Overview
EN ISO 6865:2000 defines a laboratory method for the determination of crude fibre in animal feedingstuffs using a procedure with intermediate filtration. The standard describes both a manual and a semi-automatic procedure and is applicable to samples with crude fibre content greater than 10 g/kg. It is also explicitly applicable to cereals and pulses. For feeds with crude fibre ≤ 10 g/kg, ISO 6541 is recommended.
The method is widely used in feed-testing laboratories for routine quality control and regulatory compliance because it provides a reproducible, traceable measurement of the insoluble cellulosic fraction after acid and alkali treatment.
Key Topics
- Scope and applicability: animal feedingstuffs, cereals and pulses; intended for samples with crude fibre > 10 g/kg.
- Principle: the test portion is subjected to boiling dilute sulfuric acid followed by boiling potassium hydroxide. Residues are separated by filtration, washed, dried and ashed; the mass loss on ashing corresponds to crude fibre content.
- Procedures: both manual and semi‑automatic workflows are provided to accommodate different laboratory capacities and equipment.
- Typical test steps:
- Grind and prepare representative test sample (passes 1 mm sieve).
- Weigh test portion (~1 g) and carry out acid digestion, intermediate filtration, and washing.
- Perform alkali digestion, second filtration and washing.
- Dry residue (oven, 130 °C), weigh, then ash (muffle furnace, about 500 ± 25 °C) and reweigh.
- Include blank determinations and, where needed, defatting or carbonate removal steps.
- Reagents & apparatus: dilute sulfuric acid and potassium hydroxide solutions, filter aids, filter crucibles, cold-extraction/solvent devices and muffle furnace; water for analytical laboratory use (ISO 3696) is specified.
- Quality control: blank tests, repeatability and reproducibility data are reported (Annex A) and should be considered in method validation.
Applications
- Routine quality control of animal feed and feed ingredients.
- Analytical testing of cereals and pulses for formulation and nutritional labelling.
- Regulatory compliance testing where standardised, interlaboratory-comparable crude fibre results are required.
- Laboratories using either manual workflows or semi-automated digestion/filtration systems seeking an ISO-aligned method.
Related Standards
- ISO 6541 - alternative method for crude fibre ≤ 10 g/kg.
- ISO 3696 - water quality for analytical laboratory use.
- ISO 6498 - preparation of test samples of animal feedingstuffs.
- ISO 5725 - guidance on precision of methods (interlaboratory tests).
This concise summary highlights practical value: EN ISO 6865:2000 offers a reproducible, documented procedure suitable for feed testing laboratories that need consistent crude fibre measurements using intermediate filtration in manual or semi-automatic setups.