I think it will be ground water that contaminated some tomatoes, and they ended up in circulation. My best bet is Spain. or Cucumbers with the same deal. its a heavy water vegetable and common on salads, so they drink the contaminated ground water, grow with it INside the vege and even if you wash in bleach water, its on the INSIDE.

I am glad they cleared that farm in Germany. Scary stuff. Most organic places work very hard to be clean, and are cautious with how they treat their food.