PCR-DGGE approaches have been applied less frequently to characterize the
yeast or bacterial populations on wine grapes. Prakitchaiwattana, et al. (2004)
found mostly the Aureobasidium pullulans, a ubiquitous environmental yeast, on
undamaged grapes and Metschnikowia and Hanseniaspora sp., as well as
Au. pullulans, on damaged grapes. The authors noted that PCR-DGGE was not as
sensitive as plating and could not detect yeasts at population levels lower than 104
CFU per gram (of grapes), however, they did note that a greater diversity of fungal
species from grapes could be witnessed by DGGE. Recently Renouf and Lonvaud-
Funel (2007) developed a modified enrichment method, followed by PCR-DGGE
and other molecular methods, to demonstrate that the grapes may be a source for
the spoilage yeast Br. bruxellensis (teleomorph Dekkera bruxellensis). This remarkable
finding provides a clue as to a non-winery source for this problematic yeast.