FIL-IDF and the International Organization for Standardization (ISO) have jointly published ISO 9877 | IDF 258, a new international standard for the determination of ash content in milk and milk products.
This first edition, published in 2026, provides a precise and harmonised analytical methodology, applicable to a wide range of dairy products, including:
- Milk and milk powder
- Whey powder and whey protein concentrate
- Infant formula
- Milk permeate powder
- Milk protein concentrate
The standard specifies an incineration method for determining ash content, supporting consistent measurement and reporting across laboratories worldwide. It is intended for use by laboratories, regulators, industry and other stakeholders involved in dairy analysis and quality control.
Supporting global alignment and trade
ISO 9877 | IDF 258 was developed through close collaboration between the IDF Standing Committee on Analytical Methods for Composition and ISO/TC 34/SC 5 “Milk and Milk Products”. It reflects the shared commitment of IDF and ISO to align analytical methods and sampling practices globally, supporting consistency, reliability and international trade in dairy products.
Note: For the determination of ash (“fixed ash”) in caseins and caseinates, ISO 5544 | IDF 89 remains the applicable reference method.















