Food losses in sub-Saharan Africa could be greatly reduced and billions of dollars a year could be saved by tackling the problem of post-harvest waste, the UN\'s food agency said on Tuesday. \"Investing in post-harvest technologies to reduce food losses could significantly increase the food supply in sub-Saharan Africa,\" the Food and Agriculture Organisation said in a new report produced with the World Bank. The report, done in collaboration with Britain\'s Natural Resources Institute, estimates the value of post-harvest grain losses in sub-Saharan Africa to be around $4 billion (2.8 billion euros) a year. The estimated annual grain production is worth $27 billion, meaning $4 billion dollars would be a roughly 15-percent loss of output. \"This lost food could meet the minimum annual food requirements of at least 48 million people,\" FAO deputy chief Maria Helena Semedo said in the report. \"If we agree that sustainable agricultural systems need to be developed to feed 9 billion people by 2050, addressing waste across the entire food chain must be a critical pillar of future national food strategies,\" she added. In eastern and southern Africa alone, food losses are valued at $1.6 billion a year, or about 13.5 percent of the total value of grain production. \"Losses occur when grain decays or is infested by pests, fungi or microbes, and physical losses are only part of the equation,\" the report said. \"Losses can also be economic, resulting from low prices and lack of access to markets for poor quality grain, or nutritional, arising from poor quality or contaminated food.\" The Rome-based agency said such losses \"contribute to high food prices by removing part of the food supply from the market.\" It warned that they also have negative environmental impacts because \"land, water and non-renewable resources such as fertilizer and energy are used to produce, process, handle and transport food that no one consumes.\" The report suggested ways to reduce post-harvest losses, including crop protectants and storage containers, but said more research and piloting was needed to make sure steps taken were \"sensitive to local conditions.\" \"Technologies that have taken off in Asia, such as small-scale rice-drying technology and the introduction of pedal threshers and rice mills, have had successful adoption in some parts of Africa,\" FAO said. The report said governments could help tackle food losses by reducing market costs by investing in infrastructure such as roads, electricity and water.