Global food companies are aggravating poverty in developing countries by dominating markets, buying up seed firms and forcing down prices for staple goods including tea, coffee, milk, bananas and wheat, according to a report to be launched today. Two companies dominate sales of half the world's bananas, three trade 85% of the world's tea, and one, Wal-mart, now controls 40% of Mexico's retail food sector. It also found that Monsanto controls 91% of the global GM seed market.