Coke requires kola beans which do not grow in non-tropical environments, generally; however, some are cultivated in northern italy or southern germany, according to this map:
http://upload.wikimedia.org/wikipedi...lanutYield.png
Also note a crapton are grown in central southern California, but well enough away from LA that they might not be fallout contaminated.
What was the yield of weapons used on and around that region?
We can use nukemap to maybe determine what the crops would be like...
Also: I had a character (didn't get to play, unfortunately) among his treasures was a 12 pack of canned coke.