The decentralized 19th-century agricultural model, in which farms and food production were integrated into communities, may be one ironically progressive solution to righting the wobbly petroleum-wheeled food cart. And if the peak-oil scenarios are right, and $300-a-barrel oil is in our imminent future, a 2,000-mile salad from the Salinas Valley of California will be considered a luxury food item, right up there with Perigord black truffles and foie gras. The environmental awakening of the past decade has been encouraging,   Doing Good by Doing Good in the Food Business