Some manufacturers pasteurize their kombucha. In doing so, they will also kill off beneficial bacteria. They may supplement their pasteurized kombucha with probiotics, which may be claimed and noted on their labeling. Those bacteria strains are not a natural byproduct of the fermentation process.
Raw kombucha, on the other hand, is unpasteurized. This means you are getting a kombucha that is brewed using traditional methods closer to brewing techniques that go back hundreds of years. CCK does not pasteurize its kombucha and prefers to keep it in its live form.