ISO 5061:1983

Animal feeding stuffs — Determination of castor oil seed husks — Microscopical method

The limit of detection is 5 mg/kg. The method consists in boiling a test portion successively with nitric acid solution and sodium hydroxide solution, washing and separation of the residue by decantation, drying, microscopical identification of fragments of oil seed husks and weighing. 7 figures show examples of the structure under low magnification.