UNITED NATIONS : The United Nations has reported a climb in global food prices after experiencing a decline over the past three months.The FAO monthly Food Price Index rose six per cent in July, mostly driven by a surge in grain and sugar prices, and averaged 213 points, up 12 points from June. The index measures the monthly change in international prices of a basket of 55 food commodities, including meat, dairy, sugar, and cereals. According to FAO, which is based in Rome, the severe deterioration of maize crop prospects in the United States, following extensive drought damage, pushed up maize prices by 23pc in July.