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Nieto-Arribas P.,University of Castilla - La Mancha | Sesena S.,University of Castilla - La Mancha | Poveda J.M.,University of Castilla - La Mancha | Poveda J.M.,Instituto Regional Of Investigacion Cientifica Aplicada Irica | And 2 more authors.
Food Microbiology

Twenty-seven Leuconostoc (Ln.) isolates from Manchego cheese were characterized by phenotypic and genotypic methods, and their technological abilities studied in order to test their potential use as dairy starter components. While phenotypic diversity was evaluated by studying the biochemical characteristics of technological interest (i.e. acidifying and aminopeptidase activities), genotypic diversity was evidenced by using Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR). Additional technological abilities such as lipolytic, proteolytic and autolytic activities, salt and pH tolerance and production of dextran, flavour compounds and biogenic amines, were investigated. The marked differences among strains reflected the existing biodiversity in naturally fermented products. After statistically evaluating their performance, strains C0W2, belonging to Ln. lactis, and C16W5 and N2W5, belonging to Ln. mesenteroides subsp. dextranicum, revealed the best properties to be used in mixed dairy starter cultures. This study evidences the fact that natural environments can be considered as a proper source of useful strains, for the dairy industry. © 2009 Elsevier Ltd. All rights reserved. Source

Nieto-Arribas P.,University of Castilla - La Mancha | Sesena S.,University of Castilla - La Mancha | Poveda J.M.,University of Castilla - La Mancha | Poveda J.M.,Instituto Regional Of Investigacion Cientifica Aplicada Irica | And 3 more authors.
Food Microbiology

Enterococci represent a considerable proportion of the microbiota in Manchego cheeses. In this study, a total of 132 enterococci isolated from good quality Manchego cheeses from two dairies at different ripening times were genotypically characterized and identified using molecular techniques. Representative isolates from the clusters obtained after genotyping were assayed for some enzymatic activities considered to have a potential role in cheese ripening, and for 2,3-butanedione and acetoin production, evaluation of odor intensity and appearance in milk and safety evaluation. Enterococcus faecalis was the predominant specie, accounting for 81.8% of the total isolates, while Enterococcus faecium, Enterococcus hirae and Enterococcus avium were present in low proportions. The number of genotypes involved at each ripening time varied both between dairies and with the ripening times; genotype E. faecalis Q1 being present in almost all the samples from both dairies. Eight isolates showed a higher proteolytic activity and 3 isolates produced high quantities of acetoin-diacetyl, for which reason they are interesting from a technological standpoint. A low antibiotic resistance was found and almost all the strains were susceptible to clinically important antibiotics. On the contrary, only four isolates (E. faecalis C4W1 and N0W5, and E. faecium N32W1 and C16W2) did not harbor some of the virulence genes assayed. © 2010 Elsevier Ltd. Source

Romo-Sanchez S.,Instituto Regional Of Investigacion Cientifica Aplicada Irica | Alves-Baffi M.,Sao Paulo State University | Arevalo-Villena M.,Instituto Regional Of Investigacion Cientifica Aplicada Irica | Ubeda-Iranzo J.,Instituto Regional Of Investigacion Cientifica Aplicada Irica | Briones-Perez A.,Instituto Regional Of Investigacion Cientifica Aplicada Irica
Food Microbiology

The aim of this study was to know the yeast biodiversity from fresh olive (Olea europaea L.) fruits, olive paste (crush olives) and olive pomace (solid waste) from Arbequina and Cornicabra varieties. Yeasts were isolated from fruits randomly harvested at various olive groves in the region of Castilla La Mancha (Spain). Olive paste and pomace, a byproduct of the processing of this raw material, were also collected in sterile flasks from different oil mills. Molecular identification methodology used included comparison of polymerase chain reaction (PCR) amplicons of their 5.8S rRNA gene and internal transcribed spacers ITS1 and ITS2 followed by restriction pattern analysis (RFLP). For some species, sequence analysis of the 5.8S rDNA gene was necessary. The results were compared to sequences held in public databases (BLAST). These techniques allowed to identify fourteen different species of yeasts, belonging to seven different genera (Zygosaccharomyces, Pichia, Lachancea, Kluyveromyces, Saccharomyces, Candida, Torulaspora) from the 108 yeast isolates. Species diversity was thus considerable: Pichia caribbica, Zygosaccharomyces fermentati (Lachancea fermentati) and Pichia holstii (Nakazawaea holstii) were the most commonly isolated species, followed by Pichia mississippiensis, Lachancea sp., Kluyveromyces thermotolerans and Saccharomyces rosinii. The biotechnological properties of these isolates, was also studied. For this purpose, the activity of various enzymes (β-glucosidase, β-glucanase, carboxymethylcellulase, polygalacturonase, peroxidase and lipase) was evaluated. It was important that none of species showed lipase activity, a few had cellulase and polygalacturonase activities and the majority of them presented β-glucanase, β-glucosidase and peroxidase activities. © 2010 Elsevier Ltd. All rights reserved. Source

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