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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.
Int J Food Microbiol ; 325: 108626, 2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32325345

RESUMO

AIMS: The aim of this study was to evaluate the performance of sampling methods [contact plates, sponges, and swabs] in the recovery of biofilm Listeria monocytogenes populations considering the seafood environment conditions (nature of conditioning, of materials and bacterial species). METHODS AND RESULTS: Different materials (stainless steel, polyvinyl chloride, polyurethane) were conditioned with two fish filtrates, the ready-to-eat the most consumed in Europe (smoked salmon, cod). After, we added the suspension of Listeria monocytogenes, alone or with Pseudomonas fluorescens or Carnobacterium strains, and incubated for 48 h at 8 °C. Then, the 48 h-biofilms were sampled with different methods (contact plates, sponges, and swabs). The cultivable bacterial populations were enumerated on agar, while the L. monocytogenes total and viable populations were quantified by qPCR and propidium monoazide-qPCR (PMA-qPCR), respectively. The amount of L. monocytogenes in biofilms was affected only by the nature of the conditioning with lowest adherent bacteria with cod versus with smoked salmon conditioning. Considering the amount of total population, the swab displayed the lowest values versus the sponges and the contact plates. An explanation was that the observations of the swab by microscopy showed the bacteria trapped within it. The recovery of cultivable bacterial populations was not significantly different with the three sampling methods. On the contrary, we showed that the VBNC populations were only detached by two of three methods (contact plates, sponges) while for the dead populations, those were contact plates and swabs. CONCLUSIONS: The nature of the conditioning influenced the amount of the bacteria in biofilms. And the performance of the recovery of the bacterial populations (dead, VBNC, cultivable) was dependent on the methods used. SIGNIFICANCE AND IMPACT OF THE STUDY: This study showed that the seafood environmental conditions influenced the biofilm formation and the assessment of the efficiency of cleaning and disinfectant operations could be significantly affected by the used sampling methods.


Assuntos
Biofilmes/crescimento & desenvolvimento , Microbiologia de Alimentos/métodos , Listeria monocytogenes/isolamento & purificação , Alimentos Marinhos/microbiologia , Ágar , Animais , Azidas/química , Carnobacterium/isolamento & purificação , Desinfetantes/farmacologia , Europa (Continente) , Peixes/microbiologia , Propídio/análogos & derivados , Propídio/química , Pseudomonas fluorescens/isolamento & purificação , Aço Inoxidável/análise
3.
Food Res Int ; 123: 601-611, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31285009

RESUMO

Cooked pork products, i.e., sliced cooked hams maintained under modified-atmosphere-packaging (MAP), were analysed both microbiologically and with respect to volatile levels during storage. Three storage temperature ranges were compared (4-6 °C, 7-9 °C, and 11-13 °C), representing different refrigeration conditions at household level. The microbial loads were determined by plating samples on six different agar media, followed by (GTG)5-PCR fingerprinting of genomic DNA of selected isolates, and identification of representative isolates by 16S rRNA, pheS, and rpoA gene sequencing. Carnobacterium maltaromaticum, Lactobacillus sakei, and Serratia proteamaculans were the major bacterial species found among the 619 isolates identified. The volatiles produced during storage were followed by selected ion flow tube-mass spectrometry (SIFT-MS) and the identity of the volatiles was confirmed by headspace solid-phase microextraction combined with gas chromatography and time-of-flight mass spectrometry (HS-SPME-GC-TOF-MS). SIFT-MS analysis showed that volatiles, such as 2,3-butanediol, acetoin, and ethanol, may serve as potential markers for spoilage development. Differences in volatile production between samples were likely due to discrepancies in the initial microbial load and the effect of storage conditions. In conclusion, this study combines the use of new mass spectrometric techniques to examine volatile production during spoilage as an additional source of information during microbiological community analysis.


Assuntos
Embalagem de Alimentos , Produtos da Carne/análise , Produtos da Carne/microbiologia , RNA Ribossômico 16S/isolamento & purificação , Compostos Orgânicos Voláteis/análise , Animais , Carga Bacteriana , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Carnobacterium/isolamento & purificação , Carnobacterium/metabolismo , Contagem de Colônia Microbiana , Culinária , Contaminação de Alimentos , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Lactobacillus sakei/isolamento & purificação , Lactobacillus sakei/metabolismo , Espectrometria de Massas , RNA Ribossômico 16S/metabolismo , Refrigeração , Análise de Sequência de DNA , Serratia/isolamento & purificação , Serratia/metabolismo , Microextração em Fase Sólida , Suínos
4.
Food Res Int ; 122: 517-527, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31229107

RESUMO

Chicken meat is one of the most widely consumed meats worldwide. The microbiota on the whole body of chicken is a potential source of foodborne pathogens that can be transmitted to humans during the preparation of raw meat. However, to date, there have been no studies comparing the microbiota of packaged chicken products and those of raw chicken carcasses from butcher shops, although such information could be useful for identifying sources of contamination in cases of food poisoning. We addressed this in the present study by analyzing the microbiota of 80 chicken meat samples collected from various butcher shops and processing plants in South Korea with the Illumina MiSeq system based on the 16S rRNA gene sequence. The bacterial amounts in chicken samples were estimated by quantitative real-time PCR. Although different microbial members were present in unpackaged meat from butcher shops as compared to those in packaged products from commercial sources, seasonal differences (sample obtained in January vs. July) in microbiota were more significant even in the packaged products from the same company. We also investigated the influence of contaminated foodborne pathogen on the indigenous microbiota (64 chicken samples) by artificially inoculated with Salmonella enterica serotype Virchow on chicken carcasses under various conditions, and carrying out 16S rRNA gene and whole metagenome sequencing. The amount of contaminated Salmonella in chicken meat samples was the highest and lowest in samples stored at 27 °C and 4 °C after washing, respectively. Additionally, the relative abundance of virulence genes was detected lower in samples stored at 4 °C after washing in both butcher shop and commercial samples. These results could be useful for reducing the risk of foodborne illness caused by cross-contamination during the preparation of chicken meat.


Assuntos
Galinhas , Doenças Transmitidas por Alimentos/epidemiologia , Doenças Transmitidas por Alimentos/microbiologia , Aves Domésticas/microbiologia , Animais , Carga Bacteriana , Brochothrix/isolamento & purificação , Brochothrix/metabolismo , Carnobacterium/isolamento & purificação , Carnobacterium/metabolismo , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Embalagem de Alimentos , Sequenciamento de Nucleotídeos em Larga Escala , Metagenômica , Microbiota , Moraxella/isolamento & purificação , Moraxella/metabolismo , Pseudomonas/isolamento & purificação , Pseudomonas/metabolismo , RNA Ribossômico 16S , República da Coreia/epidemiologia , Salmonella enterica/isolamento & purificação , Salmonella enterica/metabolismo , Estações do Ano , Análise de Sequência de DNA , Temperatura
5.
Food Res Int ; 119: 196-206, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30884649

RESUMO

Cooked poultry products are nutritious and economically valuable products that are at risk of bacterial spoilage, which can be postponed by cooling and modified-atmosphere-packaging (MAP). In this study, a cooked chicken product was stored at three different temperature ranges (4-6 °C, 7-9 °C, and 11-13 °C) and volatile production was measured over time using selected ion flow tube-mass spectrometry (SIFT-MS). The identities of the volatiles formed were confirmed by headspace solid-phase microextraction coupled with gas chromatography time-of-flight mass spectrometry (HS-SPME-GC-TOF-MS) analysis. In total, 33 volatiles were proposed using the latter technique and their concentrations were calculated using product ion counts after assignment of these counts to specific volatiles. The results indicated that 1-octen-3-ol, 2,3-butanediol, acetoin, benzaldehyde, ethanol, methylbutanal, and methylbutanol may serve as biomarkers for bacterial growth and/or chemical degradation of cooked poultry products. In parallel, the bacterial loads of the product samples were determined on selective agar media. A total of 495 bacterial isolates was classified and identified by (GTG)5-PCR fingerprinting, followed by gene sequencing of representative cluster isolates. Carnobacterium divergens, Carnobacterium maltaromaticum, Rahnella aquatilis, and Serratia proteamaculans were the most commonly found species, besides minor contributions of Lactobacillus sakei and Hafnia alvei. Differences in volatile profiles could thus be ascribed to variations in bacterial loads and storage temperatures.


Assuntos
Culinária , Cromatografia Gasosa-Espectrometria de Massas , Produtos Avícolas/análise , Compostos Orgânicos Voláteis/análise , Carga Bacteriana , Carnobacterium/isolamento & purificação , Carnobacterium/metabolismo , Contagem de Colônia Microbiana , Enterobacteriaceae/isolamento & purificação , Enterobacteriaceae/metabolismo , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Embalagem de Alimentos , Armazenamento de Alimentos , Concentração de Íons de Hidrogênio , Lactobacillales/isolamento & purificação , Lactobacillales/metabolismo , Microextração em Fase Sólida , Temperatura
6.
Food Microbiol ; 81: 40-50, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30910087

RESUMO

The major aim of the study was to establish the routes via which spoilage associated psychrotrophic bacteria contaminate poultry products at a large processing plant located in Belgium. Environmental samples were collected consisting of samples of air and swabs of food contact surfaces. Product samples were also collected consisting of modified atmosphere packaged (MAP) chicken wings and legs, which were analyzed microbiologically on the same day they were produced as well as after their sell-by date. Psychrotrophic bacteria from these samples were subsequently clustered and identified by means of MALDI-TOF MS and 16S rRNA gene sequencing. Carnobacterium maltaromaticum was determined to dominate the spoilage flora of both wings and legs. Other psychrotrophic bacteria able to grow on MRS which were identified on expired wings and legs included Carnobacterium divergens, Brocothrix thermosphacta, Lactobacillus curvatus, and Lactobacillus brevis. These were determined to arise from food contact surfaces such as cutting blades, leg hooks, Ertalon and polyurethane conveyor belts, working tables, and the hands of the operators. Importantly, it was determined that cleaning and disinfection was largely inadequate. Air was also determined to be an important vector of psychrotrophic bacteria in the processing environment, potentially contaminating the products directly or indirectly.


Assuntos
Bactérias/metabolismo , Contaminação de Alimentos , Manipulação de Alimentos , Microbiologia de Alimentos , Carne/microbiologia , Microbiologia do Ar , Animais , Bacillales/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Sequência de Bases , Bélgica , Carnobacterium/isolamento & purificação , Galinhas , Lactobacillus/isolamento & purificação , RNA Ribossômico 16S/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
7.
Int J Food Microbiol ; 293: 102-113, 2019 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-30677559

RESUMO

Thawed hake (Merluccius capensis and M. paradoxus) and plaice (Pleuronectes platessa) fillets were used as a model to evaluate the effect of storage temperature (0 or 10 °C) and biological variability (fish species, lot to lot) on bacterial growth kinetics and microbial successions. Both culture dependent methods (plate counts on non-selective and selective media) and culture independent methods (qPCR and 16S rRNA gene metabarcoding) were used. Bacterial counts exceeded 107 cfu/g within 2-3 days at 10 °C and 7-8 days at 0 °C. Plate counts on three media (Plate Count Agar +0.5% NaCl, Iron Agar Lyngby and Pseudomonas Selective medium) and 16S rRNA gene counts estimated by qPCR were highly correlated. Growth was modelled using the D-model and specific growth rate ranged between 0.97 and 1.24 d-1 and 3.54 and 5.90 d-1 at 0 and 10 °C, respectively. The initial composition of the microbiota showed lot-to-lot variation, but significant differences between the two fish species were detected. Alpha diversity significantly decreased during storage. When bacterial counts exceeded 107 cfu/g, the microbiota was dominated by members of the genera Pseudomonas, Psychrobacter, Acinetobacter, Serratia, Flavobacterium, Acinetobacter, Carnobacterium, Brochothrix and Vagococcus. However, Photobacterium and Shewanella, two genera frequently associated with fish spoilage, were either absent or minor components of the microbiota. As expected, storage temperature significantly affected the abundance of several species. The inference of microbial association networks with three different approaches (an ensemble approach using the CoNet app, Sparse Correlations for Compositional data, and SParse InversE Covariance Estimation for Ecological Association Inference) allowed the detection of both a core microbiota, which was present throughout storage, and a number of taxa, which became dominant at the end of spoilage and were characterized by a disproportionate amount of negative interactions.


Assuntos
Contaminação de Alimentos/análise , Armazenamento de Alimentos , RNA Ribossômico 16S/isolamento & purificação , Alimentos Marinhos/microbiologia , Acinetobacter/genética , Acinetobacter/isolamento & purificação , Animais , Carga Bacteriana , Brochothrix/genética , Brochothrix/isolamento & purificação , Carnobacterium/genética , Carnobacterium/isolamento & purificação , Temperatura Baixa , Contagem de Colônia Microbiana , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Peixes , Microbiologia de Alimentos , Consórcios Microbianos , Photobacterium/genética , Photobacterium/isolamento & purificação , Pseudomonas/genética , Pseudomonas/isolamento & purificação , Psychrobacter/genética , Psychrobacter/isolamento & purificação , RNA Ribossômico 16S/genética , Shewanella/genética , Shewanella/isolamento & purificação
8.
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
9.
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
10.
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
11.
J Appl Microbiol ; 125(1): 142-147, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29495109

RESUMO

AIMS: To investigate the transmission route of Carnobacterium from the farm environment to the meat-manufacturing plant and potential risk for meat spoilage. METHODS AND RESULTS: A sheep farm-level survey of Carnobacterium, consisting of 150 environmental and animal (no 100) associated samples, was carried out on two farms. A further 20 lamb carcass samples were taken from an abattoir servicing one of the farms. The majority of Carnobacterium maltaromaticum isolates were associated with fleece followed by hard sheep contact surfaces, rectal-anal mucosal swabs and carcasses. Enterobacterial repetitive intergenic consenus PCR (ERIC-PCR) profiling revealed four distinct ERIC types. Each ERIC type was found on both farms, three of which were also found on lamb carcasses. CONCLUSIONS: Enterobacterial repetitive intergenic consenus PCR was effective at demonstrating within-species variability in C. maltaromaticum. This study provides initial information showing that farm sources maybe an important transmission route of Carnobacterium for contamination of lamb carcasses and subsequently the meat processing environment. SIGNIFICANCE AND IMPACT OF THE STUDY: Data on distribution, diversity, sources and transmission routes for meat product contamination is limited for spoilage bacteria. This study highlights the importance of good hygienic slaughter practices and cleaning routines to remove accumulated detritus from the handling of animals that may lead to cross-contamination.


Assuntos
Matadouros , Carnobacterium/isolamento & purificação , Fazendas , Carne/microbiologia , Ovinos , Animais , Microbiologia de Alimentos
12.
Meat Sci ; 131: 34-39, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28458086

RESUMO

This report builds on the earlier studies of the shelf-life of chilled Australian vacuum packaged (VP) beef primals (striploin and cube roll), products distinguished in the global marketplace for unusually long shelf-life. Notable findings in those studies were a shelf-life of at least 26weeks at -0.5°C, low microbial counts, and relatively high sensory scores. However, growth rates for total viable counts (TVC) and lactic acid bacteria (LAB) varied among the different abattoirs. The present study adds to these findings, by providing greater definition about temporal changes in bacterial communities using terminal restriction fragment length polymorphism (TRFLP) and clone library analyses of 16S ribosomal RNA (16S rRNA) gene, and measuring statistical associations among abattoir, beef cut, storage time and sensory attributes. Bacterial communities changed over time, with Carnobacterium spp. typically predominating (29-97%) at the end of storage. Variation in TRFLP profiles showed that different Carnobacterium strains predominated in different abattoirs, and that additional variation was due to the presence of other taxa typical of VP meat microbiomes. TRFLP-based community structure correlated significantly (P≤0.01) with sensorial characteristics, such as vacuum integrity, confinement odour, and intact pack appearance of beef. This study shows that Carnobacterium spp. predominate on extended shelf-life VP beef primals, while other taxa may produce subtle effects on shelf-life duration.


Assuntos
Matadouros , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Embalagem de Alimentos , Carne Vermelha/microbiologia , Animais , Austrália , Bactérias/classificação , Carnobacterium/isolamento & purificação , Bovinos , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Armazenamento de Alimentos , Odorantes/análise , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S
13.
Food Microbiol ; 65: 236-243, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28400008

RESUMO

Pork-based cooked products, such as cooked hams, are economically valuable foods that are vulnerable to bacterial spoilage, even when applying cooling and modified atmosphere packaging (MAP). Besides a common presence of Brochothrix thermosphacta, their microbiota are usually dominated by lactic acid bacteria (LAB). Yet, the exact LAB species diversity can differ considerably among products. In this study, 42 sliced cooked pork samples were acquired from three different Belgian supermarkets to map their bacterial heterogeneity. The community compositions of the dominant bacterial species were established by analysing a total of 702 isolates from selective agar media by (GTG)5-PCR fingerprinting followed by gene sequencing. Most of the isolates belonged to the genera Carnobacterium, Lactobacillus, and Leuconostoc, with Leuconostoc carnosum and Leuconostoc gelidum subsp. gelidum being the most dominant members. The diversity of the dominant bacterial species varied when comparing samples from different production facilities and, in some cases, even within the same product types. Although LAB consistently dominated the microbiota of sliced cooked pork products in the Belgian market, results indicated that bacterial diversity needs to be addressed on the level of product composition and batch variation. Dedicated studies will be needed to substantiate potential links between such variability and microbial composition. For instance, the fact that higher levels of lactobacilli were associated with the presence of potassium lactate (E326) may be suggestive of selective pressure but needs to be validated, as this finding referred to a single product only.


Assuntos
Biodiversidade , Carnobacterium/isolamento & purificação , Culinária , Embalagem de Alimentos , Lactobacillaceae/isolamento & purificação , Leuconostoc/isolamento & purificação , Produtos da Carne/microbiologia , Carne Vermelha/microbiologia , Animais , Atmosfera , Bélgica , Carnobacterium/efeitos dos fármacos , Carnobacterium/genética , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Embalagem de Alimentos/normas , Conservação de Alimentos , Lactatos/farmacologia , Lactobacillaceae/efeitos dos fármacos , Lactobacillaceae/genética , Leuconostoc/efeitos dos fármacos , Leuconostoc/genética , Microbiota/efeitos dos fármacos , Reação em Cadeia da Polimerase , Suínos
14.
Meat Sci ; 123: 97-104, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27665069

RESUMO

The bacterial ecology of long term ohmic- (LTOH) and water bath- (WB) cooked pork longissimus lumborum during refrigerated storage was investigated by culture-dependent and amplicon sequencing of 16S rRNA gene. High bacterial diversity was observed in both LTOH- and WB-cooked meat, and the diversity decreased with prolonged storage, however, it was more complex in LTOH-cooked meat compared with WB treated ones. Bacillus, Pseudomonas, Enterococcus and Lactococcus were the most prevalent genera in the first two weeks and were replaced by Carnobacterium by the end of storage. Brevundimonas, Bacteroidaceae, Lactobacillaceae, uncultured Clostridiales Family_XIII, Alcaligenaceae and Micrococcales were more abundant in LTOH-cooked meat, while only Moraxellaceae were more abundant in WB-cooked samples. The different abundances may have resulted from the reaction of bacteria to different heating mechanisms. Overall, LTOH-cooked meat has a similar shelf-life with shorter processing time compared to WB treated ones.


Assuntos
Culinária/métodos , Carne Vermelha/microbiologia , Análise de Sequência de DNA , Animais , Bacillus/isolamento & purificação , Carnobacterium/isolamento & purificação , Clostridiales/isolamento & purificação , Contagem de Colônia Microbiana , DNA Bacteriano/isolamento & purificação , Enterococcus/isolamento & purificação , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Temperatura Alta , Concentração de Íons de Hidrogênio , Lactobacillaceae/isolamento & purificação , Lactococcus/isolamento & purificação , Viabilidade Microbiana , Nitrogênio/análise , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/isolamento & purificação , Carne Vermelha/análise , Suínos , Compostos Orgânicos Voláteis/análise
15.
Food Microbiol ; 62: 147-152, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27889141

RESUMO

Understanding the factors influencing meat bacterial communities is important as these communities are largely responsible for meat spoilage. The composition and structure of a bacterial community on a high-O2 modified-atmosphere packaged beef product were examined after packaging, on the use-by date and two days after, to determine whether the communities at each stage were similar to those in samples taken from different production lots. Furthermore, we examined whether the taxa associated with product spoilage were distributed across production lots. Results from 16S rRNA amplicon sequencing showed that while the early samples harbored distinct bacterial communities, after 8-12 days storage at 6 °C the communities were similar to those in samples from different lots, comprising mainly of common meat spoilage bacteria Carnobacterium spp., Brochothrix spp., Leuconostoc spp. and Lactococcus spp. Interestingly, abundant operational taxonomic units associated with product spoilage were shared between the production lots, suggesting that the bacteria enable to spoil the product were constant contaminants in the production chain. A characteristic succession pattern and the distribution of common spoilage bacteria between lots suggest that both the packaging type and the initial community structure influenced the development of the spoilage bacterial community.


Assuntos
Embalagem de Alimentos , Armazenamento de Alimentos/normas , Microbiota , Carne Vermelha/microbiologia , Animais , Carga Bacteriana , Brochothrix/genética , Brochothrix/isolamento & purificação , Carnobacterium/genética , Carnobacterium/isolamento & purificação , Bovinos , DNA Bacteriano , Microbiologia de Alimentos , Lactococcus/genética , Lactococcus/isolamento & purificação , Leuconostoc/genética , Leuconostoc/isolamento & purificação , Microbiota/genética , Microbiota/fisiologia , RNA Ribossômico 16S/genética
16.
J Dairy Res ; 83(3): 383-6, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27600975

RESUMO

During the last years the interest in donkey milk has increased significantly mainly because of its compelling functional elements. Even if the composition and nutritional properties of donkey milk are known, its microbiota is less studied. This Research Communication aimed to provide a comprehensive characterisation of the lactic acid bacteria in raw donkey milk. RAPD-PCR assay combined with 16S rDNA sequencing analysis were used to describe the microbial diversity of several donkey farms in the North West part of Italy. The more frequently detected species were: Lactobacillus paracasei, Lactococcus lactis and Carnobacterium maltaromaticum. Less abundant genera were Leuconostoc, Enterococcus and Streptococcus. The yeast Kluyveromyces marxianus was also isolated. The bacterial and biotype distribution notably diverged among the farms. Several of the found species, not previously detected in donkey milk, could have an important probiotic activity and biotechnological potential. This study represents an important insight to the ample diversity of the microorganisms present in the highly selective ecosystem of raw donkey milk.


Assuntos
Equidae/microbiologia , Lactobacillaceae/classificação , Lactobacillaceae/isolamento & purificação , Leite/microbiologia , Animais , Biodiversidade , Carnobacterium/genética , Carnobacterium/isolamento & purificação , DNA Bacteriano/análise , Ecossistema , Itália , Kluyveromyces/isolamento & purificação , Lactobacillaceae/genética , Lactobacillus/genética , Lactobacillus/isolamento & purificação , Lactococcus lactis/genética , Lactococcus lactis/isolamento & purificação , Probióticos , RNA Ribossômico 16S/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico/veterinária
17.
J Appl Microbiol ; 121(5): 1268-1274, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27489131

RESUMO

AIMS: The purpose of this study was to isolate, characterize and determine the structure and the antibacterial activities of a bacteriocin produced by Carnobacterium maltaromaticum CPN, a strain isolated from unpasteurized milk Camembert cheese. METHODS AND RESULTS: This bacteriocin, termed maltaricin CPN, was produced at higher amounts in MRS broth at temperatures between 15°C and 25°C. It was purified to homogeneity from culture supernatant by using a simple method consisting of cation-exchange and reversed-phase chromatographies. Mass spectrometry showed that maltaricin was a 4427·29 Da bacteriocin. Its amino acid sequence was determined by Edman degradation which showed that it had close similarity with bacteriocins of the class IIa. Maltaricin CPN consisted in fact of 44 unmodified amino acids including two cysteine residues at positions 9 and 14 linked by a disulphide bond. The antimicrobial activity of maltaricin CPN covered a range of bacteria, with strong activity against many species of Gram-positive bacteria, especially the food-borne pathogen Listeria monocytogenes, but no activity against Gram-negative ones. CONCLUSIONS: In the studied conditions, C. maltaromaticum CPN produced a new class IIa bacteriocin with strong anti-Listeria activity. SIGNIFICANCE AND IMPACT OF THE STUDY: The study covers the purification and the structural characterization of a new bacteriocin produced by strain C. maltaromaticum CPN isolated from Camembert cheese. Its activity against strains of L. monocytogenes and higher production rates at relatively low temperatures show potential technological applications to improve the safety of refrigerated food.


Assuntos
Antibacterianos/química , Bacteriocinas/química , Bacteriocinas/farmacologia , Carnobacterium/metabolismo , Queijo/microbiologia , Sequência de Aminoácidos , Animais , Antibacterianos/biossíntese , Antibacterianos/farmacologia , Bacteriocinas/biossíntese , Bacteriocinas/classificação , Carnobacterium/isolamento & purificação , Bactérias Gram-Positivas/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos
18.
Food Microbiol ; 60: 84-91, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27554149

RESUMO

Modified atmosphere packaging (MAP) is widely used in food industry to extend the microbiological shelf-life of meat. Typically, poultry meat has been packaged in a CO2/N2 atmosphere (with residual low O2). Recently, some producers use high O2 MAP for poultry meat to empirically reach comparable shelf lifes. In this work, we compared spoilage microbiota of skinless chicken breast in high (80% O2, 20% CO2) and low O2 MAP (65% N2 and 35% CO2). Two batches of meat were incubated in each atmosphere for 14 days at 4 °C and 10 °C. Atmospheric composition of each pack and colony forming units (25 °C, 48 h, BHI agar) of poultry samples were determined at seven timepoints. Identification of spoilage organisms was carried out by MALDI-TOF MS. Brochothrix thermosphacta, Carnobacterium sp. and Pseudomonas sp. were the main organisms found after eight days at 4 °C and 10 °C in high O2 MAP. In low O2 MAP, the main spoilage microbiota was represented by species Hafnia alvei at 10 °C, and genera Carnobacterium sp., Serratia sp., and Yersinia sp. at 4 °C. High O2 MAP is suggested as preferential gas because were less detrimental and pathogens like Yersinia were not observed.


Assuntos
Bactérias/crescimento & desenvolvimento , Embalagem de Alimentos , Carne/microbiologia , Microbiota/fisiologia , Aves Domésticas , Animais , Bactérias/isolamento & purificação , Brochothrix/crescimento & desenvolvimento , Brochothrix/isolamento & purificação , Carnobacterium/crescimento & desenvolvimento , Carnobacterium/isolamento & purificação , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Armazenamento de Alimentos , Oxigênio , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Temperatura
19.
Meat Sci ; 121: 253-260, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27376249

RESUMO

Changes in the microbiota of lamb were investigated under vacuum packaging (VP) and under 20% CO2/80% N2 (LC), 60% CO2/40% N2 (MC), and 100% CO2 (HC) modified atmosphere packaging (MAP) during chilled storage. Viable counts were monitored, and the total microbial communities were assessed by high-throughput sequencing. The starting community had the highest microbial diversity, after which Lactococcus and Carnobacterium spp. outcompeted during the 28-day storage. The relative abundances of Brochothrix spp. in the LC atmosphere were much higher than those of the other groups on days 7 and 28. The bacterial inhibiting effect of the MAP environments on microbial growth was positively correlated with the CO2 concentration. The HC atmosphere inhibited microbial growth and delayed changes in the microbial community composition, extending the lamb's shelf life by approximately 7days compared with the VP atmosphere. Lamb packaged in the VP atmosphere had a more desirable colour but a higher weight loss than lamb packaged in the MAP atmospheres.


Assuntos
Microbiologia de Alimentos , Embalagem de Alimentos/métodos , Microbiota , Carne Vermelha/microbiologia , Animais , Dióxido de Carbono/análise , Carnobacterium/isolamento & purificação , Contagem de Colônia Microbiana , Cor , DNA Bacteriano/isolamento & purificação , Qualidade dos Alimentos , Armazenamento de Alimentos , Sequenciamento de Nucleotídeos em Larga Escala , Concentração de Íons de Hidrogênio , Lactococcus/isolamento & purificação , Nitrogênio/análise , Carne Vermelha/análise , Ovinos , Vácuo
20.
Int J Food Microbiol ; 218: 86-95, 2016 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-26623935

RESUMO

Accumulation of volatile organic compounds was monitored in association with sensory quality, bacterial concentrations and culture-independent microbial community analyses in raw pork loin and pork collar during storage under high-oxygen modified atmosphere at +4 °C. Of the 48 volatile compounds detected in the pork samples, the levels of acetoin, diacetyl and 3-methyl-1-butanol had the highest correlations with the sensory scores and bacterial concentrations. These compounds accumulated in all of the four monitored lots of non-sterile pork but not in the sterilized pork during chilled storage. According to the culture-dependent and culture-independent characterization of bacterial communities, Brochothrix thermosphacta, lactic acid bacteria (Carnobacterium, Lactobacillus, Lactococcus, Leuconostoc, Weissella) and Photobacterium spp. predominated in pork samples. Photobacterium spp., typically not associated with spoilage of meat, were detected also in 8 of the 11 retail packages of pork investigated subsequently. Eleven isolates from the pork samples were shown to belong to Photobacterium phosphoreum by phenotypic tests and sequencing of the 16S rRNA and gyrB gene fragments. Off-odors in pork samples with high proportion of Photobacterium spp. were associated with accumulation of acetoin, diacetyl and 3-methyl-1-butanol in meat, but these compounds did not explain all the off-odors reported in sensory analyses.


Assuntos
Embalagem de Alimentos , Odorantes/análise , Photobacterium/metabolismo , Carne Vermelha/microbiologia , Compostos Orgânicos Voláteis/análise , Acetoína/análise , Animais , Carnobacterium/genética , Carnobacterium/isolamento & purificação , DNA Girase/genética , Diacetil/análise , Microbiologia de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Lactococcus/genética , Lactococcus/isolamento & purificação , Leuconostoc/genética , Leuconostoc/isolamento & purificação , Pentanóis/análise , Photobacterium/isolamento & purificação , RNA Ribossômico 16S/genética , Suínos
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