oh yes, powder if fine, I just don't like the way it can get up the nose. ;)
Eat as many different sources of fermented foods as you can. Primal defense is expensive, and really you only need it like once a year for "housekeeping" purposes. Primal Defense is made up of soil based organisms, these are not the residents but the visitors that aid the residents.
For resident microbes you need to eat things like fermented veggies, chutneys, kefir, yogurt. You can buy your own kefir grains and make your own kefir in fact. The Body Ecology Diet book and webpage, and the Nourishing Traditions book, has info on how to ferment things.