Interactions BetweenLeuconostoc oenosandPediococcusspp. During Vinification of Red Wines

Strains of Pediococcus parvulus were inoculated into sterile-filtered Cabernet Sauvignon and Merlot wines in which malolactic fermentation was either not induced (MLF (-) wines) or induced by Leuconostoc oenos (MLF (+) wines) prior to filtration. While most strains grew in MLF (-) wines, the viability of all strains declined from an initial population of ca 105 CFU/mL to between <300 and 104 CFU/mL after inoculation into MLF (+) wines. The initial decline in viability appears to be due to formation of an inhibitory substance(s) by L. oenos. This antagonism was not permanent since most strains of P. parvulus eventually entered logarithmic phase of growth. Changes in pH, titratable and volatile acidities, or acetoin (plus diacetyl) were not evident in MLF (+) Merlot wines. Comparison of the bouquet characteristics of wines, with and without the growth of P. parvulus WS-29A, indicated significant differences (p = 0.03) in the MLF (-) but not the MLF (+) Cabernet Sauvignon wines.