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Benameur F, Belkaaloul K, Kheroua O. Isolation of 60 strains from fermented milk of mares and donkeys in Algeria and identification by 16S rRNA sequencing of lactobacilli: Assessment of probiotic skills of important strains and aromatic productivity power. Vet World 2024; 17:829-841. [PMID: 38798294 PMCID: PMC11111728 DOI: 10.14202/vetworld.2024.829-841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 03/14/2024] [Indexed: 05/29/2024] Open
Abstract
Background and Aim Donkey and mare milk have high nutritional and functional values, but their lactic acid bacteria (LAB) content remains poorly studied and undervalued in the Algerian dairy industry. This study aimed to isolate and select LAB strains that produce antimicrobial substances during fermentation and to characterize the probiotic profiles of each extracted strain to indicate their potential for antioxidant and proteolytic activity. Materials and Methods This study focuses on isolating and identifying lactic acid bacterial strains from 10 Equid-fermented milk samples collected in two regions of El Bayed Wilaya (Algeria). Identification of LAB strains was obtained by 16S rRNA sequencing. The probiotic properties of important strains and their aromatic productivity power are assessed. To evaluate their antibacterial activity against Listeria monocytogenes, Staphylococcus aureus, Chryseobacterium joostei, Pseudomonas aeruginosa, and Escherichia coli, we selected 21 strains. Different induction methods have been used to amplify the antibacterial effects against these pathogenic strains. Results Among a total of 60 identified strains, 31 had a probiotic profile, and most were catalase-negative. Aromatic productivity power was observed in eight strains: Lactiplantibacillus plantarum, Lactobacillus casei, Lactobacillus paracasei, Weissella confusa, Weissella cibaria, Leuconostoc mesenteroides, Leuconostoc lactis, and Lactobacillus sp1. Conclusion Our results provide insight into the considerable diversity of LAB present in fermented donkey and mare milk. To meet the expectations of the Algerian dairy industry, it is important that the probiotic skills of the nine selected strains are met. In addition, a significant number of these strains may have important probiotic activity and biotechnological potential.
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Affiliation(s)
- Fouzia Benameur
- Laboratory of Physiology of Nutrition and Food Safety, Department of Biology, Faculty of Natural and Life Sciences, University Oran 1 Ahmed Ben Bella, Oran, Algeria
| | - Kawthar Belkaaloul
- Laboratory of Physiology of Nutrition and Food Safety, Department of Biology, Faculty of Natural and Life Sciences, University Oran 1 Ahmed Ben Bella, Oran, Algeria
| | - Omar Kheroua
- Laboratory of Physiology of Nutrition and Food Safety, Department of Biology, Faculty of Natural and Life Sciences, University Oran 1 Ahmed Ben Bella, Oran, Algeria
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2
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Bagel A, Delignette-Muller ML, Lopez C, Michel V, Sergentet D, Douellou T. Strain- and serotype-dependent affinity of Shiga toxin-producing Escherichia coli for bovine milk fat globules. J Dairy Sci 2022; 105:8688-8704. [PMID: 36175225 DOI: 10.3168/jds.2022-21840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 07/01/2022] [Indexed: 11/19/2022]
Abstract
Shiga toxin-producing Escherichia coli (STEC) are widely detected in raw milk products intended for human consumption. Although STEC are a worldwide public health problem, the pathogenicity of STEC in cheese remains unclear. In fact, bacterial association with compounds in raw milk cheeses could reduce their pathogenicity. A previous study showed the association of 2 STEC strains with raw milk cream in a natural creaming assay. Different concentrations of each strain were required to saturate the cream. In this study, we hypothesized that all STEC strains could be associated with milk fat globules (MFG) in raw milk and that the bacterial load required for saturation of the cream is serotype dependent. We evaluated the affinity of STEC strains belonging to the O157:H7, O26:H11, and O103:H2 serotypes for bovine raw milk cream and analyzed saturation of the cream layer by natural creaming assay. We used 12 STEC strains and 3 strains belonging to another pathotype to assess the effects of serotypes on this phenomenon. We performed sucrose density gradient centrifugation assays with 2 STEC model strains to confirm the results obtained by natural creaming. The localization of STEC within MFG-enriched creams was observed by confocal and electron microscopy. We recovered approximately 10 times more STEC from the cream layer after natural creaming than from raw bovine milk. The concentration of STEC required to saturate the cream layer (the saturation concentration) was estimated for each strain by nonlinear regression, highlighting a strain and serotype effect. Moreover, the concentration of STEC in the cream was milk fat level dependent. However, even in nonsaturating conditions, a high level of STEC was still present in the aqueous phase, after fat separation. Thus, natural creaming should not be used as the sole preventive measure to remove STEC from naturally contaminated raw milk. The results of our study suggest that cream saturation is a complex mechanism, most likely involving specific interactions between STEC and raw MFG.
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Affiliation(s)
- A Bagel
- Bacterial Opportunistic Pathogens and Environment Research Group, Université de Lyon, UMR 5557 Ecologie Microbienne Lyon, National Center of Scientific Research, VetAgro Sup, 69280 Marcy-l'Etoile, France
| | - M-L Delignette-Muller
- Laboratoire de Biométrie et Biologie Evolutive, UMR 5558, Université de Lyon, VetAgro Sup, National Center of Scientific Research, 69622 Villeurbanne, France
| | - C Lopez
- INRAE, UR BIA, F-44316, Nantes, France
| | - V Michel
- Actalia, 74800 La Roche-sur-Foron, France
| | - D Sergentet
- Bacterial Opportunistic Pathogens and Environment Research Group, Université de Lyon, UMR 5557 Ecologie Microbienne Lyon, National Center of Scientific Research, VetAgro Sup, 69280 Marcy-l'Etoile, France; VetAgro Sup-Campus Vétérinaire, Laboratoire d'Etudes des Microorganismes Alimentaires Pathogènes-French National Reference Laboratory for Escherichia coli including Shiga toxin-producing E. coli (NRL-STEC), Université de Lyon, 69280, Marcy-l'Etoile, France.
| | - T Douellou
- Bacterial Opportunistic Pathogens and Environment Research Group, Université de Lyon, UMR 5557 Ecologie Microbienne Lyon, National Center of Scientific Research, VetAgro Sup, 69280 Marcy-l'Etoile, France
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Tarazanova M, Huppertz T, Starrenburg M, Todt T, van Hijum S, Kok J, Bachmann H. Transcriptional response of Lactococcus lactis during bacterial emulsification. PLoS One 2019; 14:e0220048. [PMID: 31344087 PMCID: PMC6657864 DOI: 10.1371/journal.pone.0220048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/08/2019] [Indexed: 12/25/2022] Open
Abstract
Microbial surface properties are important for interactions with the environment in which cells reside. Surface properties of lactic acid bacteria significantly vary and some strains can form strong emulsions when mixed with a hydrocarbon. Lactococcus lactis NCDO712 forms oil-in-water emulsions upon mixing of a cell suspension with petroleum. In the emulsion the bacteria locate at the oil-water interphase which is consistent with Pickering stabilization. Cells of strain NCDO712 mixed with sunflower seed oil did not stabilize the oil droplets. This study shows that the addition of either ethanol or ammonium sulfate led to cell aggregation, which subsequently allowed stabilizing oil-in-water emulsions. From this, we conclude that bacterial cell aggregation is important for emulsion droplet stabilization. To determine how bacterial emulsification influences the microbial transcriptome RNAseq analysis was performed on lactococci taken from the oil-water interphase. In comparison to cells in suspension 72 genes were significantly differentially expressed with a more than 4-fold difference. The majority of these genes encode proteins involved in transport processes and the metabolism of amino acids, carbohydrates and ions. Especially the proportion of genes belonging to the CodY regulon was high. Our results also point out that in a complex environment such as food fermentations a heterogeneous response of microbes might be caused by microbe-matrix interactions. In addition, microdroplet technologies are increasingly used in research. The understanding of interactions between bacterial cells and oil-water interphases is of importance for conducting and interpreting such experiments.
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Affiliation(s)
- Mariya Tarazanova
- TI Food and Nutrition, AN Wageningen, The Netherlands
- NIZO, Ede BA, The Netherlands
- Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - Thom Huppertz
- TI Food and Nutrition, AN Wageningen, The Netherlands
- NIZO, Ede BA, The Netherlands
| | - Marjo Starrenburg
- TI Food and Nutrition, AN Wageningen, The Netherlands
- NIZO, Ede BA, The Netherlands
- Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - Tilman Todt
- Radboud University Medical Centre CMBI, Geert Grooteplein Nijmegen, The Netherlands
- HAN, University of Applied Sciences, PGL Nijmegen, The Netherlands
| | - Sacha van Hijum
- TI Food and Nutrition, AN Wageningen, The Netherlands
- NIZO, Ede BA, The Netherlands
- Radboud University Medical Centre CMBI, Geert Grooteplein Nijmegen, The Netherlands
| | - Jan Kok
- TI Food and Nutrition, AN Wageningen, The Netherlands
- Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - Herwig Bachmann
- TI Food and Nutrition, AN Wageningen, The Netherlands
- NIZO, Ede BA, The Netherlands
- * E-mail:
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Nguyen ATB, Nigen M, Jimenez L, Ait-Abderahim H, Cunault C, Marchesseau S, Picart-Palmade L. A multi-scale approach to identify the role of heat treatment, milk protein composition and starter culture on the gel formation and the texture defects of acid milk gel. Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2018.07.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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5
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Tarazanova M, Huppertz T, Kok J, Bachmann H. Influence of lactococcal surface properties on cell retention and distribution in cheese curd. Int Dairy J 2018. [DOI: 10.1016/j.idairyj.2018.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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6
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Effect of interactions of plant phenolics with bovine meat proteins on their antibacterial activity. Food Control 2018. [DOI: 10.1016/j.foodcont.2018.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Tarazanova M, Huppertz T, Kok J, Bachmann H. Altering textural properties of fermented milk by using surface-engineered Lactococcus lactis. Microb Biotechnol 2018; 11:770-780. [PMID: 29745037 PMCID: PMC6011991 DOI: 10.1111/1751-7915.13278] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/20/2018] [Accepted: 03/30/2018] [Indexed: 01/23/2023] Open
Abstract
Lactic acid bacteria are widely used for the fermentation of dairy products. While bacterial acidification rates, proteolytic activity and the production of exopolysaccharides are known to influence textural properties of fermented milk products, little is known about the role of the microbial surface on microbe-matrix interactions in dairy products. To investigate how alterations of the bacterial cell surface affect fermented milk properties, 25 isogenic Lactococcus lactis strains that differed with respect to surface charge, hydrophobicity, cell chaining, cell-clumping, attachment to milk proteins, pili expression and EPS production were used to produce fermented milk. We show that overexpression of pili increases surface hydrophobicity of various strains from 3-19% to 94-99%. A profound effect of different cell surface properties was an altered spatial distribution of the cells in the fermented product. Aggregated cells tightly fill the cavities of the protein matrix, while chaining cells seem to be localized randomly. A positive correlation was found between pili overexpression and viscosity and gel hardness of fermented milk. Gel hardness also positively correlated with clumping of cells in the fermented milk. Viscosity of fermented milk was also higher when it was produced with cells with a chaining phenotype or with cells that overexpress exopolysaccharides. Our results show that alteration of cell surface morphology affects textural parameters of fermented milk and cell localization in the product. This is indicative of a cell surface-dependent potential of bacterial cells as structure elements in fermented foods.
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Affiliation(s)
- Mariya Tarazanova
- NIZO B.V.P.O. Box 206710 BAEdeThe Netherlands
- TiFNP.O. Box 5576700 ANWageningenThe Netherlands
- Molecular GeneticsUniversity of GroningenNijenborgh 79747AGGroningenThe Netherlands
| | - Thom Huppertz
- NIZO B.V.P.O. Box 206710 BAEdeThe Netherlands
- TiFNP.O. Box 5576700 ANWageningenThe Netherlands
- Present address:
FrieslandCampinaStationsplein 43818 LE AmersfoortThe Netherlands
| | - Jan Kok
- TiFNP.O. Box 5576700 ANWageningenThe Netherlands
- Molecular GeneticsUniversity of GroningenNijenborgh 79747AGGroningenThe Netherlands
| | - Herwig Bachmann
- NIZO B.V.P.O. Box 206710 BAEdeThe Netherlands
- TiFNP.O. Box 5576700 ANWageningenThe Netherlands
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8
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Douëllou T, Galia W, Kerangart S, Marchal T, Milhau N, Bastien R, Bouvier M, Buff S, Montel MC, Sergentet-Thevenot D. Milk Fat Globules Hamper Adhesion of Enterohemorrhagic Escherichia coli to Enterocytes: In Vitro and in Vivo Evidence. Front Microbiol 2018; 9:947. [PMID: 29867855 PMCID: PMC5963252 DOI: 10.3389/fmicb.2018.00947] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/23/2018] [Indexed: 12/13/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC; E. coli) are food-borne agents associated with gastroenteritis, enterocolitis, bloody diarrhea and the hemolytic-uremic syndrome (HUS). Bovine milk glycans have been shown to contain oligosaccharides which are similar to host epithelial cell receptors and can therefore prevent bacterial adhesion. This study aimed to describe interactions between EHEC O157:H7 EDL933 and O26:H11 21765 and milk fat globules (MFGs) in raw milk and raw milk cheese, and the impact of MFGs on EHEC strains adhesion to the intestinal tract in vitro and in vivo. Both EHEC serotypes clearly associated with native bovine MFGs and significantly limited their adhesion to a co-culture of intestinal cells. The presence of MFGs in raw milk cheese had two effects on the adhesion of both EHEC serotypes to the intestinal tracts of streptomycin-treated mice. First, it delayed and reduced EHEC excretion in mouse feces for both strains. Second, the prime implantation site for both EHEC strains was 6 cm more proximal in the intestinal tracts of mice fed with contaminated cheese containing less than 5% of fat than in those fed with contaminated cheese containing 40% of fat. Feeding mice with 40% fat cheese reduced the intestinal surface contaminated with EHEC and may therefore decrease severity of illness.
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Affiliation(s)
- Thomas Douëllou
- Institut National de Recherche Agronomique, Unité de Recherches Fromagères, Aurillac, France.,Université de Lyon, Research Group "Bacterial Opportunistic Pathogens and Environment", UMR5557 Ecologie Microbienne Lyon, Université Lyon 1, CNRS, VetAgro Sup, Marcy-l'Étoile, France
| | - Wessam Galia
- Université de Lyon, Research Group "Bacterial Opportunistic Pathogens and Environment", UMR5557 Ecologie Microbienne Lyon, Université Lyon 1, CNRS, VetAgro Sup, Marcy-l'Étoile, France
| | - Stéphane Kerangart
- Université de Lyon, Research Group "Bacterial Opportunistic Pathogens and Environment", UMR5557 Ecologie Microbienne Lyon, Université Lyon 1, CNRS, VetAgro Sup, Marcy-l'Étoile, France
| | - Thierry Marchal
- UPSP ICE 2011.03.101 & CRB ANIM (ANR11.INBS.0003), Université de Lyon, VetAgro Sup, Marcy-l'Étoile, France
| | - Nadège Milhau
- UPSP ICE 2011.03.101 & CRB ANIM (ANR11.INBS.0003), Université de Lyon, VetAgro Sup, Marcy-l'Étoile, France
| | - Renaud Bastien
- Department of Collective Behaviour, Max Planck Institute for Ornithology, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Marion Bouvier
- Université de Lyon, Research Group "Bacterial Opportunistic Pathogens and Environment", UMR5557 Ecologie Microbienne Lyon, Université Lyon 1, CNRS, VetAgro Sup, Marcy-l'Étoile, France.,Laboratoire d'Études des Microorganismes Alimentaires Pathogènes - French National Reference Laboratory for Escherichia coli Including Shiga Toxin Producing E. coli, Université de Lyon, VetAgro Sup Campus Vétérinaire, Marcy-l'Étoile, France
| | - Samuel Buff
- UPSP ICE 2011.03.101 & CRB ANIM (ANR11.INBS.0003), Université de Lyon, VetAgro Sup, Marcy-l'Étoile, France
| | - Marie-Christine Montel
- Institut National de Recherche Agronomique, Unité de Recherches Fromagères, Aurillac, France
| | - Delphine Sergentet-Thevenot
- Université de Lyon, Research Group "Bacterial Opportunistic Pathogens and Environment", UMR5557 Ecologie Microbienne Lyon, Université Lyon 1, CNRS, VetAgro Sup, Marcy-l'Étoile, France.,Laboratoire d'Études des Microorganismes Alimentaires Pathogènes - French National Reference Laboratory for Escherichia coli Including Shiga Toxin Producing E. coli, Université de Lyon, VetAgro Sup Campus Vétérinaire, Marcy-l'Étoile, France
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9
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Burgain J, Scher J, Francius G, Borges F, Corgneau M, Revol-Junelles A, Cailliez-Grimal C, Gaiani C. Lactic acid bacteria in dairy food: surface characterization and interactions with food matrix components. Adv Colloid Interface Sci 2014; 213:21-35. [PMID: 25277266 DOI: 10.1016/j.cis.2014.09.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 08/30/2014] [Accepted: 09/01/2014] [Indexed: 02/07/2023]
Abstract
This review gives an overview of the importance of interactions occurring in dairy matrices between Lactic Acid Bacteria and milk components. Dairy products are important sources of biological active compounds of particular relevance to human health. These compounds include immunoglobulins, whey proteins and peptides, polar lipids, and lactic acid bacteria including probiotics. A better understanding of interactions between bioactive components and their delivery matrix may successfully improve their transport to their target site of action. Pioneering research on probiotic lactic acid bacteria has mainly focused on their host effects. However, very little is known about their interaction with dairy ingredients. Such knowledge could contribute to designing new and more efficient dairy food, and to better understand relationships between milk constituents. The purpose of this review is first to provide an overview of the current knowledge about the biomolecules produced on bacterial surface and the composition of the dairy matter. In order to understand how bacteria interact with dairy molecules, adhesion mechanisms are subsequently reviewed with a special focus on the environmental conditions affecting bacterial adhesion. Methods dedicated to investigate the bacterial surface and to decipher interactions between bacteria and abiotic dairy components are also detailed. Finally, relevant industrial implications of these interactions are presented and discussed.
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10
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Burgain J, Gaiani C, Francius G, Revol-Junelles A, Cailliez-Grimal C, Lebeer S, Tytgat H, Vanderleyden J, Scher J. In vitro interactions between probiotic bacteria and milk proteins probed by atomic force microscopy. Colloids Surf B Biointerfaces 2013; 104:153-62. [DOI: 10.1016/j.colsurfb.2012.11.032] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 11/14/2012] [Accepted: 11/20/2012] [Indexed: 01/19/2023]
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11
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Lan CH, Son CK, Ha HP, Florence H, Binh LT, Mai LT, Tram NTH, Khanh TTM, Phu TV, Dominique V, Yves W. Tropical traditional fermented food, a field full of promise. Examples from the Tropical Bioresources and Biotechnology programme and other related French-Vietnamese programmes on fermented food. Int J Food Sci Technol 2013. [DOI: 10.1111/ijfs.12064] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | - Le Thanh Binh
- Institute of Biotechnology; Vietnam Academy of Science and Technology (VAST); Hanoi; Vietnam
| | | | - Nguyen Thi Hoai Tram
- Department of Biotechnology Food Industries Research Institute-FIRI; Hanoi; Vietnam
| | | | | | - Valentin Dominique
- Centre des Sciences du Goût et de l'Alimentation; UMR 6265 CNRS INRA UB; Dijon; France
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Mahony J, Ainsworth S, Stockdale S, van Sinderen D. Phages of lactic acid bacteria: the role of genetics in understanding phage-host interactions and their co-evolutionary processes. Virology 2012; 434:143-50. [PMID: 23089252 DOI: 10.1016/j.virol.2012.10.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 09/12/2012] [Accepted: 10/01/2012] [Indexed: 12/26/2022]
Abstract
Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.
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Affiliation(s)
- Jennifer Mahony
- Department of Microbiology, University College Cork, Western Road, Cork, Ireland.
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Roche Y, Cao-Hoang L, Perrier-Cornet JM, Waché Y. Advanced fluorescence technologies help to resolve long-standing questions about microbial vitality. Biotechnol J 2012; 7:608-19. [PMID: 22253212 DOI: 10.1002/biot.201100344] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Revised: 11/11/2011] [Accepted: 12/06/2011] [Indexed: 11/08/2022]
Abstract
Advances in fundamental physical and optical principles applied to novel fluorescence methods are currently resulting in rapid progress in cell biology and physiology. Instrumentation devised in pioneering laboratories is becoming commercially available, and study findings are now becoming accessible. The first results have concerned mainly higher eukaryotic cells but many more developments can be expected, especially in microbiology. Until now, some important problems of cell physiology have been difficult to investigate due to interactions between probes and cells, excretion of probes from cells and the inability to make in situ observations deep within the cell, within tissues and structures. These technologies will enable microbiologists to address these topics. This Review aims at introducing the limits of current physiology evaluation techniques, the principles of new fluorescence technologies and examples of their use in this field of research for evaluating the physiological state of cells in model media, biofilms or tissue environments. Perspectives on new imaging technologies, such as super-resolution imaging and non-linear highly sensitive Raman microscopy, are also discussed. This review also serves as a reference to those wishing to explore how fluorescence technologies can be used to understand basic cell physiology in microbial systems.
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Affiliation(s)
- Yann Roche
- Laboratory GPMA, IFR92, Université de Bourgogne & AgroSup Dijon, Dijon, France.
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Cao-Hoang L, Chaine A, Grégoire L, Waché Y. Potential of nisin-incorporated sodium caseinate films to control Listeria in artificially contaminated cheese. Food Microbiol 2010; 27:940-4. [PMID: 20688236 DOI: 10.1016/j.fm.2010.05.025] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 05/20/2010] [Accepted: 05/25/2010] [Indexed: 10/19/2022]
Abstract
A sodium caseinate film containing nisin (1000 IU/cm(2)) was produced and used to control Listeria innocua in an artificially contaminated cheese. Mini red Babybel cheese was chosen as a model semi-soft cheese. L. innocua was both surface- and in-depth inoculated to investigate the effectiveness of the antimicrobial film as a function of the distance from the surface in contact with the film. The presence of the active film resulted in a 1.1 log CFU/g reduction in L. innocua counts in surface-inoculated cheese samples after one week of storage at 4 degrees C as compared to control samples. With regard to in-depth inoculated cheese samples, antimicrobial efficiency was found to be dependent on the distance from the surface in contact with the active films to the cheese matrix. The inactivation rates obtained were 1.1, 0.9 and 0.25 log CFU/g for distances from the contact surface of 1 mm, 2 mm and 3 mm, respectively. Our study demonstrates the potential application of sodium caseinate films containing nisin as a promising method to overcome problems associated with post-process contamination, thereby extending the shelf life and possibly enhancing the microbial safety of cheeses.
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Affiliation(s)
- Lan Cao-Hoang
- DSAN, UP Biotechnologie et Microbiologie Alimentaire, AgroSup Dijon, 1 Esplanade Erasme, F-21000 DIJON, France.
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