Effect of temperature and water activity on the interaction of a strain of Metschnikowia pulcherrima with Alternaria alternata.

ANTONELLA STOCCO; MARIANO DIAZ; CECILIA ROJO; LAURA MERCADO; LORENA PONSONE

San Carlos de Bariloche

Simposio; 34 International Specialized Symposium of Yeasts (34 ISSY); 2018

The presence of Alternaria spp, mainly A. alternata, has been observed duringpostharvest in table grapes cv. Red Globe from Mendoza, Argentina. One of thestrategies to reduce postharvest losses and the use of SO2 could be to use biological control agents during this stage. Epiphytic yeasts were isolated from grapes harvested in Argentinean vineyards. The strains were identified by molecular methods. The effect of a strain of Metschnikowia pulcherrima on lag phase and growth rate of Alternaria alternata was evaluated in a 3% must agar based medium under different conditions of water activity (0.88, 0.991 and 0.995 aW) and temperature (0, 4, 15 and 28 °C), these conditions were selected considering the water activity of grapes during the maturation stages and the range of temperature during phenological cycle and postharvest of table grapes. The growth rate and the lag phase were influenced by all the interactionsevaluated (p< 0,05). Studies are in progress to evaluate these strains in vivo under postharvest conditions.