DETERMINATION OF SUBSPECIES OF LACTOCOCCUS LACTIS

摘要

PROBLEM TO BE SOLVED: To accurately, rapidly and simply determine the subject subspecies of lactic acid bacterium in order to obtain a lactic acid fermentation product such as cheese having good flavor by examining whetherγ-aminolactic acid is present or not in a cultured product of Lactococcus lactis which is a lactic acid bacterium. SOLUTION: Lactococcus lactis which is a lactic acid bacterium is cultured at 30 deg.C for 4 day in a nonfat milk culture medium and 30% trichloroacetic acid is added to the cultured product and the solution is centrifuged at 3,000 rpm for 20 min to provide supernatant and 0.1 N hydrochloric acid is added thereto and the mixture is filtered and analysis ofγ-aminolactic acid amount in the resultant filtrate is carried out and whetherγ-aminolactic acid is present or not in the cultured product is examined to determine whether the subsp. of Lactococcus lactis is Lactococcus lactis subsp. Lactis havingγ-aminolactic acid-producing ability or Lactococcus lactis subsp. cremoris having noγ- aminolactic acid-producing ability.