OSLO, Feb 19 (Reuters) - The United Nations treated government ministers and officials to a meal of blemished African fruit and vegetables on Tuesday to highlight how perfectly edible food is being rejected by European supermarkets. The five-course meal for 500 delegates at a week-long United Nations Environment Programme (UNEP) event in the Kenyan capital included grilled sweet corn tamales, yellow lentil dal and mangomisu - a tropical version of the Italian dessert tiramisu.