Pesticides in fermentative processes of wine

The influence of six fungicides (azoxystrobin, cyprodinil, fludioxonil, mep anipyrim, pyrimethanil, and tetraconazole) on the fermentative activity of two yeasts (Saccharomyces cerevisiae and Kloeckera apiculata) and two lacti c bacteria (Leuconostoc oenos and Lactobacillus plantarum) was studied. The possibility of their being degraded by these yeasts and bacteria was also investigated. The presence of the pesticides did not affect alcoholic ferme ntation, not even with levels higher than those normally found in grapes in field experiments. On the contrary, their presence stimulated the yeast, e specially K. apiculata, to produce more alcohol. The fermentative process d id not affect the amount of pesticides either by degradation or by adsorpti on. During malolactic fermentation by Le. oenos, malic acid decreased sligh tly less (by similar to 15%) in the presence of all pesticides, except mepa nipyrim. A lower effect (similar to 5%) was found during the fermentative p rocess with La. plantarum. The bacteria studied did not show a degradative effect on pesticides during malolactic fermentation.