Overview
ISO 8851-3:2004 (also published as IDF 191-3:2004) defines the routine calculation of fat content in butter. Rather than prescribing a new analytical extraction, this part of the ISO/FIL series specifies the mathematical procedure to derive butter fat content by difference from the results of moisture and solids‑not‑fat (SNF) determinations performed according to ISO 8851-1 and ISO 8851-2.
Keywords: ISO 8851-3:2004, butter fat calculation, fat content by difference, routine methods, moisture, solids-not-fat, SNF.
Key topics and requirements
- Purpose: Calculation of butter fat content as a mass fraction expressed in percent by subtracting moisture and SNF from 100%.
- Core formula:
Fat (%) = 100.0% − (Water (%) + Solids‑not‑fat (%))
(Water and SNF values are obtained using ISO 8851-1 and ISO 8851-2 routine methods.)
- Measurement precision and expression:
- Input values: water and SNF reported to two decimal places.
- Final fat result: express with one decimal.
- Precision (from interlaboratory studies reported in Annex A):
- Repeatability (r): difference between two results in the same lab will exceed 0.35% in at most 5% of cases.
- Reproducibility (R): difference between different labs will exceed 0.54% in at most 5% of cases.
- Test report requirements: include full sample identification, sampling method (if known), reference to ISO 8851-3, any operational details or incidents, and the reported result(s) or verified final result.
Applications
- Routine laboratory determination of butter composition for:
- Quality control in dairy processing and butter manufacturing.
- Regulatory compliance and labeling (fat declaration).
- Incoming/outgoing goods verification and specification conformance.
- Useful for dairy testing laboratories, quality assurance teams, food regulators, and researchers needing a standardized, reproducible method to report butter fat content derived from moisture and SNF analyses.
- Integrates with routine moisture and SNF tests-facilitates streamlined workflows without requiring additional fat extraction procedures.
Related standards
- ISO 8851-1 / IDF 191-1 - Determination of moisture (routine methods)
- ISO 8851-2 / IDF 191-2 - Determination of solids‑not‑fat (SNF) (routine methods)
- ISO 707 - Sampling of milk and dairy products
- ISO 5725-1 and ISO 5725-2 - Accuracy (trueness and precision) of measurement methods
ISO 8851-3:2004 is a concise, practical standard focused on the calculation and reporting rules for butter fat content using established routine analyses, ensuring consistency and traceability across laboratories and the dairy industry.
Open preview (PDF)Butter — Determination of moisture, non-fat solids and fat contents (Routine methods) — Part 3: Calculation of fat content
