If it makes you feel better, the food miles in canned foods is higher than you think. Raw material is mined in WA or South America. It's then shipped to Asia to be pressed into sheets, back to Australia to be made into cans, and then on to to wherever whatever is being produced is canned.

So the food miles on a can of Italian tomatoes can actually be less that the coutn for an Aussie product. But, yeah, I agree, tomatoes are pretty easy, although possums can be an issue in Melbs.