ISO 1841-2:1996

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.