Identification, technological and safety characterization of Lactobacillus sakei and Lactobacillus curvatus isolated from Argentinean anchovies (Engraulis anchoita)

In this study, the identification and characterization of Lactobacillus previously isolated from fresh anchovies (Engraulis anchoita) are investigated. 16S rDNA partial sequencing assigned all the isolates to belong to the Lactobacillus sakei/curvatus group. Fourteen out of 15 isolates were identified as L. sakei by phenotypic traits: they exhibited catalase activity and fermented melibiose, although only 10 of them hydrolyzed arginine. These results were confirmed by multiplex PCR-based restriction enzyme analysis with HindIII and by restriction fragment length polymorphic (RFLP) analysis of the 16S-23S rDNA intergenic spacer region with TaqI. Among identified isolates, four L. sakei strains and the sole L. curvatus strain showing sensitivity to chloramphenicol, erythromycin and tetracycline and exhibiting high tolerance to NaCl (10-18%) were unable to produce neither dextran nor biogenic amines. Based on technological and safety features, L. sakei SACB704 and L. curvatus SACB03a naturally present in fresh anchovies may be promising strains for the development of a starter culture to accelerate and control the fermentation of salt fermented anchovy-based products.Fil: Belfiore, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Raya, Raul Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Vignolo, Graciela Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

Antilisterial peptides from Spanish dry-cured hams: Purification and identification

The typical Spanish dry-cured ham has a particular sensory quality that makes it a distinctive food, highly appreciated for consumers worldwide. Its particular physicochemical properties, such as high salt content and reduced water activity contribute to their shelf-stability. However, post-processing actions carried out for the commercialization of these products such as slicing may increase the risk of development of pathogenic microorganisms as Listeria monocytogenes. During ripening, muscle proteins are hydrolyzed by muscle peptidases releasing peptides and free amino acids. Some of these peptides have been described to exert biological activities such as antioxidant and ACE-inhibition. In this study, a peptidomic strategy using mass spectrometry techniques has been used to identify and sequence those naturally generated peptides showing antilisterial activity. One hundred and five peptides have been identified in active fractions and some synthesized and their MIC calculated. Ten peptides were able to inhibit the growth of L. monocytogenes, being the pentapeptide RHGYM the most effective showing a MIC value of 6.25 mM. This study proves for the first time the potential antimicrobial action against L. monocytogenes of certain naturally generated peptides obtained from Spanish dry-cured ham.The postdoctoral fellowship from the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina of P.C. is acknowledged. Grant AGL2013-47169-R from MINECO and FEDER funds as well as HIGHVALFOOD project grant no 614281 from EU-FP7 Marie Curie CIG scheme are fully acknowledged. L.M. is grateful to the JAEDOC-CSIC postdoctoral contract cofunded by European Social Fund.Peer reviewe

Peptides with angiotensin I converting enzyme (ACE) inhibitory activity generated from porcine skeletal muscle proteins by the action of meat-borne Lactobacillus

Angiotensin I-converting enzyme (ACE) inhibitory activity of peptides derived from the hydrolysis of sarcoplasmic and myofibrillar porcine proteins by the action of Lactobacillus sakei CRL1862 and Lactobacillus curvatus CRL705 (whole cells + cell free extracts) was investigated at 30 °C for 36 h. The protein hydrolysates were subjected to RP-HPLC in order to fractionate the extracts for further evaluate the ACE inhibitory activity of the collected peptide fractions. Bioactive fractions were only found from the hydrolysis of sarcoplasmic proteins by both assayed lactic acid bacteria. Identification of peptides contained in these bioactive fractions was carried out by tandem mass spectrometry using a nanoLC-ESI-QTOF instrument and the mascot seach engine. A total of eighteen peptides were characterized from the two most active fractions obtained from the hydrolysis made by L. sakei CRL1862. Regarding L. curvatus CRL705, its proteolytic action was able to generate thirty and twenty peptides, which were identified in the two most active fractions, respectively. It is worth noting that the sequence FISNHAY was generated by the proteolytic action of the two species. Sequence similarity analyses between the peptides identified in this study and those previously identified as ACE inhibitory peptides and detailed in the BIOPEP database were outlined. Results suggest that lactic acid bacteria selected in this study were able to generate peptides with ACE inhibitory activity, thus having potential to be used in the development of functional fermented products.Fil: Castellano, Patricia Haydee. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentina;Fil: Aristoy, María Concepción. Consejo Superior de Investigaciones Cientificas. Instituto de Ciencia y Teconologia de Alimentos y Nutricion; España;Fil: Sentandreu, Miguel Ángel. Consejo Superior de Investigaciones Cientificas. Instituto de Ciencia y Teconologia de Alimentos y Nutricion; España;Fil: Vignolo, Graciela Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentina;Fil: Toldrá, Fidel. Consejo Superior de Investigaciones Cientificas. Instituto de Ciencia y Teconologia de Alimentos y Nutricion; España

Hydrolysis of raw fish proteins extracts by Carnobacterium maltaromaticum strains isolated from Argentinean freshwater fish

Lactic acid bacteria (LAB) isolated from freshwater fish (hatcheries and captures) from Paraná river (Argentina) were analyzed by using culture-dependent approaches. The species belonging to Carnobacterium (C.) divergens, C. inhibens, C. maltaromaticum, C. viridans and Vagococcus (V.) salmoninarum were identify as predominant by RAPD-PCR and 16 s rRNA gene sequencing. C. maltaromaticum (H-17, S-30, B-42 and S-44) grew in raw fish extract and slightly reduced the medium pH (5.81–5.91). These strains exhibited moderate fish sarcoplasmic protein degradation (≤ 73 %) releasing small peptides and free amino acids, being alanine, glycine, asparagine and arginine concentrations increased in a higher extent (17.84, 1.47, 1.26 and 0.47 mg/100 mL, respectively) by S-44 strain at 96 h incubation. Interestingly C. maltaromaticum H-17 was able to inhibit Listeria monocytogenes. Results suggest that these strains would contribute to the development of new safe and healthy fishery products with improved nutritional and sensory characteristics.Fil: Dallagnol, Andrea Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Pescuma, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Gamarra Espínola, Natalia. Universidad Nacional de Misiones; ArgentinaFil: Vera, Mariela Natalia. Universidad Nacional de Misiones; ArgentinaFil: Vignolo, Graciela Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

Lactobacillus sakei CRL1862 improves safety and protein hydrolysis in meat systems

Aims The capacity of Lactobacillus sakei CRL1862 to prevent the growth of pathogens and its ability to degrade sarcoplasmic and myofibrillar proteins in pork meat systems was evaluated. In addition, basic safety aspects of Lact. sakei CRL1862 such as production of biogenic amines and antibiotic susceptibility were addressed. Methods and Results The bacteriocin-producing Lact. sakei CRL1862 showed respectively bactericide and bacteriostatic effect against Listeria monocytogenes and Staphylococcus aureus in beaker sausage assay during 9 days of storage at 22°C. The hydrolytic effect of Lact. sakei CRL1862 on protein extracts was evaluated by SDS-PAGE and reverse phase HPLC. A more pronounced proteolysis was evidenced in inoculated sarcoplasmic proteins compared with myofibrillar extracts with the generation of predominantly hydrophilic peptides and increase of total free amino acids concentration. Lactobacillus sakei CRL1862 produced neither histamine nor tyrosine and exhibited no resistance to the antibiotics assayed. Conclusions Lactobacillus sakei CRL1862 effectively controlled the growth of L. monocytogenes and Staph. aureus; moreover, it was able to hydrolyse pork meat extracts generating peptides and amino acids, which may improve hygienic and sensorial attributes of fermented meat products. Significance and Impact of the Study The use of an integrated approach to evaluate the major traits of Lact. sakei CRL1862 showed it can be applied as an autochthonous functional starter in meat fermentation.Fil: Castellano, Patricia Haydee. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Aristoy, Maria Concepción. Consejo Superior de Investigaciones Científicas. Instituto de Agroquímica y Tecnología de Alimentos; EspañaFil: Sentandreu, Miguel Angel. Consejo Superior de Investigaciones Científicas. Instituto de Agroquímica y Tecnología de Alimentos; EspañaFil: Vignolo, Graciela Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Toldrá, Fidel. Consejo Superior de Investigaciones Científicas. Instituto de Agroquímica y Tecnología de Alimentos; Españ

Proteomic analysis of Listeria monocytogenes FBUNT during biofilm formation at 10°C in response to Lactocin AL705

Listeria monocytogenes is one of the major food-related pathogens and is able to survive and multiply under different stress conditions. Its persistence in industrial premises and foods is partially due to its ability to form biofilm. Thus, as a natural strategy to overcome L. monocytogenes biofilm formation, the treatment with lactocin AL705 using a sublethal dose (20AU/ml) was explored. The effect of the presence of the bacteriocin on the biofilm formation at 10°C of L. monocytogenes FBUNT was evaluated for its proteome and compared to the proteomes of planktonic and sessile cells grown at 10°C in the absence of lactocin. Compared to planktonic cells, adaptation of sessile cells during cold stress involved protein abundance shifts associated with ribosomes function and biogenesis, cell membrane functionality, carbohydrate and amino acid metabolism, and transport. When sessile cells were treated with lactocin AL705, proteins? up-regulation were mostly related to carbohydrate metabolism and nutrient transport in an attempt to compensate for impaired energy generation caused by bacteriocin interacting with the cytoplasmic membrane. Notably, transport systems such as β-glucosidase IIABC (lmo0027), cellobiose (lmo2763), and trehalose (lmo1255) specific PTS proteins were highly overexpressed. In addition, mannose (lmo0098), a specific PTS protein indicating the adaptive response of sessile cells to the bacteriocin, was downregulated as this PTS system acts as a class IIa bacteriocin receptor. A sublethal dose of lactocin AL705 was able to reduce the biofilm formation in L. monocytogenes FBUNT and this bacteriocin induced adaptation mechanisms in treated sessile cells. These results constitute valuable data related to specific proteins targeting the control of L. monocytogenes biofilm upon bacteriocin treatment.Fil: Melian, Constanza Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Castellano, Patricia Haydee. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Segli, Julio Franco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Mendoza, Lucia Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Vignolo, Graciela Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

Indigenous starter cultures to improve quality of artisanal dry fermented sausages from Chaco (Argentina)

Lactic acid bacteria (LAB) and coagulase negative cocci (CNC) were isolated from artisanal dry sausages sampled from the northeastern region of Chaco, Argentina. In order to evaluate their performance in situ and considering technological features of the isolated strains, two mixed selected autochthonous starter cultures (SAS) were designed: (i) SAS-1 (Lactobacillus sakei 487 + Staphylococcus vitulinus C2) and (ii) SAS-2 (L. sakei 442 + S. xylosus C8). Cultures were introduced into dry sausage manufacturing process at a local small-scale facility. Microbiological and physicochemical parameters were monitored throughout fermentation and ripening periods, while sensory attributes of the final products were evaluated by a trained panel. Lactic acid bacteria revealed their ability to colonize and adapt properly to the meat matrix, inhibiting the growth of spontaneous microflora and enhancing safety and hygienic profile of the products. Both SAS showed a beneficial effect on lipid oxidation and texture of the final products. Staphylococcus vitulinus C2, from SAS-1, promoted a better redness of the final product. Sensory profile revealed that SAS addition preserved typical sensory attributes. Introduction of these cultures could provide an additional tool to standardize manufacturing processes aiming to enhance safety and quality while keeping typical sensory attributes of regional dry fermented sausages.Fil: Palavecino Prpich, Noelia Zulema. Universidad Nacional del Chaco Austral. Departamento de Ciencias Basicas y Aplicadas. Laboratorio de Microbiología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Castro, Marcela Paola. Universidad Nacional del Chaco Austral. Departamento de Ciencias Basicas y Aplicadas. Laboratorio de Microbiología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cayre, María Elisa. Universidad Nacional del Chaco Austral. Departamento de Ciencias Basicas y Aplicadas. Laboratorio de Microbiología de Alimentos; ArgentinaFil: Garro, Oscar Alfredo. Universidad Nacional del Chaco Austral. Departamento de Ciencias Basicas y Aplicadas. Laboratorio de Microbiología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vignolo, Graciela Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin

Strategies for Pathogen Biocontrol Using Lactic Acid Bacteria and Their Metabolites: A Focus on Meat Ecosystems and Industrial Environments

The globalization of trade and lifestyle ensure that the factors responsible for the emergence of diseases are more present than ever. Despite biotechnology advancements, meat-based foods are still under scrutiny because of the presence of pathogens, which causes a loss of consumer confidence and consequently a fall in demand. In this context, Lactic Acid Bacteria (LAB) as GRAS organisms offer an alternative for developing pathogen-free foods, particularly avoiding Listeria monocytogenes, with minimal processing and fewer additives while maintaining the foods’ sensorial characteristics. The use of LAB strains, enabling us to produce antimicrobial peptides (bacteriocins) in addition to lactic acid, with an impact on quality and safety during fermentation, processing, and/or storage of meat and ready-to-eat (RTE) meat products, constitutes a promising tool. A number of bacteriocin-based strategies including the use of bioprotective cultures, purified and/or semi-purified bacteriocins as well as their inclusion in varied packaging materials under different storage conditions, have been investigated. The application of bacteriocins as part of hurdle technology using non-thermal technologies was explored for the preservation of RTE meat products. Likewise, considering that food contamination with L. monocytogenes is a consequence of the post-processing manipulation of RTE foods, the role of bacteriocinogenic LAB in the control of biofilms formed on industrial surfaces is also discussed.EEA FamailláFil: Castellano, Patricia Haydee. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Pérez Ibarreche, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Blanco Massani, Mariana Raquel. Instituto Nacional de Tecnología Industrial; Argentina.Fil: Fontana, Cecilia Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Vignolo, Graciela Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

Soil microbial community responses to different sugarcane management strategies as revealed by 16S metagenomics

XXX Congress of the ISSCT (International Society of Sugar Cane Technologists), Tucumán, from 31 August to 8 September 2019Sugarcane cultivation in Argentina is distributed in three geographic regions: Tucumán, Northern (Salta and Jujuy) and Littoral (Santa Fe and Misiones), covering about 376,223 ha. Tucumán has traditionally been the most important region with 68% of the total production. Since new agricultural techniques, such as green-cane harvesting and sugarcane crop rotation with soybean, were implemented in the last decade, changes in the agroecosystem of sugarcane, specific pathosystems and epidemiological parameters have been observed. A 16S metagenomics approach to investigate total bacterial communities associated with sugarcane rhizospheric soil when soybean was the predecessor crop in a cultivation area with a high incidence of red stripe disease was applied; soil from sugarcane monoculture was also included. Two commercial sugarcane cultivars (Saccharum spp. hybrids) with differential responses to red stripe infection (tolerant and susceptible) were evaluated. Sampling was carried out in 2013-2014 and in 2014-2015 (first and second ratoon, respectively) at 30, 90 and 180 days after harvest. Total soil DNA was obtained using FastPrep® technology. The 16S RNA gene (variable region V3-V4) was sequenced using a MiSeq platform Illumina. Taxonomic assignment revealed Bacillales, Rhyzobiales, Rhodospirilliales, Xanthomonadales and Acidobacteriales among the most abundant orders in all samples. Soil samples from sugarcane without soybean rotation showed a marked decrease in Bacillaes, Rhizobiales and Sphingomonadales. Cluster analysis grouped together samples from the tolerant genotype, while those from the susceptible genotype formed two subgroups that were distinguished according to sampling time after harvest. The analysis showed that samples from sugarcane under monoculture were grouped distant to the rest of the samples showing different microbiota composition. The sugarcane rhizosphere microbiome and its biotechnological potential open a new opportunity in the concept of sustainable crop management. The data contribute significant knowledge about the microbial diversity in agricultural ecosystems.El cultivo de caña de azúcar en Argentina se distribuye en tres regiones geográficas: Tucumán, Norte (Salta y Jujuy) y Litoral (Santa Fe y Misiones), que cubren alrededor de 376,223 ha. Tucumán ha sido tradicionalmente la región más importante con el 68% de la producción total. En la última década, como consecuencia de los cambios en el manejo como la rotación con soja y la cosecha en verde, se han observado cambios en el agroecosistema de la caña de azúcar, en patosistemas específicos y parámetros epidemiológicos. En el presente estudio, se aplicó un enfoque metagenómica de gen 16S ARNr para investigar las comunidades bacterianas asociadas con el suelo rizosférico de caña de azúcar en un sistema con soja como cultivo predecesor en un área de cultivo con una alta incidencia de estría roja. A fines comparativos, se incluyó en el estudio muestras de suelo monocultivo de caña de azúcar. Se evaluaron dos cultivares comerciales de caña de azúcar (Saccharum spp. híbridos) con respuestas diferenciales a la infección de estría roja (tolerante y susceptible). A partir del ADN total del suelo de muestras obtenidas en las campañas 2013-2014 y en 2014-2015 (soca 1 y 2, respectivamente) a los 30, 90 y 180 días después de la cosecha, se amplificó la región variable V3-V4 del 16S rRNA y se secuenció utilizando una plataforma MiSeq Illumina. La asignación taxonómica de las secuencias, reveló Bacillales, Rhyzobiales, Rhodospirilliales, Xanthomonadales y Acidobacteriales entre las órdenes más abundantes en todas las muestras. Las muestras de suelo de caña de azúcar sin rotación con soja mostraron una marcada disminución en Bacillaes, Rhizobiales y Sphingomonadales. El análisis de conglomerados agrupó las muestras del genotipo tolerante, mientras que las del genotipo susceptible formaron dos subgrupos que se distinguieron según el tiempo de muestreo después de la cosecha. El análisis mostró además que las muestras de caña de azúcar provenientes de un sistema de monocultivo se agruparon distantes del resto de las muestras evidenciando las diferencias en la composición de microbiota. El microbioma de la rizosfera de la caña de azúcar y su potencial biotecnológico abren una nueva oportunidad en el concepto de manejo sostenible de cultivos. Los datos aportan un conocimiento significativo sobre la diversidad microbiana en los ecosistemas agrícolas.La culture de la canne à sucre en Argentine est répartie dans trois régions géographiques: Tucumán, le Nord (Salta et Jujuy) et le Littoral (Santa Fe et Misiones), couvrant environ 376 223 ha. Tucumán est traditionnellement la région la plus importante avec 68% de la production totale. Depuis que de nouvelles techniques agricoles, telles que la récolte de la canne verte et la rotation de la canne à sucre avec le soja, ont été mises en place au cours de la dernière décennie, des changements dans l’écosystème de la canne à sucre, des pathosystèmes spécifiques et des paramètres épidémiologiques ont été observés. Une approche métagénomique 16S pour étudier les communautés bactériennes totales associées au sol rhizosphérique de la canne à sucre lorsque le soja était la culture précédente dans une zone de culture présentant une incidence élevée de maladie à rayures rouges a été appliquée; le sol issu de la monoculture de canne à sucre a également été inclus. Deux cultivars commerciaux de la canne à sucre (hybrides Saccharum spp.) avec des réponses différentielles à l'infection à rayures rouges (tolérants et sensibles) ont été évalués. L'échantillonnage a été réalisé en 2013-2014 et en 2014-2015 (première et deuxième repousses, respectivement) à 30, 90 et 180 jours après la récolte. L'ADN total du sol a été obtenu en utilisant la technologie FastPrep®. Le gène de l'ARN 16S (région variable V3-V4) a été séquence en utilisant une plate-forme MiSeq Illumina. L'analyse taxonomique a révélé que Bacillales, Rhyzobiales, Rhodospirilliales, Xanthomonadales et Acidobacteriales étaient parmi les ordres les plus abondants dans tous les échantillons. Des échantillons de sol de canne à sucre sans rotation de soja ont montré une diminution marquée des bacilles, des rhizobiales et des sphingomonadales. L'analyse a regroupé des échantillons du génotype tolérant, tandis que ceux du génotype sensible ont formé deux sous-groupes qui ont été distingués en fonction de la période d'échantillonnage après la récolte. L'analyse a montré que les échantillons provenant de la canne à sucre en monoculture étaient regroupés à distance du reste des échantillons présentant une composition de microbiote différente. Le microbiome de la rhizosphère de canne à sucre et son potentiel biotechnologique ouvrent une nouvelle opportunité dans le concept de gestion durable des cultures. Les données fournissent des connaissances significatives sur la diversité microbienne dans les écosystèmes agricoles.EEA FamailláFil: Fontana, Paola Daniela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Orru, L. Council for Agricultural Research and Economics (CREA). Research Centre for Genomics & Bioinformatics; ItaliaFil: Fontana, Cecilia Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Cocconcelli, P.S. Università Cattolica del Sacro Cuore. Dipartimento di Scienze e Tecnologie Alimentari per una filiera agro-alimentare Sostenibile (DISTAS); ItaliaFil: Vignolo, Graciela Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia Para Lactobacilos; ArgentinaFil: Salazar, Sergio Miguel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; Argentin

Differential proteomic analysis of lactic acid bacteria - Escherichia coli O157:H7 interaction and its contribution to bioprotection strategies in meat

Original ResearchHuman infection by Enterohemorrhagic Escherichia (E.) coli (EHEC) occurs through the ingestion of contaminated foods such as milk, vegetable products, water-based drinks, and particularly minced meats. Indeed EHEC is a pathogen that threatens public health and meat industry. The potential of different Lactic Acid Bacteria (LAB) strains to control EHEC in a meat-based medium was evaluated by using a simple and rapid method and by analyzing the growth kinetics of co-cultures (LAB-EHEC) in a meat-based medium. The activity of LAB toward EHEC in co-cultures showed variable inhibitory effect. Although, LAB were able to control EHEC, neither the produced acid nor bacteriocins were responsible of the inhibition. The bacteriocinogenic Enteroccus (Ent.) mundtii CRL35 presented one of the highest inhibition activities. A proteomic approach was used to evaluate bacterial interaction and antagonistic mechanisms between Ent. mundtii and EHEC. Physiological observations, such as growth kinetics, acidification ability and EHEC inhibitory potential were supported by the proteomic results, demonstrating significant differences in protein expression in LAB: (i) due to the presence of the pathogen and (ii) according to the growth phase analyzed. Most of the identified proteins belonged to carbohydrate/amino acid metabolism, energy production, transcription/translation, and cell division. These results contribute to the knowledge of competition strategies used by Ent. mundtii during its co-culture with EHEC setting new perspectives for the use of LAB to control this pathogen in meatinfo:eu-repo/semantics/publishedVersio