Yeasts associated to Malbec grape berries from Mendoza, Argentina

COMBINA M., MERCADO L., BORGO P., ELÍA A., JOFRÉ V., GANGA A., MARTINEZ C., CATANIA C.

JOURNAL OF APPLIED MICROBIOLOGY

Blackwell Publishing

Lugar: United Kingdom; Año: 2005 vol. 98 p. 1055 - 1061

1364-5072

Aims: The aims of this work were to evaluate different pre-isolation treatments applied to complete yeast extraction from grapes and to identify the yeast microflora associated to Malbec grapes from two vineyards located in Mendoza, Argentina.Methods & Results: The pre-isolation treatments evaluated were shaking, jet streaming with pressurized water and grape blending. The overall results clearly indicated that when a more vigorous and disruptive pre-isolation treatment was applied; larger numbers of yeast species were recovered. The yeast population on healthy and ripe Malbec grapes was in the order of 105 – 106 cfu g-1. Eight different yeast species were isolated from berries, including Kloeckera apiculata, Metschnikowia pulcherrima, Pichia membranifaciens, Saccharomycodes ludwigii, Candida species (C. stellata and C. raghi), Issatchenkia orientalis, and Rhodotorula spp.Conclusions: Grape blending gave the highest yeast counts. Rainfall near grape harvest time quantitatively and qualitatively modifies the yeast microflora. The yeast species identified on ripe grapes from the Mendoza region, partially match those previously documented in different parts of the world related. S. ludwigii has not been previously reported in grapes. Significance & Impact of Study: There is a first report on yeast microbiota in grapes from Mendoza, Argentina. Saccharomycodes ludwigii was found in high percentage (17%), this species has not been described before in grapes surface. The importance of pre-isolation steps to the recovery of high number of yeasts was showed. Influence of climatic conditions near harvest time on microflora was confirmed.