Rapid detection of acetic acid bacteria in the traditional pot-fermented rice vinegar Kurozu

Abstract

Knowledge of the microbial population, particularly that of acetic acid bacteria (AAB), present during the fermentation process is required to produce good quality traditional rice vinegar (Kurozu). We focused on the internal transcribed spacer (ITS) region between the 16S and 23S rRNA genes of AAB for easy and rapid detection of AAB from Kurozu. Five PCR primer sets were designed to amplify the five specific DNA fragments within the ITS region of AAB. PCR amplification with these primer sets resulted in the detection of specific fragments from AAB chromosomal DNA, but not from other bacteria or yeast. Use of a DNA sample directly isolated from Kurozu mash as a template gave the same distinct PCR fragment pattern with these primer sets. This one-step PCR analysis is an easy tool for rapid detection of AAB during the long process of Kurozu fermentation and maturation.