An alternative is to buy locally produced food, which often is also organic. It may have a shorter shelf life, but it's sitting on your shelf most of that time, not on the shelf at the grocers waiting to be bought.
I guess it depends on where you live, but at my local farmers market there is a sizable percentage of the vendors that either meet the FDA organic standards or meet a fraction of them (no pesticides or no antibiotics). With respect to preservatives and flavor enhancers, I have no specific knowledge, but I would imagine that whatever are applied to local produce would necessarily be less than or equal to whatever is normally applied when something has to be shipped from across the world, absence of any evidence to the contrary.
Finally, with respect to your energy/environmental argument: I am not advocating buying local as a way to save on energy costs; I am advocating buying local as a way to get significantly fresher produce. With that said, even if buying local saves a single cent per pound of produce (not unreasonable [1] at current gas prices) that could be savings of upwards of $5.4B per year if every american shopped local ($0.01/lb * ~300 million amercians * ~1800 lbs of food consumed/american/year).
