The world's four largest grain traders, responsible for the vast majority of global corn, soya and wheat trading and processing, have been accused of large-scale tax evasion in a landmark series of cases being brought against them by the Argentinian government. Ricardo Echegaray, the head of Afip, the country's revenue and customs service, has given a detailed account of the charges his department is bringing against ADM, Bunge, Cargill and Dreyfus. These companies have gone into criminality," Echegaray said. "2008 was when agricultural commodities prices spiked and was the best year for them in prices, yet we could see that the companies with the biggest sales showed very little profit in this country." Afip is seeking to claim $476m (290m) for what it says are unpaid tax and duties from Bunge, $252m from Cargill and $140m from Dreyfus. With the global food system and who controls it under intense scrutiny in recent weeks, thanks to record prices, the legal battle between Afip and the "ABCD four", as they are known, has taken on heightened significance. Oxfam, in a report earlier this week, warned of spiralling prices and a huge increase in global hunger over the next two decades, and said that corporate concentration in the global food trade was a structural flaw in the system.