Isolation of bacteriophages from must and wine for the elimination of contaminating bacteria as an alternative to the use of sulfurous

Abstract

Acetic and some lactic acid bacteria are the main reason for the loss of quality of musts and wines, giving rise to defects such as "vinegary", "chopped" or preventing alcoholic and / or malolactic fermentation. The solution to this problem consists in the application of authorized bactericidal agents, such as sulfurous. The aim of this work is to isolate bacteriophages from musts and wines of different grape varieties, able to eliminate lactic and acetic acid bacteria spoilages. Musts obtained from grape-berries of Vitis vinifera cv. Chardonnay and Moscatel and a red wine made with the Tintilla de Rota variety were used to isolate bacteriophages. It were isolated by classical virology methods and identified by electron microscopy. Host bacteria used in the study were the lactic acid bacteria of the species Lactobacillus hilgardii, L. plantarum and Oenococcus oeni and the acetic bacteria Acetobacter aceti. A comparative study was performed on musts and wines, previously inoculated with bacteria, by phage titration and SO2 addition to study the effectiveness of bacteriophages against bacteria. Bacteriophages were obtained from all musts and wine, belonging to the order of Caudovirals and Tectivirals. The comparative study showed that a cocktail of bacteriophages at low concentration is as effective as sulfur.