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1.
Chem Pharm Bull (Tokyo) ; 68(1): 46-57, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31902901

RESUMO

Over the past decade, a number of new 1,4-naphthoquinones have been isolated from natural sources and new 1,4-naphthoquinones with diverse structural features have been synthesized. Cardioprotective, anti-ischemic, hepatoprotective, neuroprotective and some other new properties were found for these compounds; their role in protecting against neurodegenerative diseases has been established. Their anti-inflammatory, antimicrobial and antitumor activities have been studied in more detail; new, previously unknown intracellular molecular targets and mechanisms of action have been discovered. Some compounds of this class are already being used as a medicinal drugs and some substances can be used as biochemical tools and probes for non-invasive detection of pathological areas in cells and tissues in myocardial infarction and neurodegenerative diseases using modern molecular imaging techniques.


Assuntos
Anti-Infecciosos/química , Anti-Inflamatórios/química , Naftoquinonas/química , Substâncias Protetoras/química , Anti-Infecciosos/farmacologia , Anti-Inflamatórios/farmacologia , Bactérias/efeitos dos fármacos , Citocinas/metabolismo , Humanos , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Naftoquinonas/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Substâncias Protetoras/farmacologia , Trypanosoma/efeitos dos fármacos
2.
Anticancer Res ; 40(1): 551-556, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31892611

RESUMO

BACKGROUND/AIM: To investigate the effects of vitamin D3 supplementation on gut microbiota. PATIENTS AND METHODS: Twenty adults with vitamin D insufficiency/deficiency [25(OH)D <30 ng/ml] were enrolled and given 600, 4,000 or 10,000 IUs/day of oral vitamin D3 Stool samples were collected at baseline and 8 weeks for identifying gut microbiota using 16S rRNA gene amplification and sequencing. RESULTS: Baseline serum 25(OH)D was associated with increased relative abundance of Akkermansia and decreased relative abundance of Porphyromonas (p<0.05). After the intervention, we observed a dose-dependent increase in relative abundance of Bacteroides with a significant difference between the 600 IUs and the 10,000 IUs groups (p=0.027), and Parabacteroides with a significant difference between the 600 IUs and the 4,000 IUs groups (p=0.039). CONCLUSION: Increased serum 25(OH)D was associated with increased beneficial bacteria and decreased pathogenic bacteria. A dose-dependent increase in bacteria associated with decreased inflammatory bowel disease activity was observed after vitamin D3 supplementation.


Assuntos
Colecalciferol/administração & dosagem , Colecalciferol/farmacologia , Suplementos Nutricionais , Microbioma Gastrointestinal/efeitos dos fármacos , Administração Oral , Adulto , Bactérias/efeitos dos fármacos , Relação Dose-Resposta a Droga , Método Duplo-Cego , Humanos
3.
Orv Hetil ; 161(2): 50-55, 2020 Jan.
Artigo em Húngaro | MEDLINE | ID: mdl-31902236

RESUMO

Introduction: Exudative tonsillitis is a common clinical picture during childhood. The majority of these cases are caused by viruses (Epstein-Barr virus [EBV], cytomegalovirus [CMV], influenza virus, parainfluenza virus, and adenovirus), and only some infections are caused by bacteria, mainly group A streptococci (GAS). On the basis of international guidelines, routine use of early antibiotic treatment is not recommended in these cases, because it seems not to prevent GAS-associated complications. Aim: Our aim was to determine those laboratory results which are useful to distinguish between bacterial and viral infections in children with exudative tonsillitis to reduce antibiotic overuse. Method: In our study, we evaluated 135 clinical data from 133 children with exudative tonsillitis. Patients were grouped according to the following criteria: the first group contained patients with acute CMV or EBV infections, while in the second group, CMV or EBV infections were not confirmed using serology. Results: On the basis of our results, EBV or CMV infections (66/135, 48.8%) were serologically confirmed in the majority of cases with exudative tonsillitis between 2016 and 2017, while the causative role of GAS was minimal in this patient group (3/65, 4.61%). In spite of this finding, the majority of patients (92%) were treated with antibiotics. Conclusion: Our retrospective findings confirmed that it is not possible to determine the causative agent of this clinical picture on the basis of symptoms, and physical findings, moreover laboratory results, such as high white blood cell count could not confirm bacterial infection. At the same time, elevated transaminase levels may refer to viral origin of infection, especially EBV or CMV with high predictive value; the use of extended laboratory tests may reduce the unnecessary antibiotic consumption. Orv Hetil. 2020; 161(2): 50-55.


Assuntos
Infecções Estreptocócicas/etiologia , Tonsilite/etiologia , Viroses/etiologia , Antibacterianos/uso terapêutico , Anticorpos Antibacterianos/análise , Anticorpos Antivirais/análise , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/tratamento farmacológico , Criança , Humanos , Faringe/microbiologia , Faringe/virologia , Estudos Retrospectivos , Tonsilite/tratamento farmacológico , Viroses/diagnóstico , Viroses/tratamento farmacológico
4.
Medicine (Baltimore) ; 99(1): e18494, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31895783

RESUMO

INTRODUCTION: Peripherally inserted central catheters (PICC-line) are devices inserted through peripheral venous access. In our institution, this technology has been rapidly adopted by physicians in their routine practice. Bacteremia on catheters remains an important public health issue in France. However, the mortality attributable to bacteremia on PICC-line remains poorly evaluated in France and in the literature in general. We report in our study an exhaustive inventory of bacteremia on PICC-line and their 30 days mortality, over a 7 years period. MATERIAL AND METHODS: From January 2010 to December 2016, we retrospectively matched PICC-line registers of the radiology department, blood culture records of the microbiology laboratory and medical records from the Hospital Information Systems. RESULTS: The 11,334 hospital stays during which a PICC-line was inserted were included over a period of 7 years. Among them, 258 episodes of PICC-line-associated bacteremia were recorded, resulting in a prevalence of 2.27%. Hematology units: 20/324 (6.17%), oncology units: 55/1375 (4%) and hepato-gastro-enterology units: 42/1142 (3.66%) had the highest prevalence of PICC-line related bacteremia. The correlation analysis, when adjusted by exposure and year, shows that the unit profile explains 72% of the variability in the rate of bacteremia with a P = .023. Early bacteremia, occurring within 21 days of insertion, represented 75% of cases. The crude death ratio at 30 days, among patients PICC-line associated bacteremia was 57/11 334 (0.50%). The overall 30-day mortality of patients with PICC-line with and without bacteremia was 1369/11334 (12.07%). On day 30, mortality of patients with bacteremia associated PICC-line was 57/258 or 22.09% of cases, compared to a mortality rate of 1311/11076, or 11.83% in the control group (P < .05, RR 2.066 [1.54-2.75]). Kaplan-Meier survival analysis revealed a statistically significant excess mortality between patients with PICC-line associated bacteremia and PICC-line carriers without bacteremia (P < .0007, hazard ratio 1.89 [1307-2709]). CONCLUSION: Patients with PICC-line associated bacteremia have a significant excess mortality. The implementation of a PICC-line should remain the last resort after a careful assessment of the benefit/risk ratio by a senior doctor.


Assuntos
Infecções Relacionadas a Cateter/mortalidade , Cateterismo Venoso Central/efeitos adversos , Cateterismo Periférico/efeitos adversos , Cateteres de Demora/efeitos adversos , Idoso , Bacteriemia/microbiologia , Bacteriemia/mortalidade , Estudos de Casos e Controles , França/epidemiologia , Hospitais Públicos/estatística & dados numéricos , Humanos , Estimativa de Kaplan-Meier , Tempo de Internação/estatística & dados numéricos , Pessoa de Meia-Idade , Estudos Retrospectivos
5.
ISME J ; 14(1): 10-11, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31551529

Assuntos
Bactérias , Ecossistema
6.
Chemosphere ; 238: 124655, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31472344

RESUMO

The effectiveness of nitrate-mediated souring control highly depends on the interactions of sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB). Biosurfactants produced by natural NRB are promising bio-agents for enhancing NRB competence towards SRB. However, the function of NRB-produced biosurfactants in NRB-SRB interactions remains unexplored due to the rarely successful isolation of natural biosurfactant-producing NRB. Hereby, biosurfactant-aided inhibitory control of SRB strain Desulfomicrobium escambiense ATCC 51164 by biosurfactant-producing NRB strain Pseudomonas stutzeri CX3, reported in our previous work, was investigated. Under non-sour conditions, insufficient nitrate injection resulted in limited SRB inhibition. Phospholipid fatty acid (PLFA) biomarkers traced the overall bacterial responses. Compositional PLFA patterns revealed biosurfactant addition benefitted both SRB and NRB towards stressful conditions. Under sour conditions, nitrite oxidation of sulfide proved to be the primary mechanism for sulfide removal. The subsequent elevation of redox potential and pH inhibited SRB activities. NRB-produced biosurfactants significantly enhanced SRB inhibition by NRB through more efficient sulfide removal and effective duration of nitrate in the microcosms. Biosurfactants specially produced by the NRB strain are for the first time reported to significantly strengthen SRB inhibition by NRB via reduced nitrate usage and prolonged effective duration of nitrate, which has encouraging potential in nitrate-dependent souring control.


Assuntos
Bactérias/isolamento & purificação , Desulfovibrio/metabolismo , Nitratos/metabolismo , Sulfetos/isolamento & purificação , Tensoativos/metabolismo , Bactérias/metabolismo , Ácidos Graxos/análise , Oxirredução
7.
Biophys Chem ; 256: 106269, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31733408

RESUMO

The distribution of the protein isoelectric point (pI) in the protein-protein interaction (PPI) networks across the domains of life has not been investigated yet. This work attempts to correlate the pI with the number of direct interacting partners in the experimentally supported networks involving 226.085 PPIs from 14 various organisms including human, mouse, yeast, bacteria, viruses and 53.606 virus-host interactions. The results showed that the acidic proteins (pI<3) have the highest average number of interactions in eukaryotes, while in bacteria more neutral proteins. On the contrary, the basic proteins (pI>11) have the lowest average number of interactions in human, mouse, yeast, bacteria and human-viral interactomes and the highest average in intraviral interactomes. We examined the correlation of the pI of the interacting partners by calculating the assortativity index of various PPI networks. We found that the interactions between the acidic, neutral and basic proteins have a fairly random mix, implying weak if any association between the acidic and basic proteins. Furthermore, protein features such as biological function, structurally order and disorder, subcellular localization, and homodimerization were classified according to pI in prokaryote and eukaryote proteomes.


Assuntos
Mapas de Interação de Proteínas , Proteínas/química , Animais , Bactérias/metabolismo , Bases de Dados de Proteínas , Humanos , Ponto Isoelétrico , Camundongos , Saccharomyces cerevisiae/metabolismo , Vírus/metabolismo
8.
Water Res ; 170: 115353, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31881501

RESUMO

Microbial regrowth during drinking water distribution can result in a variety of problems such as a deviating taste and odor, and may even pose a risk to public health. Frequent monitoring is essential to anticipate events of biological instability, and relevant microbial parameters for operational control of biostability of drinking water should be developed. Here, online flow cytometry and derived biological metrics were used to assess the biological stability of a full-scale drinking water tower during normal and disturbed flow regime. Pronounced operational events, such as switching from drinking water source, and seasonal changes, were detected in the total cell counts, and regrowth was observed despite the short hydraulic residence time of 6-8 h. Based on the flow cytometric fingerprints, the Bray-Curtis dissimilarity was calculated and was developed as unambiguous parameter to indicate or warn for changing microbial drinking water quality during operational events. In the studied water tower, drastic microbial water quality changes were reflected in the Bray-Curtis dissimilarity, which demonstrates its use as an indicator to follow-up and detect microbial quality changes in practice. Hence, the Bray-Curtis dissimilarity can be used in an online setup as a straightforward parameter during full-scale operation of drinking water distribution, and combined with the cell concentration, it serves as an early-warning system for biological instability.


Assuntos
Água Potável , Bactérias , Microbiologia da Água , Qualidade da Água , Abastecimento de Água
9.
Chemosphere ; 238: 124570, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31437629

RESUMO

Inhibition of anammox activities was tested with two ranges of chloramphenicol (CAP) concentration (5, 10, 20, 50, and 100 mg L-1) and (100, 500, and 1000 µg L-1). In a short-term study, strong inhibition of activity was dependent of CAP concentration in both attached-growth (SBR-A) and suspended-growth (SBR-S) systems. The activities of attached-growth cultures at all CAP concentrations were reversible after 1 day, while activities for suspended-growth cultures were only gradually reversible dependent on the CAP concentrations. In long-term studies with daily additions of 6 mg L-1 CAP, the anammox activity on day 41 in SBR-A had decreased to 18% baseline (SAA reduced from 0.528 to 0.096 mg N mg-1 VSS d-1). More rapid reduction of anammox activity was observed in SBR-S, down to 17% baseline after only 27 days (SAA decreased from 0.576 to 0.096 mg N mg-1 VSS d-1). Inhibition was irreversible in both SBR-S and SBR-A after the long-term study. With lower CAP additions (100-1000 µg L-1), the activities in both reactors were stable during daily CAP addition for two weeks. Attached-growth cultures tended to be more tolerant of CAP addition than suspended-growth cultures. Both un-competitive and non-competitive models could be used to compare anammox activities with the higher CAP concentrations. The SAAmax [fx] (the maximum specific anammox activity) and hKi (the inhibition constant) of SBR-A were 0.48 mg N mg-1 VSS d-1 and 98.3 mg L-1, respectively. The SAAmax[fx] and Ki of SBR-S were 1.25 mg N mg-1 VSS d-1and 71.1 mg L-1, respectively.


Assuntos
Compostos de Amônio/metabolismo , Antibacterianos/farmacologia , Bactérias Anaeróbias/crescimento & desenvolvimento , Bactérias Anaeróbias/metabolismo , Reatores Biológicos/microbiologia , Cloranfenicol/farmacologia , Anaerobiose , Nitrogênio , Oxirredução
10.
Chemosphere ; 238: 124597, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31450106

RESUMO

In this study, we focused on the proportion of particular bacterial groups and changes in microbial community structure in relation to the anammox process parameters and the feeding medium strategy in the Sequencing Batch Reactor (SBR). In order to present an insight into the microbial dynamics while feeding medium shift from synthetic wastewater to landfill leachate, fluorescent in situ hybridization (FISH), Real Time PCR, PCR - DGGE (Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis) and Reverse Transcription PCR-DGGE analysis were used. Feeding medium change has the strongest impact on relative abundance of denitrifiers and representatives of Planctomycetes. The relative abundancy of specific genes for all investigated nitrogen removal bacterial groups dropped after landfill leachate implementation. However, anammox consortium were able to adapt to the new reactor operating conditions and time for adaptation was estimated at the level of 90 days.


Assuntos
Compostos de Amônio/metabolismo , Reatores Biológicos/microbiologia , Planctomycetales/metabolismo , Águas Residuárias/química , Poluentes Químicos da Água/metabolismo , Eletroforese em Gel de Gradiente Desnaturante , Desnitrificação/fisiologia , Hibridização in Situ Fluorescente , Nitrogênio/metabolismo , Oxirredução , Planctomycetales/genética
11.
Food Microbiol ; 85: 103281, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500700

RESUMO

This study investigated the effectiveness of three thermal treatments; hot air (HA), hot water immersion (HWI), and hot water spraying (HWS); alone and in combination with radio frequency (RF) on the inactivation of Salmonella Typhimurium in shell eggs. In addition, the physical quality of the treated eggs and their functional capability to produce angel food cakes were determined. The results showed that HWI and HWS were significantly (P < 0.05) more effective at pasteurizing shell eggs than HA, and the pasteurization time was significantly reduced when eggs were first processed with RF. The times needed for RF/HWI and RF/HWS to achieve 5-log reductions of S. Typhimurium were 19.5 and 24.5 min, respectively. Yolk index was unaffected by heating, but Haugh unit and albumen turbidity were increased dependent on the length of treatment. Eggs after HWI, combined RF/HWI, and RF/HWS treatments were able to make good angel food cakes if whipping times were extended. The results of this study demonstrated that combined RF/HWS treatment was comparable to RF/HWI treatment in terms of shell egg pasteurization without damaging egg quality. Therefore, both HWS and HWI may be used as the second step of radio frequency pasteurization.


Assuntos
Casca de Ovo/microbiologia , Temperatura Alta , Viabilidade Microbiana , Pasteurização/métodos , Ondas de Rádio , Ar , Animais , Salmonella typhimurium , Água
12.
Food Microbiol ; 85: 103306, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500703

RESUMO

Spray dried egg white powder (EWP) is traditionally processed by hot room treatment for a prolonged period of time (67 °C for 15 days) to enhance its functionality (foaming and gelling) and to improve microbial safety of EWP. Our prior research demonstrated that radio-frequency (RF) assisted thermal processing can considerably reduce the processing time, without compromising the functional properties of EWP. In this study, continuous RF processing was evaluated for pasteurization of EWP. EWP samples were inoculated with a 5-strain Salmonella cocktail or Enterococcus faecium NRRL B-2354 for the microbial challenge studies. To evaluate the inoculation method, stability and homogeneity tests were conducted for both Salmonella and E. faecium in EWP. Continuous RF heating of EWP was conducted in a 6-kW, 27.12 MHz pilot-scale parallel-plate RF heating system. RF-assisted thermal processing of EWP at 80 °C for 2 h provided >6.69 log reduction for Salmonella. E. faecium was found to be a suitable surrogate for Salmonella due to its higher resistance and similar inactivation kinetics during RF heating of EWP. The validated RF-assisted thermal process can be scaled up for use in the egg industry.


Assuntos
Clara de Ovo/microbiologia , Microbiologia de Alimentos/métodos , Análise de Perigos e Pontos Críticos de Controle/métodos , Temperatura Alta , Pasteurização/métodos , Ondas de Rádio , Contagem de Colônia Microbiana , Pós/análise , Salmonella
13.
Food Microbiol ; 85: 103285, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500704

RESUMO

The objective of this study was to determine the kinetic parameters and apply Markov Chain Monte Carlo (MCMC) simulation to predict the growth of Clostridium perfringens from spores in cooked ground chicken meat during dynamic cooling. Inoculated samples were exposed to various cooling conditions to observe dynamic growth. A combination of 4 cooling profiles was used in one-step inverse analysis with the Baranyi model as the primary model and the cardinal parameters model as the secondary model. Six kinetic parameters of the Baranyi model and the cardinal parameters model, including Q0, Ymax, µopt, Tmin, Topt, and Tmax, were estimated. The estimated Tmin, Topt, and Tmax were 14.8, 42.9, and 50.5 °C, respectively, with a µopt of 5.25 h-1 and maximum cell density of 8.4 log CFU/g. Correlation analysis showed that both Q0 and Ymax are weakly correlated to other parameters, while the remaining parameters are mostly mildly to strongly correlated with each other. Although it may be difficult to estimate highly correlated parameters using a single temperature profile, one-step analysis with multiple different temperature profiles helped estimate them successfully. The estimated parameters were used as the prior information to construct the posterior distribution for Bayesian analysis. MCMC simulation was used to predict the bacterial growth using different dynamic temperature profiles for validation of the accuracy of the predictive models. The MCMC simulation results showed that the Bayesian analysis produced more accurate predictions of bacterial growth during cooling than the deterministic method. With Bayesian analysis, the root-mean-square-error (RMSE) of prediction was only 0.1 log CFU/g with all residual errors within ±0.25 log CFU/g. Therefore, Bayesian analysis is recommended for predicting the growth of C. perfringens in cooked meat during cooling.


Assuntos
Clostridium perfringens/crescimento & desenvolvimento , Culinária , Manipulação de Alimentos , Produtos da Carne/microbiologia , Temperatura Ambiente , Animais , Teorema de Bayes , Galinhas , Contagem de Colônia Microbiana , Simulação por Computador , Cinética , Cadeias de Markov , Modelos Biológicos , Método de Monte Carlo , Esporos Bacterianos/crescimento & desenvolvimento
14.
Food Microbiol ; 85: 103280, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500706

RESUMO

Listeria monocytogenes causes severe diseases in humans, including febrile gastroenteritis and systemic infections that has a high mortality despite antibiotic treatment. This pathogen may cause massive outbreaks associated to the consumption of contaminated food products, which highlight its importance in public health. In the last decade, L. monocytogenes has emerged as a foodborne pathogen of major importance in Chile. A previous work showed that in Chile during 2008 and 2009, L. monocytogenes serotypes 1/2a, 1/2b and 4b were the most frequently identified in food and clinical strains. Here we report the molecular characterization of L. monocytogenes strains isolated from 2008 to 2017 in the country. Our results indicate that serotypes 1/2a, 1/2b and 4b continue to be the most commonly found in food products. In addition, we identify persistent and widespread PFGE subtypes. This study reports ten years of epidemiological surveillance ofL. monocytogenes in Chile.


Assuntos
Monitoramento Epidemiológico , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/epidemiologia , Listeria monocytogenes/genética , Listeriose/epidemiologia , Chile/epidemiologia , Contagem de Colônia Microbiana , DNA Bacteriano/genética , Surtos de Doenças , Doenças Transmitidas por Alimentos/microbiologia , Gastroenterite/epidemiologia , Gastroenterite/microbiologia , Variação Genética , Humanos , Listeria monocytogenes/patogenicidade , Produtos da Carne/microbiologia , Epidemiologia Molecular , Saúde Pública , Sorogrupo , Sorotipagem , Fatores de Virulência/genética
15.
Food Microbiol ; 85: 103287, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500707

RESUMO

Wine-related non-Saccharomyces yeasts are becoming more widely used in oenological practice for their ability to confer wine a more complex satisfying aroma, but their metabolism remains unknown. Our study explored the nitrogen utilisation profile of three popular non-Saccharomyces species, Torulaspora delbrueckii, Metschnikowia pulcherrima and Metschnikowia fructicola. The nitrogen source preferences to support growth and fermentation as well as the uptake order of different nitrogen sources during wine fermentation were investigated. While T. delbrueckii and S. cerevisiae strains shared the same nitrogen source preferences, Metschnikowia sp. Displayed a lower capacity to efficiently use the preferred nitrogen compounds, but were able to assimilate a wider range of amino acids. During alcoholic fermentation, the non-Saccharomyces strains consumed different nitrogen sources in a similar order as S. cerevisiae, but not as quickly. Furthermore, when all the nitrogen sources were supplied in the same amount, their assimilation order was similarly affected for both S. cerevisiae and non-Saccharomyces strains. Under this condition, the rate of nitrogen source consumption of non-Saccharomyces strains and S. cerevisiae was comparable. Overall, this study expands our understanding about the preferences and consumption rates of individual nitrogen sources by the investigated non-Saccharomyces yeasts in a wine environment. This knowledge provides useful information for a more efficient exploitation of non-Saccharomyces strains that improves the management of the wine fermentation.


Assuntos
Fermentação , Nitrogênio/metabolismo , Vinho/microbiologia , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo , Aminoácidos/metabolismo , Metschnikowia/crescimento & desenvolvimento , Odorantes , Saccharomyces cerevisiae , Torulaspora/crescimento & desenvolvimento
16.
Food Microbiol ; 85: 103302, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500708

RESUMO

This study dealt with the influence of the temperature on the bacterial dynamics of two spontaneously fermented wheat sourdoughs, propagated at 21 ±â€¯1 °C (SD1) and 30 ±â€¯1 °C (SD2), during nine backslopping steps (BS1 to BS9). Proteobacteria was the only phylum found in flour. Escherichia hermannii was predominant, followed by Kosakonia cowanii, besides species belonging to the genera Pantoea and Pseudomonas. After one step of propagation, Clostridium and Bacillus cereus group became predominant. Lactobacillus curvatus was found at low relative abundance. For the second backslopping step, Clostridium was flanked by L. curvatus and Lactobacillus farciminis. From BS4 (6th day) onward, lactic acid bacteria (LAB) became predominant. L. farciminis overcame L. curvatus and remained dominant until the end of propagations for both sourdoughs. At 21 °C, Bacillus, Clostridium, Pseudomonas, and Enterobacteriaceae were gradually inhibited. At the end of propagation, SD1 harbored only LAB. Otherwise, the temperature of 30 °C favored the persistence of atypical bacteria in SD2, as Pseudomonas and Enterobacteriaceae. Therefore, the temperature of 21 °C was more suitable for sourdough propagation in Brazil. This study enhanced the knowledge of temperature's influence on microbial assembly and contributed to the elucidation of sourdough microbial communities in Brazil.


Assuntos
Pão/microbiologia , Fermentação , Metagenoma , Proteobactérias/classificação , Brasil , Contagem de Colônia Microbiana , DNA Bacteriano/genética , Farinha/microbiologia , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Microbiota , Proteobactérias/crescimento & desenvolvimento , RNA Ribossômico 16S/genética , Temperatura Ambiente
17.
Food Microbiol ; 85: 103286, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500709

RESUMO

Hispanic style soft non-fermented cheeses, such as queso fresco (QF) have been linked to outbreaks and recalls. Salmonella is one of the main causes of these incidents. Due to lack of ripening or post-processing antimicrobial treatments, incorporating GRAS antimicrobials to production process may be a suitable approach to minimize microbial risk in QF. The aim of this study was to evaluate the efficiency of nisin (N), caprylic acid (CA) and trans-cinnamaldehyde (CN) as single or combined treatments to reduce Salmonella populations in QF during storage. Batches of QF were inoculated after curding with approx. 4 Log CFU/g of 5-strain cocktails of Salmonella and stored at 8 °C for 20 days. The final Salmonella counts in control samples ranged from 6.96 to 7.14 Log CFU/g. Application of CN at 0.6 g/kg inhibited Salmonella growth during storage, resulting in at least 3 Log CFU/g difference with the untreated controls (p < 0.05). Addition of N (0.5 g/kg) and CA (0.4 g/kg) with CN (0.3 and 0.6 g/kg) further enhanced the antimicrobial activity resulting in complete suppression of growth and even caused a 1 Log CFU/g reduction by the end of the experimental period compared to initial counts. Samples treated with the combined treatment (N, CA, CN) were evaluated in a consumer panel (n = 112). Participants preferred the control and commercial QF to the treated samples. However, treated samples with 0.3 g/kg CN were still within the acceptable range of neutral to like slightly. Results obtained, revealed that combined treatment of N, CA and CN can provide a solution to reduce the count of Salmonella in QF, whether in process or during storage.


Assuntos
Antibacterianos/farmacologia , Queijo/microbiologia , Microbiologia de Alimentos/métodos , Viabilidade Microbiana/efeitos dos fármacos , Salmonella/efeitos dos fármacos , Caprilatos/farmacologia , Contagem de Colônia Microbiana , Manipulação de Alimentos , Conservação de Alimentos , Nisina/farmacologia
18.
Food Microbiol ; 85: 103282, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500713

RESUMO

Two biopreservation approaches for fresh lettuce, rocket salad, parsley and spinach were studied. The potential of Pediococcus pentosaceus DT016, as a protective culture, to suppress Listeria monocytogenes in vegetables during storage was evaluated. The pathogen numbers in the vegetables inoculated with P. pentosaceus DT016 were significantly (p < 0.01) lower throughout the storage period and, at the last storage day, a minimum difference of 1.4 log CFU/g was reported when compared with the vegetables without the protective culture. Moreover, by using two levels of L. monocytogenes (about 6 and 4 log CFU/g), it was observed that the antagonist effect of P. pentosaceus was higher for the lower pathogen numbers. The second approach evaluated a pediocin DT016 solution to inactivate and control L. monocytogenes proliferation. The pathogen load was studied after washing with: water, chlorine and the pediocin solution and along storage at 4  °C. Comparing the various washing solutions, the vegetables washed with pediocin presented significantly (p < 0.01) lower pathogen numbers throughout storage, by a minimum of 3.2 and 2.7 log CFU/g, than in vegetables washed with water and chlorine, respectively. The proposed methodologies are promising alternatives to maintain the safety of fresh vegetables during extended storage at refrigeration temperature.


Assuntos
Antibiose , Microbiologia de Alimentos/métodos , Conservação de Alimentos/métodos , Listeria monocytogenes/fisiologia , Verduras/microbiologia , Carga Bacteriana , Cloro/farmacologia , Temperatura Baixa , Qualidade de Produtos para o Consumidor , Manipulação de Alimentos/métodos , Alface/microbiologia , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Pediocinas/farmacologia , Pediococcus pentosaceus/fisiologia , Petroselinum/microbiologia , Refrigeração , Spinacia oleracea/microbiologia , Água
19.
Food Microbiol ; 85: 103274, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500714

RESUMO

The impact of plant development, environmental conditions at the time of inoculation, and inoculum concentration on survival of attenuated BSL1 Escherichia coli O157:H7 strain ATCC 700728 on field-grown romaine lettuce was evaluated over 3 years. E. coli 700728 was inoculated onto 4- and 6-week-old romaine lettuce plants in the Salinas Valley, CA, at night or the next morning with either low (5 log) or high (7 log) cell numbers per plant to simulate a single aqueous contamination event. At night, when leaf wetness and humidity levels were high, E. coli cell numbers declined by 0.5 log CFU/plant over the first 8-10 h. When applied in the morning, E. coli populations declined up to 2 log CFU/plant within 2 h. However, similar numbers of E. coli were retrieved from lettuce plants at 2 and 7 days. E. coli cell numbers per plant were significantly lower (P < 0.05) 7 days after application onto 4-week-old compared to 6-week-old plants. E. coli 700728 could be recovered by plating or enrichment from a greater proportion of plants for longer times when inoculated at high compared with low initial concentrations and after inoculation of 6-week-old plants compared with 4-week-old plants, even at the low initial inoculum. A contamination event near harvest or when leaf wetness and humidity levels are high may enhance survivability, even when low numbers of E. coli are introduced.


Assuntos
Escherichia coli O157/crescimento & desenvolvimento , Alface/microbiologia , Viabilidade Microbiana , Folhas de Planta/microbiologia , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Microbiologia de Alimentos , Umidade , Fatores de Tempo
20.
Food Microbiol ; 85: 103309, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500715

RESUMO

The production of Chinese horse bean-chili-paste (CHCP) involves three fermentation phases: chili-to-moromi fermentation (CF) phase, horse bean-to-meju fermentation (HF) phase and moromi-meju mixed fermentation (MF) phase. To understand the microbial dynamics among these three phases and the potential roles of viable microbes for fermentation, microbial community dynamics was investigated by using culture-dependent and culture-independent methods. Furthermore, the capacities of enzyme-producing of the isolates were determined. During the CF phase, reducing sugar content increased from 3.1% to 3.49%, while pH declined from 4.85 to 4.5. The protein content in the HF phase and MF phase reduced sharply from 22.23% to 10.29% and 4.39%-1.19%, respectively. Bacillus sp., Staphylococcus sp., Oceanobacillus sp., Candida sp., Zygosaccharomyces sp. and Aspergillus sp. dominated the CF phase, while Bacillus sp., Candida sp. and Zygosaccharomyces sp. were the dominant microorganisms in both the HF and MF phases. B. amyloliquefaciens, B. methylotrophicus, B. subtilis, B. licheniformis and A. oryzae possessed strong capacities of producing enzymes, i.e. α-amylase, cellulase and xylanase, acid protease and leucine aminopeptidase, and could make a great contribution to CHCP fermentation.


Assuntos
Bactérias/isolamento & purificação , Fermentação , Microbiologia de Alimentos , Microbiota , Soja/microbiologia , Biodiversidade , Capsicum/microbiologia , Células-Tronco , Vicia faba/microbiologia
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