What are your favorite tips for fresh-food storage on extended trips?

For extended trips (Pan-American, Trans-World, Cape Town to London) without a fridge/freezer, are there any tips for food provisions while traveling overland? Aside from canned goods, powdered milk, and trips to local markets for "fresh food" I'd love to hear what tricks your team has come up with over the years.

- B. Cooper, Austin, TX (via email)