How much is a First Class stamp? rheumatoid arthritis methotrexate not working WELLINGTON/COLOMBO, Aug 11 (Reuters) - New Zealand-baseddairy giant Fonterra Co-operative Ltd said on Sunday ithad withdrawn milk powder under orders from the Sri Lankanauthorities for showing traces of the toxic agriculturalchemical dicyandiamide (DCD), although it disputed the accuracyof the testing.