I will be staying in Tuscany - San Quirico - for the next month and would like to stock up with organic/natural foods. Goji berries, raw almonds, almond milk, fresh vegetables/fruits, quinoa, etc.. Something like one would find at a Whole Foods Market (obviously do not expect anything of that scale in the Italian countryside). Any suggestions would be greatly appreciated.
The Conad grocery chain operates on a cooperative business model, and has arguably the most established organic food retail market in central Italy. They are based in Bologna, and have stores in Florence and Perugia (113 km and 96 km from San Quirico respectively).
They offer a mobile app for ordering on-line and they may be able to special order any of the more exotic products you are searching for if it's not stocked locally.
You did not mention how you are reaching San Quirico, but you may find it more convenient to visit one of their outlets in Rome before setting off to Tuscany. You can contact them via their Facebook page or via the organic page on their main site.