Freezing does not help much with life that has any chance of surviving the yeast onslaught; the only thing it probably does - it slows cell development down to about same amount of time it takes dry yeast to wake up, thus with a starter you get more of head start for the good guys, and that’s all that you really need. Freezing also often results in better sugar availability, as some plants (well I suppose berries mostly) trigger sugar conversion on overwintering naturally. D47 is good for fruits, I maintain its descendant in a pure culture and it’s one of my favorites for mead.