Each bottle of Yakult contains 6.5 billion live Lactobacillus casei Shirota strain This probiotic/beneficial bacterium was named after Dr Shirota who first discovered this unique strain in 1930. The beneficial bacteria strain in Yakult is scientifically proven to survive the journey through the gastric juices to reach the small intestine alive. Each 65ml bottle contains 6.5 billion of these highly acid resistant bacteria, exclusive to Yakult. This means that every millilitre of Yakult contains 100 million (100, 000, 000) of the live Lactobacillus casei Shirota strain!