, 0.125%, 0.25%, 0.5%, and 1% bile salt (Sigma-Aldrich) was examined according to the method of Sabir, Beyatli, Cokmus, and Onal-Darilmaz (2010). ...
This study was conducted to determine whether the potential health benefits of cheese-related Streptococcus (S.) infantarius, S. gallolyticus, and S. lutetiensis strains taxonomically belonging to the S. bovis/S. equinus complex (SBSEC) could be addressed without safety concern. All strains showed antagonistic effect against Staphylococcus (S.) aureus ATCC 25923 and produced a high amount of exopolysaccharide (293.48–365.95 μg/mL). Moreover, they presented high hydrophobicity towards n-hexadecane and xylene. The highest cholesterol assimilation (13.95–19.30%) and β-galactosidase activity (35.17–43.33 MU) were determined in isolates 930 and 120. Besides, all isolates neither showed hemolytic activity nor harbored virulence genes (asa1, gelE, cylA, cylB, epfSTR, hylSTR, mrpSTR, slySTR, bay046STR). However, only isolate 937 harbored the arcSTR virulence gene. Besides, isolates 937 and 120 were observed to degrade arginine. All isolates, except for isolate 937, were susceptible to penicillin, ampicillin, chloramphenicol, and vancomycin. All isolates had biofilm-forming capability. Considering all benefits and safety features, isolate 930 can be suggested for further in vivo and in situ investigations. This study does not claim that the SBSEC group bacteria, which are associated with many diseases, are actually beneficial, but only supports the view that clinical origin SBSEC group bacteria can be evaluated differently from those isolated from fermented products.
... To confer beneficial properties on the host, the microorganism is expected to be able to colonize the gut and have tolerance to the harsh condition in the intestinal tract of the host [2]. Numerous Lactic acid bacteria (LAB) isolated from varieties of food sources in different countries around the world have been reported to confer health benefits and possess good probiotic characteristics [3,4]. Fermented foods have been Sample Collection: Samples for the isolation of probiotic organisms (freshly prepared Ogi and Kunu) were obtained from sales points in Ota, Ogun State. ...
Fermented foods have been the major carrier of probiotics. The fermentation process of foods is made possible by microorganisms. Probiotic lactic acid bacteria previously isolated from Ogi and Kunu-zaki was investigated for their effect on some biomarkers in healthy male albino Wistar rats. The two strains that showed good probiotic potentials were chosen based on tolerance to low pH and bile salt, and antibiotic susceptibility test. Thirty Albino Wistar rats were divided into six groups based on different treatments for each group. Four groups were administered orally with the two probiotic strains at different concentrations (1.0x109, 2.0x108). One group was administered with the combination of the two strains (2.0x108 each), while the last group, which was the control received normal saline for two weeks. The blood samples and livers were collected at the end of the treatment. The analysis of certain biomarkers (fasting blood glucose (FBG), aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), creatinine, bilirubin, total protein and antioxidant profile) was carried out. The ALT, AST and superoxide dismutase (SOD) activity in the test animals were found to improve significantly while no significant difference was observed in the activity of other biomarkers in the treated groups compared to the control. The results showed that the two strains had a positive impact on the health status of the rats with the combined group having the higher impact. However, more studies need to be done to explore other health benefits associated with these organisms.
... None of the tested strains showed ability to deconjugate bile salts (Tokatl et al., 2015). The absence of BSH activity in LAB strains isolated from table olives was also reported (Bautista-Gallego et al., 2013). Araujo et al. (2016) assessed the ability of 8 P. acidilactici strains isolated from rainbow trout to deconjugate bile salts (sodium salts of taurocholate or taurodeoxycholate in MRS agar containing l-cysteine). ...
The selection of potential probiotic strains that possess the physiological capacity of performing successfully in the gastrointestinal tract (GIT) is a critical challenge. Probiotic microorganisms must tolerate the deleterious effects of various stresses to survive passage and function in the human GIT. Adhesion to the intestinal mucosa is also an important aspect. Recently, numerous studies have been performed concerning the selection and evaluation of novel probiotic microorganisms, mainly probiotic bacteria isolated from dairy and nondairy products. Therefore, it would be crucial to critically review the assessment methods employed to select the potential probiotics. This article aims to review and discuss the recent approaches, methods used for the selection, and outcomes of the evaluation of novel probiotic strains with the main purpose of supporting future probiotic microbial assessment studies. The findings and approaches used for assessing acid tolerance, bile metabolism and tolerance, and adhesion capability are the focus of this review. In addition, probiotic bile deconjugation and bile salt hydrolysis are explored. The selection of a new probiotic strain has mainly been based on the in vitro tolerance of physiologically related stresses including low pH and bile, to ensure that the potential probiotic microorganism can survive the harsh conditions of the GIT. However, the varied experimental conditions used in these studies (different types of media, bile, pH, and incubation time) hamper the comparison of the results of these investigations. Therefore, standardization of experimental conditions for characterizing and selecting probiotics is warranted.
... Not surprisingly, Lactobacillus species were reported to adhere to mucin as well as intestinal cells with specific surface-associated proteins, including mucus-binding proteins (MUBs), surface layer proteins (SLPs), surface-layer-associated proteins (SLAPs), and moonlighting proteins [69][70][71]. As a screening criterion, hydrophobicity is a desirable trait of probiotics that should generally be used in the analysis [72,73]. ...
Over the last decades, aquaculture production increased rapidly. The future development of the industry highly relies on the sustainable utilization of natural resources. The need for improving disease resistance, growth performance, food conversion, and product safety for human consumption has stimulated the application of probiotics in aquaculture. Probiotics increase growth and feed conversion, improve health status, raise disease resistance, decrease stress susceptibility, and improve general vigor. Currently, most probiotics still originate from terrestrial sources rather than fish. However, host-associated (autochthonous) probiotics are likely more persistent in the gastrointestinal tract of fish and may, therefore, exhibit longer-lasting effects on the host. Probiotic candidates are commonly screened in in vitro assays, but the transfer to in vivo assessment is often problematic. In conclusion, modulation of the host-associated microbiome by the use of complex probiotics is promising, but a solid understanding of the interactions involved is only in its infancy and requires further research. Probiotics could be used to explore novel ingredients such as chitin-rich insect meal, which cannot be digested by the fish host alone. Most importantly, probiotics offer the opportunity to improve stress and disease resistance, which is among the most pressing problems in aquaculture.
... To investigate the BSH activity of strains, plate assay method was performed (Gallego et al., 2013). To test the activity, overnight grown cultures were plated on MRS agar plates using spread plate method on MRS agar plates containing different bile salts (as mentioned in bile salt tolerance). ...
In the present study, a total of 80 presumed lactic acid bacteria (LAB) were isolated from camel milk. Selected LAB were identified as Lactococcus lactis (cam 12), Enterococcus lactis (cam 14) and Lactobacillus plantarum (cam 15) and their potential were tested by tolerance & de-conjugation of bile salts, antimicrobial activity, surface hydrophobicity and adhesion potential) along with this of probiotics were evaluated for curd formation and assessed for sensory properties and syneresis. Selected LABs showed antimicrobial activity against wide range of pathogenic bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus and Escherchiaia. coli). LAB (cam 12, cam 14 and cam15) were highly sceptible to chloramphenicol, vancomycin, and tetracyclin. In vitro adhesion studies with Caco-2 cells demonstrated strong adhesion activity with hydrophobicity (99%) was observed. Acute oral toxicity of E. lactis and L. plantarum showed non-toxic, non-virulent and safe for industrial application. The study provides potential LAB which may act as a substitute of functional food, synthetic feed and industrial curd formulation with in the shortest span (240 min at 28–32 °C).
Fermented cereal products, such as corn, millet, rice, and wheat, are popular in West Africa due to their affordability and health benefits. These grains undergo nutritional and biochemical changes, enriched by microorganisms like lactic acid bacteria (LAB) group, yeasts, and probiotic strains which are essential for maintaining gut microbiota and immune system balance. Dairy products, particularly cow’s milk, are providing protein, vitamins, and calcium. West African indigenous fermented foods are produced with kpété-kpété, Kudemé, and rabilé as starter cultures. Consuming cereal-based fermented foods enriches the intestinal microbiome with gram-positive bacteria, yeast, and fungi species, providing health benefits. Probiotic bacteria have potential applications in managing insulin-independent diabetes and obesity, and their consumption may exert antidiabetic and antioxidant properties. Yeasts play a crucial role in the quality, taste, texture, and flavor of fermented food products, contributing to flavor formation and improving nutritional value. Traditional fermented foods in Africa are produced through fermentation with lactic acid (LAB) or yeasts, or mixtures of both. However, food safety concerns arise due to raw materials, packaging, and unhygienic conditions. Therefore, it is essential to have a standardized starter cultures.
The suitability of Lactiplantibacillus plantarum (L. plantarum) as a functional starter culture in Nham fermentation was investigated, with a focus on evaluating both its probiotic attributes and fermentation capability. L. plantarum BCC 4352 (LpbBCC4352) exhibited colony-associated antimicrobial activity against Kocuria rhizophila, L. plantarum, Latilactobacillus sakei ssp. sakei, and Pediococcus pentosaceus, as well as the zoonotic Streptococcus suis. LpbBCC4352 exhibited impressive acid (pH 2.5) and bile resistance, coupled with notable survival rates in a simulated human digestive model. In addition, the strain is able to utilize fructo-oligosaccharides in simulated human colon conditions. It also displayed robust adhesion to human colon cell monolayers (Caco-2) and gastric mucin. Furthermore, it showed a promising cholesterol reduction ability in the fermentation medium. The safety of LpbBCC4352 for human consumption was confirmed through a hemolytic activity assay and antibiotic susceptibility testing. Moreover, using LpbBCC4352 as a starter culture not only enhanced the firmness of Nham but also ensured consumer satisfaction. The overall findings emphasize the potential use of LpbBCC4352 as a safe and effective functional starter culture, particularly in the production of Nham.
This study aimed to investigate the probiotic properties of Lactic Acid Bacteria (LAB) isolates derived from various milk sources. These isolates identified based on their morphological characteristics and 16S rRNA gene sequencing. Four strains of Lactococcus lactis and two strains of Weissella confusa were identified with over 96% 16S rRNA gene similarity according to the NCBI-BLAST results. The survival of the isolates was determined in low pH, pepsin, bile salts, and pancreatin, and their adhesion ability was assessed by in vitro cell adhesion assay, hydrophobicity, auto- and co-aggregation, and safety criteria were determined by hemolytic, gelatinase activities, and DNAse production ability tests. The results showed that the LAB isolates had different levels of resistance to various stress factors. L. lactis subsp. cremoris MH31 showed the highest resistance to bile salt, while the highest pH resistance was observed in L. lactis MH31 at pH 3.0. All the isolates survived in pepsin exposure at pH 3.0 for 3 h. The auto-aggregation test results showed that all strains exhibited auto-aggregation ranging from 84.9 to 91.4%. Co-aggregation percentage ranged from 19 – 54% and 17 – 57% against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213, respectively. The hydrophobicity capacity of the LAB isolated ranged from 35–61%. These isolates showed different adhesion abilities to Caco-2 cells (81.5% to 92.6%). None of the isolates exhibited DNase, gelatinase and hemolytic activity (γ-hemolysis). All results indicate that these LAB strains have the potential to be used as probiotics.
Probiotics are health promoting gut microbiota which has been used in commercial products to extend its benefits for supporting the gut function and immunity. Besides these, probiotics contribute to reducing blood cholesterol, diabetics, coronary heart disease, and allergic symptoms as well as improving mood along with cognitive activities, reducing skin aging, and promoting longevity. Probiotics aid in promoting longevity as a function of antioxidant activity which allows it to be a potential source of supplement. These factors open an interesting prospect of screening well known probiotics community containing higher antioxidant activity from various Thai local fermented foods. This study aimed to screen targeted lactic acid bacteria (LAB) from 15 plant and animal based Thai local fermented foods by CaCO 3 containing MRS agar and analyzed its antioxidant and probiotic properties. It was found that all 11 isolates considered as potential LAB as it had shown clear zone on CaCO 3 containing MRS agar, exhibited over 70% inhibition of DPPH in both supernatant and pellet. But only one isolate from plant based fermented food showed potential probiotic properties, including acid-bile tolerance, hydrophobicity, and antimicrobial activity, and it was the one that had the highest antioxidant activity. This isolated strain might be further analyzed and developed as a potential longevity promoting supplement.
Vol.9, No.2 pages 35-52 Research Article
The knowledge about the microbial diversity of different olives varieties from diverse regions in the Mediterranean basin is limited. This work aimed to determine the microbial diversity of three different fermented olive varieties, collected from different regions in Cyprus, via Next Generation Sequencing (NGS) analysis. Olives were spontaneously fermented for 120 days, microbial DNA was extracted from the final products, and subjected to 16S rRNA gene and ITS1 loci metabarcoding analysis for the determination of bacterial and fungal communities, respectively. Results revealed that the bacterial profile of the studied varieties was similar, while no noteworthy differences were observed in olives from different regions. The bacterial profile was dominated by the co-existence of Lactobacillus and Streptococcus , while the genera Lactococcus and Salinivibrio and the family Leuconostocaceae were also present in increased relative abundances. Regarding fungal communities, the analysis indicated discrimination among the different varieties, especially in Kalamata ones. The most abundant fungi were mainly the genera Aspergillus , Botryosphaeria , Meyerozyma , and Zygosaccharomyces for Cypriot olives, the genera Botryosphaeria , Saccharomyces , Geosmithia , and Wickeromyces for Kalamata variety, while the dominant fungi in the Picual variety were mainly members of the genera Candida , Penicillium , Saccharomyces , Hanseniospora and Botryosphaeria . Potential microbial biomarkers that distinguish the three varieties are also proposed. Moreover, interaction networks analysis identified interactions among the key taxa of the communities. Overall, the present work provides useful information and sheds light on an understudied field, such as the comparison of microbiota profiles of different varieties from several regions in Cyprus. The study enriches our knowledge and highlights the similarities and the main differences between those aspects, booming in parallel the need for further works on this frontier, in the attempt to determine potentially olives’ microbial terroir in Cyprus. Our work should be used as a benchmark for future works in this direction.
Fermented olives contain a complex microbial consortium and include beneficial microorganisms that may contribute to the well‐being of consumers. Multifunctional cultures with probiotic properties isolated from table olives may serve as food fortifying agents or as a multifunctional starter or adjunct cultures in the fermentation of table olives. Probiotic bacteria are mainly lactic acid bacteria (LAB) beneficial for human health, with an increasing research interest in the recent years regarding the probiotic LAB isolated from fermented foods of plant origin. The main benefits of table olive fermentation are the control of microbial growth, the improvement of sensory characteristics, the enhancement of the safety and prolonged shelf life of the final product. Table olives like other plant origin products are by nature functional foods due to their high content in nutraceuticals, such as dietary fibers, polyunsaturated fatty acids, proteins, peptides, amino acids, keto acids, minerals, antioxidative vitamins, and other antioxidants.
Salmonella spp is one of the leading causes of bacterial foodborne illnesses worldwide resulting in acute gastroenteritis. The current study aimed to explore the inhibitory activity of two newly isolated probiotic candidates Lactiplantibacillus plantarum MYSAS1 and Enterococcus faecium MYSAS4 from fermented black cherry fruit, against Salmonella enterica subsp. enterica serovar Paratyphi A. Results demonstrated effective inhibitory activity of selected Lactic acid bacteria (LAB) strains against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella Paratyphi A. In addition, the cell-free supernatant (CFS) of both strains showed potent antimicrobial activity on growth of S. Paratyphi A were demonstrated by agar well diffusion, broth microdilution assay, in vitro time-kill assay, and co-culture experiments. Besides, Salmonella sessile cells were effectively reduced by 70% after treatment with the CFS of L. plantarum MYSAS1 and E. faecium MYSAS4, as determined by crystal violet and 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyltetra bromide (MTT) biofilm assays. The antimicrobial substances of CFS were thermostable but sensitive to pH neutralization, suggesting that the observed antisalmonella activity is likely due to organic acids. Liquid Chromatography- Tandem Mass Spectrometry (LC-MS/MS) analysis of CFS revealed that the antimicrobial activity is likely due to the presence of 11 different organic acids. The isolated strains exhibited important probiotic characteristics, such as sensitivity to most of the antibiotics tested (except vancomycin and kanamycin), anti-hemolytic activity, tolerance to acidic pH and 0.3% bile, and survival ability at different temperatures. L. plantarum MYSAS1 and E. faecium MYSAS4 also exhibited auto-aggregation and cell surface hydrophobicity of 45 and 80%, respectively. Our findings demonstrated important probiotic features isolated from black cherry fruits while inhibiting multiple pathogens, suggesting possible applications of these potential probiotic strains as alternatives for antibiotics and chemical preservatives in the veterinary and food sectors.
Diseases of fish caused by pathogenic bacteria are an important constraint on aquaculture production. Antibiotics have been widely used to control infectious diseases, but this has led to the emergence of drug-resistant bacteria and affected human health. In this context, probiotics are used as an alternative to antibiotics for the prevention and control of diseases in aquaculture. The aim of this study was to obtain probiotic candidate strains of Bacillus spp. from the gut of Rhynchocypris Lagowskii. Strains were screened by enzyme-producing ability, antagonism assay and antibiotic susceptibility. The safety of the strains to host fish has also been established. The isolated Bacillus licheniformis (LSG1-1) and Bacillus subtilis (LSG2-1) were characterized and performed well in tolerance experiments. In addition, LSG1-1 and LSG2-1 were detected to have higher self-aggregation ability and surface hydrophobicity. In the in vitro adhesion model, LSG1-1 and LSG2-1 showed good adhesion ability and had obvious adhesion inhibitory effect on three pathogens of Aeromonas. Based on the characteristics observed so far, Bacillus licheniformis LSG1-1 and Bacillus subtilis LSG2-1 could form potential probiotic candidates in the digestive tract of R. lagowskii to help combat diseases in aquaculture.
Streptococcus mutans (S. mutans) is the most important oral pathogenic bacterial cause of dental caries. Here we investigated the abilities of probiotic lactobacillus strains of Lactobacillus curvatus (L. curvatus) BSF206 and Pediococcus pentosaceus (P. pentosaceus) AC1-2 to control S. mutans. Both probiotic strains are acid and bile salt tolerant and are resistant to hydrogen peroxide and lysozyme to promote their survival within the oral environment. In addition, both strains are highly hydrophobic and are also capable of engaging in electrostatic interactions. These properties enhance abilities of both strains to adhere to gingival epithelial cells and HT-29 for improved colonization of oral tissues, while also enabling these probiotics auto-aggregate and to form aggregates with S. mutans that both may prevent S. mutans from colonizing oral tissues and facilitate the clearance of the cariogenic bacteria from the mouth during swallowing of food and saliva. Furthermore, results presented herein revealed that L. curvatus BSF206 and P. pentosaceus AC1-2 effectively inhibited S. mutans activities (biofilm formation, secretion of extracellular matrix components, synthesis of water-insoluble glucans) and led to downregulation of expression of key S. mutans genes involved in biofilm production (gtfA, gtfB, ftf, brpA). Taken together, these results indicate that L. curvatus BSF206 and P. pentosaceus AC1-2 can inhibit S. mutans biofilm formation as a new strategy for preventing dental caries.
Probiotic microorganisms play a very important role in food and medicines. These microorganisms improve the food quality, enhance bioavailability of the nutrients, produce antimicrobial and antioxidant compounds, degrade toxic compounds such as phytic acid and mycotoxins, and improve the digestion process. Probiotic microorganisms are extensively used in food and food products such as in yogurt, cheese, kefir, kimchi, formula milk, fermented food, medicines, and many other applications. There are two most important genera of the probiotic bacteria such as Lactobacillus and Bifidobacterium which are widely used in food products. Probiotic microorganisms help to cure many diseases such as irritable bowel syndrome and inflammatory bowel disease, reduce allergy and diarrhea, and reduce the saturated fatty acid level from the bloodstream. They reduce the chances of occurrence of breast cancer in females. These bacteria compete for the necessary nutrients and leave a very small amount of nutrients for the pathogenic bacteria and bind to the intestinal epithelium through adhesion sites and colonize and prevent the pathogenic bacteria to bind by reducing the surface area. Probiotic bacteria boost the immune system through signaling mechanism by releasing the cytokines for the destruction of pathogenic bacteria. Although there have been remarkable uses and application of probiotics from the last three decades, it still needs a lot of research to ensure the safety and stability of these food products.
The normal vaginal flora of women is mainly dominated by species of Lactobacillus. Lactobacilli produces lactic acid, hydrogen peroxide, and other inhibitory substances which hinder the growth of yeasts and pathogenic microorganisms, thereby keeping the vagina healthy by maintaining a slightly acidic pH. Probiotic vaginal lactobacilli form an important part of the vaginal microbiome and play protective roles against any form of bacterial, fungal, or opportunistic infection in females, especially women of reproductive age and the sexually active ones. Disruption of the normal vaginal flora may lead to loss of Lactobacillus species and can predispose the vagina to unpleasant conditions, making women susceptible to different forms of infections and sexually transmitted diseases. Candida vaginitis and Bacterial vaginosis are the two most common causes of vaginitis. Scientific evidence has linked the positive roles and impact of live dietary microbes (especially probiotics) on human health, and there is much evidence that supports the consumption of probiotics to promote the health and wellbeing of humans. In the attempt to effectively improve, restore, and maintain healthy vaginal flora, several researchers have recommended diets supplemented with probiotic Lactobacillus species.
The aim of this study is to isolate and characterize lactic acid bacteria from spontaneous fermentation of jalapeno pepper. Three strains of lactic acid bacteria were isolated from the spontaneous fermentation of peppers: Lactobacillus brevis P.16564, Lactobacillus brevis P.36564 and Lactobacillus rossiae P.26562, which were identified by amplification of the 16S rRNA gene. All strains showed marked viability after exposure to simulated gastric and pancreatic juice. Strain P.36564 showed greater viability when exposed to sequential stress from gastric and pancreatic juice. All strains showed antimicrobial activity on Escherichia coli (ATCC® 25922) and Salmonella sp. (ATCC® 700623). As for safety aspects, all strains are considered safe for human consumption. All strains have a high percentage of hydrophobicity and autoggregation. On the other hand, the percentage of coaggregation of lactic acid bacteria with E. coli was low. These results suggest that lactic acid bacteria isolated from pepper may have a probiotic potential.
The aim of this study is to isolate and characterize potential aroma producing lactic acid bacteria with some probiotic properties from artisanal cheese environment. For this purpose, 40 of lactic acid bacteria isolates were obtained from traditionally produced White cheese samples. They were preliminary characterized in Enterococcus genus by morphological, physiological, biochemical tools. Technological properties such as milk acidifying, lipolytic and proteolytic activities were also screened. Most of them were good acid producers. Aroma producing ability was determined by diacetyl production and among 40 isolates, 18 of them could produce this compound. DNA isolation and 16 S rRNA ribosomal gene sequence analysis of selected isolates indicated that they were identified as E. faecium, E. faecalis and E. durans. Aroma producers were screened for their probiotic characteristics and they showed variable acid tolerance, hydrophobicity, auto-aggregation, antimicrobial activity and antibiotic sensitivity. All of them tolerated bile salt. In conclusion, particularly two isolate, MD 30 and MD 38 identified as E. faecium were found to be the most promising bacteria due to both technological and probiotic traits.
Lactic acid bacteria (LAB) cultures used in food fermentation are often dried to reduce transportation costs and facilitate handling during use. Dried LAB ferments are generally lyophilized to ensure high cell viability. Spray drying has come to the forefront as a promising technique due to its versatility and lower associated energy costs. Adverse conditions during spray drying, such as mechanical stress, dehydration, heating, and oxygen exposure, can lead to low LAB cell viability. This reduced viability has limited spray drying's industrial applications thus far. This review aims to demonstrate the operations and thermodynamic principles that govern spray drying, then correlate them to the damage suffered by LAB cells during the spray‐drying process. The particularities of spray drying that might cause LAB cell death are detailed in this review, and the conclusion may enhance future studies on ways to improve cell viability.
The selection of potential probiotic strains that possess the physiological capacity of performing successfully in the gastrointestinal tract (GIT) is a critical challenge. Probiotic microorganisms must tolerate the deleterious effects of various stresses to survive passage and function in the human GIT. Adhesion to the intestinal mucosa is also an important aspect. Recently, numerous studies have been performed concerning the selection and evaluation of novel probiotic microorganisms, mainly probiotic bacteria isolated from dairy and nondairy products. Therefore, it would be crucial to critically review the assessment methods employed to select the potential probiotics. This article aims to review and discuss the recent approaches, methods used for the selection, and outcomes of the evaluation of novel probiotic strains with the main purpose of supporting future probiotic microbial assessment studies. The findings and approaches used for assessing acid tolerance, bile metabolism and tolerance, and adhesion capability are the focus of this review. In addition, probiotic bile deconjugation and bile salt hydrolysis are explored. The selection of a new probiotic strain has mainly been based on the in vitro tolerance of physiologically related stresses including low pH and bile, to ensure that the potential probiotic microorganism can survive the harsh conditions of the GIT. However, the varied experimental conditions used in these studies (different types of media, bile, pH, and incubation time) hamper the comparison of the results of these investigations. Therefore, standardization of experimental conditions for characterizing and selecting probiotics is warranted.
In the present study, nine Enterococcus (Ent.) faecium isolates were isolated from Tulum cheese produced traditionally in the central Taurus Mountains, Turkey during ripening period and were characterized to investigate their probiotic potential via gastrointestinal resistance, and adhesion ability, functional properties tests, and safety (haemolytic activity, antibiotic resistance, biogenic amine production, and PCR detection of some virulence factors) analyses. All of these strains proved to be resistant to bile salt and simulated gastric juice. All the isolates displayed good safety assessment regarding vancomycin susceptibility except for isolate 1050. Additionally, the majority of isolates showed high exopolysaccharide production while isolate 12 showed a desirable cholesterol removal rate. Also, five of Ent. faecium isolates indicated antibacterial activity against both Listeria monocytogenes ATCC 7644 and Staphylococcus aureus ATCC 25923. Isolates 394 and 894 were examined based on the presence of virulence genes encoding for aggregation substance (asa1), cytolysin (CylLL, CylLs, CylM, CylB, CylA), gelatinase (gelE), and hyaluronidase (hylefm). Isolate 894 harbored three virulence determinants including asa1, gelE and CylA while the virulence cylLL,S, cylM, Hylefm, gelE, and CylA genes were detected in isolate 394. Overall, isolate 894 was shown to be a potential candidate for further in vivo investigations as a probiotic culture.
The açai palm ( Euterpe oleracea ) is native to the Amazon basin, a humid tropical forest. High levels of total mesophilic bacteria with high diversity have been consistently reported in açai fruits. As local consumers have few digestive problems, the results of the present study reveal the lactic acid bacteria (LAB) recovered from açai fruits with characteristics that suggest they are possible candidates for probiotics and antagonistic potential against pathogens for the first time. Açai fruits were sampled from five different locations in the Eastern Amazonia floodplains. Sixty-six isolates were recovered from fruits and tested for some probiotic characteristics following FAO/WHO guidelines. Approximately 65% of the isolates showed no catalase or oxidase activity, Gram-positive staining or cocci and bacilli cell morphology. Furthermore, 48% of the isolates demonstrated preliminary characteristics that suggest safety for use, as they presented no coagulase enzyme activity or gamma-hemolysis. These strains were identified as belonging to the genera Lactiplantibacillus and Pediococcus , and 32 strains also presented resistance to vancomycin, ciprofloxacin and streptomycin. In addition, 28 isolates showed a survival rate, expressed as log cycle reduction, higher than 0.9 under gastric conditions (pH 2). All strains tested positive in bile salts deconjugation tests and showed a survival rate higher than 0.8 in the presence of this salt. Regarding antimicrobial activity against pathogens, all strains were able to inhibit Salmonella Typhimurium (ATCC ® 14028 TM ) and 97% were capable of inhibiting Escherichia coli (ATCC ® 25922 TM ). Concerning the results of in vitro antagonistic assays, three isolates (B125, B135, and Z183 strains) were selected for antagonistic tests using açai juice contaminated with these two pathogens. All tested LAB strains were able to inhibit pathogen growth in açai juice. In summary, açai fruits are a potential source of LAB isolates to be investigated as probiotics.
A series of lactobacilli isolated from dairy products were characterized using biotyping and ribotyping with EcoRI and HindIII restriction enzymes. Biotyping assigned 14 strains as Lactobacillus casei, 6 strains as Lactobacillus paracasei subsp. paracasei and 12 as Lactobacillus rhamnosus. The obtained ribotype patterns separated all analyzed strains into two clearly distinguished groups corresponding to L. rhamnosus and L. casei/L. paracasei subsp. paracasei. The HindIII ribotypes of individual strains representing these two groups were visually very similar. In contrast, EcoRI ribotyping revealed high intraspecies variability. All ribotypes of L. casei and L. paracasei subsp. paracasei dairy strains were very close and some strains even shared identical ribotype profiles. The type strains L. casei CCM 7088(T) (= ATCC 393(T)) and Lactobacillus zeae CCM 7069(T) revealing similar ribopatterns formed a separate subcluster using both restriction enzymes. In contrast, the ribotype profile of L. casei CCM 7089 (= ATCC 334) was very close to ribopatterns obtained from the dairy strains. These results support synonymy of L. casei and L. paracasei species revealed by other studies as well as reclassification of the type strain L. casei CCM 7088(T) as L. zeae and designation of L. casei CCM 7089 as the neotype strain.
Arbequina table olives are produced according to a traditional process involving an spontaneous fermentation in brine. The aim of this study was to evaluate for the first time the different microorganism populations in brine during the processing of Arbequina table olives.Yeasts were the main organisms involved in fermentation but lactic acid bacteria were important when the olives were being matured before packaging. The main yeast species identified were Candida boidinii, Candida diddensiae, Candida membranaefaciens, Kluyveromyces lactis, Pichia kluyveri, Pichia membranaefaciens and Rhodotolura glutinis. Lactobacillus pentosus and Lactobacillus paraplantarum were the species of lactic acid bacteria involved in the process. Some of the microbial species identified in this work have not been previously reported in the fermentation processes of table olives. Moreover, no relevant differences in microbial species diversity were observed at different depths of the vat. Nevertheless, the development of lactic acid bacteria was delayed in deep brine.
The present work was aimed at identifying strains of lactic acid bacteria (LAB) from kimchi, with properties suitable for use as starter cultures in yogurt fermentation.
A total of 2344 LAB strains were obtained from two different sources, one group consisted of commercial LAB strains from kimchi, and the second group consisted of those strains isolated from various types of kimchi. The LAB strains from both groups were screened for resistance to biological barriers (acid and bile salts), and the four most promising strains were selected. Further analysis revealed that KFRI342 of the four selected strains displayed the greatest ability to reduce the growth of the cancer cells, SNU-C4. The in vivo efficacy of strains in quinone reductase induction assay was evaluated, and the extent of DNA strand breakage in individual cells was investigated using the comet assay. Strain KFRI342 was identified as Lactobacillus acidophilus by 16S rRNA sequence analysis, showed protection against tumour initiation and imparted immunostimulation as well as protection against DNA damage.
Strain KFRI342, which showed probiotic characteristics reducing cancer cell growth, could be a suitable starter culture for yogurt fermentation because of its strong acid production and high acid tolerance.
This is the first report to describe a bacterium, isolated from kimchi, Lact. acidophilus KFRI342 which has the probiotic characteristics and the acid tolerance needed for its use as a starter culture in yogurt fermentation.
Lactobacillus pentosus DSM 16366, a strain originally isolated from olive fermentation, was used as a starter culture for "Azeiteira" the preparation of Spanish style green olives. Inoculum was added to the fermentors as a freezedried starter culture or as a culture in the nutritive media. Lactic acid fermentation induction produced a more rapid acidification of brines and reduced the survival period of Enterobacteriaceae compared with the uninoculated process. The best results were obtained using the nutritive media as a culture carrier rather than the freeze-dried starter.
En este trabajo se empleo el inóculo Lactobacillus pentosus DSM 16366 liofilizado y en caldo nutritivo para preparación de aceitunas "Azeiteira" tipo verde, estilo sevillano. En las salmueras inoculadas se observó una acidificación más rápida y reducción del periodo de supervivencia de las Enterobacteriaceae , especialmente cuando se aplicó el inóculo en caldo nutritivo.
The microflora of naturally fermented green olives produced in Western Algeria was studied over 15, 60 and 90 day fermentation periods. Different microorganisms (aerobic bacteria, conforms, staphylococci, lactic acid bacteria, lactobacilli, enterococci, yeasts, psychrotrophs and lipolytic bacteria) were recorded at 15 and 60 days of fermentation. After 90 days (pH 4.40) of fermentation, the lactic acid bacteria population became dominant and persisted together with yeasts throughout the fermentation period. The lactic acid bacteria isolated (343 isolates) were identified as L. casei, L. rhamnosus, L. paracasei, L. plantarum, L. lactis subsp. lactis, E. faecalis, E. faecium and E. durans. The dominant species was L. plantarum. Yeasts were isolated from all samples (32 isolates) and were identified as Saccharomyces cerevislae or Candida parapsilosis. Also, in this study we reported that brine solutions obtained at the end of olive fermentation were able to stimulate the growth of several L. plantarum strains.
'Galega' is the main Portuguese olive variety providing the greatest percentage of table olive production from homemade and industrial methods. In this work a better understanding about the fermentation involved in both methods is intended. Yeasts and lactic acid bacteria (LAB) constitute the microflora acting in olive fermentation, being Pichia membranaefaciens the dominant yeast specie present throughout the process. LAB develop their activity mainly along the second fermentation stage where Lactobacillus plantarum and Lactobacillus pentosus were isolated and identified, as well as Leuconostoc mesenteroides and Pediococcus pentosaceus. Results of a chemical analysis have shown the effectiveness of both homemade and industrial fermentation methods. Nevertheless, the chemical composition of the brines from homemade samples was more similar than those from the industrial ones. Remarkable differences were found in the phenolic compounds profile mainly on the final fermentation stage. The amount of volatile compounds has enhanced on the same phase in both methods and some differences were found between them. Sensorial analysis has shown the best results obtained through the homemade method.
In this study, we succeeded in differentiating Lactobacillus plantarum, Lactobacillus pentosus, andLactobacillus paraplantarum by means ofrecA gene sequence comparison. Short homologous regions of about 360 bp were amplified by PCR with degenerate consensus primers,
sequenced, and analyzed, and 322 bp were considered for the inference of phylogenetic trees. Phylograms, obtained by parsimony,
maximum likelihood, and analysis of data matrices with the neighbor-joining model, were coherent and clearly separated the
three species. The validity of the recA gene and RecA protein as phylogenetic markers is discussed. Based on the same sequences, species-specific primers were designed,
and a multiplex PCR protocol for the simultaneous distinction of these bacteria was optimized. The sizes of the amplicons
were 318 bp for L. plantarum, 218 bp for L. pentosus, and 107 bp for L. paraplantarum. This strategy permitted the unambiguous identification of strains belonging to L. plantarum, L. pentosus, and L. paraplantarum in a single reaction, indicating its applicability to the speciation of isolates of the L. plantarum group.
Probiotic cultures are increasingly being added to foods in order to develop products with health-promoting properties. Although the literature is abundant on the beneficial effects of bifidobacteria and Lactobacillus acidophilus on health, little information is available on the challenges industry faces in adding these probiotic cultures to food products. The aim of this article is to examine seven issues that should be addressed when developing functional foods: 1) type or form of probiotic that should be used; 2) addition level required to have a beneficial effect; 3) toxicity; 4) effect of the processing steps on viability; 5) determination, in the product, of the cell populations added; 6) stability during storage; 7) changes in sensory properties of the foods.
With the aim of developing new functional foods, a traditional product, the table olive, was used as a vehicle for incorporating
probiotic bacterial species. Survival on table olives of Lactobacillus rhamnosus (three strains), Lactobacillus paracasei (two strains), Bifidobacterium bifidum (one strain), and Bifidobacterium longum (one strain) at room temperature was investigated. The results obtained using a selected olive sample demonstrated that bifidobacteria
and one strain of L. rhamnosus (Lactobacillus GG) showed a good survival rate, with a recovery of about 106 CFU g−1 after 30 days. The Lactobacillus GG population remained unvaried until the end of the experiment, while a slight decline (to about 105 CFU g−1) was observed for bifidobacteria. High viability, with more than 107 CFU g−1, was observed throughout the 3-month experiment for L. paracasei IMPC2.1. This strain, selected for its potential probiotic characteristics and for its lengthy survival on olives, was used
to validate table olives as a carrier for transporting bacterial cells into the human gastrointestinal tract. L. paracasei IMPC2.1 was recovered from fecal samples in four out of five volunteers fed 10 to 15 olives per day carrying about 109 to 1010 viable cells for 10 days.
The ability of potentially probiotic strains of Lactobacillus plantarum and Lactobacillus paracasei to survive on artichokes for at least 90 days was shown. The anchorage of bacterial strains to artichokes improved their
survival in simulated gastrointestinal digestion. L. paracasei IMPC2.1 was further used in an artichoke human feeding study involving four volunteers, and it was shown that the organism
could be recovered from stools.
Principal component analysis has often been dealt with in textbooks as a special case of factor analysis, and this tendency has been continued by many computer packages which treat PCA as one option in a program for factor analysis—see Appendix A2. This view is misguided since PCA and factor analysis, as usually defined, are really quite distinct techniques. The confusion may have arisen, in part, because of Hotelling’s (1933) original paper, in which principal components were introduced in the context of providing a small number of ‘more fundamental’ variables which determine the values of the p original variables. This is very much in the spirit of the factor model introduced in Section 7.1, although Girschick (1936) indicates that there were soon criticisms of Hotelling’s method of PCs, as being inappropriate for factor analysis. Further confusion results from the fact that practitioners of ‘factor analysis’ do not always have the same definition of the technique (see Jackson, 1981). The definition adopted in this chapter is, however, fairly standard.
Inoculation of untreated green olives of the Conservolea cultivar ( Olea europea media rotunda ) with a commercial strain of Lactobacillus pentosus with/without glucose supplement was studied. Despite an initial loss in viability of 0.5 log cycles on average, due to lack of adaptation of the starter to the saline environment of the brine, cultures grew well and initiated an accelerated fermentation process. Inoculation reduced the survival period of Enterobacteriaceae , and consequently potential spoilage, and caused a quicker acidification of brines and decrease in pH compared with control uninoculated processes. The diffusion of phenolic compounds was slow, hindered by the epidermis of the fruits, and had no effect on the growth of the starter. HPLC analysis revealed that lactic and acetic acids were among the end‐products during the fermentation of green olives. Citric, tartaric and malic acids were also detected but at much lower concentrations. Results obtained from this work can be applied directly to industry for the effective use of starter cultures on natural fermentation processes of green olives without prior lye treatment.
© 2003 Society of Chemical Industry
Aims: To investigate aggregation and adhesiveness of Lactobacillus acidophilus M92 to porcine ileal epithelial cells in vitro, and the influence of cell surface proteins on autoaggregation and adhesiveness of this strain.
Methods and Results:Lactobacillus acidophilus M92 exhibits a strong autoaggregating phenotype and manifests a high degree of hydrophobicity determined by microbial adhesion to xylene. Aggregation and hydrophobicity were abolished upon exposure of the cells to pronase and pepsin. Sodium dodecyl sulphate polyacrylamide gel electrophoresis of cell surface proteins revealed the presence of potential surface layer (S-layer) proteins, approximated at 45 kDa, in L. acidophilus M92. The relationship between autoaggregation and adhesiveness to intestinal tissue was investigated by observing the adhesiveness of L. acidophilus M92 to porcine ileal epithelial cells. Removal of the S-layer proteins by extraction with 5 mol l−1 LiCl reduced autoaggregation and in vitro adhesion of this strain.
Conclusions: These results demonstrate that there is relationship between autoaggregation and adhesiveness ability of L. acidophilus M92, mediated by proteinaceous components on the cell surface.
Significance and Impact of the Study: This investigation has shown that L. acidophilus M92 has the ability to establish in the human gastrointestinal tract, which is an important determinant in the choice of probiotic strains.
PCR amplification of repetitive bacterial DNA elements fingerprinting using the (GTG)5 primer ((GTG)5-PCR) was proven to be useful for differentiation of a wide range of lactobacilli (i.e. 26 different (sub)species) at the species, subspecies and potentially up to the strain level. Using this rapid and reproducible genotypic technique, new Lactobacillus isolates recovered from different types of fermented dry sausage could be reliable identified at the (sub)species level. In conclusion, (GTG)5-PCR was found to be a promising genotypic tool for rapid and reliable speciation and typing of lactobacilli and other lactic acid bacteria important in food-fermentation industries.
The survival of Bifidobacterium bifidum BBI and Lactobacillus acidophilus LAI in reduced-fat (liquid) and full-fat (set) yoghurts produced with two commercial lactic starter cultures (SID and SISD) was investigated. The viability of the probiotic bacteria was also assayed in milk acidified with lactic acid at different pH values. Samples were stored at 5°C for up to 4 weeks. There was a great variability in the survival ability of the probiotic cultures in the two yoghurt types. L. acidophilus LAI demonstrated, in general, a lower resistance to the yoghurt environment than B. bifidum BBI. On the other hand, the full-fat yoghurt was a more inhibitory medium than the reduced-fat one, especially for B. bifidum BBI. Regarding the lactic starters used, the results showed that the culture SISD was clearly more inhibitory for both probiotic organisms than the culture SID. The loss of cell viability in yoghurt samples was different (higher in some cases and lower in others) from that due to lactic acid only. In general, pH values of 4.5 or lower jeopardised the cell viability of the probiotic organisms in yoghurt stored at 5°C. This work shows the importance of selecting a suitable combination of probiotic strains and starter cultures when different yoghurt types are formulated.
The definition for probiotics has gradually changed with increasing understanding of the mechanisms by which they influence human health. Health effects related to changes in the intestinal microflora also accompany or are related to adhesion and immune system effects, competitive exclusion or metabolic and nutritional effects, with an increasing array of other potential modes of action. Most clinically documented and validated health effects have been studied using either fermented milks containing viable cultures or viable pure cultures. Specific targets for the future include controlled studies comparing foods containing viable strains to those containing non-viable strains and to assess the combined effects of multiple probiotics.
A number of cell surface properties were compared in 15 pairs of lactococcal strains in order to gain an understanding of cell surface diversity and the relationship between the acquisition of the phage-resistance phenotype and alteration of cell surface properties. Each pair comprised a parent strain and a derivative resistant to a phage (ØR) or a number of phages. Three cell surface hydrophobicity patterns were found: (1) three parent strains were more hydrophobic than their ØR derivatives; (2) five ØR derivatives were more hydrophobic than their parent strains; (3) there were no differences for seven strain pairs. Loosely associated cell surface material was removed without cell lysis, and concentration differences between 28 strains of 40-, 23- and 11-fold were found for the extracted protein, hexose and rhamnose, respectively. These three surface components were extracted in higher concentrations from the ØR derivative for seven strain pairs and from the parent strain for three strain pairs, and no differences were observed for four strain pairs. Intracellular and extracellular lipoteichoic acid concentrations varied in four of six strain pairs studied. The extracted protein profiles determined on polyacrylamide gels and by Superose 12 chromatography and the compositions of the extracted polysaccharide were different between most of the strain pairs. In addition, the surface properties, particularly cell hydrophobicity, varied according to growth conditions for some strains.
Foods are carriers for the delivery of probiotics to the human body. In addition, foods help to buffer the probiotic through the gastrointestinal tract, regulate their colonization and contain other functional ingredients, such as bioactive components, which may interact with probiotics to alter their functionality and efficacy. The growth and survival of probiotics during gastric transit is affected by the physico-chemical properties of food carriers. Gastric acid, juices and bile tolerance, adherence to gastrointestinal epithelium and the acid production of probiotics are also affected by the food ingredients used in probiotic delivery. Same probiotic strains could vary in functional and technological properties in the presence of different food ingredients. Prebiotic food ingredients encourage the growth of probiotic bacteria. The appropriate combination of prebiotics and probiotics manifest higher potential for a synergistic effect. Originally, probiotic delivery was consistently associated with foods, particularly dairy foods. But nowadays, there is an increasing trend toward using probiotics in different food systems despite its original sources and even as nutraceuticals, such as in capsules. This changing trend in delivering probiotics may lead to a reduction in functional efficacy due to the exclusion of the potential synergistic effect of the food. Thus, selection of suitable food systems to deliver probiotics is a vital factor that should be considered in developing functional probiotic foods. This review focuses on information related to the effect of processed food products on functional efficacy of probiotics.
Lactic acid bacteria (LAB) have long been used as starter cultures in the production of fermented dry sausages and other meat-derived commodities. These cultures are generally designed to meet food safety, shelf-life, technological effectiveness and economic feasibility criteria. Besides all these traditional properties, novel starter cultures should take into account the risks posed by the formation of biogenic amines in food, and the development and spreading of bacterial resistance to antibiotics. Further, 'functional starters' could protect consumers from harmful bacteria either by a rapid acidification or by the production of antimicrobials (bacteriocins). Specially-selected cultures may also provide probiotic benefits, and, if properly modified, they may even be endorsed with nutraceutical traits. The present review discusses the technological and new selection criteria that should be taken into account when selecting LAB starter cultures for the production of fermented dry sausages.
A total of 147 lactic acid bacteria was isolated from two types of naturally fermented dry sausages at four different stages of the ripening process studied in order to select the most suitable strains according to their technological characteristics including probiotic properties and antimicrobial activity against food-borne pathogens. Identification of the isolates revealed that 90% were lactobacilli, 4% enterococci, 3% Pediococcus sp. and sporadic isolates of Weissella viridescens, Leuconostoc pseudomesenteroides, and Leuconostoc sp. The isolated strains of Lactobacillus sakei (49 isolates), Lactobacillus curvatus (24 isolates) and Lactobacillus plantarum (7 isolates) were further characterized. All strains could grow at 15 °C, whereas the majority of the strains was able to grow in the presence of 6.5% NaCl and on acetate agar. The enzymatic potential of the strains was evaluated using the API ZYM system. During in vitro investigations all strains exhibited high leucine and valine aminopeptidase activities and moderate acid phosphatase and phosphohydrolase activities. Some strains showed very weak lipolytic activity. The enzyme profiling is an important factor for selection of strains as starter cultures. A large majority of the strains tolerated 0.1% bile salts whereas 58% of Lactobacillus curvatus strains and all Lactobacillus plantarum strains were resistant to 0.3% bile salts. All Lactobacillus sakei strains and the majority of Lactobacillus curvatus and Lactobacillus plantarum strains exhibited an anti-listerial activity against three Listeria monocytogenes strains. A percentage of 75, 50 and 29% of Lactobacillus sakei, L. curvatus and L. plantarum strains, respectively, could inhibit two Staphylococcus aureus strains. The contribution of the selected strains to a possible inhibition of Listeria monocytogenes and S. aureus in situ on fermented meats would be of considerable interest to enhance the hygienic quality of these products.
This study reports the dynamics of microbial populations adhering on the surface of debittered green olives cv. Bella di Cerignola in fermentation sets inoculated with the probiotic strain Lactobacillus paracasei IMPC2.1 in different brining conditions (4% and 8% (w/v) NaCl) at room temperature and 4 degrees C. The probiotic strain successfully colonized the olive surface dominating the natural LAB population and decreasing the pH of brines to <or=5.0 after 30 days until the end of fermentation. The dynamics of microbial populations associated with olive surface and belonging to the different groups indicated that inoculated olives held at room temperature did not host Enterobacteriaceae at the end of fermentation. Yeast populations were present in a low number (<or=log(10) 5.7 CFU/g) throughout the process. A considerable genetic diversity of LAB species colonizing the olive surface was found mainly in inoculated set brined in 8% NaCl, as indicated by the Shannon diversity index calculated for each set. Generally, strains of Lactobacillus coryniformis, L. paracasei, L. plantarum, L. pentosus, L. rhamnosus, L. brevis, L. mali, L. vaccinostercus, L.casei, Leuconostoc mesenteroides, Leuc. pseudomesenteroides, Lactococcus lactis, Weissella paramesenteroides, W. cibaria, Enterococcus casseliflavus group and E. italicus were identified during the whole process. In particular, L. pentosus was the most frequently isolated species and it showed a high strain diversity throughout fermentation in all processes except for the one held at 4 degrees C. Also a notable incidence of Leuc. mesenteroides on olives was highlighted in this study during all fermentation. Results indicated that the human strain L. paracasei IMPC2.1 can be considered an example of a strain used in the dual role of starter and probiotic culture which allowed the control of fermentation processes and the realization of a final probiotic product with functional appeal.
An agar plate assay was developed to detect bile salt hydrolase activity in lactobacilli. On Lactobacillus-selective MRS or Rogosa SL medium supplemented with taurodeoxycholic, taurocholic, or taurochenodeoxycholic acids, bile salt hydrolysis was manifested at two intensities: (i) the formation of precipitate halos around colonies or (ii) the formation of opaque granular white colonies. Sixty-six lactobacilli were tested for bile salt hydrolase activity by both the plate assay and a sensitive radiochemical assay. No false-positive or false-negative results were detected by the plate assay. Based on results of experiments with Eubacterium lentum and Bacteroides species, the plate assay was dependent on two factors: (i) the presence of bile salt hydrolytic activity and (ii) the ability of the organism to sufficiently acidify the medium to protonate free bile acids. The availability of a differential medium for determination of bile salt hydrolase activity will provide a rapid method for determining shifts in a specific functional activity of intestinal Lactobacillus species and provide a rapid screening capability for identifying bile salt hydrolase-deficient mutants. The latter application should allow bile salt hydrolase activity to be used as a marker enzyme in genetic experiments.
Cultures of lactobacilli identified as Lactobacillus acidophilus from the intestinal contents of young calves varied in their ability to grow in broth containing .3% oxgall compared with control broth. Frozen concentrated cultures were prepared from a strain exhibiting low tolerance to bile and from a strain exhibiting high tolerance to bile. Plate counts were comparable from the concentrated cultures before and after frozen storage on lactobacilli MRS agar with and without .15% oxgall. In a feeding trial involving newborn dairy calves supplementation of the diet with the more bile resistant strain of Lactobacillus acidophilus caused greater increases of numbers of facultative lactobabilli in the upper small intestines than did the strain exhibiting lower resistance to bile. It was not possible to determine whether the lactobacilli would prevent intestinal infections in the calves challenged with enteropathogenic Escherichia coli. This portion of the study failed as the challenge with Escherichia coli did not cause infections even in control animals.
To identify bacterial traits related to adhesion ability in human bifidobacteria, 13 strains of Bifidobacterium longum isolated from human gastric juice and intestine were studied. Strains were tested for their capability to adhere to Caco-2 cells and classified as adhesive (Adh+) or non-adhesive (Adh-). Adh+ and Adh- strains were then investigated for their autoaggregation ability and surface hydrophobicity. Comparing the properties of Adh+ and Adh-, we observed that strains were able to adhere to cell monolayers if they autoaggregate and manifest a good degree of hydrophobicity as determined by microbial adhesion to hydrocarbons. These two traits could be used for preliminary screening to identify potentially adherent isolates.
The study was carried out to evaluate the use of randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) as a method for the identification of lactobacilli isolated from meat products.
RAPD-PCR with primers M13 and D8635 was applied to the identification and intraspecific differentiation of 53 lactobacilli isolates originating from traditional fermented sausages and artisanal meat plants of the Veneto region (Italy). Most of the isolates were assigned to the species Lactobacillus sakei and Lact. curvatus; differentiation of groups of strains within the species was also possible.
RAPD-PCR could be applied to the identification of lactobacilli species most commonly found in meat products.
The method, which is easy and rapid to perform, could be useful for the study of the lactobacilli populations present in fermented sausages, and could help in the selection of candidate strains to use as starter cultures in meat fermentation.
Inoculation at alkaline pH (above 9) of lye-treated green olives with starter cultures of Lactobacillus pentosus CECT 5138 was studied. Despite an initial loss of viability in the order of 1-2 log cycles on average, depending mainly on time of application, cultures grew and initiated an accelerated fermentation process. Inoculation reduced the population of Enterobacteriaceae, and thereby potential spoilage, and produced a quicker acidification of brines and decrease of pH, when compared with control uninoculated batches. Results obtained throughout three consecutive seasons demonstrated that utilization at high pH of starter cultures of lactobacilli is feasible, provided that the inoculum size takes into account the initial low survival.
The overall growth kinetics of four potentially probiotic strains (Lactobacillus fermentum, Lact. reuteri, Lact. acidophilus and Lact. plantarum) cultured in malt, barley and wheat media were investigated. The objectives were to identify the main factors influencing the growth and metabolic activity of each strain in association with the cereal substrate.
All fermentations were performed without pH control. A logistic-type equation, which included a growth inhibition term, was used to describe the experimental data. In the malt medium, all strains attained high maximum cell populations (8.10-10.11 log10 cfu ml(-1), depending on the strain), probably due to the availability of maltose, sucrose, glucose, fructose (approx. 15 g l(-1) total fermentable sugars) and free amino nitrogen (approx. 80 mg l(-1)). The consumption of sugars during the exponential phase (10-12 h) resulted in the accumulation of lactic acid (1.06-1.99 g l(-1)) and acetic acid (0.29-0.59 g l(-1)), which progressively decreased the pH of the medium. Each strain demonstrated a specific preference for one or more sugars. Since small amounts of sugars were consumed by the end of the exponential phase (17-43%), the decisive growth-limiting factor was probably the pH, which at that time ranged between 3.40 and 3.77 for all of the strains. Analysis of the metabolic products confirmed the heterofermentative or homofermentative nature of the strains used, except in the case of Lact. acidophilus which demonstrated a shift towards the heterofermentative pathway. All strains produced acetic acid during the exponential phase, which could be attributed to the presence of oxygen. Lactobacillus plantarum, Lact. reuteri and Lact. fermentum continued to consume the remaining sugars and accumulate metabolic products in the medium, probably due to energy requirements for cell viability, while Lact. acidophilus entered directly into the decline phase. In the barley and wheat media all strains, especially Lact. acidophilus and Lact. reuteri, attained lower maximum cell populations (7.20-9.43 log10 cfu ml(-1)) than in the malt medium. This could be attributed to the low sugar content (3-4 g l(-1) total fermentable sugar for each medium) and the low free amino nitrogen concentration (15.3-26.6 mg l(-1)). In all fermentations, the microbial growth ceased at pH values (3.73-4.88, depending on the strain) lower than those observed for malt fermentations, which suggests that substrate deficiency in sugars and free amino nitrogen contributed to growth limitation.
The malt medium supported the growth of all strains more than barley and wheat media due to its chemical composition, while Lact. plantarum and Lact. fermentum appeared to be less fastidious and more resistant to acidic conditions than Lact. acidophilus and Lact. reuteri.
Cereals are suitable substrates for the growth of potentially probiotic lactic acid bacteria.
The study of two human strains of Lactobacillus to be used as probiotics in the gastrointestinal tract.
The Lactobacillus acidophilus UO 001 and Lact. gasseri UO 002, were resistant to the gastrointestinal conditions (pH 2 and 3, presence of pepsin, pancreatin or bile salts), the resistance was enhanced in the presence of skimmed milk. Additionally, adhered to Caco-2 cells through glycoproteins in Lact. gasseri and carbohydrates in the case of Lact. acidophilus. These strains are able to inhibit the growth of certain enteropathogens: Salmonella, Listeria and Campylobacter without interfering with the normal microbiota of the gastrointestinal tract, as stated by using the mixed culture and the spot agar test. Finally, strongly adherent Lact. gasseri were found to inhibit the attachment of Escherichia coli O111 to intestinal Caco-2 cells under the condition of exclusion.
These results indicate that the two strains of Lactobacillus from human origin present important properties for survival in, and colonization of, the gastrointestinal tract, that give them potential probiotic.
Two strains of Lactobacillus isolated from human vagina of healthy premenopausal women could be promising candidates to be used in the preparation of probiotic products and for their use as health-promoting bacteria.
This study investigated the phenotypic and genotypic characteristics of lactic acid bacteria in naturally fermented green olives, collected from different areas of Sicily. Both classical biochemical tests and PCR/Restriction Fragments Length Polymorphism (RFLP) of 16S rDNA were used to characterize the isolates. The identity of the isolates was obtained by the partial sequencing analysis of the 16S rDNA. The BioMerieux software assigned the 13 heterofermentative strains to the Lactobacillus brevis species; 24 homofermentative strains were classified as Lactobacillus casei and the remaining 11 homofermentative lactobacilli were identified as Lactobacillus plantarum. The rapid ID 32 STREP test identified coccal-shaped strains as Enterococcus faecium species. The PCR/RFLP analysis showed a remarkable bacterial heterogeneity within the isolates. The 16S rDNA partial sequencing did not confirm biochemical identification, revealing a strong dominance of isolates belonging to the L. casei species. It is noteworthy that this species has never been reported as dominant species in fermented vegetables.A combination of molecular and biochemical analysis allowed the identification of species involved in natural food fermentations.
The changes that take place during the shelf life of "seasoned" olives (packing conditions: 4% NaCl, 0.1%citric acid, and 0.0175% sorbate) using fresh (FF) and stored (SF) cracked fruits were studied. Texture, L, b, NaCl, and pH experienced slight changes. Values of a and titratable and combined acidity increased following a first-order kinetic with higher constants for FF. Glucose was completely exhausted, and mannitol showed only a slight decline. Hydroxytyrosol and tyrosol contents in brines increased rapidly from the acidic hydrolysis of oleuropein, hydroxytyrosol-4-beta -d-glucoside, and salidroside, the concentrations of which decreased. Sorbate content decreased with time and disappeared completely in SF. Yeasts grew rapidly in FF and were markedly inhibited in SF. There was a moderate growth of lactic acid bacteria in FF, whereas they grew markedly in SF during the first few days. Some of these changes limit the shelf life of the product.
Vegetarians may have subtle nutritional deficiencies which have been related to the occurrence of an unrecognized malabsorption syndrome. The excess phytate content in cereals, nuts, legumes and oilseeds which represent the mainstay of their food intake, seems to play a central role in the pathogenesis of this malabsorption syndrome as an inverse relationship has been shown to link the phytate content of the diet with the intestinal absorption of trace minerals and proteins. We postulate that manipulating the endogenous digestive microflora of subjects on a vegetarian diet through administering probiotic lactic bacteria would represent an innovative tool to counteract the occurrence of the malabsorption syndrome dependent on the high phytate content of their diet. Even though there are no data about the composition of endogenous digestive microflora in subjects on a vegetarian diet, we expect that probiotic lactobacilli can interact with or affect distinct yet interrelated components within the intestinal milieu, such as epithelial cells, enteric flora, and/or mucosal immune cells. This would ultimately translate into the correction of the unregulated mechanisms implicated in the altered intestinal absorption of trace metals and proteins commonly seen in vegetarians. Clinical experience with probiotic therapy of patients with inflammatory bowel disease fully agrees with this view. One additional point of interest is that probiotic lactobacilli, and other species of the endogenous digestive microflora as well, are an important source of the enzyme phytase which catalyses the release of phosphate from phytate and hydrolyses the complexes formed by phytate and metal ions or other cations, rendering them more soluble ultimately improving and facilitating their intestinal absorption. The regular intake of probiotic preparation, may represent a cheap and safe tool in order to convert a diet with a low potential for bioavailability of trace minerals and proteins, such as the vegetarian diet, into a diet with a high bioavailability potential. The benefit of such an approach would not be restricted to vegetarians.
Disposition of green table olives alkaline solutions (GTOS) remains a major task for the industry with serious environmental implications. The presence of high concentrations of polyphenols in olives also presents a problem for direct brining and successful fermentation step. In this study we evaluated the effect of ozone treated GTOS on the growth of Saccharomyces cerevisiae and Lactobacillus pentosus. GTOS were treated with ozone for 24 and 72 h. The treatment caused a rapid destruction of polyphenols but did not affect sugar concentration. S. cerevisiae grew in the original and treated liquids, although its maximum specific growth rate (mu(m)) and its population size increased as the ozone treatment was longer. L. pentosus was completely inhibited in the original and 24 h ozone treated GTOS, but grew in 72 h treated solutions. Co-culture with S. cerevisiae improved L. pentosus performance. Diluting the original GTOS with distilled water in several ratios, and adding MRS medium (50 g/L) to ensure nutrient availability, showed that a complete inhibition on L. pentosus did never occur; however, its mu(m) progressively increased, and the lag phase period (lambda) decreased linearly, with increasing dilutions levels. The inhibition effect was lower in 24 h ozone treated GTOS and disappeared completely in those treated for 72 h. Furthermore, treatment of GTOS with ozone always improved microbial growth.
The effect of inclusion of various C18 fatty acids with 0-2 double bonds in either cis or trans configuration on Lactobacillus rhamnosus GG survival was analysed in simulated gastric juice at pH 2.5. The incorporation of Tween 80 (1 g l-1) in the growth media enhanced subsequent survival of stationary-phase cultures up to 1000-fold following 90 min acid exposure compared with controls grown without Tween 80. There was a significant (P<0.05) increase in bacterial content of oleic acid [C18:1 (9c), up to 55-fold] after growth of bacteria in MRS supplemented with Tween 80. The inclusion of various C18 fatty acids in the growth media revealed that only oleic and vaccenic acids [C18:1 (11t)] had protective effects on the survival of Lb. rhamnosus GG when exposed to the acidic environment. Comparative analysis with other lactobacilli indicated that all strains exhibited increased survival when grown in the presence of Tween 80. Further work with a neomycin-resistant mutant with 48% of the F0F1-ATPase activity of the parent indicated that the Tween 80 effect was independent of the complex. The mechanisms behind the effect of fatty acid protection were investigated and proton permeability assays showed that cultures grown in the presence of Tween 80 had higher extracellular pH than controls. Furthermore, there was a significant reduction of oleic acid and a significant increase in stearic acid (C18:0) (P<0.05) content of bacterial cells following exposure of Tween 80-supplemented cultures to simulated gastric juice. Overall, the data suggest that probiotic lactobacilli can use an exogenous oleic acid source to increase their acid survival and the underlying mechanism most likely involves the ability of increased membrane oleic acid to be reduced by H+ to stearic acid.
Bacteriocins from lactic acid bacteria are ribosomally synthesized anti-microbial compounds that may find applications from food preservation to healthcare. Food preservation, using in situ bacteriocin production is the most obvious and simple. Frequently, the best conditions for bacteriocin production are those prevailing during food fermentation but a better understanding of the relationship between growth and bacteriocin production is required. In this work, we evaluate the effects of some environmental factors on bacteriocin production by Lactobacillus plantarum 17.2b. A first screening design showed that NaCl, temperature, pH and the type and concentration of carbon and nitrogen sources were most influents. A moderate stimulatory effect of ethanol and oleuropein was also registered. Two consecutive central composite designs were used to examine the effect of the selected variables and to compute its optimum. The evolution of changes produced by the alterations in environmental factors was further examined trough perturbation plots. Bacteriocin production by L. plantarum 17.2b was very sensitive to environmental conditions and uncoupled from growth. Maximum production required suboptimal growth temperatures, pH values above growth's optimum and no NaCl. A preliminary approach to kinetics showed that bacteriocin production by this strain apparently follows mixed metabolite kinetics.
The water used to reduce the excess NaOH after the immersion of green olives in lye becomes a heavily polluted, alkaline wastewater (AW) once it has come into contact with the fruits. Its treatment with ozonated air for 72 h (TAW) destroyed all polyphenols in the solution. A comparison of the microbial, physicochemical, and organoleptic characteristics of olives processed in the traditional way (W) and those reusing AW or TAW was made. The reuse of TAW or diluted TAW (TAW + W) as fermentation brines led to a shorter lag phase, higher maximum specific growth of lactobacillus, and higher lactic acid accumulation (in TAW) than the traditional process; differences among other physicochemical characteristics were not relevant, except that reused brines (AW) always had higher polyphenol contents. The organoleptic panel test did not detect significant differences among treatments in acidic taste, firmness, pit detachment, or olive color. Overall quality was fairly similar for olives from the traditional process and those from the reused TAW. Direct (or diluted) reuse of AW was also possible but produced a more bitter tasting olive.
The effect of controlled fermentation processes on the microbial association and biochemical profile of cv. Conservolea naturally black olives processed by the traditional anaerobic method was studied. The different treatments included (a) inoculation with a commercial starter culture of Lactobacillus pentosus, (b) inoculation with a strain of Lactobacillus plantarum isolated from a fermented cassava product and (c) uninoculated spontaneous process. Microbial growth, pH, titratable acidity, organic acids and volatile compounds were monitored throughout the fermentation. The initial microbiota consisted of Gram-negative bacteria, lactic acid bacteria and yeasts. Inhibition of Gram-negative bacteria was evident in all processes. Both starter cultures were effective in establishing an accelerated fermentation process and reduced the survival period of Gram-negative bacteria by 5 days compared with the spontaneous process, minimizing thus the likelihood of spoilage. Higher acidification of the brines was observed in inoculated processes without any significant difference between the two selected starter cultures (113.5 and 117.6mM for L. plantarum and L. pentosus, respectively). L. pentosus was also determined as the major species present during the whole process of spontaneous olive fermentation. It is characteristic that lactic acid fermentation was also initiated rapidly in the spontaneous process, as the conditions of fermentation, mainly the low salt level (6%, w/v) favored the dominance of lactic acid bacteria over yeasts. Lactic, acetic and propionic were the organic acids detected by HPLC in considerable amounts, whereas citric and malic acids were also present at low levels and degraded completely during the processes. Ethanol, methanol, acetaldehyde, ethyl acetate were the major volatile compounds identified by GC. Their concentrations varied among the different treatments, reflecting varying degrees of microbial activity in the brines. The results obtained from this study could help the Greek table olive industry to improve the existing processing schemes in order to increase product consistency and quality expanding the international market for naturally black olives.
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