Inactivation of L. fructivorans in Sake Using a Continuous Flow System for High-Pressure Carbonation

Abstract

The inactivation kinetics of lactic acid bacteria, Lactobacillus fructivorans, which is responsible for the deterioration of sake (Japanese rice wine) quality, was investigated using a continuous flow system for high-pressure carbonation. In addition, the effects of ethanol and sugar concentration on lactic acid bacteria inactivation were investigated. Cells of L. fructivorans (1×10⁶CFU/ml) were inactivated at a treatment temperature of 40°C and a pressure of 20MPa, with a residence time of 1.7min. The D-values (decimal reduction time) at 30 and 35°C were 4.3 and 0.6min, respectively. In addition to ethanol, glucose in sake also increased the inactivation efficiency of L. fructivorans by the carbonation treatment. These results suggest that the present technique is an effective microbial inactivation method for alcoholic beverages such as sake.