Overview
EN ISO 11816-2:2024 - Milk and milk products: Determination of alkaline phosphatase activity, Part 2 (Fluorimetric method for cheese) is a CEN-endorsed ISO/IDF standard that specifies a fluorimetric analytical method to measure alkaline phosphatase (ALP) activity in cheese. Published in 2024, this third edition updates and replaces the 2016 version and aligns instrument instructions with the newer FLM300 fluorimeter (the FLM200 has been discontinued). The method is intended for quality control and verification of processing in soft, semi‑hard and hard cheeses, with specific sampling rules for large hard cheeses and exclusions for cheeses with internal mould (e.g., blue‑veined types).
Key topics and technical requirements
- Scope and applicability: Fluorimetric determination of ALP activity in cheese; applicable when mould is surface‑only.
- Instrument capability: Supernatant ALP readings up to 7 000 mU/kg. FLM300 instrument and heater block are referenced for operation.
- Method content:
- Principle of the fluorimetric assay and required reagents and apparatus
- Sampling requirements (Clause 7) and test‑sample preparation (Annex B examples)
- Verification of instrument performance, daily checks and calibration procedures
- Determination steps and calculation (including calibration ratio and result expression)
- Controls: reagent controls, negative/positive controls, interfering‑substance and heat‑stable microbial ALP control tests
- Reporting requirements and precision data (interlaboratory study, repeatability, reproducibility)
- Validation and quality assurance: Includes procedures for calibration, control testing and performance verification to ensure reproducible results across laboratories.
Applications and users
Who uses EN ISO 11816-2:2024:
- Dairy quality control laboratories and cheese manufacturers performing in‑house testing
- Food safety and regulatory agencies assessing pasteurization indicators and product compliance
- Third‑party testing labs and proficiency testing organizers
- Instrument and reagent suppliers developing fluorimetric ALP test systems
Practical uses:
- Monitoring residual ALP activity as an indicator of milk heat treatment and process control in cheese production
- Routine QC testing to detect processing deviations or contamination with microbial ALP
- Supporting HACCP, validation and product release protocols in dairy operations
Related standards
- EN ISO 11816 series (other parts covering ALP determination methods and sampling guidance)
- Supersedes EN ISO 11816-2:2016 (this edition updates instrument guidance and user interface for FLM300)
Keywords: EN ISO 11816-2:2024, alkaline phosphatase, ALP activity, fluorimetric method, cheese testing, dairy quality control, FLM300, milk and milk products.
