Dr. Minoru Shirota


Yakult’s  probiotics, Lactobacillus casei strain Shirota were the discovery of our founder, Dr. Minoru Shirota.  In 1930, Dr. Shirota, a doctor from Kyoto Imperial University School of Medicine, succeeded in isolating and biotechnologically strengthening a Lactobacillus strain.  The fortified bacteria strain was later named after him as Lactobacillus casei strain Shirota.   The robust Lactobacillus casei strain Shirota shows good viability in the intestines by withstanding the gastric juice and bile and has excellent beneficial effects on the digestive tracts.

Dr. Shirota’s discovery, Lactobacillus casei strain Shirota was made into a cultured milk drink, Yakult in 1935 so that as many people as possible could enjoy its benefits.

Profile of Lactobacillus casei strain Shirota

  1. Name
    Lactobacillus   casei   strain  Shirota
    Genus species strain
  2. Morphology : Rod-shape gram-positive bacteria (bacilli)
    Length : 1 – 2 µm
    Width   : 0.4 – 0.8 µm      (1µm = 1/1,000 mm)

  3. Conditions for growth
    • Proliferate under both anaerobic and aerobic condition (facultative anaerobe)
    • Temperature 15 – 41ºC (optimum temperature : 37ºC)
    • Acid tolerant, and survive at about pH3
  4. Metabolites

    • Produce lactic acid from sugar.
    • Produce Vitamins B1, B2, B6 and B12.
    • Produce no harmful substances such as ammonia, hydrogen sulfide, indole, phenol and amines.


Strengthening of Lactobacillus casei strain Shirota


Beneficial effects of Lactobacillus casei strain Shirota are scientifically proven

The beneficial effects of Lactobacillus casei strain Shirota are scientifically proven which are:

  1. Modulation of Intestinal Condition:
    • Increase  the number of good bacteria in the intestines
    • Help to suppress the harmful bacteria
    • Help in digestion
    • Improvement of bowel movement
    • Help to maintain a healthy digestive system
  2. Risk Reduction of Carcinogenesis
  3. Help In the Maintenance of Immune Function