Overview
ISO 5553:2024 - Meat and meat products - Detection of condensed phosphates specifies a laboratory method for detecting linear condensed phosphates added to meat and meat products using thin‑layer chromatography (TLC). The method targets condensed phosphates that are still present in the sample at analysis time (they can be gradually hydrolyzed by meat enzymes or heat). This second edition updates reagents, sampling guidance, limit of detection and validation information.
Key topics and technical requirements
- Scope: Detection of added linear condensed phosphates (not applicable to completely hydrolyzed residues).
- Principle: Extraction with trichloroacetic acid, serum clarification (ethanol/diethyl ether), TLC separation on cellulose plates and colour development with two spray reagents.
- Sample requirements: Start from a representative sample (recommendation: ≥200 g received; homogenize and analyse promptly - serum prep from 50 g test portion).
- Reagents & apparatus: Lists analytical‑grade reagents (trichloroacetic acid, ammonium molybdate, 1‑amino‑2‑naphthol‑4‑sulphonic acid, developing solvent) and TLC equipment (cellulose plates, spreading device, developing tank, pipettes, oven).
- Procedure highlights:
- Prepare cellulose TLC plates (or use ready‑made).
- Apply serum and a reference mixture (orthophosphate, diphosphate, triphosphate, hexametaphosphate) to the plate.
- Develop with a specified isopropyl alcohol / trichloroacetic acid / ammonium hydroxide solvent.
- Detect with Spray Reagent I (yellow spots) and optionally Spray Reagent II (intense blue spots) for improved detection.
- Limit of detection (LOD): 0.5 g/kg for orthophosphate, diphosphate, triphosphate and hexametaphosphate.
- Validation: Contains interlaboratory test data; includes repeatability and reproducibility guidance and Rf (R) reference ranges for the reference mixture.
Applications and users
- Food testing laboratories performing food safety and quality control analysis for meat products.
- Regulatory authorities and inspection bodies verifying compliance with labeling and additive use rules.
- Meat processors and quality assurance teams monitoring process control, ingredient addition and traceability.
- Research laboratories studying phosphate degradation/hydrolysis in meat matrices.
Related standards
- ISO 3696 - Water for analytical laboratory use (referenced for water quality).
- CAC/GL 50‑2004 - Recommended sampling method for foods (sampling guidance mentioned).
Keywords: ISO 5553:2024, condensed phosphates, meat testing, thin layer chromatography, TLC, limit of detection, food quality control, phosphate detection, analytical method.