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1.
Microbiol Res ; 248: 126769, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33873140

RESUMO

Toddy is a traditional mild-alcoholic drink of India, which is produced from fresh palm saps by natural fermentation. We studied the successional changes in bacterial and fungal communities during the natural fermentation (0 h-96 h) of toddy. During fermentation, alcohol content of the fermenting saps increased significantly from 0.6 %±0.15 to 5.6 %±0.02, pH decreased from 6.33 %±0.02-3.93 ± 0.01, volatile and titratable acidity acidity (g/100 mL) increased from 0.17 ± 0.02 (0 h) to 0.48 ± 0.02 (96 h) and 1.30 ± 0.005 (0 h) to 2.47 ± 0.005 (96 h), respectively. Total sugar content and ˚BRIX also decreased during the fermentation. Firmicutes (78.25 %) was the most abundant phylum followed by Proteobacteria (21.57 %). Leuconostoc was the most abundant genus in the early stages of fermentation. However, Lactobacillus and Gluconoacetobacter were found abundant with increase in pH during the later phases of fermentation (72 h-96 h). Ascomycota (99.02 %) was the most abundant fungal phylum. Hanseniaspora was the abundant yeast in the initial stages of fermentation, whereas the population of Saccharomyces increased significantly after 24 h of fermentation. Torulaspora, Lachancea and Starmerella showed their heterogeneous distribution throughout the fermentation. Computational analysis of metagenomes based on KEGG and MetaCyc databases showed different predictive functional profiles such as folate biosynthesis, glutathione metabolism, terpenoids biosynthesis and biosynthesis of amino acids with significant differences between the fresh palm saps and fermenting saps during toddy fermentation.


Assuntos
Bebidas Alcoólicas/microbiologia , Ascomicetos/metabolismo , Bactérias/metabolismo , Microbiota , Phoeniceae/microbiologia , Bebidas Alcoólicas/análise , Álcoois/análise , Álcoois/metabolismo , Ascomicetos/classificação , Ascomicetos/genética , Ascomicetos/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Fermentação , Flores/metabolismo , Flores/microbiologia , Índia , Phoeniceae/metabolismo , Açúcares/metabolismo
2.
Meat Sci ; 165: 108128, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32220814

RESUMO

Ciauscolo is a fermented sausage with the Protected Geographical Indication (PGI) status. To disclose the microbial ecology of a model Ciauscolo salami manufacture during its natural fermentation, viable counting, amplicon-based sequencing and real-time PCR were applied. The volatilome during fermentation was also characterized. The results allowed previously undetected species to be discovered. The core microbiota was composed by Lactobacillus algidus, Leuconostoc carnosum, Lactobacillus sakei, Debaryomyces hansenii, Glomus hyderabadensis, Tilletiopsis washingtonensis, and Kurtzmaniella zeylanoides. Salmonella spp. and Listeria monocytogenes were absent in all the samples; moreover, multiplex real-time PCR revealed the absence of the target genes bont/A, bont/B, bont/E, bont/F, and 4gyrB (CP), encoding botulinic toxins. Volatilome, deeply depending on microbiological metabolism, was characterized by spices-derived components. Limonene, sabinene, α- and ß-pinene, 3-carene, and α-thujene were the most represented monoterpene hydrocarbons, whereas ß- and α-copaene were the most represented sesquiterpene hydrocarbons. Allyl methyl sulphide and diallyl disulphide were the major aliphatic sulphur compounds, together with diallyl sulphide and allyl methyl disulphide.


Assuntos
Microbiologia de Alimentos , Produtos da Carne/microbiologia , Microbiota , Animais , Bactérias/isolamento & purificação , Toxinas Botulínicas/genética , Fermentação , Fungos/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala , Produtos da Carne/análise , Reação em Cadeia da Polimerase Multiplex/métodos , Sus scrofa , Compostos Orgânicos Voláteis/análise , Leveduras/isolamento & purificação
3.
Food Funct ; 10(12): 7767-7781, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31750489

RESUMO

Strawberries are vulnerable to physical injuries and microbial invasion. To explore if beneficial lactic acid bacteria can improve the shelf life and edible quality of postharvest strawberry fruits, the effects of Lactobacillus delbrueckii subsp. bulgaricus (ital.) F17 (F17) and Leuconostoc lactis (ital.) H52 (H52) inoculation on the strawberry microbial community structure and saleable characteristics were examined by bacterial 16S rRNA and fungal ITS sequencing techniques. Lactobacillus (ital.) F17 and Leuconostoc lactis (ital.) H52 isolated from the traditional fermented yak milk in the Qinghai-Tibetan Plateau were used as the potential probiotic inocula. Samples from treated strawberries stored at 25 °C for 0, 12, 24, 48, and 72 hours were analyzed for their pH, weight loss percentage, decay percentage, total soluble solid content (SSC) and microbial counts, and for microbiome community diversity and canonical correspondence analysis. The results showed that F17 and H52 did not only significantly reduce the weight loss and decay percentage of strawberry fruits, but also delayed the decrease of the total SSC and pH (P < 0.05). In addition, F17 and H52 significantly inhibited the growth and colonization of aerobic mesophilic bacteria, yeast, mold and coliform bacteria. In particular, by comparing the microbiota composition of the samples, F17 significantly inhibited Pantoea, Mycospherella, unclassified_Pleosporales, Aureobasidium and Phoma at the genus level, whereas H52 inhibited Bacillus, Streptophyta, Mycospherella, Aureobasidium and Phoma. Moreover, analysis of alpha and beta diversity revealed that F17 and H52 had a significantly greater inhibitory effect on bacterial species compared to fungi. The results of canonical correspondence analysis revealed that the total SSC and pH were positively correlated with bacteria, whereas the decay percentage, weight loss percentage and total SSC were positively associated with fungi. Additionally, Podosphaera, Hanseniaspora, Botrytis and unclassified_Pleosporales were positively correlated with strawberry fruit decay and weight loss percentage. As a general result, Lactobacillus F17 and Leuconostoc lactis H52 have the potential to promote biological preservation, which is economically important to reduce the loss due to strawberry spoilage.


Assuntos
Conservação de Alimentos/métodos , Fragaria/microbiologia , Frutas/microbiologia , Lactobacillus delbrueckii/fisiologia , Leuconostoc/fisiologia , Microbiota , Animais , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Bovinos , Armazenamento de Alimentos , Fragaria/química , Fragaria/efeitos dos fármacos , Frutas/química , Frutas/efeitos dos fármacos , Fungos/classificação , Fungos/efeitos dos fármacos , Fungos/genética , Fungos/isolamento & purificação , Leite/microbiologia , Probióticos/farmacologia
4.
Food Microbiol ; 80: 62-69, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30704597

RESUMO

The effect of high pressure processing (HPP) on the microbiota of ripened Iberian ham of different water activity, salt concentration and intramuscular fat content was investigated before and after a 5-month refrigeration period. At the beginning of the refrigeration period, the only significant effects of chemical composition were those of water activity on psychrotrophs and Micrococcaceae in untreated hams, and of the salt-in-lean ratio on lactic acid bacteria in HPP-treated hams. At the end of the refrigeration period, the only significant effect was that of intramuscular fat content on moulds and yeasts in HPP-treated samples. All microbial groups were significantly affected by HPP, with reductions ranging from 1.7 to 2.0 log cycles after treatment. A significant recovery of all microbial groups took place in HPP-treated hams during the refrigeration period, with increases ranging from 0.5 to 1.1 log cycles. In spite of this recovery, microbial levels in HPP-treated hams remained significantly lower than in untreated hams. Staphylococcus accounted for 93.4% of Iberian ham bacterial isolates, with S. equorum as the most abundant species. Representatives of the Tetragenococcus, Carnobacterium and Streptomyces genera, not previously reported in dry-cured ham, were also isolated. Most of the yeast isolates (75.0%) were identified as Debaryomyces hansenii.


Assuntos
Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Carne/microbiologia , Microbiota/genética , Refrigeração , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , Gorduras na Dieta/análise , Conservação de Alimentos , Alimentos em Conserva/análise , Alimentos em Conserva/microbiologia , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Carne/análise , Tipagem Molecular , Pressão , Cloreto de Sódio na Dieta/análise , Suínos , Água/análise
5.
Sci Rep ; 8(1): 8783, 2018 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-29884862

RESUMO

Leprosy is a chronic infectious peripheral neuropathy that is caused by Mycobacterium leprae, and the skin is one of its preferred target sites. However, the effects of this infection on the skin microbiome remain largely unexplored. Here, we characterize and compare the lesional and non-lesional skin microbiomes of leprosy patients and healthy individuals through the deep sequencing of 16 S rRNA genes. Additionally, a subset of patients was monitored throughout the multi-drug therapy to investigate its effect on the leprous skin microbiome. Firmicutes-associated OTUs (primarily Staphylococcus) prevailed in healthy individuals. By contrast, Firmicutes was underrepresented and Proteobacteria was enriched in the patients' skin, although a single dominant taxon has not been observed at a finer taxonomic resolution. These differences can be explained by the significant decrease in Staphylococcus and Streptococcus as well as the enrichment in Brevundimonas. The overrepresentation of Micrococcus in patients is also remarkable. Genus-level compositional profiles revealed no significant intrapersonal difference between lesional and non-lesional sites. Treatment-associated changes indicated a loss of diversity and a shift in the community composition, with stronger impacts on the OTUs that are considered indigenous bacteria. Therefore, the molecular signatures associated with leprosy identified herein might be of importance for early diagnostics.


Assuntos
Bactérias/isolamento & purificação , Hanseníase/microbiologia , Microbiota , Pele/microbiologia , Antibacterianos/uso terapêutico , Bactérias/classificação , Bactérias/genética , Brasil/epidemiologia , Firmicutes/classificação , Firmicutes/genética , Firmicutes/isolamento & purificação , Humanos , Hanseníase/tratamento farmacológico , Hanseníase/epidemiologia , Microbiota/efeitos dos fármacos , Mycobacterium leprae/efeitos dos fármacos , Estudos Prospectivos , Proteobactérias/classificação , Proteobactérias/genética , Proteobactérias/isolamento & purificação
6.
J Appl Microbiol ; 124(6): 1377-1392, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29464844

RESUMO

AIMS: The objective was to determine the effects of dietary substitution of fishmeal (FM) with live yeast and increasing water temperature on the diversity and composition of gut microbiota in rainbow trout. METHODS AND RESULTS: Fish were fed either FM or yeast (Saccharomyces cerevisiae) and reared in water temperatures of either 11°C (cold) or 18°C (warm) for 6 weeks. Luminal content and mucosa were collected from the distal gut and the load, diversity and species abundance of yeast and bacteria were analysed using agar plating, MALDI-TOF and rRNA gene amplicon sequencing. Yeast in the gut of fish fed FM were represented by S. cerevisiae, Rhodotorula spp. and Debaryomyces hansenii, while fish fed yeast contained 4-5 log higher CFU per g of yeast that were entirely represented by S. cerevisiae. For gut bacteria, sequencing of 16S rRNA gene amplicons using Illumina MiSeq showed lower bacterial diversity and abundance of lactic acid bacteria, especially Lactobacillus, in fish reared in warm rather than cold water. Fish fed yeast had similar bacterial diversity and lower abundance of Leuconostocaceae and Photobacterium compared with fish fed FM. CONCLUSIONS: Feeding live yeast mainly increased yeast load in the gut, while increased water temperature significantly altered the gut microbiota of rainbow trout in terms of bacterial diversity and abundance. SIGNIFICANCE AND IMPACT OF THE STUDY: Live yeast can replace 40% of FM without disrupting bacteria communities in the gut of rainbow trout, while increased water temperature due to seasonal fluctuations and/or climate change may result in a gut dysbiosis that may jeopardize the health of farmed fish.


Assuntos
Ração Animal/microbiologia , Bactérias/isolamento & purificação , Microbioma Gastrointestinal , Oncorhynchus mykiss/microbiologia , Saccharomyces cerevisiae/metabolismo , Ração Animal/análise , Animais , Bactérias/classificação , Bactérias/genética , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/microbiologia , Oncorhynchus mykiss/crescimento & desenvolvimento , Oncorhynchus mykiss/metabolismo , RNA Ribossômico 16S/genética , Saccharomyces cerevisiae/genética , Temperatura , Água/química
7.
Int J Food Microbiol ; 266: 42-51, 2018 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-29175763

RESUMO

Culture-dependent and culture-independent strategies were applied to investigate the microbiota of autumn undamaged and damaged berries, winter berries and ice wine must samples of Grüner Veltliner (Veltlínske zelené) from Small Carpathian wine-producing region. One hundred twenty-six yeasts and 242 bacterial strains isolated from several microbiological media (YPD, PDA, R2A, GYC, MRS and MRS-T) were clustered by ITS-PCR and subsequent Qiaxcel electrophoresis. Representatives of each cluster were identified by sequencing. The extracellular hydrolytic properties and intracellular activities of esterase and ß-glucosidase of isolates were assayed. The culture-independent approach permitted the analysis of extracted DNA and RNA coupling DGGE fingerprinting with construction of clone libraries (bacterial and fungal; DGGE-cloning). The combination of the two approaches provided comprehensive data that evidenced the presence of a complex microbiota in each analyzed sample. RNA and DNA analyses facilitated differentiation of living microorganisms from the entire microbiota. Diverse microbial communities colonized the autumn and winter berries. Generally, the combination of results obtained by the methods suggested that the must samples contained mainly Saccharomyces cerevisiae, Metschnikowia spp., Hanseniaspora uvarum, Lactococcus lactis and Leuconostoc spp. The strains exhibited interesting esterase and ß-glucosidase properties, which are important for aroma formation in wine. Fermentation strategies utilising these microorganisms, could be attempted in the future in order to modulate the ice wine characteristics.


Assuntos
Bactérias/isolamento & purificação , Fermentação , Vinho/microbiologia , Leveduras/isolamento & purificação , Bactérias/genética , Biodiversidade , DNA Espaçador Ribossômico/genética , Esterases/metabolismo , Hanseniaspora/metabolismo , Leuconostoc/genética , Metschnikowia/genética , Reação em Cadeia da Polimerase , Saccharomyces cerevisiae/metabolismo , Leveduras/genética , beta-Glucosidase/metabolismo
8.
J Microbiol Biotechnol ; 28(1): 105-108, 2018 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-29081086

RESUMO

Beef was dry aged for 40-60 days under controlled environmental conditions in a refrigerated room with a relative humidity of 75%-80% and air-flow. To date, there is little information on the microbial diversity and characteristics of dry aged beef. In this study, we explored the effect of change in meat microorganisms on dry aged beef. Initially, the total bacteria and LAB were significantly increased for 50 days during all dry aging periods. There was an absence of representative foodborne pathogens as well as coliforms. Interestingly, fungi including yeast and mold that possess specific features were observed during the dry aging period. The 5.8S rRNA sequencing results showed that potentially harmful yeasts/molds (Candida sp., Cladosporium sp., Rhodotorula sp.) were present at the initial point of dry aging and they disappeared with increasing dry aging time. Interestingly, Penicillium camemberti and Debaryomyces hansenii used for cheese manufacturing were observed with an increase in the dry aging period. Taken together, our results showed that the change in microorganisms exerts an influence on the quality and safety of dry aged beef, and our study identified that fungi may play an important role in the palatability and flavor development of dry aged beef.


Assuntos
Bactérias/isolamento & purificação , Biota , Dessecação , Fungos/isolamento & purificação , Carne/microbiologia , Técnicas Microbiológicas/métodos , Animais , Bactérias/classificação , Bovinos , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Fungos/classificação , Fungos/genética , Filogenia , RNA Ribossômico 5,8S/genética , Análise de Sequência de DNA
9.
Microbiol Res ; 206: 1-8, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29146247

RESUMO

The microbial assemblies on the surface of plants correlate with specific climatic features, suggesting a direct link between environmental conditions and microbial inhabitation patterns. At the same time however, microbial communities demonstrate distinct profiles depending on the plant species and region of origin. In this study, we report Next Generation Sequencing-based metagenomic analysis of microbial communities associated with apple and blackcurrant fruits harvested from Lithuania and the Czech Republic. Differences in the taxonomic composition of eukaryotic and prokaryotic microorganisms were observed between plant types. Our results revealed limited geographic differentiation between the bacterial and fungal communities associated with apples. In contrast, blackcurrant berries harvested from different regions demonstrated high diversity in both bacterial and fungal microbiota structures. Among fungal and bacterial microorganisms, we identified both potentially beneficial (Cryptococcus, Hanseniaspora, Massilia, Rhodotorula, Sphingomonas) and phytopathogenic microorganisms (Cladosporium, Pantoea, Phoma, Pseudomonas, Septoria, Taphrina) indicating their important roles in ecological and evolutionary processes.


Assuntos
Malus/microbiologia , Consórcios Microbianos , Microbiota , Ribes/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , República Tcheca , DNA Bacteriano/isolamento & purificação , DNA Fúngico/isolamento & purificação , Ecologia , Frutas/microbiologia , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Lituânia , Metagenômica/métodos , Microbiota/genética , Filogenia
10.
World J Microbiol Biotechnol ; 33(12): 211, 2017 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-29134289

RESUMO

Cultivable microbiota presents in a coffee semi-dry processing wastewater treatment plant (WTP) was identified. Thirty-two operational taxonomic units (OTUs) were detected, these being 16 bacteria, 11 yeasts and 4 filamentous fungi. Bacteria dominated the microbial population (11.61 log CFU mL- 1), and presented the highest total diversity index when observed in the WTP aerobic stage (Shannon = 1.94 and Simpson = 0.81). The most frequent bacterial species were Enterobacter asburiae, Sphingobacterium griseoflavum, Chryseobacterium bovis, Serratia marcescens, Corynebacterium flavescens, Acetobacter orientalis and Acetobacter indonesiensis; these showed the largest total bacteria populations in the WTP, with approximately 10 log CFU mL- 1. Yeasts were present at 7 log CFU mL- 1 of viable cells, with Hanseniaspora uvarum, Wickerhamomyces anomalus, Torulaspora delbrueckii, Saturnispora gosingensis, and Kazachstania gamospora being the prevalent species. Filamentous fungi were found at 6 log CFU mL- 1, with Fusarium oxysporum the most populous species. The identified species have the potential to act as a biological treatment in the WTP, and the application of them for this purpose must be better studied.


Assuntos
Bactérias/classificação , Café , Manipulação de Alimentos , Fungos/classificação , Águas Residuárias/microbiologia , Leveduras/classificação , Bactérias/isolamento & purificação , Biodiversidade , Fungos/isolamento & purificação , Microbiota , Filogenia , Leveduras/isolamento & purificação
11.
New Microbiol ; 40(4): 269-278, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28825446

RESUMO

Foodborne pathogens can be associated with a wide variety of food products and it is very important to identify them to supply safe food and prevent foodborne infections. Since traditional techniques are timeconsuming and laborious, this study was designed for rapid identification and clustering of foodborne pathogens isolated from various restaurants in Al-Qassim region, Kingdom of Saudi Arabia (KSA) using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Sixty-nine bacterial and thirty-two fungal isolates isolated from 80 food samples were used in this study. Preliminary identification was carried out through culture and BD Phoenix™ methods. A confirmatory identification technique was then performed using MALDI-TOF MS. The BD Phoenix results revealed that 97% (67/69 isolates) of bacteria were correctly identified as 75% Enterobacter cloacae, 95.45% Campylobacter jejuni and 100% for Escherichia coli, Salmonella enterica, Staphylococcus aureus, Acinetobacter baumannii, and Klebsiella pneumoniae. While 94.44% (29/32 isolates) of fungi were correctly identified as 77.77% Alternaria alternate, 88.88% Aspergillus niger and 100% for Aspergillus flavus, Penicillium digitatum, Candida albicans and Debaryomyces hansenii. However, all bacterial and fungal isolates were 100% properly identified by MALDI-TOF MS fingerprinting with a score value ≥2.00. A gel view illustrated that the spectral peaks for the identified isolates fluctuate between 3,000 and 10,000 Da. The results of main spectra library (MSP) dendrogram showed that the bacterial and fungal isolates matched with 19 and 9 reference strains stored in the Bruker taxonomy, respectively. Our results indicated that MALDI-TOF MS is a promising technique for fast and accurate identification of foodborne pathogens.


Assuntos
Bactérias/isolamento & purificação , Microbiologia de Alimentos , Fungos/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Bactérias/classificação , Bactérias/genética , Análise por Conglomerados , Fungos/classificação , Fungos/genética , Humanos , Restaurantes , Arábia Saudita , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/economia , Fatores de Tempo
12.
Child Obes ; 13(1): 78-84, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27007700

RESUMO

BACKGROUND: Differences in relative proportions of gut microbial communities in adults have been correlated with intestinal diseases and obesity. In this study we evaluated the gut microbiota biodiversity, both bacterial and fungal, in obese and normal-weight school-aged children. METHODS: We studied 28 obese (mean age 10.03 ± 0.68) and 33 age- and sex-matched normal-weight children. BMI z-scores were calculated, and the obesity condition was defined according to the WHO criteria. Fecal samples were analyzed by 16S rRNA amplification followed by denaturing gradient gel electrophoresis (DGGE) analysis and sequencing. Real-time polymerase chain reaction (PCR) was performed to quantify the most representative microbial species and genera. RESULTS: DGGE profiles showed high bacterial biodiversity without significant correlations with BMI z-score groups. Compared to bacterial profiles, we observed lower richness in yeast species. Sequence of the most representative bands gave back Eubacterium rectale, Saccharomyces cerevisiae, Candida albicans, and C. glabrata as present in all samples. Debaryomyces hansenii was present only in two obese children. Obese children revealed a significantly lower abundance in Akkermansia muciniphyla, Faecalibacterium prausnitzii, Bacteroides/Prevotella group, Candida spp., and Saccharomyces spp. (P = 0.031, P = 0.044, P = 0.003, P = 0.047, and P = 0.034, respectively). CONCLUSION: Taking into account the complexity of obesity, our data suggest that differences in relative abundance of some core microbial species, preexisting or diet driven, could actively be part of its etiology. This study improved our knowledge about the fungal population in the pediatric school-age population and highlighted the need to consider the influence of cross-kingdom relationships.


Assuntos
Bactérias/isolamento & purificação , Fungos/isolamento & purificação , Trato Gastrointestinal/microbiologia , Obesidade Infantil/microbiologia , Bactérias/classificação , Índice de Massa Corporal , Estudos de Casos e Controles , Criança , Fezes/microbiologia , Comportamento Alimentar , Fungos/classificação , Microbioma Gastrointestinal/fisiologia , Humanos , Obesidade Infantil/etiologia , RNA Ribossômico 16S/análise , Reação em Cadeia da Polimerase em Tempo Real
13.
Int J Food Microbiol ; 241: 298-307, 2017 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-27835773

RESUMO

The microbiota of Serrano dry-cured ham of different chemical composition, subjected or not to high-pressure processing (HPP), was investigated using culture-dependent and culture-independent methods. Microbial counts were submitted to analysis of variance with physicochemical parameters (aw, NaCl concentration, salt-in-lean ratio and intramuscular fat content) or HPP as main effects. In untreated hams, physicochemical parameters significantly affected counts of aerobic mesophiles, psychrotrophs, and moulds and yeasts. NaCl concentration and fat content influenced the levels of four and three of the five studied microbial groups, respectively, whereas no influence of aw was stated. The HPP treatment had a significant effect on counts of all investigated microbial groups. Culture-independent methods showed the presence of bacteria such as Staphylococcus equorum, Staphylococcus succinus, Bacillus subtilis and Cellulosimicrobium sp., moulds like Penicillium commune, Aspergillus fumigatus, Sclerotinia sclerotiorum, Eurotium athecium and Moniliella mellis, and yeasts like Debaryomyces hansenii and Candida glucosophila. Absence of B. subtilis bands and weaker bands of E. athecium were recorded for HPP-treated hams. The higher microbial levels found in lean ham might result in a quicker deterioration. HPP treatment confirmed its suitability as a procedure to control spoilage microorganisms. DGGE did not seem to be sensitive enough to highlight changes caused by HPP treatment in the microbiota of ham, but contributed to the detection of microbial species not previously found in ham.


Assuntos
Bactérias/isolamento & purificação , Conservação de Alimentos/métodos , Fungos/isolamento & purificação , Produtos da Carne/microbiologia , Microbiota , Animais , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Manipulação de Alimentos , Conservação de Alimentos/instrumentação , Fungos/genética , Fungos/crescimento & desenvolvimento , Produtos da Carne/análise , Pressão , Cloreto de Sódio/análise , Suínos
14.
Lett Appl Microbiol ; 63(5): 347-355, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27454854

RESUMO

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a powerful biotyping tool increasingly used for high-throughput identification of clinical microbial isolates, however, in food fermentation research this approach is still not well established. This study examines the microbial biodiversity of cocoa bean fermentation based on the isolation of micro-organisms in cocoa-producing regions, followed by MALDI-TOF MS in Switzerland. A preceding 6-week storage test to mimic lengthy transport of microbial samples from cocoa-producing regions to Switzerland was performed with strains of Lactobacillus plantarum, Acetobacter pasteurianus and Saccharomyces cerevisiae. Weekly MALDI-TOF MS analysis was able to successfully identify microbiota to the species level after storing live cultures on slant agar at mild temperatures (7°C) and/or in 75% aqueous ethanol at differing temperatures (-20, 7 and 30°C). The efficacy of this method was confirmed by on-site recording of the microbial biodiversity in cocoa bean fermentation in Bolivia and Brazil, with a total of 1126 randomly selected isolates. MALDI-TOF MS analyses revealed known dominant cocoa bean fermentation species with Lact. plantarum and Lactobacillus fermentum in the lactic acid bacteria taxon, Hanseniaspora opuntiae and S. cerevisiae in the yeast taxon, and Acet. pasteurianus, Acetobacter fabarum, Acetobacter ghanensis and Acetobacter senegalensis in the acetic acid bacteria taxon. SIGNIFICANCE AND IMPACT OF THE STUDY: Microbial identification with MALDI-TOF MS has increased the number of samples that can be analysed in a given time, a prerequisite for high-throughput methods. This method is already widely used for the identification of clinical microbial isolates, whereas in food fermentation research, including cocoa bean fermentation, microbiota is mostly identified by time-consuming, biochemical-based phenotyping and molecular approaches. This study presents the use of MALDI-TOF MS for characterizing the microbial biodiversity of cocoa bean fermentation. The feasibility of MALDI-TOF MS identification of cocoa-specific microbiota has been shown with samples collected during on-site studies in two countries of origin, Bolivia and Brazil.


Assuntos
Bactérias/isolamento & purificação , Técnicas de Tipagem Bacteriana , Cacau/microbiologia , Microbiota , Técnicas de Tipagem Micológica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Leveduras/isolamento & purificação , Ácido Acético , Bolívia , Brasil , Etanol , Fermentação
15.
Appl Environ Microbiol ; 81(22): 7893-904, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26341209

RESUMO

Microbial contamination in food processing plants can play a fundamental role in food quality and safety. In this study, the microbiota in a dairy plant was studied by both 16S rRNA- and 26S rRNA-based culture-independent high-throughput amplicon sequencing. Environmental samples from surfaces and tools were studied along with the different types of cheese produced in the same plant. The microbiota of environmental swabs was very complex, including more than 200 operational taxonomic units with extremely variable relative abundances (0.01 to 99%) depending on the species and sample. A core microbiota shared by 70% of the samples indicated a coexistence of lactic acid bacteria with a remarkable level of Streptococcus thermophilus and possible spoilage-associated bacteria, including Pseudomonas, Acinetobacter, and Psychrobacter, with a relative abundance above 50%. The most abundant yeasts were Kluyveromyces marxianus, Yamadazyma triangularis, Trichosporon faecale, and Debaryomyces hansenii. Beta-diversity analyses showed a clear separation of environmental and cheese samples based on both yeast and bacterial community structure. In addition, predicted metagenomes also indicated differential distribution of metabolic pathways between the two categories of samples. Cooccurrence and coexclusion pattern analyses indicated that the occurrence of potential spoilers was excluded by lactic acid bacteria. In addition, their persistence in the environment can be helpful to counter the development of potential spoilers that may contaminate the cheeses, with possible negative effects on their microbiological quality.


Assuntos
Bactérias/genética , Microbiologia de Alimentos , Microbiota/fisiologia , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/metabolismo , Queijo/microbiologia , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Manipulação de Alimentos , Ácido Láctico/metabolismo , Metagenoma , Filogenia , RNA Ribossômico/genética , RNA Ribossômico/metabolismo , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Análise de Sequência de DNA
16.
Int J Food Microbiol ; 211: 23-31, 2015 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-26159472

RESUMO

We measured changes in the main physical and chemical properties, flavour compounds and microbial diversity in suan-cai during natural fermentation. The results showed that the pH and concentration of soluble protein initially decreased but were then maintained at a stable level; the concentration of nitrite increased in the initial fermentation stage and after reaching a peak it decreased significantly to a low level by the end of fermentation. Suan-cai was rich in 17 free amino acids. All of the free amino acids increased in concentration to different degrees, except histidine. Total free amino acids reached their highest levels in the mid-fermentation stage. The 17 volatile flavour components identified at the start of fermentation increased to 57 by the mid-fermentation stage; esters and aldehydes were in the greatest diversity and abundance, contributing most to the aroma of suan-cai. Bacteria were more abundant and diverse than fungi in suan-cai; 14 bacterial species were identified from the genera Leuconostoc, Bacillus, Pseudomonas and Lactobacillus. The predominant fungal species identified were Debaryomyces hansenii, Candida tropicalis and Penicillium expansum.


Assuntos
Bactérias/metabolismo , Biodiversidade , Aromatizantes/metabolismo , Fungos/metabolismo , Verduras/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , China , Fermentação , Manipulação de Alimentos , Microbiologia de Alimentos , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação
17.
Int J Food Microbiol ; 210: 102-12, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26119187

RESUMO

The evaluation of the microbiota present during coffee wet fermentation was done in two distinct regions of Minas Gerais, Brazil: one farm in the South of Minas Gerais (Lavras=L) and another farm in the savannah region (Monte Carmelo=MC). The yeast population ranged from 2.48 to 4.92 log CFU/g and from 2 to 4.81 log CFU/g, the mesophilic bacteria population ranged from 3.83 to 8.47 log CFU/g and from 5.37 to 7.36 log CFU/g, and the LAB population ranged from 2.57 to 5.66 log CFU/g and from 3.40 to 4.49 log CFU/g in the L and MC farms, respectively. Meyerozyma caribbica and Hanseniaspora uvarum were the dominant yeasts in coffee wet fermentation at L farm, and Torulaspora delbrueckii was the dominant yeast at MC farm. The species Staphylococcus warneri and Erwinia persicina were the predominant bacteria at L farm, and Enterobacter asburiae and Leuconostoc mesenteroides were the dominant species at MC farm. Lactic acid was the principal acid detected, reaching 2.33 g/kg at L farm and 1.40 g/kg at MC farm by the end of the process. The volatiles composition was similar for roasted coffee from the two different regions and furans, acids, and alcohol were the main groups detected. Temporal Dominance Sensation (TDS) analyses showed that the coffee beverage from L farm was dominated by citrus and herbaceous sensory characteristics, while the coffee from MC farm was dominated by citrus, herbaceous, and nuts sensory characteristics. Evaluating the microbiota in these two regions was important in improving the knowledge of the microbial species present during coffee wet fermentation in Brazil.


Assuntos
Fenômenos Fisiológicos Bacterianos , Café/microbiologia , Fermentação , Microbiologia de Alimentos , Leveduras/fisiologia , Bactérias/isolamento & purificação , Brasil , Café/química , Células-Tronco , Leveduras/isolamento & purificação
18.
Clin Microbiol Rev ; 28(1): 208-36, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25567228

RESUMO

A pure bacterial culture remains essential for the study of its virulence, its antibiotic susceptibility, and its genome sequence in order to facilitate the understanding and treatment of caused diseases. The first culture conditions empirically varied incubation time, nutrients, atmosphere, and temperature; culture was then gradually abandoned in favor of molecular methods. The rebirth of culture in clinical microbiology was prompted by microbiologists specializing in intracellular bacteria. The shell vial procedure allowed the culture of new species of Rickettsia. The design of axenic media for growing fastidious bacteria such as Tropheryma whipplei and Coxiella burnetii and the ability of amoebal coculture to discover new bacteria constituted major advances. Strong efforts associating optimized culture media, detection methods, and a microaerophilic atmosphere allowed a dramatic decrease of the time of Mycobacterium tuberculosis culture. The use of a new versatile medium allowed an extension of the repertoire of archaea. Finally, to optimize the culture of anaerobes in routine bacteriology laboratories, the addition of antioxidants in culture media under an aerobic atmosphere allowed the growth of strictly anaerobic species. Nevertheless, among usual bacterial pathogens, the development of axenic media for the culture of Treponema pallidum or Mycobacterium leprae remains an important challenge that the patience and innovations of cultivators will enable them to overcome.


Assuntos
Bactérias/crescimento & desenvolvimento , Técnicas Bacteriológicas/história , Técnicas Bacteriológicas/tendências , Microbiologia , Bactérias/isolamento & purificação , Infecções Bacterianas/microbiologia , Meios de Cultura , História do Século XX , História do Século XXI , Microbiologia/história , Microbiologia/tendências
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