Comprehensive investigation on volatile and non-volatile metabolites in broccoli juices fermented by animal- and plant-derived Pediococcus pentosaceus.

A metabolomics approach was employed to investigate differences and correlations among key odorants and non-volatile metabolites in broccoli juices fermented by plant- and animal-derived Pediococcus pentosaceus. Forty volatile metabolites were identified by headspace solid-phase microextraction/gas chromatography-mass spectrometry. According to orthogonal projections to latent structures-differential analysis, 24 and 21 differential volatiles were detected after fermentation by plant- and animal-derived P. pentosaceus, respectively. The concentrations of 10 odorants (OAV ≥ 1) detected by gas chromatography-olfactometry changed significantly after fermentation by P. pentosaceus. Using ultrahigh-pressure liquid chromatography/quadrupole time-of-flight mass spectrometry, 49.47% of the non-volatile metabolites were classified as lipids and lipid-like molecules. The relative expressions of five non-volatile metabolites that exhibited significant correlations with odorants using Spearman correlation analysis changed significantly after fermentation. Fermentation with animal- and plant-derived P. pentosaceus can therefore change key odorants and non-volatile metabolites in broccoli juice that contribute to the characteristic organoleptic properties of products.

Fermentation Enhanced Biotransformation of Compounds in the Kernel of Chrysophyllum albidum.

Chrysophyllum albidum Linn (African star apple) is a fruit with extensive nutritional and medicinal benefits. The fruit and kernel in the seed are both edible. Strains of lactic acid bacteria (LAB) were isolated from fermented seeds and assessed for probiotic characteristics. The extracts in both the unfermented and the fermented aqueous extracts from the kernels obtained from the seeds of C. albidum were subjected to analysis using the gas chromatography/mass spectrometry (GC-MS) method. This analysis identified the bioactive compounds present as possible substrate(s) for the associated organisms inducing the fermentation and the resultant biotransformed products formed. Three potential probiotic LAB strains identified as Lactococcus raffinolactis (ProbtA1), Lactococcus lactis (ProbtA2a), and Pediococcus pentosaceus (ProbtA2b) were isolated from the fermented C. albidum seeds. All strains were non hemolytic, which indicated their safety, Probt (A1, A2a, and A2b) grew in an acidic environment (pH 3.5) during the 48-h incubation time, and all three strains grew in 1% bile, and exhibited good hydrophobicity and auto-aggregation properties. Mucin binding proteins was not detected in any strain, and bile salt hydrolase was detected in all the strains. l-lactic acid (28.57%), norharman (5.07%), formyl 7E-hexadecenoate (1.73%), and indole (1.51%) were the four major constituents of the fermented kernel of the C. albidum, while 2,5-dimethylpyrazine (C1, 1.27%), 3,5-dihydroxy-6-methyl-2,3-dihydropyran-4-one (C2, 2.90%), indole (C3, 1.31%), norharman (C4, 3.01%), and methyl petroselinate (C5, 4.33%) were the five major constituents of the unfermented kernels. The isolated LAB are safe for consumption. The fermenting process metabolized C1, C2, and C5, which are possible starter cultures for the growth of probiotics. Fermentation is an essential tool for bioengineering molecules in foods into safe and health beneficial products.

Pediococcus pentosaceus B49 from human colostrum ameliorates constipation in mice.

Constipation is a prevalent and burdensome gastrointestinal (GI) disorder that seriously affects the quality of human life. This study evaluated the effects of the P. pentosaceus B49 (from human colostrum) on loperamide (Lop)-induced constipation in mice. Mice were given P. pentosaceus B49 (5 × 109 CFU or 5 × 1010 CFU) by gavage daily for 14 days. The result shows that P. pentosaceus B49 treatment relieved constipation in mice by shortening the defecation time, increasing the GI transit rate and stool production. Compared with the constipation control group, the P. pentosaceus B49-treated groups showed decreased serum levels of inhibitory neurotransmitters (vasoactive intestinal peptide and nitric oxide), increased serum levels of excitatory neurotransmitters (acetylcholinesterase, motilin, and gastrin), and elevated cecal concentration of short chain fatty acids (SCFAs). Analysis of cecal microbiota reveals that P. pentosaceus B49 was colonized in the intestine of constipated mice, and altered the cecal microbiota by increasing beneficial SCFAs-producing bacteria (i.e., Lactobacillus, Ruminococcaceae_UCG-014, and Bacteroidales_S24-7) and decreasing potential pathogenic bacteria (i.e., Staphylococcus and Helicobacter). Moreover, transcriptome analysis of the colon tissue shows that P. pentosaceus B49 partly normalized the expression of genes related to GI peristalsis (i.e., Ache, Chrm2, Slc18a3, Grp, and Vip), water and electrolyte absorption and transport (i.e., Aqp4, Aqp8, and Atp12a), while down-regulating the expression of pro-inflammatory and pro-oncogenic genes (i.e., Lbp, Lgals2, Bcl2, Bcl2l15, Gsdmc2, and Olfm4) in constipated mice. Our findings indicate that P. pentosaceus B49 effectively relieves constipation in mice and is a promising candidate for treating constipation.

Evaluation of antibacterial properties of lactic acid bacteria from traditionally and industrially produced fermented sausages from Germany.

With regards to the frequently reported findings of spoilage bacteria and pathogens in various foods there is a need to explore new ways to control hazards in food production and to improve consumer safety. Fermented sausages from traditional and industrial production in Germany were screened for lactic acid bacteria with antibacterial effects towards important foodborne pathogens (Escherichia coli DSM 1103, Listeria innocua DSM 20649, Listeria monocytogenes DSM 19094, Pseudomonas aeruginosa DSM 939, Staphylococcus aureus DSM 799 and Salmonella Typhimurium DSM 19587). The obtained isolates and their cell-free supernatants were tested for their antibacterial activity by agar well diffusion assay. Isolates with an inhibitory effect were examined for the underlying antibacterial mechanism. Among the 169 collected isolates, 12.4% showed antibacterial effects only against Listeria innocua DSM 20649 and Listeria monocytogenes DSM 19094. In 6.5% of the isolates, bacteriocins were responsible for the effect. On the remaining test strains, the lactic bacteria isolates exerted no antibacterial effect. Two isolates were selected based on their antibacterial potential against Listeria spp. and the thermostability of the deriving cell free supernatants, traditional product: Pediococcus pentosaceus LMQS 331.3, industrial product: Pediococcus acidilactici LMQS 154.1, were investigated further and confirmed for the presence of bacteriocin structural genes by real-time PCR. Enriched crude bacteriocin preparations were obtained by ammonium sulfate precipitation and were found to remain stable under different pH milieus and to be active towards an extended set of Listeria spp. strains. Fermented meat products from German production are a promising source for bacteriocin-producing lactic acid bacteria. Two bacteriocin-producing isolates were identified which have the potential to contribute to product and consumer safety.

A comparison of methods for enumerating bacteria in direct fed microbials for animal feed.

Aerobic plate counts are the standard enumeration method for probiotic-containing products. This counting method is limited by the ability of many cells to enter a viable but non-culturable (VBNC) state upon exposure to stressful conditions like dehydration and heating commonly used in probiotic product preparation. Alternative enumeration methods are available including flow cytometry (FC) which counts total live/dead cells by assessing cellular integrity and/or metabolic activity, and quantitative polymerase chain reaction (qPCR) in which enumeration is correlated with the quantity of a nucleic acid target. These three methods were compared for enumerating three lactic acid bacteria (LAB): Pediococcus acidilactici, Pediococcus pentosaceus, and Lactobacillus plantarum, and a Bacillus subtilis related strain in twenty samples of a mixed probiotic product ranging in age from one to 825 days post-production. Flow cytometry and qPCR enumerations were similar and much higher compared to plate counts at later storage times, suggesting that some strains in the population were entering the VBNC state and were only countable by FC and qPCR. We propose the use of FC and/or qPCR as an alternative to plate counts for more accurate enumeration of bacteria in probiotic products.

Influence of the early bacterial biofilms developed on vats made with seven wood types on PDO Vastedda della valle del Belìce cheese characteristics.

Early vat bacterial biofilms developed spontaneously through contact with whey have been characterized on seven wood types (Castanea sativa Miller, Cedrus libani, A. Rich., Prunus avium L., Fraxinus ornus L., Juglans regia L., Pinus nigra J.F. Arnold and Populus nigra L.). The present study aimed to evaluate the influence of these biofilms on the microbiological, chemical, physical and sensory characteristics of PDO Vastedda della valle del Belìce (VdB) cheese, processed traditionally from raw ewe's milk using wooden tools. To this purpose, the experimental cheeses after 15 d of refrigerated storage were examined. Lactic acid bacteria (LAB) populations dominated the microbial community of all samples. The species more frequently identified were Lactococcus lactis among starter LAB and Lactobacillus paracasei, Lactobacillus rhamnosus, Lactobacillus fermentum and Pediococcus pentosaceus among non starter LAB. Culture-independent analysis of microbiota diversity was performed by MiSeq Illumina that identified Streptococcus as major group followed by members of Enterobacteriaceae family, Lactococcus and Lactobacillus. Generally, the seven tree species did not negatively affect the physicochemical composition of VdB cheeses. Chestnut (both Sicilian and Calabrian) vats produced cheeses with significant lower hue angle (a*/b*) than other wood types. Among chemical parameters, significant variations were registered for aw, primary and secondary lipid oxidation state (significantly lower for the VdB cheeses produced with poplar wood), and volatile organic compounds (VOCs). The significant differences detected among the VOCs emitted from cheeses were not perceived by the panelists who recognized all cheeses from the different trials as similar. This study confirmed the suitability of cedar, cherry, ash, walnut, black pine and poplar as alternative woods to chestnut for the production of the wooden vats employed in cheese making for the Sicilian traditional dairy productions.

Characteristics of Pediococcus pentosaceus Q6 isolated from Elymus nutans growing on the Tibetan Plateau and its application for silage preparation at low temperature.

AIMS: Characteristics of a strain Pediococcus pentosaceus Q6 isolated from Elymus nutans growing on the Tibetan plateau and its effects on E. nutans silage fermentation stored at low temperature were investigated. METHODS AND RESULTS: Sugar fermentation pattern and growth profiles of the strain Q6 and its reference strain APP were characterized. The strain Q6 and APP were inoculated to E. nutans at ensiling respectively; and ensiled at different temperatures (10, 15 and 25°C) for 30, 60 and 90 days. The results indicated that Q6 could grow at pH 3·0 and at 4°C. In contrast to APP, Q6 could ferment mannitol, saccharose, sorbitol and rhamnose. Lower pH in Q6-treated silages fermented for 60 days at 10 and 15°C was found compared with the control and APP-treated groups. For the silages that were stored at 10 or 15°C, the greatest lactic acid content were detected in Q6-inoculated silages ensiled for 30 and 60 days respectively. There were no differences in pH and lactic acid content between Q6- and APP-treated silages ensiled at 10 and 15°C for 90 days respectively. CONCLUSIONS: Inoculation of the strain P. pentosaceus Q6 could improve fermentation quality of ensiled E. nutans at the early stage of ensiling stored at low temperature (10 or 15°C). SIGNIFICANCE AND IMPACT OF THE STUDY: The selection of P. pentosaceus inoculants for improving silage quality at low temperature, which provides a candidate strain to make high-quality silage in regions with frigid climate.

Infective endocarditis caused by Lactococcus lactis subsp. lactis and Pediococcus pentosaceus: A case report and literature review.

RATIONALE: Lactococcus lactis and Pediococcus pentosaceus are rare pathogens which rarely caused infections in humans. Several cases with L. lactis endocarditis have been reported in the literature, among them few were caused by L. lactis subsp. Lactis. Opportunistic P. pentosaceus infections were rarely reported. PATIENT CONCERNS: A 66-year-old man presented to our hospital due to persistent fever for 15 days. A physical checking revealed a grade II holosystolic murmur at the heart apex. A chest computed tomography (CT) scan suggested bronchitis. L. lactis subsp. lactis was identified in blood cultures. Transthoracic and transesophageal echocardiography revealed the presence of a large hyperechogenic mass in the left atrium, and a large floating vegetation on the mitral valve with a severe mitral regurgitation. DIAGNOSIS: Infectious endocarditis caused by L. lactis subsp. Lactis was diagnosed. INTERVENTIONS: Levofloxacin (0.5 g/day) was used for 20 days; however, L. lactis subsp. lactis remained to be isolated from blood culture. Therefore, vancomycin (2 g/day) was used to replace levofloxacin. Six days after the treatment with vancomycin, the blood culture revealed no L. lactis subspecies lactis, but yielded a growth of gram-positive and non-spore forming cocci; and P. pentosaceus was identified. Antimicrobial susceptibility test revealed P. pentosaceus was sensitive to penicillin and levofloxacin. Vancomycin was discontinued, and levofloxacin (0.5 g/day) was restarted and treated for another 7 days. The patient recovered with negative blood culture results, and discharged from the hospital. OUTCOMES: The patient recovered with negative blood culture results, and discharged from the hospital. LESSONS: Our patient had a long-period of antibiotic treatment with strategy alterations. Standard interpretation criteria of Clinical and Laboratory Standards Institute (CLSI) for L. lactis should be established, and molecular tests will increase the identification rate of L. lactis infections.

A laboratory exercise for detecting microbial contaminants.

The development and evaluation of a 6-hours laboratory class, based on capillary electrophoresis (CE) and the detection of microbial contaminants, is described. It can be easily scaled up or down, to suit class sizes up to 188 and completed in a shorter time scale. CE uses narrow-bore fused-silica capillaries to separate a complex array of large and small molecules. A laboratory exercise has been devised to illustrate how CE-based genetic analysis system processes DNA fragment analysis to detect three microbial contaminants. The protocol is relatively inexpensive and uses standard molecular biology reagents and equipment. © 2018 by The International Union of Biochemistry and Molecular Biology, 46(3):279-284, 2018.

Antibacterial activity of Lactobacillus plantarum isolated from Tibetan yaks.

The main purpose of our study was to isolate the Lactobacillus strains from Tibetan yaks, which may have antibacterial activity. Three Lactobacillus plantarum (L. plantarum) strains named LP1, LP2, LP3 and one Pediococcus pentosaceus (P. pentosaceus) named PT2 were isolated from fecal samples of Tibetan yaks. We regarded indigenous Escherichia coli (E. coli ATCC 25922) and Staphylococcus aureus (S. aureus ATCC 25923) as indicator pathogens. The Bacteriocins derived from these isolated strains manifested high antibacterial activity against E. coli, the highest activity was observed in the case of LP1. On the other hand, PT2 had the most powerful bacteriostatic ability against S. aureus. In addition, all strains were positive for Ent A, which plays an important role in secreting pediocin-like bacteriocins and shows potential probiotic traits of bile and low PH tolerance. Overall, L. plantarum strains in present study could be employed as effective antibacterial substances and can help to remit the problem of antibiotic resistance in veterinary medicine.

Pediococcus acidolactici and Pediococcus pentosaceus isolated from a rainbow trout ecosystem have probiotic and ABF1 adsorbing/degrading abilities in vitro.

Probiotics are being used in biological control of bacterial pathogens, as an alternative to antibiotics, to improve health and production parameters in fish farming. Fish farming production is severely affected by aflatoxins (AFs), which are a significant problem in aquaculture systems. Aflatoxins exert substantial impact on production, causing disease with high mortality and a gradual decline of reared fish stock quality. Some aspects of aflatoxicosis in fish, particularly its effects on the gastrointestinal tract, have not been well documented. The aim of the present study was to evaluate probiotic properties of lactic acid bacterial (LAB) strains isolated from rainbow trout intestine and feed. Moreover, AFB1-binding and/or degrading abilities were also evaluated to assess their use in the formulation of feed additives. Growth at pH 2, the ability to co-aggregate with bacterial pathogens, inhibition of bacterial pathogens, and determination of the inhibitory mechanism were tested. Aflatoxin B1 (AFB1) adsorption and degradation ability were also tested. All strains were able to maintain viable (107 cells ml-1) at pH 2. Pediococcus acidilactici RC001 and RC008 showed the strongest antimicrobial activity, inhibiting all the pathogens tested. The strains produced antimicrobial compounds of different nature, being affected by different treatments (catalase, NaOH and heating), which indicated that they could be H2O2, organic acids or proteins. All LAB strains tested showed the ability to coaggregate pathogenic bacteria, showing inhibition percentages above 40%. Pediococcus acidilactici RC003 was the one with the highest adsorption capacity and all LAB strains were able to degrade AFB1 with percentages higher than 15%, showing significant differences with respect to the control. The ability of some of the LAB strains isolated in the present work to compete with pathogens, together with stability against bile and gastric pH, reduction of bioavailability and degradation of AFB1, may indicate the potential of LAB for use in rainbow trout culture.

Isolating and evaluating lactic acid bacteria strains for effectiveness on silage quality at low temperatures on the Tibetan Plateau.

Four lactic acid bacteria (LAB) strains isolated from straw silages on the Tibetan Plateau were characterized, and their effects on the fermentation quality of Italian ryegrass (Lolium multiflorum Lam.) at different temperatures (10°C, 15°C and 25°C) were studied. These LAB isolates were evaluated using the acids production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. All the isolates (M1, LM8, LO7 and LOG9) could grow at 5-20°C, pH 3.5-7.0 and NaCl (3.0%, 6.5%). Strains M1, LM8, LO7 and LOG9 were identified as Lactobacillus plantarum, L. coryniformis, Pediococcus pentosaceus and P. acidilactici, respectively, by sequencing 16S ribosomal DNA. The four isolates were added to Italian ryegrass for ensiling for 30 days at various temperatures. Compared with the corresponding control, inoculating with isolates M1, LM8 and LO7 could improve the silage quality of Italian ryegrass at low temperatures, indicated by significantly (P < 0.05) higher lactic acid (LA) contents and ratios of lactic acid/acetic acid (LA/AA), and significantly (P < 0.05) lower pH and ammonia nitrogen/total nitrogen (AN/TN). Compared with other isolates, LM8 performed better at 10°C and 15°C, indicated by the higher (P < 0.05) LA content and ratio of LA/AA, and the lower (P < 0.05) pH and AN/TN.

Selection of a candidate probiotic strain of Pediococcus pentosaceus from the faecal microbiota of horses by in vitro testing and health claims in a mouse model of Salmonella infection.

AIMS: The aim of this study was to verify the suitable use of candidate 'probiotics' selected by in vitro tests and the importance of in vivo assays to nominate micro-organisms as probiotics and alternative prophylactic treatments for Salmonella Typhimurium infection. METHODS AND RESULTS: Thirty-three lactic acid bacteria (LAB) isolated from foal's faeces were assessed based on the main desirable functional in vitro criteria. Based on these results, Pediococcus pentosaceus strain 40 was chosen to evaluate its putative probiotic features in a mouse model of Salmonella infection. Daily intragastric doses of Ped. pentosaceus 40 for 10 days before and 10 days after Salmonella challenge (106 CFU of Salm. Typhimurium per mouse) led to a significant aggravation in mouse health by increasing weight loss, worsening clinical symptoms and anticipating the time and the number of deaths by Salmonella. Pediococcus pentosaceus modulated cell-mediated immune responses by up-regulation of the gene expression of the proinflammatory cytokines IFN-γ and TNF-α in the small intestine. CONCLUSION: The usual criteria were used for in vitro screening of a large number of LAB for desirable probiotic functional properties. However, the best candidate probiotic strain identified, Ped. pentosaceus #40, aggravated the experimental disease in mice. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings emphasize the need for prophylactic or therapeutic effectiveness to be demonstrated in in vivo models to make precise health claims.

Isolation of lactic acid bacteria exhibiting high scavenging activity for environmental hydrogen peroxide from fermented foods and its two scavenging enzymes for hydrogen peroxide.

To obtain lactic acid bacteria that scavenge environmental hydrogen peroxide, we developed a specialized enrichment medium and successfully isolated Pediococcus pentosaceus Be1 strain from a fermented food. This strain showed vigorous environmental hydrogen peroxide scavenging activity over a wide range of hydrogen peroxide concentrations. High Mn-catalase and NADH peroxidase activities were found in the cell-free extract of the P. pentosaceus Be1 strain, and these two hydrogen peroxide scavenging enzymes were purified from the cell-free extract of the strain. Mn-catalase has been purified from several microorganisms by several researchers, and the NADH peroxidase was first purified from the original strain in this report. After cloning the genes of the Mn-catalase and the NADH peroxidase, the deduced amino acid sequences were compared with those of known related enzymes.