yes, i don't see why you coulnd't. i mean you can ferment these SBO products. i have thought about adding some SBO's to my homemade kefir and seeing what happens. i think i will give it a try. although magnolia says that sometimes the different strains of bacteria cancel each other out, so you never really know lest you try. should be an interesting experiment anyway.
but the reason i am interested in the natto is that it costs $1.89!! i could keep that in the freezer and eat it when i am low on other forms of SBO's, ya know?