Overview
EN ISO 11816-1:2024 - "Milk and milk products - Determination of alkaline phosphatase activity - Part 1: Fluorimetric method for milk and milk-based drinks" - is the latest (2024) CEN-endorsed edition of the international standard for measuring alkaline phosphatase (ALP, EC 3.1.3.1) in milk using a fluorimetric assay. It supersedes earlier editions and standardizes a fluorimetric procedure and associated quality checks for raw and heat-treated dairy liquids and reconstituted milk powder.
Key topics and requirements
- Scope and sample types: Applies to raw and heat-treated whole, semi‑skimmed, skimmed and flavoured milks, milk-based drinks from cow, sheep and goat, and reconstituted milk powder.
- Analytical method: Fluorimetric determination of ALP activity with instruments capable of reading up to 7 000 mU/l. If the sample exceeds this range, the standard requires dilution with ALP‑free milk to bring readings within range.
- Instrumentation: The standard reflects the transition from FLM200 to FLM300 (upgraded user interface/electronics); the assay chemistry and test procedure remain unchanged. The instrument now includes an integrated heater block.
- Quality controls and checks: Includes requirements for verification of instrument performance, daily instrument tests, reagent suitability controls, calibration procedures, and test‑sample related controls.
- Procedure and data handling: Covers sampling, reagent and apparatus requirements, sample preparation (including dilution), calibration ratio and calculation, expression of results, precision (interlaboratory study, repeatability, reproducibility), and the required content of the test report.
Applications
- Dairy quality control: Routine lab testing to quantify ALP activity as part of process control and product release.
- Heat treatment verification: Provides objective measurement of residual ALP to support verification of pasteurization and other heat processes.
- Regulatory and compliance testing: Used by conformity assessment bodies and official laboratories to demonstrate compliance with national/regional dairy safety criteria.
- Product development and troubleshooting: Useful for manufacturers assessing processing efficacy, ingredient compatibility, or effects of formulation on enzyme activity.
Who uses this standard
- Dairy industry QC/analytical laboratories
- Food safety and regulatory laboratories
- Milk processors and pasteurization facilities
- Instrument manufacturers and test-kit suppliers
- Standards bodies and accreditation laboratories
Related standards
- Other parts of the ISO 11816 / IDF 155 series (see ISO website for the complete list) cover complementary methods and details for alkaline phosphatase determination in dairy products.
Keywords: EN ISO 11816-1:2024, alkaline phosphatase, ALP activity, fluorimetric method, milk testing, dairy quality control, pasteurization verification, milk-based drinks, reconstituted milk powder.
