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1.
Sci Rep ; 10(1): 7335, 2020 04 30.
Article in English | MEDLINE | ID: mdl-32355239

ABSTRACT

While competition targeting food-borne pathogens is being widely documented, few studies have focused on competition among non-pathogenic food bacteria. Carnobacterium maltaromaticum is a genetically diverse lactic acid bacterium known for comprising several bacteriocinogenic strains with bioprotective potentialities against the food-borne pathogen Listeria monocytogenes. The aim of our study is to examine the network properties of competition among a collection of 73 strains of C. maltaromaticum and to characterize their individual interaction potential. The performed high-throughput competition assays, investigating 5 329 pairwise interactions, showed that intraspecific competition was major in C. maltaromaticum with approximately 56% of the sender strains antagonizing at least one receiver strain. A high diversity of inhibitory and sensitivity spectra was identified along with a majority of narrow inhibitory as well as sensitivity spectra. Through network analysis approach, we determined the highly nested architecture of C. maltaromaticum competition network, thus showing that competition in this species is determined by both the spectrum width of the inhibitory activity of sender strains and the spectrum width of the sensitivity of receiver strains. This study provides knowledge of the competition network in C. maltaromaticum that could be used in rational assembly of compatible microbial strains for the design of mixed starter cultures.


Subject(s)
Antibiosis , Carnobacterium/physiology , Food Contamination , Food Microbiology , Listeria monocytogenes/physiology , Microbial Sensitivity Tests , Animals , Bacteriocins , Binding, Competitive , Fish Products , Fishes/microbiology , Humans , Lactic Acid/metabolism , Meat Products , Species Specificity
2.
Arch Microbiol ; 202(7): 1945-1955, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32462213

ABSTRACT

In this study, in situ-expressed metabolic routes of Brochothrix (B.) thermosphacta and Carnobacterium (C.) divergens were evaluated based on a metatranscriptomic dataset from bacteria growing on MAP chicken meat (O2/CO2; N2/CO2). Both species exhibited no (C. divergens) or minor transcription regulation (B. thermosphacta) within their main metabolic routes in response to different atmospheres. Both employ pathways related to glucose and ribose. Gluconeogenesis from lipid-borne glycerol is active in the progressing lack of carbohydrates. Pyruvate fates in both species comprise lactate, ethanol, acetate, CO2, formate, C4-compounds and H2O2 (only B. thermosphacta). Both species express genes for a minimal aerobic respiratory chain, but do not possess the genetic setting for a functional citric acid cycle. While products of carbohydrate and glycerol metabolism display mild to medium sensorial off-characteristics, predicted end products of their amino acid metabolism comprise, e.g., isobutyrate and isovalerate (B. thermosphacta) or cadaverine and tyramine (C. divergens) as potent spoilage compounds.


Subject(s)
Brochothrix/physiology , Carnobacterium/physiology , Food Microbiology/methods , Food Packaging/standards , Meat/microbiology , Transcriptome , Animals , Atmosphere , Colony Count, Microbial , Hydrogen Peroxide/metabolism , Poultry
3.
Meat Sci ; 162: 108035, 2020 Apr.
Article in English | MEDLINE | ID: mdl-31855662

ABSTRACT

The bioprotective effects of Carnobacterium maltaromaticum (CM) strains were assessed in vitro and in sliced cooked ham. CM strains were tested in vitro against Listeria monocytogenes (LM), Escherichia coli O157:H7 (EC) and Salmonella Typhimurium (ST). In vitro effect was evaluated using co-culture (with and without EDTA) and cell-free supernatant (CFS). CFS was tested by agar well diffusion and minimum inhibitory concentration. In cooked ham, the inhibitory effect of CM on L. innocua (LI) and on the physicochemical parameters were evaluated for 7 days at 4 °C. In co-cultures at -1 °C and 4 °C, all CM isolates inhibited LM. A slight inhibition was observed against the Gram-negative bacteria with the addition of EDTA. CFS did not show inhibitory effect under the studied conditions. In cooked ham, CM inhibited LI growth and did not affect the physicochemical parameters of the product during storage. CM strains show potential to be used as bioprotective cultures in cold-stored cooked ham and improve its safety.


Subject(s)
Carnobacterium/physiology , Food Microbiology , Food Preservation/methods , Meat Products/microbiology , Edetic Acid , Escherichia coli O157/growth & development , Listeria/growth & development , Listeria monocytogenes/growth & development , Salmonella typhimurium/growth & development
4.
Int J Food Microbiol ; 300: 14-21, 2019 Jul 02.
Article in English | MEDLINE | ID: mdl-30991234

ABSTRACT

It is well established, that certain bacteria within the Brochothrix, Carnobacterium, Lactobacillus, Lactococcus, and Leuconostoc genera have an important role in the spoilage of chill stored poultry meat packaged in modified atmosphere. However, little is known about the role of microorganisms that are difficult to culture and the microbiota during poultry spoilage. We combined traditional cultivation and culture-independent 16S rRNA amplicon sequencing to investigate the microbiota encompassing putative bacteria of whole broiler meat, packaged in modified atmosphere, during and exceeding shelf-life. Samples were taken from 6 flocks during independent slaughter days. Additional samples were analysed from the production line. There was a significant difference in the microbial community structure of 80%O2/20%CO2 retail packaged broiler meat during different times of shelf-life, mainly due to an increase of species within the Brochothrix, Carnobacterium, Vagococcus, and Janthinobacterium genera. These genera were already detected four to eight days after slaughter. However, no significant difference between flocks with respect to the microbiota encompassing putative spoilage bacteria was observed when examined in retail packaged broilers, slaughtered at the same abattoir on different days. Our study also showed that lactic acid bacteria within the Vagococcus genus can constitute a dominating part of the later shelf-life microbiota in fresh whole broiler meat packaged in 80%O2/20%CO2 modified atmosphere. A single operational taxonomic unit (OTU) assigned as Janthinobacterium lividum, an occasional spoiler of meat products, was identified as a major part of the microbiota in late shelf life broiler meat and swab samples in the cooling facility at the slaughter house production line. The combination of traditional cultivation and culture-independent methods provided a great insight into the microbiota of broiler meat during shelf-life and identified a potential point of contamination in the production line for cold tolerant Janthinobacterium.


Subject(s)
Bacterial Physiological Phenomena , Chickens/microbiology , Food Microbiology , Meat/microbiology , Microbiota/physiology , Abattoirs , Animals , Bacteria/genetics , Bacteria/growth & development , Carnobacterium/genetics , Carnobacterium/physiology , Chickens/genetics , Food Packaging , Microbiota/genetics , RNA, Ribosomal, 16S/genetics
5.
J Appl Microbiol ; 126(5): 1468-1479, 2019 May.
Article in English | MEDLINE | ID: mdl-30762266

ABSTRACT

AIM: The aim of this study is to investigate the effect of a broad spectrum of culture conditions on the acidification activity and viability of Carnobacterium maltaromaticum CNCM I-3298, the main technological properties that determine the shelf-life of biological time-temperature integrator (TTI) labels. METHODS AND RESULTS: Cells were cultivated at different temperatures (20-37°C) and pH (6-9·5) according to a modified central composite design and harvested at increasing times up to 10 h of stationary phase. Acidification activity and viability of freeze-thawed concentrates were assessed in medium mimicking the biological label. Acidification activity was influenced by all three culture conditions, but pH and harvest time were the most influential. Viability was not significantly affected by the tested range of culture conditions. CONCLUSIONS: Carnobacterium maltaromaticum CNCM I-3298 must be cultivated at 20°C, pH 6 and harvested at the beginning of stationary phase to exhibit fastest acidification activities. However, if slower acidification activities are pursued, the recommended culture conditions are 30°C, pH 9·5 and a harvest time between 4-6 h of stationary phase. SIGNIFICANCE AND IMPACT OF THE STUDY: Quantifying the impact of fermentation temperature, pH and harvest time has led to a predictive model for the production of biological TTI covering a broad range of shelf-lives.


Subject(s)
Carnobacterium , Cell Culture Techniques/methods , Carnobacterium/metabolism , Carnobacterium/physiology , Culture Media , Fermentation , Microbial Viability , Temperature
6.
Food Microbiol ; 74: 50-56, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29706337

ABSTRACT

Ricotta fresca is a whey cheese susceptible of secondary contamination, mainly from Pseudomonas spp. The extension of the shelf life of refrigerated ricotta fresca could be obtained using protective cultures inhibiting the growth of this spoilage microorganism. A commercial biopreservative, Lyofast CNBAL, comprising Carnobacterium spp was tested against Pseudomonas spp. The surface of ricotta fresca samples were inoculated either with Pseudomonas spp or Pseudomonas and Carnobacterium spp. Samples were MAP packed, stored at 4 °C and analyzed the day of the inoculum and 7, 14 and 21 days after the contamination. Microbiological analyses included total bacterial count, mesophilic lactic acid bacteria, Enterobacteriaceae, Pseudomonas spp, Listeria monocytogenes, moulds and yeasts. Pseudomonas mean initial contamination level was comparable in blank and artificially inoculated samples, respectively with values of 2.15 ±â€¯0.21 and 2.34 ±â€¯0.26 log cfu g-1. Carnobacterium spp. significantly reduced the growth of Pseudomonas spp respectively of 1.28 log and 0.83 log after 14 and 21 days of refrigerated storage. Intrinsic properties and physico-chemical composition were also investigated. Limited variation of pH was observed in samples inoculated with the protective cultures, indicating low acidification properties of Carnobacterium spp. Instead, no significant differences were observed for aW, moisture, fat and proteins during storage and between inoculated and control samples.


Subject(s)
Antibiosis , Carnobacterium/physiology , Cheese/microbiology , Food Microbiology , Food Preservation/methods , Pseudomonas/growth & development , Animals , Cheese/analysis , Colony Count, Microbial , Enterobacteriaceae/growth & development , Food Contamination/analysis , Food Contamination/prevention & control , Food Handling , Food Quality , Fungi/growth & development , Gases/analysis , Hydrogen-Ion Concentration , Lactobacillales/growth & development , Listeria monocytogenes/growth & development , Milk/microbiology , Refrigeration , Sheep , Temperature , Time Factors
7.
Article in English | MEDLINE | ID: mdl-27617232

ABSTRACT

The pathogenesis of listeriosis results mainly from the ability of Listeria monocytogenes to attach, invade, replicate and survive within various cell types in mammalian tissues. In this work, the effect of two bacteriocin-producing Carnobacterium (C. divergens V41 and C. maltaromaticum V1) and three non-bacteriocinogenic strains: (C. divergens V41C9, C. divergens 2763, and C. maltaromaticum 2762) was investigated on the reduction of L. monocytogenes Scott A plaque-forming during human infection using the HT-29 in vitro model. All Carnobacteria tested resulted in a reduction in the epithelial cell invasion caused by L. monocytogenes Scott A. To understand better the mechanism underlying the level of L. monocytogenes infection inhibition by Carnobacteria, infection assays from various pretreatments of Carnobacteria were assessed. The results revealed the influence of bacteriocin production combined with a passive mechanism of mammalian cell monolayers protection by Carnobacteria. These initial results showing a reduction in L. monocytogenes virulence on epithelial cells by Carnobacteria would be worthwhile analyzing further as a promising probiotic tool for human health.


Subject(s)
Antibiosis , Carnobacterium/physiology , Endocytosis , Epithelial Cells/microbiology , Listeria monocytogenes/pathogenicity , HT29 Cells , Humans
8.
Int J Food Microbiol ; 210: 121-30, 2015 Oct 01.
Article in English | MEDLINE | ID: mdl-26119189

ABSTRACT

The spoilage activity of Pseudomonas psychrophila and Carnobacterium maltaromaticum, two tropical shrimp (Penaeus notialis) spoilage organisms, was assessed in cooked shrimps stored at 0 to 28 °C. Microbiological, chemical and sensory analyses were performed during storage. P. psychrophila had a higher growth rate and showed a higher spoilage activity at temperatures from 0 to 15 °C, while at 28 °C, C. maltaromaticum had a higher growth rate. The spoilage activity of P. psychrophila was found to be higher in cooked shrimp than in fresh shrimp. Observed shelf-life data of shrimps stored at constant temperatures were used to validate a previously developed model that predicts tropical shrimp shelf-life at constant storage temperatures. Models predicting the growth of the spoilage organisms as a function of temperature were constructed. The validation of these models under dynamic storage temperatures simulating temperature fluctuation in the shrimp supply chain showed that they can be used to predict the shelf-life of cooked and fresh tropical shrimps.


Subject(s)
Carnobacterium/physiology , Food Handling/standards , Food Microbiology/methods , Models, Theoretical , Penaeidae/microbiology , Pseudomonas/physiology , Shellfish , Temperature , Animals , Cooking , Pseudomonas/growth & development , Shellfish/microbiology , Shellfish/standards
9.
Planta ; 239(5): 1027-40, 2014 May.
Article in English | MEDLINE | ID: mdl-24504695

ABSTRACT

The aim of the present study was to analyze induced expression of defense-related proteins in the soybean plants by rhizobacterial stain Carnobacterium sp. SJ-5 upon challenge inoculation with Fusarium oxysporum. Determination of the enzymatic activity of the different defense-related enzymes, phenylalanine ammonia lyase (PAL), lipoxygenase (LOX), peroxidase (POD) and polyphenol oxidase (PPO) was performed in the major parts of Glycine max L. Merrill using spectrophotometric method. Native-polyacrylamide gel electrophoresis analysis of the POD and PPO was employed followed by activity staining to find out the isoforms of respective enzymes. Activities of the PAL, LOX, POD and PPO were found to be highest in the bacterized root tissue of the soybean plants challenged with F. oxysporum. Isoform analysis revealed that PPO1, PPO4 and POD2 isoforms were expressed at higher levels in bacterized soybean root tissues challenge inoculated with the pathogen. Conclusively it was found that bacterial strain Carnobacterium sp. SJ-5 protect soybean plants from wilt disease caused by F. oxysporum by elicitation of the defense-related enzymes.


Subject(s)
Carnobacterium/physiology , Fusarium/physiology , Glycine max/immunology , Glycine max/microbiology , Plant Diseases/immunology , Plant Diseases/microbiology , Plant Proteins/metabolism , Antifungal Agents/pharmacology , Biological Assay , Carnobacterium/drug effects , Catechol Oxidase/metabolism , Crosses, Genetic , Fusarium/drug effects , Germination/drug effects , Hydrogen-Ion Concentration , Isoenzymes/metabolism , Lipoxygenase/metabolism , Microbial Sensitivity Tests , Native Polyacrylamide Gel Electrophoresis , Peroxidase/metabolism , Phenylalanine Ammonia-Lyase/metabolism , Phosphates/metabolism , Seeds/drug effects , Seeds/metabolism , Seeds/microbiology , Siderophores/metabolism , Solubility , Glycine max/growth & development , Glycine max/metabolism
10.
Mol Biotechnol ; 56(3): 210-22, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24037409

ABSTRACT

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.


Subject(s)
Bacterial Proteins/metabolism , Carnobacterium/genetics , Lactobacillus/genetics , Listeria/genetics , Algorithms , Carnobacterium/classification , Carnobacterium/physiology , Gene Expression Profiling , Gene Expression Regulation, Bacterial , Genes, Bacterial , Lactobacillus/classification , Lactobacillus/physiology , Listeria/classification , Listeria/physiology , Stress, Physiological
11.
World J Microbiol Biotechnol ; 30(2): 399-406, 2014 Feb.
Article in English | MEDLINE | ID: mdl-23933805

ABSTRACT

Wilt disease of soybean caused by a very common soil-borne fungus, Fusarium oxysporum is one of the most destructive diseases of the crop. The aim of the present study was to characterize plant growth-promotion activities and induced resistance of a rhizobacterial strain for the soybean plant against F. oxysporum. Rhizobacterium strain SJ-5 exhibited plant growth-promotion characteristics and antagonistic activity against the test pathogen on dual plate assay. It was identified as a Carnobacterium sp. A 950 bp PCR product was amplified from Carnobacterium sp. strain SJ-5, using zwittermicin A self-resistance gene-specific primers (zmaR). The strain produced indole 3-acetic acid (19 µg/ml) in the presence of salt stress and exhibited growth in Dworkin and Foster salt medium amended with 1-aminocyclopropane-1-carboxylate (ACC) through ACC deaminase activity (277 nmol/mg/h) as compared to the control. Strain seeds treated with the strain significantly enhanced the quorum of healthy plants after challenge inoculation at 14 days after seeding. An increase in the activity of stress enzymes after challenge inoculation with the test pathogen is reported. Treatment with the bacterium resulted in an increase in the chlorophyll content in the leaves in comparison with challenge-inoculated plants.


Subject(s)
Carnobacterium/physiology , Fusarium/growth & development , Glycine max/growth & development , Glycine max/microbiology , Plant Diseases/prevention & control , Carnobacterium/genetics , Carnobacterium/metabolism , Chlorophyll/analysis , Heat-Shock Proteins/biosynthesis , Indoleacetic Acids/metabolism , Plant Growth Regulators/metabolism , Plant Leaves/chemistry , Glycine max/enzymology
12.
Food Microbiol ; 36(2): 223-30, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24010601

ABSTRACT

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.


Subject(s)
Carnobacterium/physiology , Cheese/microbiology , Lactobacillaceae/metabolism , Milk/microbiology , Animals , Antibiosis , Carnobacterium/classification , Carnobacterium/genetics , Carnobacterium/isolation & purification , Fermentation , Food Microbiology
13.
Arch Microbiol ; 195(8): 571-7, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23708508

ABSTRACT

To understand protective roles of nitric oxide against salt stress, the effects of exogenous sodium nitroprusside on activities of lipoxygenase, peroxidase, phenylalanine ammonialyase, catalase, superoxide dismutase enzymes, proline accumulation, and distribution of sodium in soybean plants under salt were determined. Application of sodium nitroprusside + bacterium enhanced plant growth-promotion characteristics, activities of different enzymes, and proline accumulation in the presence of sodium nitroprusside under salt stress. Treatment with NaCl at 200 mM and sodium nitroprusside (0.1 mM) reduced Na⁺ levels but increased K⁺ levels in leaves in comparison with the NaCl-treated plants. Correspondingly, the plants treated with exogenous sodium nitroprusside and NaCl maintained a lower ratio of [Na⁺]/[K⁺] in NaCl-stressed plants.


Subject(s)
Carnobacterium/physiology , Glycine max/metabolism , Nitric Oxide/metabolism , Pseudomonas/physiology , Sodium Chloride/pharmacology , Stress, Physiological , Bacterial Proteins/metabolism , Nitroprusside/pharmacology , Peroxidases/metabolism , Plant Leaves/drug effects , Plant Leaves/metabolism , Potassium/metabolism , Proline/metabolism , Signal Transduction , Sodium/metabolism , Glycine max/drug effects , Glycine max/growth & development , Superoxide Dismutase/metabolism
14.
Langmuir ; 29(12): 4048-56, 2013 Mar 26.
Article in English | MEDLINE | ID: mdl-23445325

ABSTRACT

Specificity of the class IIa bacteriocin Leucocin A (LeuA), an antimicrobial peptide active against Gram-positive bacteria, including Listeria monocytogenes , is known to be dictated by the C-terminal amphipathic helical region, including the extended hairpin-like structure. However, its specificity when attached to a substrate has not been investigated. Exploiting properties of LeuA, we have synthesized two LeuA derivatives, which span the amphipathic helical region of the wild-type LeuA, consisting of 14- (14AA LeuA, CWGEAFSAGVHRLA) and 24-amino acid residues (24AA LeuA, CSVNWGEAFSAGVHRLANGGNGFW). The peptides were purified to >95% purity, as shown by analytical RP-HPLC and mass spectrometry. By including an N-terminal cysteine group, the tailored peptide fragments were readily immobilized at the gold interfaces. The resulting thickness and molecular orientation, determined by ellipsometry and grazing angle infrared spectroscopy, respectively, indicated that the peptides were covalently immobilized in a random helical orientation. The bacterial specificity of the anchored peptide fragments was tested against Gram-positive and Gram-negative bacteria. Our results showed that the adsorbed 14AA LeuA exhibited no specificity toward the bacterial strains, whereas the surface-immobilized 24AA LeuA displayed significant binding toward Gram-positive bacteria with various binding affinities from one strain to another. The 14AA LeuA did not show binding as this fragment is most likely too short in length for recognition by the membrane-bound receptor on the target bacterial cell membrane. These results support the potential use of class IIa bacteriocins as molecular recognition elements in biosensing platforms.


Subject(s)
Anti-Bacterial Agents/chemistry , Bacteriocins/chemistry , Carnobacterium/chemistry , Escherichia coli/chemistry , Immobilized Proteins/chemistry , Listeria monocytogenes/chemistry , Listeria/chemistry , Peptides/chemistry , Amino Acid Sequence , Carnobacterium/physiology , Escherichia coli/physiology , Gold/chemistry , Immobilized Proteins/chemical synthesis , Immobilized Proteins/isolation & purification , Immobilized Proteins/pharmacology , Listeria/physiology , Listeria monocytogenes/physiology , Mass Spectrometry , Microbial Sensitivity Tests , Models, Molecular , Molecular Sequence Data , Peptides/chemical synthesis , Peptides/isolation & purification , Peptides/pharmacology , Protein Binding , Protein Engineering , Protein Structure, Secondary , Structure-Activity Relationship
15.
Int J Food Microbiol ; 146(3): 228-34, 2011 Apr 29.
Article in English | MEDLINE | ID: mdl-21419508

ABSTRACT

Minimally processed refrigerated ready-to-eat fishes may offer health risk of severe infection to susceptible individuals due to contamination by the psychrotolerant bacterium L. monocytogenes. In this work, inhibition of L. monocytogenes by a plant extract and lactic acid bacteria (LAB) was studied in model fish systems kept at 5 °C for 35 days. For that, fillets of tropical fish "surubim" (Pseudoplatystoma sp.) and hydroalcoholic extract of the plant Lippia sidoides Cham. ("alecrim pimenta") were used. Fish peptone broth (FPB), "surubim" broth and "surubim" homogenate were inoculated with combinations of L. monocytogenes and bacteriocin-producing Carnobacterium maltaromaticum (C2 and A9b(+)) and non bacteriocin-producing C. maltaromaticum (A9b(-)), in the presence or absence of extract of "alecrim pimenta" (EAP). In all model systems, monocultures of L. monocytogenes and carnobacteria reached final populations ≥10(8) CFU/ml after 35 days, except for L. monocytogenes in "surubim" homogenate (10(4) CFU/ml). In FPB, EAP alone and combined with cultures of LAB inhibited L. monocytogenes but carnobacteria without EAP were only weakly antilisterial. In "surubim" broth, EAP alone did not prevent L. monocytogenes growth but cultures of carnobacteria combined or not with EAP inhibited L. monocytogenes, with more pronounced effect being observed for C. maltaromaticum C2, which produced bacteriocin. In "surubim" homogenate, EAP alone and combined with cultures of C. maltaromaticum A9b(-) and A9b(+) were strongly inhibitory to L. monocytogenes, while C. maltaromaticum C2 with EAP caused transient inhibition of L. monocytogenes. No significant inhibition of L. monocytogenes was observed for carnobacteria in "surubim" homogenate without EAP. In conclusion, it was observed that the use of EAP and cultures of carnobacteria have potential to inhibit L. monocytogenes in fish systems and the applications should be carefully studied, considering the influence of food matrix.


Subject(s)
Carnobacterium/metabolism , Fishes/microbiology , Food Microbiology , Listeria monocytogenes/pathogenicity , Plant Extracts/pharmacology , Seafood/microbiology , Animals , Antibiosis , Bacteriocins/pharmacology , Carnobacterium/physiology , Colony Count, Microbial , Food Contamination/prevention & control , Food Handling , Food Preservation , Lactobacillaceae/drug effects , Lactobacillaceae/physiology , Lippia/chemistry , Listeria monocytogenes/drug effects , Listeria monocytogenes/growth & development
16.
Food Microbiol ; 27(5): 573-9, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20510773

ABSTRACT

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.


Subject(s)
Bacterial Typing Techniques/methods , Carnobacterium/isolation & purification , Dairy Products/microbiology , Food Technology , Animals , Carnobacterium/classification , Carnobacterium/genetics , Carnobacterium/physiology , Consumer Product Safety , Food Preservation , Humans
17.
Wei Sheng Wu Xue Bao ; 50(2): 251-5, 2010 Feb.
Article in Chinese | MEDLINE | ID: mdl-20387469

ABSTRACT

OBJECTIVE: We investigated the influence of Carnobacterium sp. Hg4-03 on intestinal microflora of the 4th instar Hepialus gonggaensis larvae, an economically important insect. METHODS: The effect was observed by molecular techniques based on the sequence of 16S rDNA V3 region gene and PCR/DGGE (Denaturing gradient gel electrophoresis). The health larvae were divided randomly into treatment group 1, treatment group 2 and control group, and fed on their natural food added with different amount of Carnobacterium sp. Hg4-03 (group 1 and group 2) or ddH2O (control). After 14 days and 28 days, 6 larvae from each group were randomly selected to be dissected and contents of guts were collected for bacterial diversity analysis. RESULTS: The result showed that bacterial diversity index of treatment groups with Hg4-03 was higher than control group, and the species of bacteria increased. Comparing the bands of DGGE profiles between three groups, the intensity of band stand for Carnobacterium sp. Hg4-03 have enhanced. Another band with swelled intensity found in profiles come from treatment group 2 after 28 d fed, the sequence analysis showed it belongs to Bacillus subtilis. CONCLUSION: Feeding with Carnobacterium sp. Hg4-03 could balance the bacteria in larvae gut and increase bacteria diversity, that means the bacteria made a positive effect on the bacterial diversity of H. gonggaensis larval gut. Hg4-03 may be used as probiotic bacteria for rearing H. gonggaensis larvae in controlling conditions or the larvae's hemi-wild rearing.


Subject(s)
Bacteria/isolation & purification , Carnobacterium/physiology , Moths/microbiology , Moths/physiology , Probiotics/administration & dosage , Animals , Bacteria/classification , Bacteria/genetics , Biodiversity , Feeding Behavior , Intestines/microbiology , Larva/microbiology , Larva/physiology , Molecular Sequence Data
18.
J Appl Microbiol ; 108(2): 624-32, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19664064

ABSTRACT

AIMS: To assess the effects of bacterial treatment at the earliest stages of cod rearing on the microbial load, larval development and performance, testing three bacterial strains (Carnobacterium divergens V41, Arthrobacter sp. and Enterococcus sp.) in vivo that were previously shown to have inhibitory potential towards fish pathogens in vitro. METHODS AND RESULTS: A bacterial mixture was added eight times to the rearing water from the prehatch to the mid-larval stage (a 38-day period). Microbiological analysis of ova, larvae and rearing water was performed regularly. Larval performance and development were evaluated by survival rate, hypersalinity tolerance and physiological measurements. Different larval survival rates were observed within and between treatments, and possibly explained by variations in larval microflora and established probionts. Larvae from one silo, which had been bathed in the bacterial suspension, showed the highest survival rate (42.1%), lowest Vibrio levels, and were significantly heavier (19.3%) and more stress tolerant than control larvae (P < 0.01). This coincided with the intestinal establishment of two of the tested bacteria. CONCLUSIONS: Arthrobacter and Enterococcus strains added regularly to the rearing water from the postfertilized egg stage can become established in larval gastrointestinal tract. The Enterococcus strain was associated with increased larval growth, performance and microflora control, indicating its probiotic nature. SIGNIFICANCE AND IMPACT OF THE STUDY: Regular application of autochthonous probionts may promote larval welfare, development and stress tolerance at early stages, hence increasing production yield in intensive cod larviculture.


Subject(s)
Arthrobacter/physiology , Carnobacterium/physiology , Enterococcus/physiology , Gadus morhua/growth & development , Gadus morhua/microbiology , Probiotics , Animals , Colony Count, Microbial , Intestines/microbiology , Larva/growth & development , Larva/microbiology
19.
Food Microbiol ; 26(8): 783-93, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19835762

ABSTRACT

Cold-smoked salmon treated with divergicin M35-producing Carnobacterium divergens M35, C. divergens ATCC 35677 (a non-producer of bacteriocin), purified divergicin M35 or supernatants of C. divergens M35 culture in snow crab hepatopancreas (SCH) medium or MRS broth was challenged with Listeria monocytogenes (up to 10(3) CFU/g). Samples were stored at 4 degrees C for up to four weeks. L. monocytogenes, total bacterial and lactic acid bacterial counts were determined along with changes in total volatile base nitrogen (TVBN) and biogenic amine production as well as texture, color and odor. A 2.6 log CFU/g reduction in L. monocytogenes was obtained for up to 10 days of storage in samples treated with C. divergens M35. Purified divergicin M35 (50 microg/g), SCH supernatant or MRS supernatant brought reductions of 1 log CFU/g at the beginning of storage. However, the anti-listerial activity of the supernatants lasted for 15 days compared to 3 days for purified divergicin M35. Color and texture were affected little in samples containing C. divergens M35 compared to un-inoculated samples. TVBN and biogenic amine production, particularly tyramine, remained below the maximum acceptable level in fish appreciation. These results clearly show the potential of C. divergens M35 culture as well as divergicin M35 bio-ingredient for application to the inactivation of L. monocytogenes in ready-to-eat seafood.


Subject(s)
Anti-Bacterial Agents/pharmacology , Antibiosis , Bacteriocins/pharmacology , Carnobacterium/physiology , Food Preservation/methods , Listeria monocytogenes/growth & development , Salmon/microbiology , Seafood/microbiology , Animals , Biogenic Amines/analysis , Biogenic Amines/metabolism , Carnobacterium/metabolism , Cold Temperature , Colony Count, Microbial , Food Microbiology , Listeria monocytogenes/drug effects , Odorants/analysis , Seafood/standards , Smoke , Taste , Time Factors
20.
J Food Sci ; 74(5): M219-23, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19646051

ABSTRACT

Listeria monocytogenes is the pathogen of concern in ready-to-eat (RTE) meat products. Salt brines are used to chill processed meats. L. monocytogenes and lactic acid bacteria (LAB) can grow under saline conditions, and may compete with each other for nutrients. The objective of this study was to determine the effect of lactic acid bacteria (Enterococcus faecalis, Carnobacterium gallinarum, and Lactobacillus plantarum) on the survival of L. monocytogenes and Listeria innocua in brines stored under low temperatures for 10 d. Sterile tap water (STW) and 2 brine solutions (7.9% and 13.2% NaCl) were inoculated with 1 of 5 cocktails (L. monocytogenes, L. innocua, LAB, L. monocytogenes+ LAB, or L. innocua+ LAB) at initial concentrations of 7 log CFU/mL. Brines were stored for 10 d at 4 or 12 degrees C. Three replications of each brine concentration/cocktail/temperature combination were completed. No significant reductions of L. monocytogenes occurred in 7.9%[w/v] or 13.2%[w/v] brines when LAB were present; however, there were significant reductions after 10 d of L. monocytogenes in the STW solution when LAB were present (1.43 log CFU/mL at 4 degrees C and 3.02 log CFU/mL at 12 degrees C). L. innocua was significantly less resilient to environmental stresses of the brines than L. monocytogenes, both with and without LAB present (P< or = 0.05). These strains of lactic acid bacteria are not effective at reducing L. monocytogenes in brines at low temperatures. Furthermore, use of L. innocua as a model for L. monocytogenes is not appropriate under these environmental conditions.


Subject(s)
Lactic Acid/pharmacology , Listeria monocytogenes/drug effects , Listeria/drug effects , Salts , Carnobacterium/physiology , Colony Count, Microbial , Consumer Product Safety , Enterococcus faecalis/physiology , Food Microbiology , Lactobacillus plantarum/physiology , Listeria/growth & development , Listeria monocytogenes/growth & development , Temperature
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