ISO 5061:2002

Overview

ISO 5061:2002 - Animal feeding stuffs: Determination of castor oil seed husks - Microscope method describes a standardized laboratory procedure to detect and quantify fragments of castor oil seed (Ricinus communis) husks in single and compound animal feeding stuffs, with particular emphasis on oilseed residues. The method combines chemical digestion, physical separation and final microscopical identification. The reported limit of detection is 5 mg/kg. Final identification requires an experienced specialist in microscopic techniques.

Key topics and technical requirements

• Scope: Identification and quantification of castor oil seed husks in feed matrices.
• Detection limit: 5 mg/kg.
• Principle: Successive boiling of a test portion with dilute nitric acid and sodium hydroxide to remove organic matrix, followed by decantation, filtration and microscopical identification of husk fragments.
• Sample size and repetitions: Typical test portion ≈ 100 g; perform three determinations and report the arithmetic mean.
• Separation and equipment:
  • Nylon gauze (100 µm mesh) resistant to dilute acids/alkalis.
  • Sieve (3 mm), stereomicroscope/binocular lens for low‑magnification sorting (×5–×50) and higher‑power microscope for final identification.
  • Oven (103 °C ± 2 °C) for drying, analytical balance for weighing.
• Result calculation: Result expressed in mg/kg with a correction factor (1.3) to account for estimated losses during analysis. Report to nearest unit and include full test details.
• Personnel requirement: The final microscopical identification phase requires a specialist experienced in identifying Ricinus communis testa/husk anatomy.

Applications

• Routine quality control in feed manufacturing to detect contamination by castor seed husks.
• Verification and compliance testing for feed safety and regulatory monitoring.
• Investigation of oilseed residues or mixed feedstuffs suspected of containing castor husk contaminants.
• Forensic or investigational laboratory work where accurate microscopical identification of plant husks is required.

Who uses this standard

• Feed testing laboratories and accredited analytical facilities.
• Feed manufacturers and quality assurance teams.
• Regulatory authorities and inspection bodies monitoring feed safety.
• Agricultural labs and researchers studying oilseed by‑products.

Related standards

• ISO 6497 - Animal feeding stuffs - Sampling (recommended sampling method referenced by ISO 5061).
• Prepared by ISO/TC 34/SC 10 (Food products - Animal feeding stuffs).

Keywords: ISO 5061:2002, castor oil seed husks, Ricinus communis, animal feeding stuffs, microscope method, detection limit 5 mg/kg, microscopical identification, feed testing.