I don't know myself, but Dom recommended using fresh concord grape juice in a kefir drink on his site so maybe there is something to it? He said even the fussiest of tastebuds would drink kefir in grape juice. :) I tried some in some 100% white grape peach but neither my 14 month old daughter or my husband liked it---I thought it tasted good myself!

I've heard that grape seed extract (yes, grape not grapefruit) is antifungal and works well. Perhaps that is why grap juice is good. Maybe it would be good to try that instead of the grape juice first.

Susannah