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1.
Food Microbiol ; 91: 103539, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32539972

RESUMEN

Some beverage-spoiling lactic acid bacteria (LAB) produce capsular ß-glucans from UDP-glucose, which is accompanied by cell network formation causing viscosity increases of liquids. This feature of certain LAB is feared in breweries but could be useful for structural and nutritional improvement of baked goods, provided that these LAB are suited for the manufacture of sourdoughs. The aim of this study was to investigate the persistence and ß-glucan formation of the brewery isolates Levilactobacillus (L.) brevis TMW 1.2112 and Pediococcus (P.) claussenii TMW 2.340 in wheat and rye sourdoughs. Both the wild-type strains and the respective ß-glucan-deficient mutants were dominant in wheat and rye sourdoughs and acidified them to characteristic pH ranges. The formation of ß-glucan capsules during sourdough fermentations was stable in L. brevis TMW 1.2112 in contrast to P. claussenii TMW 2.340. Wheat sourdoughs fermented with the ß-glucan producing L. brevis TMW 1.2112 cells were significantly more viscous than doughs fermented by the P. claussenii TMW 2.340 cells and the applied mutant strains. In conclusion, L. brevis TMW 1.2112 and P. claussenii TMW 2.340 were suited and persistent wheat and rye sourdough starters, while the in situ ß-glucan formation in sourdoughs was hardly detectable in case of P. claussenii.


Asunto(s)
Cerveza/microbiología , Pan/microbiología , Lactobacillales/metabolismo , Secale , Triticum , beta-Glucanos/metabolismo , Cápsulas Bacterianas/genética , Cápsulas Bacterianas/metabolismo , Pan/análisis , Recuento de Colonia Microbiana , Fermentación , Microbiología de Alimentos , Concentración de Iones de Hidrógeno , Lactobacillales/genética , Lactobacillales/crecimiento & desarrollo , Lactobacillales/aislamiento & purificación , Levilactobacillus brevis/genética , Levilactobacillus brevis/crecimiento & desarrollo , Levilactobacillus brevis/aislamiento & purificación , Levilactobacillus brevis/metabolismo , Mutación , Pediococcus/genética , Pediococcus/crecimiento & desarrollo , Pediococcus/aislamiento & purificación , Pediococcus/metabolismo , Secale/microbiología , Triticum/microbiología , Viscosidad , beta-Glucanos/análisis
2.
Int J Food Microbiol ; 266: 173-182, 2018 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-29223035

RESUMEN

Aiming at meeting the consumers' demand in terms of bio-preservation, the potential of the combination of the lactic acid bacteria fermentation and the addition of hop extract as natural preservative in breadmaking, was exploited. The antifungal properties of a hop (Humulus lupulus) extract were investigated, showing a significant inhibition of the hyphal growth of Aspergillus parasiticus, Penicillium carneum, Penicillium polonicum, Penicillium paneum, Penicillium chermesinum, Aspergillus niger, Penicillium roqueforti. Lactic acid bacteria belonging to species of Enterococcus feacium, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus helveticus, Lactobacillus curvatus, Pediococcus pentosaceus, and Pediococcus acidilactici were isolated from hop and subjected to selection based on kinetics of growth and acidification. The sourdough (hS) enriched with hop extract (hE), started with three selected strains, had phenols concentration and antioxidant activity higher than those obtained in the same condition but without the hE. Hop-sourdough used in breadmaking delayed the fungal growth (14 days), giving a bread characterized by free aminoacids concentration, antioxidant and phytase activities higher than bread started only with baker's yeast, with or without the addition of hE. Specific volume and cell-total area of the bread containing hE improved, and its sensory profile was characterized by typical sourdough attributes, and a moderate bitter/herbaceous perception.


Asunto(s)
Aspergillus/efectos de los fármacos , Pan/microbiología , Microbiología de Alimentos , Conservación de Alimentos/métodos , Lactobacillales/efectos de los fármacos , Penicillium/efectos de los fármacos , Extractos Vegetales/farmacología , Antifúngicos/farmacología , Pan/análisis , Pan/normas , Fermentación , Humulus/química , Pediococcus/crecimiento & desarrollo , Pediococcus/aislamiento & purificación , Pediococcus/metabolismo , Saccharomyces cerevisiae/metabolismo
3.
Int J Mol Sci ; 18(7)2017 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-28754020

RESUMEN

Bacterial exopolysaccharides produced by lactic acid bacteria are of increasing interest in the food industry, since they might enhance the technological and functional properties of some edible matrices. In this work, Pediococcus parvulus 2.6, which produces an O2-substituted (1,3)-ß-d-glucan exopolysaccharide only synthesised by bacteria, was proposed as a starter culture for the production of three cereal-based fermented foods. The obtained fermented matrices were naturally bio-fortified in microbial ß-glucans, and used to investigate the prebiotic potential of the bacterial exopolysaccharide by analysing the impact on the survival of a probiotic Lactobacillus plantarum strain under starvation and gastrointestinal simulated conditions. All of the assays were performed by using as control of the P. parvulus 2.6's performance, the isogenic ß-glucan non-producing 2.6NR strain. Our results showed a differential capability of P. parvulus to ferment the cereal flours. During the fermentation step, the ß-glucans produced were specifically quantified and their concentration correlated with an increased viscosity of the products. The survival of the model probiotic L. plantarum WCFS1 was improved by the presence of the bacterial ß-glucans in oat and rice fermented foods under starvation conditions. The probiotic bacteria showed a significantly higher viability when submitted to a simulated intestinal stress in the oat matrix fermented by the 2.6 strain. Therefore, the cereal flours were a suitable substrate for in situ bio-fortification with the bacterial ß-glucan, and these matrices could be used as carriers to enhance the beneficial properties of probiotic bacteria.


Asunto(s)
Grano Comestible/microbiología , Pediococcus/crecimiento & desarrollo , beta-Glucanos/metabolismo , Avena/microbiología , Fermentación , Microbiología de Alimentos , Lactobacillus plantarum/efectos de los fármacos , Oryza/microbiología , Pediococcus/metabolismo , Prebióticos/microbiología , Probióticos , beta-Glucanos/farmacología
4.
J Food Sci ; 82(1): 167-173, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27984668

RESUMEN

We examined 10 lactic acid bacteria that have been previously characterized for commercial use as probiotic cultures, mostly for dairy products, including 1 Pediococcus and 9 Lactobacilli. Our objectives were to develop a rapid procedure for determining the long-term survivability of these cultures in acidified vegetable products and to identify suitable cultures for probiotic brined vegetable products. We therefore developed assays to measure acid resistance of these cultures to lactic and acetic acids, which are present in pickled vegetable products. We used relatively high acid concentrations (compared to commercial products) of 360 mM lactic acid and 420 mM acetic acid to determine acid resistance with a 1 h treatment. Growth rates were measured in a cucumber juice medium at pH 5.3, 4.2, and 3.8, at 30 °C and 0% to 2% NaCl. Significant differences in acid resistance and growth rates were found among the 10 cultures. In general, the acid resistant strains had slower growth rates than the acid sensitive strains. Based on the acid resistance data, selected cultures were tested for long-term survival in a simulated acidified refrigerated cucumber product. We found that one of the most acid resistant strains (Lactobacillus casei) could survive for up to 63 d at 4 °C without significant loss of viability at 108 CFU/mL. These data may aid in the development of commercial probiotic refrigerated pickle products.


Asunto(s)
Ácido Acético , Cucumis sativus/microbiología , Jugos de Frutas y Vegetales/microbiología , Ácido Láctico , Lactobacillus/crecimiento & desarrollo , Pediococcus/crecimiento & desarrollo , Probióticos , Ácido Acético/farmacología , Fermentación , Microbiología de Alimentos , Humanos , Concentración de Iones de Hidrógeno , Ácido Láctico/farmacología , Lactobacillus/efectos de los fármacos , Lacticaseibacillus casei , Pediococcus/efectos de los fármacos , Refrigeración , Sales (Química) , Cloruro de Sodio , Verduras/microbiología
5.
J Appl Microbiol ; 121(3): 657-71, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27271320

RESUMEN

AIMS: The objective of this study was to investigate the effect of temperature (5-25°C) on epiphytic lactic acid bacteria (LAB) populations during 60 days of fermentation of whole-plant corn silage. METHODS AND RESULTS: Vacuum bag mini-silos of chopped whole-plant corn were incubated at five different temperatures (5, 10, 15, 20 and 25°C), according to a completely randomized design with four repetitions. The silos were opened and sampled on day 0, 1, 2, 3, 7, 28 and 60. At 20 and 25°C, Lactobacillus plantarum- and Pediococcus  pentosaceus-related operational taxonomic units (OTU) dominated the fermentation within 1 day. After 7 days, the OTU related to the heterofermentative species Lactobacillus buchneri began to appear and it eventually dominated silages incubated at these temperatures. Population dynamic of LAB at 5 and 10°C was different. At these temperatures, Leuconostoc citreum OTU was identified at the beginning of the fermentation. Thereafter, Lactobacillus sakei- and Lactobacillus curvatus-related OTU appeared and quickly prevailed. Corn silage at 15°C acted as a transition between 20-25°C and 5-10°C, in terms of LAB diversity and succession. CONCLUSION: The conditions of silage incubation temperature affect species diversity of LAB population with notable difference along the temperature gradient. Colder temperature conditions (5 and 10°C) have led to the identification of LAB species never observed in corn silage. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated the impact of temperature gradient on the diversity and some important population shift of lactic acid bacteria communities during fermentation of corn silage.


Asunto(s)
Lactobacillus/metabolismo , Pediococcus/metabolismo , Ensilaje/microbiología , Zea mays/microbiología , Aerobiosis , Fermentación , Concentración de Iones de Hidrógeno , Lactobacillus/clasificación , Lactobacillus/crecimiento & desarrollo , Pediococcus/crecimiento & desarrollo , Temperatura
6.
Food Microbiol ; 57: 178-86, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27052717

RESUMEN

Sunflower flour provides a high content of protein with a well-balanced amino acid composition and is therefore regarded as an attractive source for protein. The use for human nutrition is hindered by phenolic compounds, mainly chlorogenic acid, which can lead under specific circumstances to undesirable discolorations. In this study, growth behavior and degradation ability of chlorogenic acid of four lactic acid bacteria were explored. Data suggested that significant higher fermentation performances on sunflower flour as compared to sunflower protein concentrate were reached by Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus gasseri and Bifidobacterium animalis subsp. lactis. In fermentation with the latter two strains reduced amounts of chlorogenic acid were observed in sunflower flour (-11.4% and -19.8%, respectively), which were more pronounced in the protein concentrate (-50.7% and -95.6%, respectively). High tolerances against chlorogenic acid and the cleavage product quinic acid with a minimum inhibitory concentration (MIC) of ≥20.48 mg/ml after 48 h were recorded for all strains except Bifidobacterium animalis subsp. lactis, which was more sensitive. The second cleavage compound, caffeic acid revealed a higher antimicrobial potential with MIC values of 0.64-5.12 mg/ml. In this proof of concept study, degradation versus inhibitory effect suggest the existence of basic mechanisms of interaction between phenolic acids in sunflower and lactic acid bacteria and a feasible way to reduce the chlorogenic acid content, which may help to avoid undesired color changes.


Asunto(s)
Bifidobacterium/metabolismo , Harina/microbiología , Helianthus/microbiología , Hidroxibenzoatos/metabolismo , Lactobacillus/metabolismo , Pediococcus/metabolismo , Bifidobacterium/crecimiento & desarrollo , Ácido Clorogénico/análisis , Ácido Clorogénico/metabolismo , Harina/análisis , Helianthus/química , Hidroxibenzoatos/análisis , Ácido Láctico , Lactobacillus/crecimiento & desarrollo , Pediococcus/crecimiento & desarrollo
7.
Int J Food Microbiol ; 216: 60-8, 2016 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-26398285

RESUMEN

Beer contains only limited amounts of readily fermentable carbohydrates and amino acids. Beer spoilage lactic acid bacteria (LAB) have to come up with metabolic strategies in order to deal with selective nutrient content, high energy demand of hop tolerance mechanisms and a low pH. The metabolism of 26 LAB strains of 6 species and varying spoilage potentialwas investigated in order to define and compare their metabolic capabilities using multivariate statistics and outline possible metabolic strategies. Metabolic capabilities of beer spoilage LAB regarding carbohydrate and amino acids did not correlate with spoilage potential, but with fermentation type (heterofermentative/homofermentative) and species. A shift to mixed acid fermentation by homofermentative (hof) Pediococcus claussenii and Lactobacillus backii was observed as a specific feature of their growth in beer. For heterofermentative (hef) LAB a mostly versatile carbohydrate metabolism could be demonstrated, supplementing the known relevance of organic acids for their growth in beer. For hef LAB a distinct amino acid metabolism, resulting in biogenic amine production, was observed, presumably contributing to energy supply and pH homeostasis.


Asunto(s)
Cerveza/microbiología , Metabolismo de los Hidratos de Carbono/fisiología , Fermentación/fisiología , Lactobacillus/metabolismo , Pediococcus/metabolismo , Aminoácidos/metabolismo , Microbiología de Alimentos , Ácido Láctico/metabolismo , Lactobacillus/crecimiento & desarrollo , Pediococcus/crecimiento & desarrollo
8.
J Biotechnol ; 217: 112-21, 2016 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-26616423

RESUMEN

Pediococcus acidilactici TY112 producing L-lactic acid and P. acidilactici ZP26 producing D-lactic acid, were engineered from the wild-type P. acidilactici DQ2 by ldhD or ldh gene disruption, and the robustness of the wild-type strain to the inhibitors derived from lignocellulose pretreatment was maintained well. In simultaneous saccharification and fermentation (SSF), 77.66 g L(-1) of L-lactic acid and 76.76 g L(-1) of D-lactic acid were obtained at 25% (w/w) solids content of dry dilute acid pretreated and biodetoxified corn stover feedstock. L- and D-Lactic acid yield and productivity were highly dependent on the inhibitor removal extent due to the significant down-regulation on the expressions of ldh and ldhD encoding lactate dehydrogenase by inhibitor, especially syringaldehyde and vanillin at the low concentrations. This study provided a prototype of industrial process for high titer L- and D-lactic acid production from lignocellulose feedstock.


Asunto(s)
Ingeniería Genética , Ácido Láctico/biosíntesis , Lignina/metabolismo , Pediococcus/genética , Pediococcus/metabolismo , Secuencia de Bases , Biomasa , Regulación hacia Abajo , Escherichia coli/genética , Escherichia coli/metabolismo , Fermentación , Ingeniería Genética/métodos , Glucosa/metabolismo , L-Lactato Deshidrogenasa/genética , L-Lactato Deshidrogenasa/metabolismo , Ácido Láctico/análisis , Ácido Láctico/metabolismo , Datos de Secuencia Molecular , Pediococcus/crecimiento & desarrollo , Xilosa/metabolismo , Zea mays
9.
J Dairy Sci ; 98(9): 5967-73, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26142849

RESUMEN

Deep sea water (DSW) has health benefits and is widely used as food supplement; however, its effect in fermented products has not been explored. Here, we investigated the effect of DSW-containing yogurt on health-related serum parameters and intestinal microbiota in mice. Animals were assigned to 3 feeding groups, which received water (control), normal yogurt (N-yogurt), or DSW-containing yogurt (DSW-yogurt) with a basal diet. Mice were killed at wk 4 or 8 of feeding and analyzed for serum parameters and microbial population in the small intestine. Both yogurt groups demonstrated increased populations of intestinal lactic acid bacteria compared with the control group. The activity of serum aspartate aminotransferase and alanine aminotransferase was markedly decreased in the DSW-yogurt and N-yogurt groups, and triglyceride level tended to be lower in the DSW-yogurt group compared with that in the control mice. Furthermore, the DSW-yogurt group showed a more significant decrease in the ratio of total cholesterol to high-density lipoprotein-cholesterol than did the N-yogurt group. These findings suggest that DSW supplementation of yogurt can increase its beneficial effects on lipid metabolism.


Asunto(s)
Microbioma Gastrointestinal , Intestinos/microbiología , Agua de Mar/análisis , Yogur/análisis , Alanina Transaminasa/sangre , Animales , Aspartato Aminotransferasas/sangre , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Lactobacillus/crecimiento & desarrollo , Ratones , Pediococcus/crecimiento & desarrollo , Triglicéridos/sangre , Yogur/microbiología
10.
Arch Microbiol ; 197(7): 955-63, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26159350

RESUMEN

The present investigation deals with the optimization of cell growth rate of the candidate probiotic Pediococcus acidilactici in the presence of the specific prebiotic inulin. Three independent variables viz. concentration of inulin, concentration of glucose and pH have been selected for optimization study using response surface methodology. Theoretical analysis indicates that the maximum cell growth rate occurs at pH 7, 20 g/dm(3) concentration of inulin and 20 g/dm(3) concentration of glucose. Validation of these values has been done through a set of programmed experiments. Studies on cell dynamics in the presence of different concentrations of inulin have also been carried out to identify any limitation on the initial inulin concentration. Results clearly indicate that cell growth is enhanced with the increase in inulin concentration. However, there is a critical value of the prebiotic concentration (20 g/dm(3) inulin) beyond which the cell growth is inhibited. A summative type growth model has been proposed to explain the growth behaviour of P. acidilactici in the presence of the dual substrate, i.e. glucose and inulin. While growth on glucose follows Monod model, Haldane-type substrate-inhibited growth model holds good for growth on inulin. Intrinsic kinetic parameters for all the model equations have been determined experimentally.


Asunto(s)
Inulina/farmacología , Pediococcus/efectos de los fármacos , Pediococcus/crecimiento & desarrollo , Ambiente , Glucosa/metabolismo , Cinética , Modelos Biológicos , Prebióticos , Probióticos
11.
Biomed Res Int ; 2015: 315819, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26101771

RESUMEN

The suitable properties of potential probiotic lactic acid bacteria (LAB) strains (preselected among 153 strains on the basis of their potential technological properties) isolated from traditional Çubuk pickles were examined in vitro. For this purpose, these strains (21 Lactobacillus plantarum, 11 Pediococcus ethanolidurans, and 7 Lactobacillus brevis) were tested for the ability to survive at pH 2.5, resistance to bile salts, viability in the presence of pepsin-pancreatin, ability to deconjugate bile salts, cholesterol assimilation, and surface hydrophobicity properties. Most of the properties tested could be assumed to be strain-dependent. However, L. plantarum and L. brevis species were found to possess desirable probiotic properties to a greater extent compared to P. ethanolidurans. In contrast to P. ethanolidurans strains, the tested L. plantarum and L. brevis strains exhibited bile salt tolerance, albeit to different extent. All tested strains showed less resistance to intestinal conditions than gastric juice environment. Based on the survival under gastrointestinal conditions, 22 of the 39 strains were selected for further characterization. The eight strains having the highest cholesterol assimilation and surface hydrophobicity ratios could be taken as promising probiotic candidates for further in vivo studies, because of the strongest variations found among the tested strains with regard to these properties.


Asunto(s)
Microbiología de Alimentos , Viabilidad Microbiana/efectos de los fármacos , Probióticos/metabolismo , Ácidos y Sales Biliares/toxicidad , Jugo Gástrico/efectos de los fármacos , Concentración de Iones de Hidrógeno , Ácido Láctico/metabolismo , Levilactobacillus brevis/efectos de los fármacos , Levilactobacillus brevis/crecimiento & desarrollo , Lactobacillus plantarum/efectos de los fármacos , Pediococcus/efectos de los fármacos , Pediococcus/crecimiento & desarrollo , Pepsina A/metabolismo , Probióticos/aislamiento & purificación
12.
J Food Prot ; 78(5): 934-9, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25951387

RESUMEN

Pediococcus acidilactici ATCC 8042 and Enterococcus faecium NRRL B-2354 were investigated as potential surrogates for Salmonella serovars using thermal death time kinetics in products such as dry pet foods. The D-values of P. acidilactici ATCC 8042, E. faecium NRRL B-2354, and a cocktail of seven Salmonella serovars associated with low-moisture products were determined in a preservative-free dry pet food product at moisture levels of 9.1, 17.9, and 27.0% and heated between 76.7 and 87.8°C. The D-values were calculated by least squares linear regression. The D-values of P. acidilactici ATCC 8042 were higher than those for the Salmonella serovar cocktail but lower than those for E. faecium NRRL 2354. At 9.1% moisture, D-values of 6.54, 11.51, and 11.66 min at 76.7°C, 2.66, 3.22, and 4.08 min at 82.2°C, and 1.07, 1.29, and 1.69 min at 87.8°C were calculated for Salmonella serovars, P. acidilactici ATCC 8042, and E. faecium NRRL B-2354, respectively. The data suggest that the thermal inactivation characteristics of P. acidilactici ATCC 8042 can be utilized as a surrogate to predict the response of Salmonella in dry pet food products that are thermally processed at <90°C.


Asunto(s)
Alimentación Animal/microbiología , Enterococcus faecium/crecimiento & desarrollo , Manipulación de Alimentos/métodos , Pediococcus/crecimiento & desarrollo , Salmonella/crecimiento & desarrollo , Alimentación Animal/análisis , Recuento de Colonia Microbiana , Enterococcus faecium/química , Contaminación de Alimentos/análisis , Calor , Cinética , Pediococcus/química , Salmonella/química , Agua/análisis
13.
J Dairy Sci ; 98(1): 478-85, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25465545

RESUMEN

The objective of this study was to compare the efficacy of using 4 commercially available microbial inoculants to improve the fermentation and aerobic stability of bermudagrass haylage. We hypothesized that the microbial inoculants would increase the fermentation and aerobic stability of the haylages. Bermudagrass (4-wk regrowth) was harvested and treated with (1) deionized water (control); (2) Buchneri 500 (B500; Lallemand Animal Nutrition, Milwaukee, WI) containing 1×10(5) of Pediococcus pentosaceus and 4×10(5) of Lactobacillus buchneri 40788; (3) Biotal Plus II (BPII; Lallemand Animal Nutrition) containing 1.2×10(5) of P. pentosaceus and Propionibacteria freudenreichii; (4) Silage Inoculant II (SI; AgriKing Inc., Fulton, IL) containing 1×10(5) of Lactobacillus plantarum and P. pentosaceus; and (5) Silo King (SK; AgriKing Inc.), containing 1×10(5) of L. plantarum, Enterococcus faecium, and P. pentosaceus, respectively. Forty round bales (8 per treatment; 441±26kg; 1.2×1.2 m diameter) were made and each was wrapped with 7 layers of plastic. Twenty bales were stored for 112 d and the remaining 20 were stored for 30 d and sampled by coring after intermediary storage periods of 0, 3, 7, and 30 d. The pH of control and inoculated haylages sampled on d 3 did not differ. However, B500 and BPII had lower pH (5.77±0.04 vs. 6.16±0.04; 5.06±0.13 vs. 5.52±0.13) than other treatments by d 7 and 30, respectively. At final bale opening on d 112, all treatments had lower pH than the control haylage (4.77±0.07 vs. 5.37±0.07). The B500, BPII, and SI haylages had greater lactic acid and lactic-to-acetic acid ratios than SK and control haylages. No differences were detected in neutral detergent fiber digestibility, dry matter losses, dry matter, lactic and acetic acid concentrations, and yeast and coliform counts. The SK haylage had lower clostridia counts compared with the control (1.19±0.23 vs. 1.99±0.23 cfu/g). Treatments B500, BPII, SI, and SK tended to reduce mold counts and they improved aerobic stability by 236, 197, 188, and 95%, respectively, compared with the control (276±22 vs. 99±22h).


Asunto(s)
Cynodon/microbiología , Ensilaje/microbiología , Zea mays/microbiología , Ácido Acético/metabolismo , Inoculantes Agrícolas , Cynodon/química , Fibras de la Dieta/metabolismo , Enterococcus faecium/crecimiento & desarrollo , Fermentación , Concentración de Iones de Hidrógeno , Ácido Láctico/metabolismo , Lactobacillus/crecimiento & desarrollo , Pediococcus/crecimiento & desarrollo , Propionibacterium/crecimiento & desarrollo , Ensilaje/análisis , Levaduras/crecimiento & desarrollo , Zea mays/química
14.
J Food Prot ; 77(9): 1501-11, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25198841

RESUMEN

The non-O157 Shiga toxigenic Escherichia coli (STEC) serogroups most commonly associated with illness are O26, O45, O103, O111, O121, and O145. We compared the thermal tolerance (D55°C) of three or more strains of each of these six non-O157 STEC serogroups with five strains of O157:H7 STEC in 7% fat ground beef. D55°C was also determined for at least one heat-tolerant STEC strain per serogroup in 15 and 27% fat ground beef. D55°C of single-pathogen cocktails of O157 and non-O157 STEC, Salmonella, and potential pathogen surrogates, Pediococcus acidilactici and Staphylococcus carnosus, was determined in 7, 15, and 27% fat ground beef and in frankfurter batter. Samples (25 g) were heated for up to 120 min at 55°C, survivors were enumerated, and log CFU per gram was plotted versus time. There were significant differences in D55°C across all STEC strains heated in 7% fat ground beef (P < 0.05), but no non-O157 STEC strain had D55°C greater than the range observed for O157 STEC. D55°C was significantly different for strains within serogroups O45, O145, and O157 (P < 0.05). D55°C for non-O157 STEC strains in 15 and 27% fat ground beef were less than or equal to the range of D55°C for O157. D55°C for pathogen cocktails was not significantly different when measured in 7, 15, and 27% fat ground beef (P ≥ 0.05). D55°C of Salmonella in frankfurter batter was significantly less than for O157 and non-O157 STEC (P < 0.05). Thermal tolerance of pathogen cocktails in ground beef (7, 15, or 27% fat) and frankfurter batter was significantly less than for potential pathogen surrogates (P < 0.05). Results suggest that thermal processes in beef validated against E. coli O157:H7 have adequate lethality against non-O157 STEC, that thermal processes that target Salmonella destruction may not be adequate against STEC in some situations, and that the use of pathogen surrogates P. acidilactici and S. carnosus to validate thermal processing interventions in ground beef and frankfurter batter would be of limited utility to processors.


Asunto(s)
Escherichia coli O157/crecimiento & desarrollo , Grasas/análisis , Productos de la Carne/microbiología , Carne/microbiología , Salmonella/crecimiento & desarrollo , Escherichia coli Shiga-Toxigénica/crecimiento & desarrollo , Animales , Bovinos , Escherichia coli O157/química , Microbiología de Alimentos , Calor , Carne/análisis , Productos de la Carne/análisis , Pediococcus/química , Pediococcus/crecimiento & desarrollo , Salmonella/química , Escherichia coli Shiga-Toxigénica/química , Staphylococcus/química , Staphylococcus/crecimiento & desarrollo
15.
BMC Microbiol ; 14: 226, 2014 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-25158757

RESUMEN

BACKGROUND: Species of the genus Pediococcus are known to produce antimicrobial peptides such as pediocin-like bacteriocins that contain YGNGVXC as a conserved motif at their N-terminus. Until now, the molecular weight of various bacteriocins produced by different strains of the genus Pediococcus have been found to vary between 2.7 to 4.6 kD. In the present study, we characterized an antimicrobial peptide produced by P. pentosaceus strain IE-3. RESULTS: Antimicrobial peptide was isolated and purified from the supernatant of P. pentosaceus strain IE-3 grown for 48 h using cation exchange chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC) techniques. While MALDI-TOF MS experiments determined the precise molecular mass of the peptide to be 1701.00 Da, the de novo sequence (APVPFSCTRGCLTHLV) of the peptide revealed no similarity with reported pediocins and did not contain the YGNGVXC conserved motif. Unlike pediocin-like bacteriocins, the low molecular weight peptide (LMW) showed resistance to different proteases. Moreover, peptide treated with reducing agent like dithiothreitol (DTT) exhibited increased activity against both Gram-positive and Gram-negative test strains in comparison to native peptide. However, peptide treated with oxidizing agent such as hydrogen peroxide (H2O2) did not show any antimicrobial activity. CONCLUSION: To our knowledge this is the lowest molecular weight peptide produced by members of the genus Pediococcus. The low molecular weight peptide shared amino acid arrangement with N-terminal sequence of Class IIa, pediocin-like bacteriocins and showed increased activity under reducing conditions. Antimicrobial peptides active under reduced conditions are valuable for the preservation of processed foods like meat, dairy and canned foods where low redox potential prevails.


Asunto(s)
Péptidos Catiónicos Antimicrobianos/farmacología , Pediococcus/metabolismo , Secuencia de Aminoácidos , Péptidos Catiónicos Antimicrobianos/química , Péptidos Catiónicos Antimicrobianos/aislamiento & purificación , Péptidos Catiónicos Antimicrobianos/metabolismo , Cromatografía Líquida de Alta Presión , Cromatografía por Intercambio Iónico , Ditiotreitol/metabolismo , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Peso Molecular , Oxidación-Reducción , Pediococcus/crecimiento & desarrollo , Sustancias Reductoras/metabolismo , Análisis de Secuencia de Proteína , Homología de Secuencia de Aminoácido , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
16.
J Dairy Sci ; 97(7): 4423-32, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24792798

RESUMEN

The objectives of this study were to characterize and quantify the microbial populations in guinea grass (Panicum maximum Jacq. cultivar Mombasa) harvested at different regrowth intervals (35, 45, 55, and 65 d). The chemical composition and fermentation profile of silages (after 60 d) with or without the addition of a microbial inoculant were also analyzed. Before ensiling, samples of the plants were used for the isolation and identification of lactic acid bacteria (LAB) in the epiphytic microbiota. A 4 × 2 factorial arrangement of treatments (4 regrowth intervals × with/without inoculant) was used in a completely randomized design with 3 replications. Based on the morphological and biochemical characteristics and the carbohydrate fermentation profile, Lactobacillus plantarum was found to be the predominant specie of LAB in guinea grass forage. Linear increases were detected in the dry matter (DM) content and concentrations of neutral detergent fiber, acid detergent fiber, acid detergent insoluble nitrogen, and DM recovery as well as linear reductions in the concentrations of crude protein and NH3-N with regrowth interval. Additionally, linear reductions for gas and effluent losses in silages were detected with increasing regrowth interval. These results demonstrate that guinea grass plants harvested after 55 d of regrowth contain a LAB population sufficiently large to ensure good fermentation and increase the DM recovery. The use of microbial inoculant further enhanced the fermentation of guinea grass at all stages of regrowth by improving the DM recovery.


Asunto(s)
Inoculantes Agrícolas/crecimiento & desarrollo , Fermentación , Panicum/microbiología , Ensilaje/microbiología , Brasil , Fibras de la Dieta/análisis , Proteínas en la Dieta/análisis , Enterococcus faecium/crecimiento & desarrollo , Concentración de Iones de Hidrógeno , Lactobacillus/crecimiento & desarrollo , Lactobacillus plantarum/crecimiento & desarrollo , Modelos Lineales , Pediococcus/crecimiento & desarrollo , Ensilaje/análisis
17.
Lett Appl Microbiol ; 59(3): 299-305, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24749686

RESUMEN

UNLABELLED: The diversity of lactic acid bacteria (LAB) species in donkey's milk was analysed by culture-dependent microbial techniques. Dominant strains were isolated on agar media generally used for enumerating LAB. To enrich the number of acidifying LAB present, the milk samples were incubated at 37°C for 24 h (cultured milk samples, CM). One of the CM samples was heat-treated at 63°C for 10 min before incubation at 37°C (heat-treated and cultured milk sample, TCM) to select thermophilic LAB. The microflora in these CM and TCM samples was then compared to that of the raw milk samples (RM). Among the 129 LAB isolates, 10 different species (four Enterococcus, five Streptococcus and one Pediococcus) were identified by molecular methods. Although the 10 LAB species were present in the RM samples, only three and two isolates were found in CM and TCM samples, respectively. Despite the selection protocol being set up to favour the isolation of all LAB isolates present in donkey milk, relatively few species and biotypes were isolated. No LAB isolates belonging to the most technologically important dairy starter species were detected. The possible factors related to the limited LAB diversity in donkey's milk have been discussed below. SIGNIFICANCE AND IMPACT OF THE STUDY: There is increased interest in using donkey's milk as a source of human nutrition. The large amounts of antimicrobial components and defence factors present in donkey's milk provide protection from microbial infections and distinguish donkey's milk from the milks of other mammals. However, the microbiota in donkey's milk has so far been poorly characterized, specifically with regard to the lactic acid bacteria (LAB). This study has identified cultivable, acidifying and thermoduric LAB that could be used to develop starter cultures. This is the first study to investigate the culturable LAB microbiota present in donkey's milk.


Asunto(s)
Enterococcus/genética , Leche/microbiología , Pediococcus/genética , Streptococcus/genética , Animales , Técnicas de Cultivo , Enterococcus/crecimiento & desarrollo , Enterococcus/aislamiento & purificación , Equidae , Genes Bacterianos , Humanos , Microbiota/genética , Tipificación Molecular , Pediococcus/crecimiento & desarrollo , Pediococcus/aislamiento & purificación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ARN , Streptococcus/crecimiento & desarrollo , Streptococcus/aislamiento & purificación
18.
Appl Microbiol Biotechnol ; 98(12): 5619-32, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24639205

RESUMEN

This work investigated the effect of the intragastric administration of five lactic acid bacteria from healthy people on acute liver failure in rats. Sprague-Dawley rats were given intragastric supplements of Lactobacillus salivarius LI01, Lactobacillus salivarius LI02, Lactobacillus paracasei LI03, Lactobacillus plantarum LI04, or Pediococcus pentosaceus LI05 for 8 days. Acute liver injury was induced on the eighth day by intraperitoneal injection of 1.1 g/kg body weight D-galactosamine (D-GalN). After 24 h, samples were collected to determine the level of liver enzymes, liver function, histology of the terminal ileum and liver, serum levels of inflammatory cytokines, bacterial translocation, and composition of the gut microbiome. The results indicated that pretreatment with L. salivarius LI01 or P. pentosaceus LI05 significantly reduced elevated alanine aminotransferase and aspartate aminotransferase levels, prevented the increase in total bilirubin, reduced the histological abnormalities of both the liver and the terminal ileum, decreased bacterial translocation, increased the serum level of interleukin 10 and/or interferon-γ, and resulted in a cecal microbiome that differed from that of the liver injury control. Pretreatment with L. plantarum LI04 or L. salivarius LI02 demonstrated no significant effects during this process, and pretreatment with L. paracasei LI03 aggravated liver injury. To the best of our knowledge, the effects of the three species-L. paracasei, L. salivarius, and P. pentosaceus-on D-GalN-induced liver injury have not been previously studied. The excellent characteristics of L. salivarius LI01 and P. pentosaceus LI05 enable them to serve as potential probiotics in the prevention or treatment of acute liver failure.


Asunto(s)
Enfermedad Hepática Inducida por Sustancias y Drogas/prevención & control , Galactosamina/toxicidad , Lactobacillus/crecimiento & desarrollo , Pediococcus/crecimiento & desarrollo , Probióticos/administración & dosificación , Alanina Transaminasa/sangre , Animales , Aspartato Aminotransferasas/sangre , Bilirrubina/sangre , Citocinas/sangre , Histocitoquímica , Íleon/patología , Hígado/patología , Pruebas de Función Hepática , Ratas Sprague-Dawley , Resultado del Tratamiento
19.
Poult Sci ; 93(2): 434-40, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24570466

RESUMEN

Yerba mate (Ilex paraguariensis) is a tea known to have beneficial effects on human health and antimicrobial activity against some foodborne pathogens. Thus, the application of yerba mate as a feed additive for broiler chickens to reduce Salmonella colonization was evaluated. The first in vitro evaluation was conducted by suspending Salmonella Enteritidis and lactic acid bacteria (LAB) in yerba mate extract. The in vivo evaluations were conducted using preventative and horizontal transmission experiments. In all experiments, day-of-hatch chicks were treated with one of the following 1) no treatment (control); 2) ground yerba mate in feed; 3) probiotic treatment (Lactobacillus acidophilus and Pediococcus; 9:1 administered once on day of hatch by gavage); or 4) both yerba mate and probiotic treatments. At d 3, all chicks were challenged with Salmonella Enteritidis (preventative experiment) or 5 of 20 chicks (horizontal transmission experiment). At d 10, all birds were euthanized, weighed, and cecal contents enumerated for Salmonella. For the in vitro evaluation, antimicrobial activity was observed against Salmonella and the same treatment enhanced growth of LAB. For in vivo evaluations, none of the yerba mate treatments significantly reduced Salmonella Enteritidis colonization, whereas the probiotic treatment significantly reduced Salmonella colonization in the horizontal transmission experiment. Yerba mate decreased chicken BW and decreased the performance of the probiotic treatment when used in combination. In conclusion, yerba mate had antimicrobial activity against foodborne pathogens and enhanced the growth of LAB in vitro, but in vivo yerba mate did not decrease Salmonella Enteritidis colonization.


Asunto(s)
Bacterias/efectos de los fármacos , Pollos , Ilex paraguariensis/química , Enfermedades de las Aves de Corral/tratamiento farmacológico , Probióticos/farmacología , Salmonelosis Animal/tratamiento farmacológico , Alimentación Animal/análisis , Animales , Bacterias/crecimiento & desarrollo , Ciego/microbiología , Dieta/veterinaria , Suplementos Dietéticos/análisis , Lactobacillus/efectos de los fármacos , Lactobacillus/crecimiento & desarrollo , Pediococcus/efectos de los fármacos , Pediococcus/crecimiento & desarrollo , Extractos Vegetales/química , Hojas de la Planta/química , Enfermedades de las Aves de Corral/microbiología , Probióticos/administración & dosificación , Salmonelosis Animal/microbiología , Salmonella enteritidis/efectos de los fármacos , Salmonella enteritidis/crecimiento & desarrollo
20.
Food Chem ; 145: 840-4, 2014 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-24128554

RESUMEN

The proteolysis in grass carp sausages inoculated with Lactobacillus plantarum ZY40 and Pediococcus pentosaceus GY23 was investigated. As fermentation progressed, sarcoplasmic and myofibrillar proteins in both sausages were obviously degraded, and the proteolytic process was more intense in sausages inoculated with P. pentosaceus GY23. The increases in α-amino nitrogen, trichloroacetic acid (TCA)-soluble peptides and free amino acids were also detected in both sausages. The differences in α-amino nitrogen content and free amino acids concentration were due to the activity of inoculated lactic acid bacteria, while endogenous enzymes contributed to the release of TCA-soluble peptides. Our findings indicate that lactic acid bacteria influence proteolytic characterisation in fermented fish sausage, with strain-dependent activity.


Asunto(s)
Carpas , Proteínas en la Dieta/metabolismo , Productos Pesqueros/análisis , Proteínas de Peces/metabolismo , Alimentos en Conserva/análisis , Lactobacillus plantarum/metabolismo , Pediococcus/metabolismo , Aminoácidos/análisis , Aminoácidos/metabolismo , Animales , China , Dieta/etnología , Proteínas en la Dieta/análisis , Proteínas en la Dieta/química , Fermentación , Productos Pesqueros/microbiología , Proteínas de Peces/análisis , Proteínas de Peces/química , Almacenamiento de Alimentos , Alimentos en Conserva/microbiología , Humanos , Concentración de Iones de Hidrógeno , Lactobacillus plantarum/crecimiento & desarrollo , Lactobacillus plantarum/aislamiento & purificación , Proteínas Musculares/análisis , Proteínas Musculares/química , Proteínas Musculares/metabolismo , Pediococcus/crecimiento & desarrollo , Pediococcus/aislamiento & purificación , Fragmentos de Péptidos/análisis , Fragmentos de Péptidos/metabolismo , Proteolisis , Cloruro de Sodio Dietético/análisis , Especificidad de la Especie
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