Identification and evaluation of the probiotic potential of Lactobacillus paraplantarum FT259, a bacteriocinogenic strain isolated from Brazilian semi-hard artisanal cheese

Susceptibility of Foodborne Pathogens to Milk-Origin Lactic Acid Bacteria Supernatants: A Comprehensive Meta-Regression Study

This systematic review and meta-analysis compile the in vitro antimicrobial efficacy of lactic acid bacteria (LAB) supernatants against three common pathogenic bacteria found in dairy products: Salmonella spp., L. monocytogenes, and Staphylococcus aureus. After screening and analysis of full papers, identified by searches in PubMed, Scopus, and Web of Science databases, thirty-nine studies were regarded as relevant, and a total of 510 observations were recorded. The effects of moderators on inhibition diameters were assessed by adjusting three pathogen-specific meta-regression models. Results showed that, in general terms, strains from the Enterococcus genus displayed the highest inhibition values against L. monocytogenes (15.90 ± 2.138 mm), whereas Lacticaseibacillus strains were more effective against S. aureus (11.89 ± 0.573 mm). The well diffusion test outperformed the spot and disk diffusion tests, and more acidic LAB supernatants resulted in higher measurements of inhibition diameters (p < 0.001). Meta-regression models incorporating LAB genus, pathogen concentration, and incubation time explained 33.8%, 52.3%, and 19.8% of the total variance in inhibition diameters for L. monocytogenes, Salmonella spp., and S. aureus, respectively. None of the three models showed evidence of publication bias. This meta-regression study demonstrated that LAB strains present in dairy products possess a variable capacity to inhibit any of the three foodborne pathogens. Overall, L. monocytogenes was found to exhibit greater susceptibility than Salmonella spp. and S. aureus; thus, the antilisterial capacity of the selected LAB strains could be exploited in developing biocontrol strategies for cheese-making.

Bacteriocinogenic anti-listerial properties and safety assessment of Enterococcus faecium and Lactococcus garvieae strains isolated from Brazilian artisanal cheesemaking environment

AIMS

This study aimed to prospect and isolate lactic acid bacteria (LAB) from an artisanal cheese production environment, to assess their safety, and to explore their bacteriocinogenic potential against Listeria monocytogenes.

METHODS AND RESULTS

Samples were collected from surfaces of an artisanal-cheese production facility and after rep-PCR and 16S rRNA sequencing analysis, selected strains were identified as to be belonging to Lactococcus garvieae (1 strain) and Enterococcus faecium (14 isolates, grouped into three clusters) associated with different environments (worktables, cheese mold, ripening wooden shelves). All of them presented bacteriocinogenic potential against L. monocytogenes ATCC 7644 and were confirmed as safe (γ-hemolytic, not presenting antibiotic resistance, no mucus degradation properties, and no proteolytic or gelatinase enzyme activity). Additionally, cell growth, acidification and bacteriocins production kinetics, bacteriocin stability in relation to different temperatures, pH, and chemicals were evaluated. According to performed PCR analysis all studied strains generated positive evidence for the presence of entA and entP genes (for production of enterocins A and enterocins P, respectively). However, pediocin PA-1 associated gene was recorded only in DNA obtained from E. faecium ST02JL and Lc. garvieae ST04JL.

CONCLUSIONS

It is worth considering the application of these safe LAB or their bacteriocins in situ as an alternative means of controlling L. monocytogenes in cheese production environments, either alone or in combination with other antimicrobials.

Milk and Its Derivatives as Sources of Components and Microorganisms with Health-Promoting Properties: Probiotics and Bioactive Peptides

Milk is a source of many valuable nutrients, including minerals, vitamins and proteins, with an important role in adult health. Milk and dairy products naturally containing or with added probiotics have healthy functional food properties. Indeed, probiotic microorganisms, which beneficially affect the host by improving the intestinal microbial balance, are recognized to affect the immune response and other important biological functions. In addition to macronutrients and micronutrients, biologically active peptides (BPAs) have been identified within the amino acid sequences of native milk proteins; hydrolytic reactions, such as those catalyzed by digestive enzymes, result in their release. BPAs directly influence numerous biological pathways evoking behavioral, gastrointestinal, hormonal, immunological, neurological, and nutritional responses. The addition of BPAs to food products or application in drug development could improve consumer health and provide therapeutic strategies for the treatment or prevention of diseases. Herein, we review the scientific literature on probiotics, BPAs in milk and dairy products, with special attention to milk from minor species (buffalo, sheep, camel, yak, donkey, etc.); safety assessment will be also taken into consideration. Finally, recent advances in foodomics to unveil the probiotic role in human health and discover novel active peptide sequences will also be provided.

Novel Dietary Approach with Probiotics, Prebiotics, and Synbiotics to Mitigate Antimicrobial Resistance and Subsequent Out Marketplace of Antimicrobial Agents: A Review

Antimicrobial resistance (AMR) is a significant public health concern worldwide. The continuous use and misuse of antimicrobial agents have led to the emergence and spread of resistant strains of bacteria, which can cause severe infections that are difficult to treat. One of the reasons for the constant development of new antimicrobial agents is the need to overcome the resistance that has developed against existing drugs. However, this approach is not sustainable in the long term, as bacteria can quickly develop resistance to new drugs as well. Additionally, the development of new drugs is costly and time-consuming, and there is no guarantee that new drugs will be effective or safe. An alternative approach to combat AMR is to focus on improving the body's natural defenses against infections by using probiotics, prebiotics, and synbiotics, which are helpful to restore and maintain a healthy balance of bacteria in the body. Probiotics are live microorganisms that can be consumed as food or supplements to promote gut health and improve the body's natural defenses against infections. Prebiotics are non-digestible fibers that stimulate the growth of beneficial bacteria in the gut, while synbiotics are a combination of probiotics and prebiotics that work together to improve gut health. By promoting a healthy balance of bacteria in the body, these can help to reduce the risk of infections and the need for antimicrobial agents. Additionally, these approaches are generally safe and well tolerated, and they do not contribute to the development of AMR. In conclusion, the continuous development of new antimicrobial agents is not a sustainable approach to combat AMR. Instead, alternative approaches such as probiotics, prebiotics, and synbiotics should be considered as they can help to promote a healthy balance of bacteria in the body and reduce the need for antibiotics.

Probiotic Properties, Safety Assessment, and Aroma-Generating Attributes of Some Lactic Acid Bacteria Isolated from Iranian Traditional Cheese

Artisanal cheeses are known as the source of beneficial lactic acid bacteria (LAB). Therefore, this study aimed to isolate and characterize LAB with different proteolytic activities from Iranian artisanal white cheeses. The isolates were classified into low, medium, and high proteolytic activity clusters via K-means clustering and identified as Lactiplantibacillus (Lpb.) pentosus L11, Lpb. plantarum L33, and Enterococcus faecium L13, respectively. Some safety tests (such as resistance to antibiotics, hemolytic activity, and biogenic amine production), probiotic properties (including cell surface hydrophobicity, auto/co-aggregation, and antibacterial activity), and production of volatile compounds were evaluated. These were non-hemolytic and non-biogenic amine producers, and showed no irregular antibiotic resistance. Lpb. plantarum L33 had the highest hydrophobicity (30.55%) and auto-aggregation (49.56%), and the highest co-aggregation was observed for Lpb. pentosus L11 with Staphylococcus aureus (61.51%). The isolates also showed a remarkable antibacterial effect against pathogenic bacteria. Moreover, Lpb. pentosus L11 and Lpb. plantarum L33 with low and medium proteolytic activity produced a wider range of volatile compounds in milk compared to the strain with a high proteolytic effect. The results showed that a probiotic strain with low or medium proteolytic activity could improve the flavor characteristics of fermented milk.

Study of Lactic Acid Bacteria Biodiversity in Fermented Cobrançosa Table Olives to Determine Their Probiotic Potential

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.

Novel Probiotic Lactic Acid Bacteria Were Identified from Healthy Infant Feces and Exhibited Anti-Inflammatory Capacities

The current study aims to evaluate the probiotic potential of lactic acid bacteria isolated from infant feces, and select candidates to be used as potential antioxidants for the treatment of oxidative stress-related diseases; To meet the criteria for probiotic attributes, the isolates were subjected to various in vitro tests and 16S rRNA genotypic characterization. Besides, anti-inflammatory and anti-oxidative effects of selected isolates were separately assessed by real-time quantitative PCR and Western blot; The selected strains belonged to Lactobacillus gasseri, Lactiplantibacillus plantarum and Lacticaseibacillus rhamnosus. Notably, three selected strains (L. gasseri FWJL-4, L. plantarum Fjias-5 and L. rhamnosus FSJ-13) particularly L. gasseri FWJL-4 significantly down-regulated mRNA expression levels of tumor necrosis factor α (TNFα), Interleukin-6 (IL-6) and IL-1β. Most importantly, three strains-treated RAW 264.7 murine macrophages displayed enhanced activities of antioxidant enzymes and reduced H₂O₂ production, which were associated with the enhanced expression levels of nuclear factor-erythroid 2 related factor 2 and heme oxygenase-1; Three selected strains, particularly L. gasseri FWJL-4, are good candidates that merit additional in vivo investigation for the validation and application of their health-promoting effects.

RNA-seq analysis of green tea polyphenols modulation of differently expressed genes in Enterococcus faecalis under low pH

Enterococcus faecalis (E. faecalis) is a resident bacterium in the host. The increase of internal stress like low pH may affect the biological effects of E. faecalis. The prebiotic-like function of tea polyphenols can enhance the beneficial effects of its tolerance to environmental stress. In this study, RNA-sequence analysis was used to explore the protective effect of green tea polyphenols (GTP) on E. faecalis under low pH stress. A total of 28 genes were found to be responsive to GTP under low pH stress, including 16 up-regulated and 12 down-regulated. GTP intervention can partly relieve some undesired negative influences, such as the down-regulation of the base excision repair gene and amino acid transport and metabolism gene. The significantly changes were associated with selenocompound metabolism and aminoacyl-tRNA biosynthesis after the intervention of GTP. The present study provided new insights into the growth and continuous adaptation of E. faecalis under stress.

Bacterial Communities in Lanna Phak-Gard-Dong (Pickled Mustard Green) from Three Different Ethnolinguistic Groups in Northern Thailand

The Lanna region, the main part of northern Thailand, is a place of ethnic diversity. In this study, we investigated phak-gard-dong (PGD), or pickled mustard green (Brassica juncea L. Czern.), for its beneficial bacteria content and to analyse the variations in bacterial compositions among the PGD of three different ethnolinguistic groups, the Karen, Lawa, and Shan. DNA was extracted from the PGD pickled brine, and 16S rRNA gene Illumina sequencing was performed. Metagenomic data were analysed and the results demonstrated that the dominant bacterial species were Weissella (54.2%, 65.0%, and 10.0%) and Lactobacillus (17.5%, 5.6%, and 79.1%) in the PGD of the Karen, Lawa, and Shan, respectively. Pediococcus was found only in the PGD of the Karen and Shan. Bacterial communities in PGD of the Lawa were distinctive from the other ethnic groups, both in the alpha and beta diversity, as well as the predicted functions of the bacterial communities. In addition, overall network analysis results were correlated to bacterial proportions in every ethnic PGD. We suggest that all ethnic PGDs have the potential to be a good source of beneficial bacteria, warranting its conservation and further development into health food products.

Exopolysaccharide produced by Lactiplantibacillus plantarum RO30 isolated from Romi cheese: characterization, antioxidant and burn healing activity

Microbial exopolysaccharides (EPSs) extracted from lactic acid bacteria (LAB) are generally recognized as safe. They have earned popularity in recent years because of their exceptional biological features. Therefore, the present study main focus was to study EPS-production from probiotic LAB and to investigate their antioxidant and burn wound healing efficacy. Seventeen LAB were isolated from different food samples. All of them showed EPS-producing abilities ranging from 1.75 ± 0.05 to 4.32 ± 0.12 g/l. RO30 isolate (from Romi cheese) was chosen, due to its ability to produce the highest EPS yield (4.23 ± 0.12 g/l). The 16S rDNA sequencing showed it belonged to the Lactiplantibacillus plantarum group and was further identified as L. plantarum RO30 with accession number OL757866. It displayed well in vitro probiotic properties. REPS was extracted and characterized. The existence of COO⁻, OH and amide groups corresponding to typical EPSs was confirmed via FTIR. It was constituted of glucuronic acid, mannose, glucose, and arabinose in a molar ratio of 2.2:0.1:0.5:0.1, respectively. The average molecular weight was 4.96 × 10⁴ g/mol. In vitro antioxidant assays showed that the REPS possesses a DPPH radical scavenging ability of 43.60% at 5 mg/ml, reducing power of 1.108 at 10 mg/ml, and iron chelation activity of 72.49% and 89.78% at 5 mg/ml and 10 mg/ml, respectively. The healing efficacy of REPS on burn wound models in albino Wistar rats showed that REPS at 0.5% (w/w) concentration stimulated the process of healing in burn areas. The results suggested that REPS might be useful as a burn wound healing agent.

Use of encapsulated lactic acid bacteria as bioprotective cultures in fresh Brazilian cheese

There is great interest for biopreservation of food products, and encapsulation may be a good strategy to extend the viability of protective cultures. In this study, Lactobacillus paraplantarum FT-259 and Lactococcus lactis QMF 11 were separately encapsulated in casein/pectin (C/P) microparticles, which were tested for antilisterial and anti-staphylococcal activity in fresh Minas cheese (FMC) stored at 8 °C. The encapsulation efficiency for both lactic acid bacteria (LAB) was 82.5%, with viability over 6.2 log CFU/g after storage of C/P microparticles for 90 days under refrigeration. Interestingly, free Lb. paraplantarum and free Lc. lactis grew significantly in refrigerated FMC, both in the presence and absence of pathogens, but only the first significatively grew when encapsulated. Encapsulation increased the antilisterial activity of Lb. paraplantarum in FMC. Moreover, Lc. lactis significantly inhibited listerial growth in FMC in both its free and encapsulated forms, whereas Staphylococcus aureus counts were only significantly reduced in the presence of free Lc. lactis. In conclusion, these results indicate that C/P microparticles are effective carriers of LAB in FMC, which can contribute for the assurance of the safety of this product.

Bacterial communities associated with Zeldia punctata, a bacterivorous soil-borne nematode

Soil inhabiting organisms are important determinants of agroecosystem productivity. Understanding the composition, the abundance, and the type of interactions established by soil microorganisms is therefore crucial to design strategies to improve agricultural practices and agroecosystem management. In this study, we collected Zeldia punctata nematodes in maize fields in South Africa and profiled their associated bacterial communities using next-generation sequencing. We observed that Z. punctata nematodes establish associations with ecologically diverse bacterial species. The most abundant species observed are Pseudomonas syringae, a phytopathogenic bacterial complex; Lactobacillus paraplantarum, a broadly distributed bacterial species that is present in soils, water bodies, and animal intestinal tracts and has certain probiotic and antimicrobial properties; and Melissococcus plutonius, a serious pathogenic bacterial species that causes brood disease in honeybees. Our study contributes to a better understanding of the soil bacterial communities associated with nematodes in maize agricultural soils in South Africa and unravels the presence of diverse detrimental and beneficial nematode-associated bacteria.

Optimization of bioprocess of Schleiferilactobacillus harbinensis Ca12 and its viability in frozen Brazilian berries (Açai, Euterpe oleracea Mart.)

Amazonian palm berries (açaí, Euterpe oleracea Mart.) are fruits with high nutritional value and antioxidant activity and have aroused the interest of consumers, popularizing fruit pulps enriched with probiotics. Amazonian palm berries (açaí, Euterpe oleracea Mart.) are fruits with high nutritional potential, providing a source of carbohydrates, fibers, proteins, lipids, vitamins, and minerals. Furthermore, açai provides several health benefits, including antioxidant activity. Nutritionally enhanced foods have aroused the interest of consumers, popularizing fruit pulps enriched with probiotics. Probiotics are dietary supplements consisting of live, beneficial microorganisms in the host which improve the intestinal microbiota. The objective of this study was to isolate, identify, and characterize the probiotic potential of an isolated Schleiferilactobacillus harbinensis strain (dubbed Ca12) and provide an optimized bioprocess for its production, using the complete factorial and central rotational compound design to supplement the frozen açai pulp. The isolated strain S. harbinensis Ca12 presented adequate resistance to gastric juice and bile salts, microbial activity against different Candida strains, self-aggregation and coaggregation properties, high adhesion in HT-29 cells, and 35% inhibition of Salmonella in HT-29 cells. When optimized, the cellular biomass production of the S. harbinensis Ca12 strain was approximately 600% higher than the unsupplemented whey, with a production of 3.6 × 1010 CFU mL^-1. The S. harbinensis Ca12 strain's viability in the creamy and traditional frozen açai pulp was shown to be stable for up to 6 months at 20 °C. The impact of this study involved for the first time the S. harbinensis Ca12 described in the Brazilian cocoa pulp with activity against Candida albicans of clinical importance, creating the potential of a new functional food with important benefits to human health as prevention for candidiasis.

Bacteriocins, A Natural Weapon Against Bacterial Contamination for Greater Safety and Preservation of Food: A Review

Nowadays, consumers have become increasingly attentive to human health and the use of more natural products. Consequently, the demand for natural preservatives in the food industry is more frequent. This has led to intense research to discover new antimicrobial compounds of natural origin that could effectively fight foodborne pathogens. This research aims to safeguard the health of consumers and, above all, to avoid potentially harmful chemical compounds. Lactobacillus is a bacterial genus belonging to the Lactic Acid Bacteria and many strains are defined GRAS, generally recognized as safe. These strains are able to produce substances with antibacterial activity against food spoilage bacteria and contaminating pathogens: the bacteriocins. The aim of this review was to focus on this genus and its capability to produce antibacterial peptides. The review collected all the information from the last few years about bacteriocins produced by Lactobacillus strains, isolated from clinical or food samples, with remarkable antimicrobial activities useful for being exploited in the food field. In addition, the advantages and disadvantages of their use and the possible ways of improvement for industrial applications were described.

Towards a Starter Culture for Cocoa Fermentation by the Selection of Acetic Acid Bacteria

Acetic acid bacteria are involved in many food and beverage fermentation processes. They play an important role in cocoa bean fermentation through their acetic acid production. They initiate the development of some of the flavor precursors that are necessary for the organoleptic quality of cocoa, and for the beans’ color. The development of starter cultures with local strains would enable the preservation of the microbial biodiversity of each country in cocoa-producing areas, and would also control the fermentation. This approach could avoid the standardization of cocoa bean fermentation in the producing countries. One hundred and thirty acetic acid bacteria were isolated from three different cocoa-producing countries, and were identified based on their 16S rRNA gene sequence. The predominate strains were grown in a cocoa pulp simulation medium (CPSM-AAB) in order to compare their physiological traits regarding their specific growth rate, ethanol and lactic acid consumption, acetic acid production, and relative preferences of carbon sources. Finally, the intraspecific diversity of the strains was then assessed through the analysis of their genomic polymorphism by (GTG)5-PCR fingerprinting. Our results showed that Acetobacter pasteurianus was the most recovered species in all of the origins, with 86 isolates out of 130 cultures. A great similarity was observed between the strains according to their physiological characterization and genomic polymorphisms. However, the multi-parametric clustering results in the different groups highlighted some differences in their basic metabolism, such as their efficiency in converting carbon substrates to acetate, and their relative affinity to lactic acid and ethanol. The A. pasteurianus strains showed different behaviors regarding their ability to oxidize ethanol and lactic acid into acetic acid, and in their relative preference for each substrate. The impact of these behaviors on the cocoa quality should be investigated, and should be considered as a criterion for the selection of acetic acid bacteria starters.

Hydrolysis of raw fish proteins extracts by Carnobacterium maltaromaticum strains isolated from Argentinean freshwater fish

•

Carnobacterium and Vagococcus genera were identified from Paraná River freshwater fishes.

•

Low acidifying and antilisterial Carnobacterium strains were selected.

•

Proteolysis of raw fish extract by C. maltaromaticum strains was confirmed.

•

C. maltaromaticum strains may be used as functional cultures to develop novel LPFP.

Lactic acid bacteria (LAB) isolated from freshwater fish (hatcheries and captures) from Paraná river (Argentina) were analyzed by using culture-dependent approaches. The species belonging to Carnobacterium (C.) divergens, C. inhibens, C. maltaromaticum, C. viridans and Vagococcus (V.) salmoninarum were identify as predominant by RAPD-PCR and 16 s rRNA gene sequencing. C. maltaromaticum (H-17, S-30, B-42 and S-44) grew in raw fish extract and slightly reduced the medium pH (5.81–5.91). These strains exhibited moderate fish sarcoplasmic protein degradation (≤ 73 %) releasing small peptides and free amino acids, being alanine, glycine, asparagine and arginine concentrations increased in a higher extent (17.84, 1.47, 1.26 and 0.47 mg/100 mL, respectively) by S-44 strain at 96 h incubation. Interestingly C. maltaromaticum H-17 was able to inhibit Listeria monocytogenes. Results suggest that these strains would contribute to the development of new safe and healthy fishery products with improved nutritional and sensory characteristics.

Transcriptome analysis of Cyclocarya paliurus flavonoids regulation of differently expressed genes in Enterococcus faecalis under low pH stress

Enterococcus faecalis (E. faecalis) is an indigenous intestinal bacterium and has potential to be applied as probiotic supplement. Low pH is one of the main stresses that E. faecalis has to deal with to colonize in the gastrointestinal tract. Previous study indicated low concentration of flavonoids may enhance the tolerance of probiotic to environmental stress. In the present research, transcriptome analysis was employed to investigate the influence of Cyclocarya paliurus flavonoids (CPF) on E. faecalis exposed to low pH environment. The results revealed that under the stress of low pH, genes related to cell wall and membrane, transmembrane transport, metabolism process, energy production, and conversion stress proteins were significantly differentially expressed. And certain undesired changes of which (such as genes for MFS transporter were downregulated) could be partially mitigated by CPF intervention, indicating their capacity to improve the low pH tolerance of E. faecalis. Results from this study deepened our understanding of the beneficial role of CPF on the probiotic in the gastrointestinal environment.

Isolation and Genetic Identification of Endophytic Lactic Acid Bacteria From the Amazonian Açai Fruits: Probiotics Features of Selected Strains and Their Potential to Inhibit Pathogens

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.

Biopreservation and probiotic potential of a large set of lactic acid bacteria isolated from Brazilian artisanal cheeses: From screening to in product approach

The increasing interest in products with functional properties has encouraged the search for new lactic acid bacteria (LAB) present in natural sources, as traditional fermented foods. In this study, a large set of wild LAB isolates (n = 220) from Brazilian artisanal cheeses (BAC) were assessed for their probiotic and biopreservation potential. First, the rational selection was performed. From the tested isolates, 92 (41.8 %) were resistant to low pH (2 and 3). These isolates were submitted to bile salt (0.4 % Oxgall powder) resistance, and 22 were selected and submitted to adhesion assays. The autoaggregation values ranged from 68.5-99% and were considered moderate to high (20-70 %). Hydrophobicity values varied significantly between LAB (5.0-64.3%), and seven isolates presented values higher than 40 %. All selected LAB (n=22) were capable of adhering to Caco-2 (> 70 %) cells, and none isolate displayed any tested gene for biogenic amine production. Most isolates (18/22) showed less than 1 log CFU reduction after passage through the simulated gastrointestinal tract (GIT) conditions. A total of twenty isolates satisfied key in vitro criteria to be considered as probiotics. A hierarchical cluster analysis (HCA) was performed, and two clusters were observed, showing high variability between Lactobacillus plantarum isolates regarding adhesion properties and survival to GIT stress and one influence of the source of isolation on these properties. After screening, the antimicrobial activity of Lb. plantarum (1QB77) was tested in microcheeses in which survival of two relevant pathogenic bacteria (Staphylococcus aureus and Listeria monocytogenes) was monitored along ripening and after a simulated GIT passage, concomitantly. L. plantarum (1QB77) has shown the ability to reach high counts (∼ 9 log CFU/g) at the end of ripening. This isolate was also able to reduce counts of S. aureus and L. monocytogenes in microcheeses in approx. 2.3 and 2.5 log CFU/g, respectively, until the 21st day of ripening; and about 3.2 and 3.5 log CFU/g after simulated GIT passage. Overall, the assessment of the probiotic properties of a large set of LAB was fundamental for gaining insights on the technological, functional, and potential regional traits of wild LAB isolates that can be used to develop starter cultures for tailored applications.

Cheese as a Potential Food Carrier to Deliver Probiotic Microorganisms into the Human Gut: A Review

:

This review presents the industrial manufacture and applications of cheese for the delivery of probiotic microorganisms into the human gut. Initially, important benefits of probiotics and advantageous characteristics of cheese for the delivery of probiotic microorganisms into the human gut in comparison with the other fermented milk products are discussed. Fresh and ripened cheeses are also separately argued followed by discussing queries respecting the viability of probiotic bacteria into these cheeses. Since fresh cheese has been demonstrated as more suitable carriers for probiotic microorganisms, factories are recommended producing it in large quantities.

Cocoa Pulp as Alternative Food Matrix for Probiotic Delivery

BACKGROUND

For screening probiotic strains with viability and stability in non-dairy foods for health benefits, we revised all patents relating to probiotics in food.

OBJECTIVE

Screening of potential probiotics from Brazilian Minas artisanal cheese and verify their survival in frozen Brazilian cocoa pulp.

METHODS

Isolation and identification of the strains. The potential probiotic characterization involved gastric juice and bile resistance, antibiotic and antimicrobial activity, hydrophobicity, autoaggregation, coaggregation and adhesion assay in HT-29 cells. Organoleptic, viability and stability of probiotic strain in frozen cocoa pulp were evaluated.

RESULTS

Fourteen strains of Lactobacillus plantarum (9), Weissella paramesenteroides (3), Lactobacillus fermentum (1), and Leuconostoc mesenteroides (1) were obtained. Most of the strains were resistant to simulated gastric acidity and bile salts. Almost all strains were sensitive to the antibiotics tested, except to ciprofloxacin and vancomycin. About 47% of the strains are potential producers of bacteriocins. High hydrophobicity was observed for four strains. Autoaggregation ranged from 8.3-72.6% and the coaggregation capacity from 5.2-60.2%. All of the assessed strains presented more than 90% of adhesion to HT-29 intestinal cells. The percentage of Salmonella inhibition in HT-29 cells ranged from 4.7-31.1%. No changes in color, aroma, and pH were observed in cocoa pulps after storage at -20 °C for 90 days.

CONCLUSION

Wild strains of acid lactic bacteria from cheese proved to be viable and stable in frozen Brazilian cocoa pulp. This work showed a promising application of L. plantarum isolated strains to be used with frozen cocoa pulp matrix in probiotics food industry.

Lactobacillus Dominate in the Intestine of Atlantic Salmon Fed Dietary Probiotics

Probiotics, the live microbial strains incorporated as dietary supplements, are known to provide health benefits to the host. These live microbes manipulate the gut microbial community by suppressing the growth of certain intestinal microbes while enhancing the establishment of some others. Lactic acid bacteria (LAB) have been widely studied as probiotics; in this study we have elucidated the effects of two fish-derived LAB types (RII and RIII) on the distal intestinal microbial communities of Atlantic salmon (Salmo salar). We employed high-throughput 16S rRNA gene amplicon sequencing to investigate the bacterial communities in the distal intestinal content and mucus of Atlantic salmon fed diets coated with the LABs or that did not have microbes included in it. Our results show that the supplementation of the microbes shifts the intestinal microbial profile differentially. LAB supplementation did not cause any significant alterations in the alpha diversity of the intestinal content bacteria but RIII feeding increased the bacterial diversity in the intestinal mucus of the fish. Beta diversity analysis revealed significant differences between the bacterial compositions of the control and LAB-fed groups. Lactobacillus was the dominant genus in LAB-fed fish. A few members of the phyla Tenericutes, Proteobacteria, Actinobacteria, and Spirochaetes were also found to be abundant in the LAB-fed groups. Furthermore, the bacterial association network analysis showed that the co-occurrence pattern of bacteria of the three study groups were different. Dietary probiotics can modulate the composition and interaction of the intestinal microbiota of Atlantic salmon.

The potential use of probiotic and beneficial bacteria in the Brazilian dairy industry

Scientific studies demonstrate the importance of intestinal microbiota to human health and how probiotic microorganisms can positively affect health when administered regularly and in adequate amounts. Probiotic bacteria can be part of fermented products and their functional importance is associated mainly with their metabolism. They are thought to benefit individuals to maintain their health and also to strengthen resistance against various types of diseases. The acceptance of probiotic cultures and products by consumers increased when these bacteria were marketed as natural cultures that help in digestion and health. Considering this, the food industry has an increasing demand for new candidates as probiotic cultures, and the dairy industry has a particular interest for fermented milks and other dairy products, since these are the most common food vehicles for probiotic cultures. Therefore, the dairy industries are increasingly seeking to improve their products with these beneficial bacteria. However, the legal peculiarities and excess of control agencies in Brazil makes the registration of these products and the collection of data very complex. Prospective analysis suggests that probiotic foods have the potential to effect a considerable expansion of the dairy industry, allowing the dairy sector to grow and for these products to be increasingly sought by consumers globally. For this, not only actions on research and innovation are necessary, but also official clarifications on the claims for considerations of microbiological security and functionality of these products. This review aims to elucidate important probiotic research regarding the isolation and characterization of beneficial cultures in Brazil, and to demonstrate the relevance of the dairy chain as a potential source of novel cultures for the development of new probiotic products to expand the Brazilian dairy industry.

Selection of indigenous lactic acid bacteria presenting anti-listerial activity, and their role in reducing the maturation period and assuring the safety of traditional Brazilian cheeses

Artisanal raw milk cheeses are highly appreciated dairy products in Brazil and ensuring their microbiological safety has been a great need. This study reports the isolation and characterization of lactic acid bacteria (LAB) strains with anti-listerial activity, and their effects on Listeria monocytogenes during refrigerated shelf-life of soft Minas cheese and ripening of semi-hard Minas cheese. LAB strains (n = 891) isolated from Minas artisanal cheeses (n = 244) were assessed for anti-listerial activity by deferred antagonism assay at 37 °C and 7 °C. The treatments comprised the production of soft or semi-hard Minas cheeses using raw or pasteurized milk, and including the addition of selected LAB only [Lactobacillus brevis 2-392, Lactobacillus plantarum 1-399 and 4 Enterococcus faecalis (1-37, 2-49, 2-388 and 1-400)], L. monocytogenes only, selected LAB co-inoculated with L. monocytogenes, or without any added cultures. At 37 °C, 48.1% of LAB isolates showed anti-listerial capacity and 77.5% maintained activity at 7 °C. Selected LAB strains presented a bacteriostatic effect on L. monocytogenes in soft cheese. L. monocytogenes was inactivated during the ripening of semi-hard cheeses by the mix of LAB added. Times to attain a 4 log-reduction of L. monocytogenes were 15 and 21 days for semi-hard cheeses produced with raw and pasteurized milk, respectively. LAB with anti-listerial activity isolated from artisanal Minas cheeses can comprise an additional barrier to L. monocytogenes growth during the refrigerated storage of soft cheese and help shorten the ripening period of semi-hard cheeses aged at ambient temperature.

Saccharomyces cerevisiae from Brazilian kefir-fermented milk: An in vitro evaluation of probiotic properties

The therapeutic use of probiotics for supporting the antibiotic action against gastrointestinal disorders is a current trend and emerging applications have gained popularity because of their support for various microbiological activities in digestive processes. Microorganisms isolated from kefir with great probiotic properties, in addition to high resistance to harsh environmental conditions, have been widely researched. Administration of probiotic yeasts offers a number of advantages, when compared to bacteria, because of particular characteristics as their larger cell size. In the present study, 28 strains of Saccharomyces cerevisiae were isolated, after in vitro digestion of kefir-fermented milk, and identified by molecular based approaches. A screening was performed to determine important quality requirements for probiotics including: antagonistic and antioxidant activities, β-galactosidase synthesis, autoaggregation, surface hydrophobicity and adhesion to epithelial cells. The results showed strains: with antagonistic activity against microbial pathogens such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis; able to produce β-galactosidase; with antioxidant activity levels higher than 90%; with hydrophobicity activity and autoaggregation ability (evaluated by adhesion test, where all the strains presented adhesion to mice ileal epithelial cells). These findings are relevant and the strains are recommended for further in vivo studies as well as for potential therapeutic applications.

Technological and safety properties of newly isolated GABA-producing Lactobacillus futsaii strains

AIM

To evaluate the technological and safety properties of Lactobacillus futsaii CS3 and CS5 isolated from Thai fermented shrimp products (Kung-Som) in order to develop a valuable gamma-aminobutyric acid (GABA)-producing starter culture.

METHODS AND RESULTS

Both strains showed a high GABA-producing ability (>8 mg ml(-1) ) in MRS broth containing 20 mg ml(-1) monosodium glutamate (MSG) for 120 h. They also exhibited inhibitory activity against foodborne pathogens and spoilage bacteria. Cell surface hydrophobicity and proteolytic activity were observed in both strains. Strain CS3 survived better under simulated gastrointestinal tract conditions with only 1·5 log-units cell decrease over 8 h. Both strains showed the ability to deconjugate taurocholate and taurodeoxycholate acid. Neither virulence genes nor biogenic amine production was detected. Strain CS3 exhibited susceptibility to all tested antibiotics with the exception of vancomycin, while strain CS5 showed resistance to vancomycin, ampicillin and chloramphenicol.

CONCLUSIONS

Based on the results obtained, Lact. futsaii CS3 is very promising as a GABA-producing and potentially probiotic starter culture strain for applications in functional fermented foods.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study focuses on the technological and safety characteristics of Lact. futsaii CS3 and CS5 including their high GABA-producing capacity for the first time. This provides a way of replacing chemical GABA by natural GABA using a GABA-producing starter culture candidate, at the same time offering the consumer new attractive food products.

Probiotic Assessment of Lactobacillus plantarum 15HN and Enterococcus mundtii 50H Isolated from Traditional Dairies Microbiota

PURPOSE

Probiotics are microorganisms, which show beneficial health effects on hosts once consumed in sufficient amounts. Among probiotic bacteria, the bioactive compounds from lactic acid bacteria (LAB) group can be utilized as preservative agents. LAB group can be isolated and characterized from traditional dairy sources. This study aimed to isolate, identify, and biologically characterize probiotic LAB strains from Iranian traditional dairy products.

METHODS

A total of 19 LAB strains were identified by sequencing of their 16S rRNA genes. They were examined for adherence to human intestinal Caco-2 cells and tolerance to low pH/high bile salts and simulated in vitro digestion conditions. Moreover, they were evaluated further to assess their ability to prevent the adhesion of Escherichia coli 026 to the intestinal mucosa, inhibitory functions against pathogens, and sensitivity to conventional antibiotics.

RESULTS

L. plantarum 15HN and E. mundtii 50H strains displayed ≥ 71% survival rates at low pH/high bile salts and ≥ 40% survival rates in digestive conditions. Their adherences to Caco-2 cells were 3.2×105 and 2.6×105 CFU mL-1 respectively and high values of anti-adhesion capability were observed (≥36%). They inhibited the growth of 13 and 11 indicator pathogens respectively. Moreover, they were sensitive or semi-sensitive to seven and three out of eight antibiotics respectively.

CONCLUSION

L. plantarum 15HN and E. mundtii 50H, which were isolated from shiraz product, displayed above-average results for all of the criteria. Therefore, they can be introduced as novel candidate probiotics that could be used in the food industry.

Probiotic Assessment of Lactobacillus plantarum 15HN and Enterococcus mundtii 50H Isolated from Traditional Dairies Microbiota

PURPOSE

Probiotics are microorganisms, which show beneficial health effects on hosts once consumed in sufficient amounts. Among probiotic bacteria, the bioactive compounds from lactic acid bacteria (LAB) group can be utilized as preservative agents. LAB group can be isolated and characterized from traditional dairy sources. This study aimed to isolate, identify, and biologically characterize probiotic LAB strains from Iranian traditional dairy products.

METHODS

A total of 19 LAB strains were identified by sequencing of their 16S rRNA genes. They were examined for adherence to human intestinal Caco-2 cells and tolerance to low pH/high bile salts and simulated in vitro digestion conditions. Moreover, they were evaluated further to assess their ability to prevent the adhesion of Escherichia coli 026 to the intestinal mucosa, inhibitory functions against pathogens, and sensitivity to conventional antibiotics.

RESULTS

L. plantarum 15HN and E. mundtii 50H strains displayed ≥ 71% survival rates at low pH/high bile salts and ≥ 40% survival rates in digestive conditions. Their adherences to Caco-2 cells were 3.2×105 and 2.6×105 CFU mL-1 respectively and high values of anti-adhesion capability were observed (≥36%). They inhibited the growth of 13 and 11 indicator pathogens respectively. Moreover, they were sensitive or semi-sensitive to seven and three out of eight antibiotics respectively.

CONCLUSION

L. plantarum 15HN and E. mundtii 50H, which were isolated from shiraz product, displayed above-average results for all of the criteria. Therefore, they can be introduced as novel candidate probiotics that could be used in the food industry.

Screening of Probiotic Activities of Lactobacilli Strains Isolated from Traditional Tibetan Qula, A Raw Yak Milk Cheese

In this study, 69 lactobacilli isolated from Tibetan Qula, a raw yak milk cheese, were screened for their potential use as probiotics. The isolates were tested in terms of: Their ability to survive at pH 2.0, pH 3.0, and in the presence of 0.3% bile salts; tolerance of simulated gastric and intestinal juices; antimicrobial activity; sensitivity against 11 specific antibiotics; and their cell surface hydrophobicity. The results show that out of the 69 strains, 29 strains (42%) had survival rates above 90% after 2 h of incubation at pH values of 2.0 or 3.0. Of these 29 strains, 21 strains showed a tolerance for 0.3% bile salt. Incubation of these 21 isolates in simulated gastrointestinal fluid for 3 h revealed survival rates above 90%; the survival rate for 20 of these isolates remained above 90% after 4 h of incubation in simulated intestinal fluid. The viable counts of bacteria after incubation in simulated gastric fluid for 3 h and simulated intestinal fluid for 4 h were both significantly different compared with the counts at 0 h (p<0.001). Further screening performed on the above 20 isolates indicated that all 20 lactobacilli strains exhibited inhibitory activity against Micrococcus luteus ATCC 4698, Bacillus subtilis ATCC 6633, Listeria monocytogenes ATCC 19115, and Salmonella enterica ATCC 43971. Moreover, all of the strains were resistant to vancomycin and streptomycin. Of the 20 strains, three were resistant to all 11 elected antibiotics (ciprofloxacin, erythromycin, tetracycline, penicillin G, ampicillin, streptomycin, polymyxin B, vancomycin, chloramphenicol, rifampicin, and gentamicin) in this study, and five were sensitive to more than half of the antibiotics. Additionally, the cell surface hydrophobicity of seven of the 20 lactobacilli strains was above 70%, including strains Lactobacillus casei 1,133 (92%), Lactobacillus plantarum 1086-1 (82%), Lactobacillus casei 1089 (81%), Lactobacillus casei 1138 (79%), Lactobacillus buchneri 1059 (78%), Lactobacillus plantarum1141 (75%), and Lactobacillus plantarum 1197 (71%). Together, these results suggest that these seven strains are good probiotic candidates, and that tolerance against bile acid, simulated gastric and intestinal juices, antimicrobial activity, antibiotic resistance, and cell surface hydrophobicity could be adopted for preliminary screening of potentially probiotic lactobacilli.

Bioactivity characterization of Lactobacillus strains isolated from dairy products

This study aimed to find candidate strains of Lactobacillus isolated from sheep dairy products (yogurt and ewe colostrum) with probiotic and anticancer activity. A total of 100 samples were randomly collected from yogurt and colostrum and 125 lactic acid bacteria were isolated. Of these, 17 Lactobacillus strains belonging to five species (L. delbrueckii, L. plantarum, L. rhamnosus, L. paracasei, and L. casei) were identified. L. plantarum 17C and 13C, which isolated from colostrums, demonstrated remarkable results such as resistant to low pH and high concentrations of bile salts, susceptible to some antibiotics and good antimicrobial activity that candidate them as potential probiotics. Seven strains (1C, 5C, 12C, 13C, 17C, 7M, and 40M), the most resistant to simulated digestion, were further investigated to evaluate their capability to adhere to human intestinal Caco-2 cells. L. plantarum 17C was the most adherent strain. The bioactivity assessment of L. plantarum 17C showed anticancer effects via the induction of apoptosis on HT-29 human cancer cells and negligible side effects on one human epithelial normal cell line (FHs 74). The metabolites produced by this strain can be used as alternative pharmaceutical compounds with promising therapeutic indices because they are not cytotoxic to normal mammalian cells.