Following the news earlier this week that the EU had discovered traces of banned antibiotics in some Thai food imports, shares in Thai food exporters have slumped. By the mid-session break today [Friday], shares in Charoen Pokphand Foods (CPF), Thailand's biggest chicken exporter, were down 1.5% to Bt6.4 (US$0.15), while GFPT had slipped 6.6% to Bt42.75.