ISO 1739:2006 PDF

Overview

ISO 1739:2006 | IDF 7:2006 defines a reference method for determining the refractive index of fat extracted from butter. Developed by the International Organization for Standardization (ISO) in collaboration with the International Dairy Federation (IDF), this standard provides a precise laboratory procedure for assessing butter fat quality by measuring how light refracts through the melted butter fat.

The standard specifies requirements for sample preparation, equipment calibration, procedure, result interpretation, and reporting. Adhering to ISO 1739:2006 ensures consistency and reliability in butter fat analysis, which is critical for dairy quality control, product authentication, and regulatory compliance.

Key Topics

• Scope and Purpose The method applies to the refractive index determination of melted butter fat at a controlled temperature of 40 °C. This index reflects the fat's optical properties, which relate to composition and quality.

• Sample Preparation Butter samples are melted and clarified by standing at 50 °C to 60 °C, followed by filtration to eliminate impurities and water content that might interfere with refractive index measurements.

• Measurement Principle Using a calibrated refractometer equipped with a sodium vapor lamp light source, the refractive index is measured precisely. The refractometer temperature must be controlled to ±0.1 °C for accuracy.

• Result Correction and Reporting A correction factor is applied if the fat acidity is high (acid value ≥ 2), using methods from ISO 1740. Results are expressed as the mean of duplicate measurements, rounded to four decimal places, ensuring repeatability with a tolerance of 0.0002.

• Instrumentation Requirements The refractometer’s scale must be graduated to three decimal places, with prisms thermostatically maintained at 40 °C for stable conditions.

• Quality Assurance The standard emphasizes proper sampling (recommendation to use ISO 707), method calibration, and detailed test reporting for traceability and reproducibility.

Applications

• Dairy Industry Quality Control Producers and laboratories use this ISO method to monitor the quality and consistency of butter fat, ensuring product standards and consumer safety.

• Regulatory Compliance and Authentication The refractive index measurement helps in detecting adulteration or confirming the purity of butter fat in compliance with food safety regulations.

• Research and Development Scientists studying milk fat characteristics utilize the refractive index as a diagnostic tool in product formulation and processing optimization.

• International Trade Consistent application of this standard facilitates trade by providing a recognized analytical method acceptable across countries.

Related Standards

• ISO 1740: Milkfat products and butter - Determination of fat acidity (Reference method) Used alongside ISO 1739 to assess fat acidity, crucial for applying correction factors in refractive index results.

• ISO 707: Milk and milk products - Guidance on sampling Provides recommended sampling procedures to ensure representative butter samples for analysis.

• Additional ISO/IDF standards on milk and milk products, which complement the suite of methods for dairy product characterization and quality assurance.

By implementing ISO 1739:2006, laboratories and manufacturers benefit from a standardized, accurate approach to butter fat analysis, essential for maintaining high-quality dairy products and meeting global market expectations.