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In this work, the yeast ecology associated with the spontaneous fermentation of Grillo cultivar grapes from 10 vineyards was analyzed from grape harvest till complete consumption of must sugars. The microbiological investigation started with the plate count onto two culture media to distinguish total yeasts (TY) and presumptive Saccharomyces (PS). Yeasts were randomly isolated and identified by a combined genotypic approach consisting of restriction fragment length polymorphism (RFLP) of 5.8S rRNA gene and 26S rRNA and sequencing of D1/D2 domain of the 26S rRNA gene, which resulted in the recognition of 14 species belonging to 10 genera. The distribution of the yeasts within the vineyards showed some differences in species composition and concentration levels among 2008 and 2009 vintages. Due to the enological relevance, all Saccharomyces cerevisiae isolates were differentiated applying two genotypic tools (interdelta analysis and microsatellite multiplex PCR of polymorphic microsatellite loci) that recognized 51 strains. Based on the low production of H2S, acetic acid and foam, ethanol resistance, growth in presence of high concentrations of potassium metabisulphite (KMBS) and CuSO4 and at low temperatures, 14 strains were selected and used as starter to ferment grape must at 13 °C and 17 °C in presence of 100 mg/L of KMBS. Three strains (CS160, CS165 and CS182) showed optimal technological aptitudes. [ABSTRACT FROM AUTHOR]

Abstract: The antagonistic activity of the essential oils (EOs) extracted by hydrodistillation from the fruit peel of several citrus genotypes (pummelo, grapefruit, orange, kumquat, mandarin and lemon) was evaluated against foodborne pathogen bacteria (43 strains of Listeria monocytogenes, 35 strains of Staphylococcus aureus and 14 strains of Salmonella enterica). Five commercial EOs were used for comparison. Most of the EOs were more effective against the Gram-positive bacteria rather than Salmonella. EOs of lemon genotypes 14 and 15 showed the best results in terms of number of strains inhibited and width of the inhibition zone. The most susceptible strain of each species (L. monocytogenes 133, St. aureus 473 and Salmonella Newport 50404) was used as indicator for the evaluation of the minimum inhibition concentration (MIC) of the EOs 14 and 15. The last two EOs, EO 16 (showing the weakest inhibition power among lemon EOs), and the commercial EO L (lemon) were analysed for their chemical composition. A total of 30 major compounds were identified by gas chromatography/mass spectrometry (GC/MS) and the oxygenated monoterpenes were suggested to be implicated in the process of bacterial inhibition by citrus EOs. [Copyright &y& Elsevier]