One particularly successful direct analysis application is the use of direct epifluorescence
technique (DEFT) in which microbial-based cleavage of a fluorescent
substrate enables direct counting of viable cells through a fluorescent microscope.
Using this method Millet and Lonvaud-Funel (2000) first demonstrated significant
non-culturable populations of both bacteria and yeast in aging wine, detecting at
least 100-fold higher viable cell numbers using DEFT by comparison to that
obtained by plating. They also demonstrated that both A. aceti and P. damnosus
inoculated into wine maintained a higher viable cell population determined by
DEFT, compared to plating.