One hundred isolates of the commercial Saccharomyces cerevisiae strain Zymaflore VL1 were recovered from spontaneous fermentations carried out with grapes collected from vineyards located close to wineries in the Vinho Verde wine region of Portugal. Isolates were differentiated based on their mitochondrial DNA restriction patterns and the evaluation of genetic polymorphisms was carried out by microsatellite analysis, interdelta sequence typing and pulsed‐field gel electrophoresis (PFGE). Genetic patterns were compared to those obtained for 30 isolates of the original commercialized Zymaflore VL1 strain. Among the 100 recovered isolates we found a high percentage of chromosomal size variations, most evident for the smaller chromosomes III and VI. Complete loss of heterozygosity was observed for two isolates that had also lost chromosomal heteromorphism; their growth and fermentative capacity in a synthetic must medium was also affected. A considerably higher number of variant patterns for interdelta sequence amplifications was obtained for grape‐derived strains compared to the original VL1 isolates. Our data show that the long‐term presence of strain VL1 in natural grapevine environments induced genetic changes that can be detected using different fingerprinting methods. The observed genetic changes may reflect adaptive mechanisms to changed environmental conditions that yeast cells encounter during their existence in nature. Copyright © 2007 John Wiley & Sons, Ltd.

Wine quality and value largely depend on grape variety, which is of primary importance in wine identification. The aim of the present work was to enhance a wine DNA extraction protocol and, subsequently, grapevine variety identification. This enhanced method is an outcome from several previously developed extraction methods and effectively allows obtaining large amounts of high-quality DNA exhibiting an optimal 260/280 ratio. Grapevine variety DNA extracted from wine was amplifiable with a specific SSR primer. This procedure was applicable for monovarietal and older commercial red and white wines. The potential of this enhanced method relies on its use for traceability as part of protecting both consumer and producer interests.