Overview
ISO 6734:2010 (IDF 15:2010) is the reference method for determining the total solids content of sweetened condensed milk. Published jointly by ISO and the International Dairy Federation (IDF), this standard defines a validated laboratory procedure used in quality control, product specification and regulatory testing of sweetened condensed milk and similar dairy products.
Key topics and technical requirements
- Principle: A measured test portion is pre-dried on a boiling-water or steam bath, then the remaining moisture is evaporated in the presence of sand in a ventilated oven. The loss of mass is used to calculate total solids (expressed as % by mass).
- Critical conditions:
- Drying oven temperature: 102 °C ± 2 °C (throughout the working space).
- Sand particle size: passes 500 µm sieve, retained by 180 µm sieve; sand must pass a suitability test (mass stability after drying and moistening).
- Dish dimensions: flat-bottom dishes, height 20–25 mm, diameter 50–75 mm, with well-fitting lids.
- Apparatus & materials: analytical balance, desiccator with fresh desiccant, boiling/steam bath, water bath (30–40 °C), quartz or sea sand, glass stirring rods.
- Sample handling: Thorough homogenization of the product, controlled warming (30–40 °C) and cooling prior to testing to ensure representative sampling and accurate results.
- Precision:
- Repeatability: difference between two single results by one operator typically ≤ 0.4 g total solids per 100 g (95% probability level).
- Reproducibility: difference between two independent laboratories typically ≤ 0.6 g total solids per 100 g (95% probability level).
- Reporting: Test report must identify the sample, reference ISO 6734:2010, provide operating details, and include the test result and any repeatability checks.
Applications and users
ISO 6734:2010 is intended for:
- Dairy laboratory analysts conducting total solids testing for sweetened condensed milk.
- Quality assurance and QC teams in dairy manufacturing to verify product composition and consistency.
- Regulatory bodies and inspection agencies that require a standardized, traceable reference method.
- Research institutions and inter-laboratory studies validating analytical performance.
Practical benefits include comparable, traceable results across laboratories, compliance with product specifications, and reliable basis for shelf-life and formulation decisions.
Related standards
- ISO 707 | IDF 50 - guidance on sampling of milk and milk products (recommended sampling method).
- ISO 5725 - precision of test methods (determination of repeatability and reproducibility), cited for precision statistics used in ISO 6734.
Keywords: ISO 6734, sweetened condensed milk, total solids content, reference method, dairy testing, milk products analysis, laboratory standard, IDF 15.