Thats interesting regarding the olive oil and the bottle. I buy ASDA (UK ssupermarket) organic extra virgin olive oil and it comes in a white glass bottle. I only buy that because none of the other brands in the superstore are organic, however some of the Italian brands are in a brown bottle.
I now know it was not the olive oil as Ive used that with tuna in springwater without any negative effects. I will try a tin of tuna in sunflower oil in a few days to see if that was the problem.