Analysis of microbial populations on Prosecco marcs devoted to the production of Grappa [Italy]

We performed a quantitative and qualitative analysis in order to evaluate the microbial biomass present on Prosecco grapes at crushing. We used conventional microbiological techniques, based on media and growth conditions selective for different microbial categories. Our data demonstrate that, besides the traditional oenological flora, many other microbial groups are present on the fruits. Since the evolution of marc is highly different from the one of must, such microbial populations could have the opportunity to develop and affect the sensory characteristics of the final product. Our results show that most conventional growth media are not sufficiently selective towards the microbial groups they are intended for, hence supplementary analyse are normally needed to reach a correct evaluation of the microbial biomass