Probiotics, like in Microflora, are live microorganisms in a dormant state. As soon as they come in contact with moisture (even from the air), they come to life. They are packed as capsules and sealed, so they never come into contact with water before your pet’s stomach because once they do, they have a limited lifespan- 2 weeks, to be exact.
Keeping them dormant until they’re ready to be used ensures that the dosage and potency are uniform. If they aren’t packed and sealed, there is a real chance that those beneficial bacteria will be spent before your pup even has a chance to benefit from them.