FANCY FOOD SHOW: Bionade Sets US Entry via Spaten Beer Net; Building Iowa Plant    Bionade, fermented soda devised by family-owned brewery in Germany that vaulted into #3 soft drink spot in there last yr, behind only Coke and Pepsi, is ready to attack US market this spring via Spaten beer importers.  In audacious move, co even has partnered with German food co to establish multi-million-dollar organic farm and bottling plant in Iowa from which to source N Amer products.  Sleek pack, unusual formulation and rocket ride in Europe meant that Bionade captured considerable buzz at this wk’s Fancy Food Show in San Diego, with sample bottles spotted stashed at quite a few other exhibitors’ booths.