Overview
ISO 1841-2:1996 specifies a potentiometric method for determining the total chloride content of meat and meat products (including poultry) where sodium chloride is ≥ 0.25% (m/m). The standard describes sample preparation, required reagents and apparatus, titration procedure using a silver electrode, calculation of chloride expressed as sodium chloride (% m/m), and reporting requirements. Precision was established by an interlaboratory study in accordance with ISO 5725.
Key topics and requirements
- Scope: Applicable to meat and meat products with NaCl ≥ 0.25% (m/m).
- Principle: Dispersion of a homogenized test portion in water, acidification, and potentiometric titration with standard silver nitrate using a silver electrode to detect the endpoint.
- Reagents (examples given in the standard):
- Distilled, halogen-free water
- Nitric acid (1 + 49 V/V)
- Silver nitrate standard volumetric solution c(AgNO3) = 0.0856 mol · L−1
- Sodium chloride standard volumetric solution c(NaCl) = 0.0856 mol · L−1
- Apparatus: Homogenizer/mincer, laboratory blender, magnetic stirrer, silver (Ag) electrode or Ag/AgCl combination electrode, reference electrode, pH/mV meter, pipettes and analytical balance.
- Procedure highlights:
- Homogenize representative sample (laboratory sample ≥ 200 g recommended).
- Blend sample with water, pipette aliquot, add dilute nitric acid, titrate with AgNO3 while recording potential to build a titration curve.
- Determine endpoint by finding the inflection point (intersection of tangents at points of greatest curvature) on the potentiometric titration curve.
- Run a blank and calculate chloride content expressed as NaCl % (m/m). Report results to the nearest 0.1% (m/m).
- Precision: Repeatability and reproducibility limits are given in the standard, based on an interlaboratory collaborative study (ISO 5725).
Applications and who uses it
- Food testing laboratories: Routine quantitative analysis of chloride/salt in meat products for compliance and labeling.
- Meat processors and QC teams: Monitoring product formulation, process control, and verification of sodium-reduction efforts.
- Regulatory and inspection bodies: Enforcement of composition and labeling regulations.
- Research and development: Evaluating effects of salt on product quality, safety, and shelf-life.
Practical benefits include accurate salt quantification for nutrition labeling, quality control, and consistency across product batches.
Related standards
- ISO 1841-1: Meat and meat products - Determination of chloride content - Part 1: Volhard method
- ISO 3100-1: Sampling and preparation of test samples (sampling guidance referenced)
- ISO 5725: Precision of measurement methods - determination of repeatability and reproducibility
- Codex and FAO/WHO working documents referenced in Annex A
Keywords: ISO 1841-2:1996, potentiometric method, chloride determination, meat testing, silver nitrate titration, sodium chloride content, food laboratory, analytical method.
Open preview (PDF)Meat and meat products — Determination of chloride content — Part 2: Potentiometric method