I believe the trick for pasturized beer is not to keep it cold, but to regulate the fluctuation of its temperature. Insulated boxcars (and tank cars, if Coors is an example) do the trick. But I'm grasping at straws, and I'm sure Dave can edumicate me on what they did in Milwaukee with all those reefers.
As for meat, there's different needs for meat products (like sausage and canned meats) and whole meats, like beef and hog sides. Same for produce, potatoes and oranges have mucho different needs.