Dr. Kenneth M. Quinn, former U.S. Ambassador to the Kingdom of Cambodia, assumed the leadership of the World Food Prize Foundation on January 1, 2000, following his retirement from the State Department after a 32 year career in the Foreign Service.    THE WORLD FOOD PRIZE is the foremost international award recognizing -- without regard to race, religion, nationality, or political beliefs -- the achievements of individuals who have advanced human development by improving the quality, quantity or availability of food in the world. The Prize recognizes contributions in any field involved in the world food supply -- food and agriculture science and technology, manufacturing, marketing, nutrition, economics, poverty alleviation, political leadership and the social sciences.