Via mark bittman's blog Bitten, check out Food and Water Watch: Global Grocer. Local is good, but I don't think the Food and Water Watch approach in encouraging it is so hot: the problems with importing all our food are great; germs aren't one of them. For them, we could use more inspectors and lessons in hygiene. In fact, the germ problem is probably no greater on imported food than on local food. The real problems with food imported from Mexico center around the fact that the food Mexico exports grows on large factory farms that pollute with pesticides and herbicides, monocrop and degrade the soil, employ far fewer people than local, small farms, don't give much of the money they make back to local people, negatively affect the genetic diversity of crops, interfere with wildlife and bird migrations, contribute to desertification and deforestation and in other ways disrupt local environments, damage water supplies....you want more?*
This is an international problem. All you local-organic folk in the states, don't just turn inward!
*Same problems in the US.