If it was made from grain harvested in the year or so after Fukushima, of course. Literally every plant grown downstream of the plume (it's not clear if North America is the only such region, just the first one across the ocean -- it's possible this is a global thing) is going to show the signature.

People are misunderstanding this. The point here isn't to point out a specific toxin in wine, it was to point out the pervasive reach of this isotope and its utility as a dating mechanism for long-stored agricultural products like wine.