Tracking the blue: A MLST approach to characterise the Pseudomonas fluorescens group

Andreani, Nadia Andrea; Martino, Maria Elena; Fasolato, Luca; Carraro, Lisa; Montemurro, Filomena; Mioni, R.; Bordin, Paola; Cardazzo, Barbara

doi:10.1016/j.fm.2013.11.012

Cited by 72 publications

(69 citation statements)

References 41 publications

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“…The four strains Ps_20, Ps_40 (non-pigmenting strains), Ps_22 and Ps_77 (blue-pigmenting strains) chosen in the present study were phenotypically and genotypically characterized in a previous work (Andreani et al, 2014). Ps_20 was isolated from UHT-milk, Ps_40 was isolated from ricotta cheese, Ps_22 from mozzarella cheese showing the blue discoloration, and Ps_77 from a blue slice of beef.…”

Section: Bacterial Strainsmentioning

confidence: 99%

“…MBM broth was chosen because MBM Agar was able to enhance the blue pigment production (Andreani et al, 2014). The growth rate was checked at T 0h , T 24h , T 27h , T 30h , T 32h , T 34h , T 36h , T 48h , and T 50h by measuring the Optical Density (O.D.)…”

Section: Assessment Of Pigment Production In Mbm Brothmentioning

confidence: 99%

“…This is due to its extreme adaptability and versatility (Silby et al, 2011) and its ability to replicate at refrigeration temperatures (Decimo et al, 2014). Specifically, P. fluorescens can cause undesirable modifications in food products as a result of enzymatic reactions or pigmented molecule production (Andreani et al, 2014). A well-known example is represented by the "blue mozzarella cheese events" which occurred in Europe in 2010 (Annual Report of RASFF), when consumers noticed blue discolorations on mozzarella cheese after opening the packages.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the genotypic and phenotypic characterization of 139 strains belonging to the P. fluorescens group revealed the presence of a genetic cluster (the so called "blue branch") including all the blue-pigmenting strains, together with a limited number of non-pigmenting strains (Andreani et al, 2014). This result suggested a close correlation between the blue phenotype and the genetic information coded by a chromosomal gene or gene cluster.…”

Section: Introductionmentioning

confidence: 99%

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A genomic and transcriptomic approach to investigate the blue pigment phenotype in Pseudomonas fluorescens

Andreani

Carraro

Martino

et al. 2015

International Journal of Food Microbiology

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a b s t r a c t a r t i c l e i n f oPseudomonas fluorescens is a well-known food spoiler, able to cause serious economic losses in the food industry due to its ability to produce many extracellular, and often thermostable, compounds. The most outstanding spoilage events involving P. fluorescens were blue discoloration of several food stuffs, mainly dairy products. The bacteria involved in such high-profile cases have been identified as belonging to a clearly distinct phylogenetic cluster of the P. fluorescens group. Although the blue pigment has recently been investigated in several studies, the biosynthetic pathway leading to the pigment formation, as well as its chemical nature, remain challenging and unsolved points. In the present paper, genomic and transcriptomic data of 4 P. fluorescens strains (2 blue-pigmenting strains and 2 non-pigmenting strains) were analyzed to evaluate the presence and the expression of blue strain-specific genes. In particular, the pangenome analysis showed the presence in the blue-pigmenting strains of two copies of genes involved in the tryptophan biosynthesis pathway (including trpABCDF). The global expression profiling of bluepigmenting strains versus non-pigmenting strains showed a general up-regulation of genes involved in iron uptake and a down-regulation of genes involved in primary metabolism. Chromogenic reaction of the bluepigmenting bacterial cells with Kovac's reagent indicated an indole-derivative as the precursor of the blue pigment. Finally, solubility tests and MALDI-TOF mass spectrometry analysis of the isolated pigment suggested that its molecular structure is very probably a hydrophobic indigo analog.

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Section: Bacterial Strainsmentioning

confidence: 99%

Section: Assessment Of Pigment Production In Mbm Brothmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A genomic and transcriptomic approach to investigate the blue pigment phenotype in Pseudomonas fluorescens

Andreani

Carraro

Martino

et al. 2015

International Journal of Food Microbiology

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“…The spoilage of food is a complex phenomenon; in ready-to-eat (RTE) foods, it usually occurs with off odors, acidification, and appearance defects (26)(27)(28). Few documented studies have dealt with the investigation of ecological niches that serve as reservoirs or commodities harboring spoilage microbiota like Pseudomonas (29)(30)(31)(32), LAB (21,(33)(34)(35)(36)(37)(38), and Brochothrix thermosphacta (39) in actual processing environments.…”

mentioning

confidence: 99%

Processing Environment and Ingredients Are Both Sources of Leuconostoc gelidum, Which Emerges as a Major Spoiler in Ready-To-Eat Meals

Pothakos

Stellato

Ercolini

et al. 2015

Appl Environ Microbiol

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bMesophilic and psychrotrophic organism viable counts, as well as high-throughput 16S rRNA gene-based pyrosequencing, were performed with the aim of elucidating the origin of psychrotrophic lactic acid bacteria (LAB) in a ready-to-eat (RTE) meal manufacturing plant. The microbial counts of the products at the end of the shelf life were greatly underestimated when mesophilic incubation was implemented due to overlooked, psychrotrophic members of the LAB. Pseudomonas spp., Enterobacteriaceae, Streptococcaceae, and Lactobacillus spp. constituted the most widespread operational taxonomic units (OTUs), whereas Leuconostoc gelidum was detected as a minor member of the indigenous microbiota of the food ingredients and microbial community of the processing environment, albeit it colonized samples at almost every sampling point on the premises. However, L. gelidum became the most predominant microbe at the end of the shelf life. The ability of L. gelidum to outgrow notorious, spoilagerelated taxa like Pseudomonas, Brochothrix, and Lactobacillus underpins its high growth dynamics and severe spoilage character under refrigeration temperatures. The use of predicted metagenomes was useful for observation of putative gene repertoires in the samples analyzed in this study. The end products grouped in clusters characterized by gene profiles related to carbohydrate depletion presumably associated with a fast energy yield, a finding which is consistent with the fastidious nature of highly competitive LAB that dominated at the end of the shelf life. The present study showcases the detrimental impact of contamination with psychrotrophic LAB on the shelf life of packaged and cold-stored foodstuffs and the long-term quality implications for production batches once resident microbiota are established in the processing environment.T heoretically, a food commodity harbors a wide range of different microorganisms (1) associated with the ecological niches wherefrom foods originate. This initial diverse community can be enriched by other biota after transportation to industrial production facilities (2). Due to handling during processing and storage, microbes are eventually subjected to a selection pressure (3), which defines a dominant microbial consortium. In this way, certain members of this association proliferate greatly and cause alterations constituting the specific spoilage organisms (SSOs) (4). In the past few years in Belgium, the persisting problem of psychrotrophic lactic acid bacteria (LAB) prevailing at the end of the shelf life of packaged and refrigerated foodstuffs has been substantiated (5-7). These cold-adapted species of LAB contaminate foods from numerous industrial plants, but little is known about their environmental occurrence and the possible contamination routes. Their introduction in production lines can be mediated by crude material, given the fact that LAB are ubiquitous in plant ecosystems and also constitute the commensal biota of livestock (8-10). Moreover, there is emerging evidence that psychrotrophic LAB ...

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Psychrotrophic bacteria

Brasca

Decimo

Morandi

et al. 2017

Microbiology in Dairy Processing

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Tracking the blue: A MLST approach to characterise the Pseudomonas fluorescens group

Cited by 72 publications

References 41 publications

A genomic and transcriptomic approach to investigate the blue pigment phenotype in Pseudomonas fluorescens

A genomic and transcriptomic approach to investigate the blue pigment phenotype in Pseudomonas fluorescens

Processing Environment and Ingredients Are Both Sources of Leuconostoc gelidum, Which Emerges as a Major Spoiler in Ready-To-Eat Meals

Psychrotrophic bacteria

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