Overview
EN ISO 13366-2:2006 - "Milk - Enumeration of somatic cells - Part 2" (ISO 13366-2:2006) gives guidance on the operation of fluoro-opto-electronic somatic cell counters. The standard covers operating conditions for counting somatic cells in both raw and chemically preserved milk using instruments that employ either a rotating disc technique or flow cytometry in the counting section. It is primarily applicable to raw cow milk, and can also be applied to goat, sheep and buffalo milk if the specified prerequisites are met.
Key topics and technical requirements
- Principle of operation: Overview of fluoro-opto-electronic counters - sample uptake, reagent mixing (buffer and fluorescent DNA stain), presentation to the counting plane, electronic pulse generation and discrimination between noise and stained somatic cells.
- Factors affecting results: Sample bottles, sampling procedures, preservation, storage and transport conditions, interfering substances, sample quality at analysis, applied chemicals, instrument condition, working factors and testing volumes.
- Calibration and reference materials: Guidance on calibration procedures and the use of reference materials in accordance with applicable ISO guidance.
- Performance checks and quality control: Routine checks such as blank checks, carry-over assessment, reagent/sample volume ratios, pilot checks, instrument surveillance, repeatability and intralaboratory reproducibility, and external comparisons.
- Species-specific remarks: Practical notes for working with cow, goat, sheep and buffalo milk, including prerequisites for accurate enumeration.
- Precision and reporting: Requirements for precision (repeatability, reproducibility) and recommended contents of the test report.
Applications and who should use this standard
- Dairy laboratories performing routine somatic cell counts for milk quality monitoring and regulatory compliance.
- Milk processors and quality control teams seeking consistent somatic cell measurement procedures to manage herd health and milk payment schemes.
- Instrument manufacturers and service engineers designing, commissioning or validating fluoro-opto-electronic counters (rotating disc or flow cytometry based).
- Regulatory bodies and auditors establishing method acceptance criteria for milk hygiene and safety programs.
- Researchers studying mastitis, milk quality trends, or comparative performance of automated somatic cell counting methods.
Using EN ISO 13366-2:2006 helps ensure reliable, reproducible somatic cell counts through standardized instrument operation, calibration, and quality control practices.
Related standards
- ISO 13366-1 (IDF 148-1): Microscopic method (reference method)
- ISO 8196-1 / IDF 128-1 and ISO 8196-2 / IDF 128-2: Indirect methods accuracy and calibration/QC
- ISO Guide 34, ISO Guide 43-1: Reference materials and proficiency testing
For consistent milk somatic cell analysis, combine the operational guidance of ISO 13366-2:2006 with the reference and QC methods cited above.
