Mercanti D.J.,CONICET |
Carminati D.,Centro Of Ricerca Per Le Produzioni Foraggere E Lattiero Casearie |
Reinheimer J.A.,CONICET |
International Journal of Food Microbiology | Year: 2011
Prophages account for most of the genetic diversity among strains of a given bacterial species, and represent a latent source for the generation of virulent phages. In this work, a set of 30 commercial, collection and dairy-isolated Lactobacillus casei group strains were used. A species-specific PCR assay allowed a reclassification, mainly of strains previously considered Lactobacillus casei, into either Lactobacillus paracasei or Lactobacillus rhamnosus. All the strains were induced with mitomycin C, allowing direct recovering of phage DNA in 25 cases, which corroborates the widely occurrence of lysogeny on Lactobacillus genomes, including probiotic strains of Lactobacillus casei group. Ten out of 11 commercial strains studied contained prophages, evidencing the potential risks of their use at industrial scale. Strains were also induced by treatment with different concentrations of hydrogen peroxide but, however, this agent was not able to evidence a prophage release for any of the strains tested. According to a RAPD-PCR fingerprinting with M13, 1254 and G1 primers, most of the commercial strains presented a high degree of homology and, regarding BglII- and BamHI-restriction profiles of phage DNA, six of them harboured the same prophage. Surprisingly, both Lactobacillus paracasei ATCC 27092 and Lactobacillus paracasei ATCC 27139 shared a second prophage with both an INLAIN collection and a commercial Lactobacillus paracasei strains, whereas two collection strains shared a third one. On the other hand, mitomycin C-inducible prophages were detected only on about a half of the strains isolated from dairy products, which had (with only one exception) from moderate to high correlation coefficients according to RAPD-PCR fingerprinting. After induction, supernatants were filtered and tested against nine Lactobacillus strains of the set sensitive to previously assayed virulent phages, allowing isolation of two new virulent phages: fcyrillic i. Lp1308 and fcyrillic i. Lp84. Both phages were able to lyse all but one strains sensitive to previously assayed phage MLC-A. © 2010 Elsevier B.V.
Pirlo G.,Centro Of Ricerca Per Le Produzioni Foraggere E Lattiero Casearie
Italian Journal of Animal Science | Year: 2012
Twenty-four life cycle assessment studies which estimated the carbon footprint of milk production in countries with modern dairy farming were examined. It proved difficult to compare the studies because of the strong discrepancies between them. The aim of this review was to examine the characteristics of LCA studies on milk production in order to understand how the variability of results can be explained. The main reason is the different methodologies adopted. However, other variables were considered: production system, stocking rate, milk productivity, mitigation strategies. Life Cycle Assessment is a promising tool for benchmarking carbon footprint among different countries or production systems. This approach could also be used as a mitigation indicator in the enforcement of political decision. Two major factors are needed for a practical application: i) a widely accepted methodology and ii) direct measurements of greenhouse gases in specific contests.© G. Pirlo, 2012.
Piscopo A.,University of Reggio Calabria |
Romeo F.V.,Centro Of Ricerca Per Le Produzioni Foraggere E Lattiero Casearie |
Poiana M.,University of Reggio Calabria
Rivista Italiana delle Sostanze Grasse | Year: 2011
In the present work the effects of the drying process on variation of the quality parameters of several almond cultivars were evaluated. The samples were collected in a field in the South of Italy and subsequently dried in a laboratory pilot dryer. Wide variations were observed in the free acidity content whereas no significant differences were investigated in percentage lipid amounts. K, Mg and Ca proved the major minerals present in all almond seeds by analysis of minerals and of trace elements. The two-ways statistical analysis revealed a general influence of the genetic characters and the drying process on fatty acids contents in all almond oils. The investigation about these components revealed that Mas Bovera cv kernels were the high quality samples in terms of monounsaturated/polyunsa-turated acids ratio compared to the other varieties. A further study regarding the genetic similarities of almonds before and after treatment was conducted by cluster analysis. Mas Bovera and Glorieta oils were the least affected by the quality decay by heat application.
Cardamone L.,CONICET |
Quiberoni A.,CONICET |
Mercanti D.J.,CONICET |
Fornasari M.E.,Centro Of Ricerca Per Le Produzioni Foraggere E Lattiero Casearie |
And 2 more authors.
Dairy Science and Technology | Year: 2011
Some species of Leuconostoc are very important for fermented dairy products, as they contribute to the organoleptic characteristics of butter and cream, and also contribute to the formation of openings in some soft, semi-hard (Edam and Gouda cheeses), many artisanal or in blue-veined cheeses, such as Roquefort. In this study, 14 Leuconostoc strains isolated from cheese and cheese-related products were characterized by genotypic and phenotypic methods, and their technological performance assessed for their potential use as dairy adjunct starters. Phenotypic characterization allowed these strains to be classified to genus level, and genotypic studies (RAPD-PCR and 16S rRNA gene sequencing) identified them to species/ subspecies level. Five Leuconostoc strains grew well and acidified milk, and most of them grew even at 8 °C. They showed moderate resistance to heat treatments (30 min t 63 °C) and grew well in the presence of 3% and 4% NaCl, and were significantly inhibited at pH ≤ 5. All strains showed resistance against the bacteriophages tested. In general, the antibacterial properties observed were slight and due to acid production, with the exception of Leuconostoc citreum MB1, which strongly inhibited Listeria monocytogenes ATCC 15313 by the production of a bacteriocin-like compound. All Leuconostoc strains studied were susceptible to gentamicin, tetracycline, erythromycin and ampicillin. Some strains also showed interesting technological and antimicrobial properties, thus being potentially appropriate as adjunct starters in fermented dairy products. This study highlights that adventitious lactic acid bacteria can be a great source of novel strains with interesting technological features that could be used for fermented dairy foods. © INRA and Springer Science+Business Media B.V. 2011.
Capra M.L.,CONICET |
Mercanti D.J.,CONICET |
Rossetti L.C.,Centro Of Ricerca Per Le Produzioni Foraggere E Lattiero Casearie |
Reinheimer J.A.,CONICET |
Journal of Applied Microbiology | Year: 2011
Aims: To isolate and characterize bacterial strains derived from Lactobacillus casei and Lactobacillus paracasei strains and resistant to phage MLC-A. Methods and Results: Two of nine assayed strains rendered resistant mutants with recovery efficiencies of 83% (Lact. paracasei ATCC 27092) and 100% (Lact. casei ATCC 27139). DNA similarity coefficients (RAPD-PCR) confirmed that no significant genetic changes occurred while obtaining resistant mutants. Neither parent nor mutant strains spontaneously released phages. Phage-resistant mutants were tested against phages PL-1, J-1, A2 and MLC-A8. Lactobacillus casei ATCC 27092 mutants showed, overall, lower phage resistance than Lact. paracasei ATCC 27092 ones, but still higher than that of the parent strain. Lactobacillus paracasei ATCC 27092 mutants moderately adsorbed phage MLC-A only in calcium presence, although their parent strain successfully did it with or without calcium. Adsorption rates for Lact. casei ATCC 27139 and its mutants were highly influenced by calcium. Again, phage adsorption was higher on the original strain. Conclusions: Several isolates derived from two Lact. casei and Lact. paracasei strains showed resistance to phage MLC-A but also to other Lact. casei and Lact. paracasei phages. Significance and Impact of the Study: This study highlights isolation of spontaneous bacteriophage-resistant mutants from Lact. casei and Lact. paracasei as a good choice for use in industrial rotation schemes. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.