ROME (AFP) - Food prices remain stubbornly high in the developing world despite a strong cereal harvest this year, and 31 countries need emergency aid, the UN food agency warned Tuesday. For the worlds poorest people who spend up to 80 percent of their household budgets on food, the food price crisis is not over yet, said Hafez Ghanem of the Food and Agriculture Organisation. Investment in agriculture in developing countries should be a global priority, the FAO assistant director general said in the Rome-based agencys latest Crop Prospects and Food Situation report. Although international food prices have fallen significantly since their peaks a couple of years ago, wheat and maize prices rose in October and rice export prices are still way above pre-crisis levels, the report said. The FAO is to host a summit on food security, dubbed the Hunger Summit, in Rome next Monday through Wednesday to focus on boosting public and private investment in agriculture as the key to fighting undernourishment. Eastern Africa is among the regions facing critical food insecurity, with drought and conflict putting some 20 million people in need of food aid, the report said.