Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Int J Food Microbiol ; 341: 109059, 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33508581

RESUMO

The microbial community of ungerminated and germinated barley grains from three different cultivars grown at four different locations in Norway was investigated by culture dependent and culture independent methods. Lactic acid bacteria (LAB) was focused in this study and was isolated from germinated barley. The number of LAB ranged between 2.8 and 4.6 log cfu/g in ungerminated grains and between 4.9 and 6.3 log cfu/g in germinated grains. In total 66 out of 190 isolates were Gram+, catalase-negative and presumptive LAB. The LAB isolates were by 16S rRNA sequencing identified to be Carnobacterium maltaromaticum (6), Lactococcus lactis (2), Enterococcus sp. (1) and Leuconostoc sp. (57). Germination significantly influenced the bacterial composition. Regarding the different cultivars and growth places no significant difference in bacterial composition was seen. The most abundant bacterial genus was Pantoea (18.5% of the total sequences), followed by Rhizobium (10.1%) and Sphingomonas (9.9%). Fungal composition was significantly influenced by the germination process and the cultivation place, but no significant difference in fungal composition was detected between the 3 cultivars. The most abundant fungal genera were Cryptococcus (43.8% of all the sequences), Cladosporium (8.2%), Pyrenophora (7.4%) and Vagicola (6.3%). This study revealed knowledge of barley grain associated microbes of Norwegian barley that can be useful to control the malt quality. Germination affected both bacterial and fungal microbiota composition. No difference in bacterial microbiota composition was seen regarding cultivars and cultivation place, however, the fungal microbiota composition was significantly influenced by the cultivation place. Differences in fungal community of ungerminated and germinated barley samples of different geographical locations were more pronounced than differences in bacterial communities.


Assuntos
Carnobacterium/isolamento & purificação , Enterococcus/isolamento & purificação , Fungos/isolamento & purificação , Hordeum/microbiologia , Lactococcus lactis/isolamento & purificação , Leuconostoc/isolamento & purificação , Carnobacterium/classificação , Carnobacterium/genética , Enterococcus/classificação , Enterococcus/genética , Fungos/classificação , Fungos/genética , Germinação/fisiologia , Lactococcus lactis/classificação , Lactococcus lactis/genética , Leuconostoc/classificação , Leuconostoc/genética , Microbiota , Noruega , RNA Ribossômico 16S/genética
2.
Appl Environ Microbiol ; 85(20)2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31399404

RESUMO

Carnobacterium maltaromaticum and Carnobacterium divergens are often predominant in the microbiota of vacuum-packaged (VP) meats after prolonged storage at chiller temperatures, and more so in recent studies. We investigated the antibacterial activities of C. maltaromaticum and C. divergens (n = 31) from VP meats by phenotypic characterization and genomic analysis. Five strains showed antibacterial activities against Gram-positive bacteria in a spot-lawn assay, with C. maltaromaticum strains having an intergeneric and C. divergens strains an intrageneric inhibition spectrum. This inhibitory activity is correlated with the production of predicted bacteriocins, including carnobacteriocin B2 and carnolysin for C. maltaromaticum and divergicin A for C. divergens The supernatants of both species cultured in meat juice medium under anaerobic conditions retarded the growth of most Gram-positive and Gram-negative bacteria in broth assay in a strain-dependent manner. C. maltaromaticum and C. divergens produced formate and acetate but not lactate under VP meat-relevant conditions. The relative inhibitory activity by Carnobacterium strains was significantly correlated (P < 0.05) to the production of both acids. Genomic analysis revealed the presence of genes required for respiration in both species. In addition, two clusters of C. divergens have an average nucleotide identity below the cutoff value for species delineation and thus should be considered to be two subspecies. In conclusion, both bacteriocins and organic acids are factors contributing significantly to the antibacterial activity of C. maltaromaticum and C. divergens under VP meat-relevant conditions. A few Carnobacterium strains can be explored as protective cultures to extend the shelf life and improve the safety of VP meats.IMPORTANCE The results of this study demonstrated that both bacteriocins and organic acids are important factors contributing to the antibacterial activities of Carnobacterium from vacuum-packaged (VP) meats. This study demonstrated that formate and acetate are the key organic acids produced by Carnobacterium and demonstrated their association with the inhibitory activity of carnobacteria under VP meat-relevant storage conditions. The role of lactate, on the other hand, may not be as important as previously believed in the antimicrobial activities of Carnobacterium spp. on chilled VP meats. These findings advance our understanding of the physiology of Carnobacterium spp. to better explore their biopreservative properties for chilled VP meats.


Assuntos
Ácidos/farmacologia , Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Carnobacterium/metabolismo , Carne/microbiologia , Acetatos/metabolismo , Antibacterianos/metabolismo , Bacteriocinas/metabolismo , Carnobacterium/classificação , Carnobacterium/genética , Microbiologia de Alimentos , Embalagem de Alimentos , Formiatos/metabolismo , Genoma Bacteriano , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Ácido Láctico/metabolismo , Testes de Sensibilidade Microbiana , Filogenia , Vácuo
3.
J Appl Microbiol ; 126(2): 377-387, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30307684

RESUMO

AIMS: Carnobacterium maltaromaticum is a lactic acid bacterium of technological interest in the field of dairy ripening and food bioprotection and is generally recognized as safe in the United States. As it is associated with fish infections, the European Food Safety Agency did not include this species in the qualified presumption safety list of micro-organisms. This implies that the risk assessment for the species has to be performed at the strain level. METHODS AND RESULTS: Multilocus sequence typing (MLST) is a tool that (i) potentially allows to discriminate strains isolated from diseased fish from apathogenic strains and (ii) to assess the genetic relatedness between both groups of strains. In this study, we characterized by MLST 21 C. maltaromaticum strains including 16 strains isolated from diseased fish and 5 apathogenic dairy strains isolated from cheese. The resulting population structure was investigated by integrating these new data to the previously published population structure (available at http://pubmlst.org), which represents an overall of 71 strains. CONCLUSIONS: This analysis revealed that none of the strains isolated from diseased fish is assigned to a clonal complex containing cheese isolates, and that 11 strains exhibit singleton genotypes suggesting that the population of diseased fish isolates is not clonal. SIGNIFICANCE AND IMPACT OF THE STUDY: This study thus provides a population structure of C. maltaromaticum that could serve in the future as a reference that could contribute to the risk assessment of C. maltaromaticum strains intended to be used in the food chain.


Assuntos
Carnobacterium/classificação , Queijo/microbiologia , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Positivas/veterinária , Animais , Carnobacterium/genética , Carnobacterium/isolamento & purificação , Peixes , Genótipo , Infecções por Bactérias Gram-Positivas/microbiologia , Tipagem de Sequências Multilocus
4.
Int J Food Microbiol ; 286: 120-127, 2018 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-30081251

RESUMO

Carnobacterium spp. are frequently isolated from vacuum-packaged (VP) meat. Specific strains of Carnobacterium and their growth characteristics may be associated with the storage life of such products. This study investigated the growth of 44 Carnobacterium isolates obtained from VP meat cuts produced at three Canadian abattoirs (A, B and C) under the following conditions: pH 5.4, 6.2 and 7.4; lactic acid at 60 and 90 mM; acetic acid at 33.6 mM. Whole genome sequencing was performed for all 44 isolates and a core genome phylogenetic tree was created to identify strain variability among isolates from different abattoirs. The isolates were clustered into 11 groups. All isolates from abattoirs B and C were identified as C. divergens, while the isolates from abattoir A included both C. maltaromaticum and C. divergens at equal proportions. C. divergens isolates from abattoir A belonged to two phylogenetic groups and none of them was found in the phylogenetic groups containing isolates from abattoirs B or C. Whole genome sequencing revealed that identical strains were isolated from different samples obtained at the same abattoir. The mean growth rate and maximum population density of the C. maltaromaticum isolates were lower than those of the C. divergens isolates. C. divergens isolates from abattoir A had higher growth rates and maximum population density than those from abattoirs B and C. In conclusion, growth characteristic and whole genome analysis both demonstrated strain variability of Carnobacterium among abattoirs, which could be a result of the difference in the antimicrobial interventions used for carcasses at different abattoirs, and may be associated with different storage lives of VP meats produced from different abattoirs.


Assuntos
Ácidos/metabolismo , Carnobacterium/classificação , Carnobacterium/crescimento & desenvolvimento , Embalagem de Alimentos/métodos , Carne Vermelha/microbiologia , Matadouros , Animais , Canadá , Carnobacterium/genética , Carnobacterium/isolamento & purificação , Filogenia , Vácuo , Sequenciamento Completo do Genoma
5.
Int J Syst Evol Microbiol ; 68(5): 1672-1677, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29616891

RESUMO

A novel, alkaliphilic, psychrotolerant, facultative anaerobe, designated CP1T, was isolated from sandy soil near the Davis Station in Antarctica. The short-rod-shaped cells displayed Gram-positive staining and did not form spores. Strain CP1T was able to grow at temperatures between 4 and 36 °C, pH 6.0-9.5, and in the presence of up to 5.0 % (w/v) NaCl. 16S rRNA gene and multilocus (pheS, rpoA, and atpA) sequence analysis revealed Carnobacterium mobile DSM 4848T and Carnobacterium iners LMG 26642T as the closest relatives (97.4 and 97.1 % 16S rRNA gene sequence similarity, respectively). The genomic G+C content was 38.1 mol%, and DNA-DNA hybridization with DSM 4848T revealed 32.4±3.4 % similarity. The major fatty acid components were C14 : 0 and C16 : 1ω9c. The cell wall contained meso-diaminopimelic acid and was of peptidoglycan type A1γ. Based on physiological, genotypic and biochemical characteristics, strain CP1T represents a novel species of the genus Carnobacterium for which the name Carnobacterium antarcticum sp. nov. is proposed. The type strain is CP1T (=DSM 103363T=CGMCC 1.15643T).


Assuntos
Carnobacterium/classificação , Filogenia , Microbiologia do Solo , Regiões Antárticas , Técnicas de Tipagem Bacteriana , Composição de Bases , Carnobacterium/genética , Carnobacterium/isolamento & purificação , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Peptidoglicano/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
6.
Int J Food Microbiol ; 226: 1-4, 2016 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-26998709

RESUMO

Carnobacterium maltaromaticum is a Lactic Acid Bacterium (LAB) of technological interest for the food industry, especially the dairy as bioprotection and ripening flora. The industrial use of this LAB requires accurate and resolutive typing tools. A new typing method for C. maltaromaticum inspired from MLVA analysis and called Repeat-based Sequence Typing (RST) is described. Rather than electrophoresis analysis, our RST method is based on sequence analysis of multiple loci containing Variable-Number Tandem-Repeats (VNTRs). The method described here for C. maltaromaticum relies on the analysis of three VNTR loci, and was applied to a collection of 24 strains. For each strain, a PCR product corresponding to the amplification of each VNTR loci was sequenced. Sequence analysis allowed delineating 11, 11, and 12 alleles for loci VNTR-A, VNTR-B, and VNTR-C, respectively. Considering the allele combination exhibited by each strain allowed defining 15 genotypes, ending in a discriminatory index of 0.94. Comparison with MLST revealed that both methods were complementary for strain typing in C. maltaromaticum.


Assuntos
Carnobacterium/classificação , Carnobacterium/genética , Microbiologia de Alimentos , Alelos , Variação Genética , Genótipo , Repetições Minissatélites/genética , Tipagem de Sequências Multilocus , Reação em Cadeia da Polimerase , Especificidade da Espécie
7.
Int J Syst Evol Microbiol ; 65(Pt 2): 556-561, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25392348

RESUMO

A novel, psychrotolerant facultative anaerobe, strain WN1359(T), was isolated from a permafrost borehole sample collected at the right bank of the Kolyma River in Siberia, Russia. Gram-positive-staining, non-motile, rod-shaped cells were observed with sizes of 1-2 µm long and 0.4-0.5 µm wide. Growth occurred in the range of pH 5.8-9.0 with optimal growth at pH 7.8-8.6 (pH optimum 8.2). The novel isolate grew at temperatures from 0-37 °C and optimal growth occurred at 25 °C. The novel isolate does not require NaCl; growth was observed between 0 and 8.8 % (1.5 M) NaCl with optimal growth at 0.5 % (w/v) NaCl. The isolate was a catalase-negative, facultatively anaerobic chemo-organoheterotroph that used sugars but not several single amino acids or dipeptides as substrates. The major metabolic end-product was lactic acid in the ratio of 86 % l-lactate : 14 % d-lactate. Strain WN1359(T) was sensitive to ampicillin, chloramphenicol, fusidic acid, lincomycin, monocycline, rifampicin, rifamycin SV, spectinomycin, streptomycin, troleandomycin and vancomycin, and resistant to nalidixic acid and aztreonam. The fatty acid content was predominantly unsaturated (70.2 %), branched-chain unsaturated (11.7 %) and saturated (12.5 %). The DNA G+C content was 35.3 mol% by whole genome sequence analysis. 16S rRNA gene sequence analysis showed 98.7 % sequence identity between strain WN1359(T) and Carnobacterium inhibens. Genome relatedness was computed using both Genome-to-Genome Distance Analysis (GGDA) and Average Nucleotide Identity (ANI), which both strongly supported strain WN1359(T) belonging to the species C. inhibens. On the basis of these results, the permafrost isolate WN1359(T) represents a novel subspecies of C. inhibens, for which the name Carnobacterium inhibens subsp. gilichinskyi subsp. nov. is proposed. The type strain is WN1359(T) ( = ATCC BAA-2557(T) = DSM 27470(T)). The subspecies Carnobacterium inhibens subsp. inhibens subsp. nov. is created automatically. An emended description of C. inhibens is also provided.


Assuntos
Carnobacterium/classificação , Pergelissolo/microbiologia , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Federação Russa , Análise de Sequência de DNA
8.
Appl Environ Microbiol ; 80(13): 3920-9, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24747901

RESUMO

Dairy products are colonized with three main classes of lactic acid bacteria (LAB): opportunistic bacteria, traditional starters, and industrial starters. Most of the population structure studies were previously performed with LAB species belonging to these three classes and give interesting knowledge about the population structure of LAB at the stage where they are already industrialized. However, these studies give little information about the population structure of LAB prior their use as an industrial starter. Carnobacterium maltaromaticum is a LAB colonizing diverse environments, including dairy products. Since this bacterium was discovered relatively recently, it is not yet commercialized as an industrial starter, which makes C. maltaromaticum an interesting model for the study of unindustrialized LAB population structure in dairy products. A multilocus sequence typing scheme based on an analysis of fragments of the genes dapE, ddlA, glpQ, ilvE, pyc, pyrE, and leuS was applied to a collection of 47 strains, including 28 strains isolated from dairy products. The scheme allowed detecting 36 sequence types with a discriminatory index of 0.98. The whole population was clustered in four deeply branched lineages, in which the dairy strains were spread. Moreover, the dairy strains could exhibit a high diversity within these lineages, leading to an overall dairy population with a diversity level as high as that of the nondairy population. These results are in agreement with the hypothesis according to which the industrialization of LAB leads to a diversity reduction in dairy products.


Assuntos
Carnobacterium/classificação , Carnobacterium/genética , Laticínios/microbiologia , Variação Genética , DNA Bacteriano/química , DNA Bacteriano/genética , Genes Bacterianos , Dados de Sequência Molecular , Tipagem de Sequências Multilocus , Análise de Sequência de DNA
9.
Mol Biotechnol ; 56(3): 210-22, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24037409

RESUMO

Eight putative consistently expressed genes in Carnobacterium maltaromaticum and Lactobacillus curvatus, and nine in Listeria innocua, were examined for their potential as references for the normalization of gene expression. Expression stability of candidate reference genes was evaluated under growth conditions of low (5 °C) and moderately high (40-42.5 °C) temperatures, and high salt (≥3 % NaCl) using the geNormplus and NormFinder algorithms. Under temperature stress, both algorithms ranked elongation factor Tu (Tuf) as the most stably expressed gene in C. maltaromaticum. In L. curvatus, at similar conditions, geNormplus identified Tuf and 6-phosphogluconate dehydrogenase (6PGDH) as suitable for normalization, while NormFinder identified phenylalanyl-tRNA synthase and recombinase A as the best pair. In L. innocua grown under the same temperatures, geNormplus ranked 6PGDH, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and Tuf as the top three most stable references, whereas NormFinder identified GAPDH and 6PGDH as suitable for normalization, with Tuf ranked as number six. There was less consistency between algorithms in the salt stress experiment. No gene was identified that exhibited such a constant level of expression as to outperform the other candidates under both experimental conditions. This study underlines the need for normalizing bacterial gene expression using multiple carefully selected references.


Assuntos
Proteínas de Bactérias/metabolismo , Carnobacterium/genética , Lactobacillus/genética , Listeria/genética , Algoritmos , Carnobacterium/classificação , Carnobacterium/fisiologia , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Lactobacillus/classificação , Lactobacillus/fisiologia , Listeria/classificação , Listeria/fisiologia , Estresse Fisiológico
10.
Food Microbiol ; 36(2): 223-30, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24010601

RESUMO

Carnobacterium maltaromaticum is a lactic acid bacterium isolated from soft cheese. The objective of this work was to study its potential positive impact when used in cheese technology. Phenotypic and genotypic characterization of six strains of C. maltaromaticum showed that they belong to different phylogenetic groups. Although these strains lacked the ability to coagulate milk quickly, they were acidotolerant. They did not affect the coagulation capacity of starter lactic acid bacteria, Lactococcus lactis and Streptococcus thermophilus, used in dairy industry. The impact of C. maltaromaticum LMA 28 on bacterial flora of cheese revealed a significant decrease of Psychrobacter sp. concentration, which might be responsible for cheese aging phenomena. An experimental plan was carried out to unravel the mechanism of inhibition of Psychrobacter sp. and Listeria monocytogenes and possible interaction between various factors (cell concentration, NaCl, pH and incubation time). Cellular concentration of C. maltaromaticum LMA 28 was found to be the main factor involved in the inhibition of Psychrobacter sp. and L. monocytogenes.


Assuntos
Carnobacterium/fisiologia , Queijo/microbiologia , Lactobacillaceae/metabolismo , Leite/microbiologia , Animais , Antibiose , Carnobacterium/classificação , Carnobacterium/genética , Carnobacterium/isolamento & purificação , Fermentação , Microbiologia de Alimentos
11.
Vet Pathol ; 50(3): 412-7, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-22452824

RESUMO

Juvenile salmon sharks beach yearly along the California coast, primarily during late summer and early fall. Fresh, frozen, and formalin-fixed tissues from 19 stranded salmon sharks were collected for examination. Histopathology revealed meningitis or meningoencephalitis in 18 of 19 shark brains with intralesional bacteria observed in 6 of the affected brains. Bacterial culture of fresh or frozen brain, liver, and/or heart blood from 13 sharks yielded pure cultures characterized molecularly and/or biochemically as belonging to the genus Carnobacterium. The 16s ribosomal DNA sequence of 7 tissue isolates from 7 separate sharks was 99% homologous to C. maltaromaticum (GenBank FJ656722.1). Sequence of the large ribosomal DNA intergenic spacer region (ISR) was 97% homologous to C. maltaromaticum (AF374295.1). This is the first report of Carnobacterium infection in any shark species, and the authors posit that brain infection caused by Carnobacterium is a significant cause of morbidity and mortality in juvenile salmon sharks found stranded along the Pacific coast of California.


Assuntos
Carnobacterium/classificação , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Positivas/veterinária , Meningoencefalite/veterinária , Tubarões , Animais , Encéfalo/microbiologia , Encéfalo/patologia , California , Carnobacterium/genética , Carnobacterium/isolamento & purificação , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Feminino , Doenças dos Peixes/patologia , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/patologia , Fígado/microbiologia , Fígado/patologia , Masculino , Meningoencefalite/microbiologia , Meningoencefalite/patologia , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA/veterinária
12.
Int J Syst Evol Microbiol ; 63(Pt 4): 1370-1375, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22798642

RESUMO

Two lactic acid-producing, Gram-stain-positive rods were isolated from a microbial mat actively growing in the littoral zone of an Antarctic lake (Forlidas Pond) in the Pensacola mountains and studied using a polyphasic taxonomic approach. The isolates were examined by phylogenetic analysis of the 16S rRNA gene, multilocus sequence analysis of pheS, rpoA and atpA, and biochemical and genotypic characteristics. One strain, designated LMG 26641, belonged to Carnobacterium alterfunditum and the other strain, designated LMG 26642(T), could be assigned to a novel species, with Carnobacterium funditum DSM 5970(T) as its closest phylogenetic neighbour (99.2 % 16S rRNA gene sequence similarity). Carnobacterium iners sp. nov. could be distinguished biochemically from other members of the genus Carnobacterium by the lack of acid production from carbohydrates. DNA-DNA relatedness confirmed that strain LMG 26642(T) represented a novel species, for which we propose the name Carnobacterium iners sp. nov. (type strain is LMG 26642(T)  = CCUG 62000(T)).


Assuntos
Carnobacterium/classificação , Filogenia , Tanques/microbiologia , Regiões Antárticas , Técnicas de Tipagem Bacteriana , Composição de Bases , Carnobacterium/genética , Carnobacterium/isolamento & purificação , DNA Bacteriano/genética , Genes Bacterianos , Dados de Sequência Molecular , Tipagem de Sequências Multilocus , Hibridização de Ácido Nucleico , Peptidoglicano/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Microbiologia da Água
13.
J Food Sci ; 77(1): S84-90, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22260135

RESUMO

UNLABELLED: Atlantic salmon were subjected to minimal preslaughter crowding stress (Control), short-term crowding for 20 min (SS-group), or long-term crowding for 24 h (LS-group). The fish were filleted prerigor, cut into 270 g pieces, and packaged in modified atmosphere (60% CO2 and 40% N2). Fillet quality analyses were determined during 22 d of storage at 0.3 °C. Bacterial growth and unpleasant sensory properties increased earlier in the LS-group. The negative effects of long-term preslaughter stress were more pronounced for raw than cooked samples, and more pronounced for odor than flavor. Sequence analyses of bacterial DNA at the end of storage revealed that 100% of the bacteria were comprised by Photobacterium phosphoreum of the SS- and LS-group, whereas the Control group also contained 21% of Carnobacterium maltaromaticum (lactic acid bacteria, LAB). Counting of LAB, using Man-Rogosa-Sharke agar, similarly showed higher numbers of the Control group after 15 d of storage. A total bacterial count of log 6 CFU/g was observed after 15 d of storage of the LS-group, which was 3 and 7 d earlier compared with the Control and SS-group, respectively. Fillet color, texture, and liquid losses were not negatively affected by preslaughter crowding stress. From the sensory and bacterial analyses, it is concluded that long-term crowding stress accelerates bacterial growth and development of unpleasant sensory properties, hence reduces the shelf life of prerigor modified atmosphere packaged (MAP) salmon. PRACTICAL APPLICATION: Stressful handling of Atlantic salmon before slaughter resulted in faster reduction of fresh taste and smell, faster bacterial growth, and hence shorter shelf life. The deteriorative effects were more pronounced of raw compared to cooked salmon. Therefore, salmon should be handled carefully in connection with slaughter to avoid impaired welfare and fillet quality, in particularly for fish that is consumed raw, such as sushi.


Assuntos
Aglomeração , Salmo salar/microbiologia , Salmo salar/fisiologia , Alimentos Marinhos/análise , Alimentos Marinhos/microbiologia , Estresse Fisiológico , Animais , Aquicultura , Carnobacterium/classificação , Carnobacterium/crescimento & desenvolvimento , Carnobacterium/isolamento & purificação , Fenômenos Químicos , Contagem de Colônia Microbiana , Manipulação de Alimentos , Temperatura Alta , Humanos , Fenômenos Mecânicos , Tipagem Molecular , Odorantes , Photobacterium/classificação , Photobacterium/crescimento & desenvolvimento , Photobacterium/isolamento & purificação , Controle de Qualidade , Sensação , Paladar , Fatores de Tempo
14.
J Microbiol ; 49(5): 703-13, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22068485

RESUMO

Members of the genus Oncorhynchus were introduced from the Pacific Northwest to the Laurentian Great Lakes basin and now constitute one of its most commercially and ecologically valuable fisheries. Recently, infections by a group of Gram-positive atypical lactobacilli belonging to the genus Carnobacterium have been detected in feral and captive Oncorhynchus spp. broodstock, some of which were associated with mortalities. Out of 1564 rainbow and steelhead trout (O. mykiss), coho salmon (O. kisutch), and Chinook salmon (O. tshawytscha) that were bacteriologically examined, 57 Carnobacterium spp. isolates were recovered from the kidneys, spleen, swimbladder, and/or external ulcerations of 51 infected fish. Phenotypic and biochemical characterization, as well as partial 16S rDNA sequencing and phylogenetic analyses of 30 representative isolates identified 29 as Carnobacterium maltaromaticum and 1 as C. divergens, though some phenotypic and genotypic heterogeneity was observed. Infections with C. maltaromaticum were associated with signitures typical of pseudokidney disease, but on occasion were also observed in fish displaying the gross and histopathological changes characteristic of nephrocalcinosis. While C. maltaromaticum infections were found to be widespread in both feral and farmed spawning populations of Oncorhynchus spp. residing within the Great Lakes basin, infection prevalence varied significantly according to fish species and strain, gender, and across time, but not by sampling location according to logistic regression analysis. The findings of this study further underscore the presence of phenotypic variations among Carnobacterium maltaromaticum strains that necessitate genotypic analysis to achieve definitive identification.


Assuntos
Carnobacterium/classificação , Carnobacterium/isolamento & purificação , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Positivas/veterinária , Oncorhynchus/microbiologia , Estruturas Animais/microbiologia , Estruturas Animais/patologia , Animais , Técnicas de Tipagem Bacteriana , Carnobacterium/genética , Carnobacterium/metabolismo , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Doenças dos Peixes/patologia , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/patologia , Histocitoquímica , Michigan , Microscopia , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
15.
Appl Environ Microbiol ; 77(20): 7382-93, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21784913

RESUMO

One hundred three isolates of Carnobacterium spp. from raw meat were analyzed by random amplification of polymorphic DNA (RAPD) and PCR and were identified by 16S rRNA gene sequencing. Forty-five strains of Carnobacterium maltaromaticum were characterized for their growth capabilities at different temperatures, NaCl concentrations, and pH values and for in vitro lipolytic and proteolytic activities. Moreover, their spoilage potential in meat was investigated by analyzing the release of volatile organic compounds (VOCs) in meat stored in air or vacuum packs. Almost all the strains were able to grow at 4, 10, and 20°C, at pH values of 6 to 9, and in the presence of 2.5% NaCl. The release of VOCs by each strain in beef stored at 4°C in air and vacuum packs was evaluated by headspace solid-phase microextraction (HS-SPME)-gas chromatography-mass spectrometry (GC-MS) analysis. All the meat samples inoculated and stored in air showed higher numbers of VOCs than the vacuum-packed meat samples. Acetoin, 1-octen-3-ol, and butanoic acid were the compounds most frequently found under both storage conditions. The contaminated meat samples were evaluated by a sensory panel; the results indicated that for all sensory odors, no effect of strain was significant (P > 0.05). The storage conditions significantly affected (P < 0.05) the perception of dairy, spoiled-meat, and mozzarella cheese odors, which were more intense in meat stored in air than in vacuum packs but were never very intense. In conclusion, different strains of C. maltaromaticum can grow efficiently in meat stored at low temperatures both in air and in vacuum packs, producing volatile molecules with low sensory impacts, with a negligible contribution to meat spoilage overall.


Assuntos
Carnobacterium/classificação , Carnobacterium/isolamento & purificação , Embalagem de Alimentos/métodos , Armazenamento de Alimentos/métodos , Carne/microbiologia , Ar , Carnobacterium/genética , Carnobacterium/metabolismo , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Cromatografia Gasosa-Espectrometria de Massas , Genótipo , Concentração de Íons de Hidrogênio , Tipagem Molecular , RNA Ribossômico 16S/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Análise de Sequência de DNA , Cloreto de Sódio/metabolismo , Temperatura , Vácuo , Compostos Orgânicos Voláteis/metabolismo
16.
Extremophiles ; 15(4): 463-72, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21509422

RESUMO

A high proportion of microorganisms that colonise cold environments originate from marine sites; hence, they must combine adaptation to low temperature with osmoregulation. However, little or nothing is known about the nature of compatible solutes used by cold-adapted organisms to balance the osmotic pressure of the external medium. We studied the intracellular accumulation of small organic solutes in the Arctic isolate Carnobacterium strain 17-4 as a function of the growth temperature and the NaCl concentration in the medium. Data on 16S rDNA sequence and DNA-DNA hybridisation tests corroborate the assignment of this isolate as a new species of the bacterial genus Carnobacterium. The growth profiles displayed maximal specific growth rate at 30°C in medium without NaCl, and maximal values of final biomass at growth temperatures between 10 and 20°C. Therefore, Carnobacterium strain 17-4 exhibits halotolerant and psychrotolerant behaviours. The solute pool contained glycine-betaine, the main solute used for osmoregulation, and an unknown compound whose structure was identified as α-glucopyranosyl-(1-3)-ß-glucopyranosyl-(1-1)-α-glucopyranose (abbreviated as gluconeotrehalose), using nuclear magnetic resonance and mass spectrometry. This unusual solute consistently accumulated to high levels (0.35 ± 0.05 mg/mg cell protein) regardless of the growth temperature or salinity. The efficiency of gluconeotrehalose in the stabilisation of four model enzymes against heat damage was also assessed, and the effects were highly protein dependent. The lack of variation in the gluconeotrehalose content observed under heat stress, osmotic stress, and starvation provides no clue for the physiological role of this rare solute.


Assuntos
Carnobacterium/metabolismo , Temperatura Baixa , Trissacarídeos/metabolismo , Animais , Carnobacterium/classificação , Carnobacterium/genética , Carnobacterium/isolamento & purificação , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , DNA Ribossômico/genética , DNA Ribossômico/metabolismo , Estabilidade Enzimática/fisiologia , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Cloreto de Sódio/metabolismo , Suínos
17.
Food Microbiol ; 27(5): 573-9, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20510773

RESUMO

Carnobacterium species constitute a genus of Lactic Acid Bacteria (LAB) present in different ecological niches. The aim of this article is to summarize the knowledge about Carnobacterium maltaromaticum species at different microbiological levels such as taxonomy, isolation and identification, ecology, technological aspects and safety in dairy products. Works published during the last decade concerning C. maltaromaticum have shown that this non-starter LAB (NSLAB) could present major interests in dairy product technology. Four reasons can be mentioned: i) it can grow in milk during the ripening period with no competition with starter LAB, ii) this species synthesizes different flavouring compounds e.g., 3-methylbutanal, iii) it can inhibit the growth of foodborne pathogens as Listeria monocytogenes due to its ability to produce bacteriocins, iv) it has never been reported to be involved in human diseases as no cases of human infection have been directly linked to the consumption of dairy products containing this species.


Assuntos
Técnicas de Tipagem Bacteriana/métodos , Carnobacterium/isolamento & purificação , Laticínios/microbiologia , Tecnologia de Alimentos , Animais , Carnobacterium/classificação , Carnobacterium/genética , Carnobacterium/fisiologia , Qualidade de Produtos para o Consumidor , Conservação de Alimentos , Humanos
18.
Int J Syst Evol Microbiol ; 59(Pt 12): 3168-71, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19643884

RESUMO

A Gram-positive, facultatively anaerobic bacterium, designated strain MS3(T), was isolated from a traditional Korean fermented food made with freshwater shrimp. Strain MS3(T) was able to grow at 4-37 degrees C, at pH 5.5-9.0 and in the presence of 0-5 % (w/v) NaCl. Optimal growth occurred at 30 degrees C, at pH 8.5 and in the presence of 2 % NaCl. The strain was catalase- and oxidase-negative. It was able to metabolize various carbohydrates as energy sources. 16S rRNA gene sequence analysis showed that strain MS3(T) was most closely related to Carnobacterium pleistocenium FTR1(T) (98.95 % similarity), but the level of DNA-DNA relatedness between the two taxa was less than 16.0 %. The genomic G+C content of strain MS3(T) was 43.9 mol% and the major fatty acid components were C(16 : 0), C(16 : 1)omega9c and C(18 : 1)omega9c. On the basis of its genotypic, physiological and biochemical characteristics, strain MS3(T) is considered to represent a novel species of the genus Carnobacterium, for which the name Carnobacterium jeotgali sp. nov. is proposed. The type strain is MS3(T) (=KCTC 13251(T)=JCM 15539(T)).


Assuntos
Carnobacterium/classificação , Carnobacterium/isolamento & purificação , Fermentação , Penaeidae/microbiologia , Saccharopolyspora/classificação , Saccharopolyspora/isolamento & purificação , Animais , Carnobacterium/genética , Carnobacterium/metabolismo , DNA Bacteriano/genética , DNA Ribossômico/genética , Coreia (Geográfico) , Dados de Sequência Molecular , Penaeidae/metabolismo , Filogenia , RNA Ribossômico 16S/genética , Saccharopolyspora/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...