5 Strains. Acid Resistant Capsules. 20 Billion Per Capsule. Jarrow Formula Senior Jarro-Dophilus contains a high percentage of Bifidobacteria to help replenish the beneficial bacteria to compensate for their age-related decline in number and diversity. . The vegetarian acid resistant capsule helps maximize survival of viable probiotic bacteria while in transit through the stomach. . Each vegetarian capsule contains a minimum of 20 billion viable cells when kept refrigerated.