Indigenous Yeasts Associated with Muscadine (Vitis rotundifolia) Grapes and Musts

Indigenous yeast flora of intact Vitis rotundifolia grape berries and corresponding musts, representing four eastern North Carolina vineyards, were qualitatively surveyed. Grape samples were obtained from two commercial and two North Carolina State Agricultural Research Service vineyards. Total microbial populations on whole berries were estimated at 10⁴ CFU/cm² of berry surface area. Yeasts represented approximately 60% of the total populations. Eighty-two yeast isolates representing 12 species were recovered from all treatments. Nine yeast species were isolated from whole berries, including Candida spp., Hanseniaspora osmophilia, Pichia membranaefaciens, Rhodotorula spp., and Saccharomyces cerevisiae. Examination of musts and carbonic maceration of intact grapes yielded numerous isolates of H. osmophilia, P. membranaefaciens, and S. cerevisiae.