ISO 6736-1982 PDF

Full title and description

ISO 6736:1982 — Dried milk — Determination of nitrate and nitrite contents — Method by cadmium reduction and photometry. This International Standard specifies a laboratory method for measuring nitrate and nitrite in dried milk (whole, partly skimmed and skimmed) using copperized cadmium reduction followed by photometric detection.

Abstract

The standard describes dissolving dried milk in water, precipitating fat and proteins, filtering the extract and reducing nitrate to nitrite with copperized cadmium; nitrite is then determined photometrically. The method includes preparation and checking of the cadmium reduction column and references sampling procedures (ISO 707). It was intended for routine analysis of dried milk powders.

General information

• Status: Withdrawn.
• Publication date: December 1982.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 67.100.10 (milk and milk products — specific methods).
• Edition / version: Edition 1 (1982).
• Number of pages: 6 pages.

Scope

Applies to the determination of nitrate and nitrite in dried milk powders (whole, partly skimmed and skimmed). The procedure covers sample preparation (dissolution, precipitation of fat/proteins), filtration, reduction of nitrate to nitrite using a copperized cadmium column and photometric measurement of nitrite. Sampling is to be carried out as specified in ISO 707 (guidance on sampling of milk and milk products).

Key topics and requirements

• Sample dissolution and clarification: dissolve dried milk, precipitate fats and proteins, and filter the extract.
• Reduction step: use a copperized cadmium column to reduce nitrate to nitrite.
• Detection: photometric (molecular absorption) measurement of nitrite after Griess-type reaction or equivalent photometric procedure.
• Apparatus and column preparation/verification: instructions for preparing, checking and regenerating the cadmium reduction column are included.
• Performance characteristics and applicability notes: limits of detection, potential interferences and suitability for different dairy matrices are addressed in related ISO dairy nitrate/nitrite methods.

Typical use and users

Used by food and dairy analytical laboratories, quality control teams in dairy processing, regulatory and inspection bodies, and research groups studying nitrate/nitrite levels in dairy powders. The method was intended for routine monitoring of dried milk to ensure compliance with safety and labeling requirements.

Related standards

This method and related dairy nitrate/nitrite methods were later consolidated and updated in the ISO 14673 series (Parts 1–3), with ISO 14673-1:2004 (cadmium reduction and spectrometry) representing a current consolidated method as of the 2004 edition. Other related documents include ISO 4099 (cheese), ISO 6739 (whey cheese) and ISO 6740 (dried whey) — all dealing with nitrate/nitrite determination in specific dairy matrices — and ISO 707 (guidance on sampling).

Keywords

dried milk; milk powder; nitrate; nitrite; cadmium reduction; copperized cadmium column; photometry; spectrometry; dairy analysis; ISO 6736.

FAQ

Q: What is this standard?

A: ISO 6736:1982 is an ISO International Standard that specified a laboratory method for the determination of nitrate and nitrite in dried milk by cadmium reduction and photometry.

Q: What does it cover?

A: It covers sample dissolution and clarification, reduction of nitrate to nitrite using a copperized cadmium column, and photometric measurement of nitrite, including column preparation and verification; sampling is referenced to ISO 707.

Q: Who typically uses it?

A: Analytical and quality-control laboratories in the dairy industry, regulatory testing laboratories, and researchers working on nitrate/nitrite in dairy products.

Q: Is it current or superseded?

A: ISO 6736:1982 has been withdrawn. Its subject matter was consolidated into later standards in the ISO 14673 series (notably ISO 14673‑1/2/3, with ISO 14673‑1:2004 providing an updated cadmium-reduction method). Users should refer to the ISO 14673 series (and current national/adopted versions) for the up-to-date procedures.

Q: Is it part of a series?

A: Yes — the method family for nitrate/nitrite determination in dairy products includes multiple ISO standards for different matrices (cheese, whey, dried whey, etc.) which were later harmonized into the ISO 14673 series.

Q: What are the key keywords?

A: Dried milk, milk powder, nitrate, nitrite, cadmium reduction, copperized cadmium column, photometry, spectrometry, dairy testing, ISO 6736.