Overview
EN ISO 2450:2008 / ISO 2450:2008 specifies the reference gravimetric method for determining the fat content of cream (raw, processed and sour creams) where no appreciable fat separation or lipolytic breakdown has occurred. Known as the Röse‑Gottlieb principle, the method extracts fat from an ammoniacal ethanolic test portion using organic solvents, removes the solvents by distillation or evaporation, and determines the fat mass by weighing the residue.
Scope highlights
- Applicable to raw, processed and sour cream without significant fat separation or lipolysis.
- Not applicable to sour creams containing starch or other thickening agents.
- Published by CEN/ISO in collaboration with IDF; serves as a laboratory reference method for dairy analysis.
Key topics and technical requirements
- Principle: Extraction of fat with a mixed solvent (diethyl ether + light petroleum), removal of solvents and gravimetric determination of extracted substances.
- Reagents: Ammonia solution (approx. 25% NH3), high‑strength ethanol (≥94% v/v), diethyl ether (peroxide‑free), light petroleum (boiling range 30–60 °C) or pentane (≈36 °C), optional Congo red indicator.
- Apparatus: Analytical balance (mg precision), Mojonnier‑type fat extraction flasks or fat‑extraction tubes, centrifuge (500–600 min‑1 recommended), distillation/evaporation equipment.
- Quality controls: Blank tests to verify reagent purity and check for residues; adherence to safety precautions for flammable solvents (diethyl ether).
- Precision and reporting: Clauses on repeatability, reproducibility and required elements for the test report; optional alternative procedures for extraction tubes are provided in annexes.
Applications and users
- Who uses it: Dairy laboratories, quality control teams in cream and dairy product manufacturing, regulatory and inspection laboratories, research institutions and standards bodies.
- Practical uses: Routine and reference determination of fat percentage for product specification, label compliance, grading, process control, and inter‑laboratory comparisons. It is the benchmark method when accurate, traceable fat measurement in cream is required.
Related standards
- ISO 8262‑3 | IDF 124‑3 - alternative method (Weibull‑Berntrop) when fat separation or breakdown occurs.
- ISO 3889 - specification for Mojonnier‑type fat extraction flasks.
- ISO 835, ISO 1042, ISO 4788 - laboratory glassware standards referenced for pipettes, volumetric flasks and measuring cylinders.
Keywords: EN ISO 2450:2008, ISO 2450:2008, cream fat determination, gravimetric method, Röse‑Gottlieb, dairy testing, reference method, fat content analysis.
