A worker checks the temperature of pistachios as they are heated in preparation for final roasting and flavouring at a nut shop in Tehran September 29, 2008. Iran may this year see its position as the world's largest producer of pistachio nuts overtaken by the United States, as the Islamic Republic suffers one of its worst harvests ever. Picture taken September 29, 2008. To match feature IRAN-PISTACHIOS/ REUTERS/Caren Firouz (IRAN)