ISO 3595-1976 PDF

Full title and description

St ISO 3595-1976 — Milk fat — Detection of vegetable fat by the phytosteryl acetate test. This International Standard specifies a laboratory test for detecting the presence of vegetable fat in milk fat by converting sterols to steryl acetates and examining their melting point and crystal form after acetylation and saponification.

Abstract

ISO 3595:1976 defines a chemical/microscopic procedure based on saponification of the fat, precipitation of sterols as steryl digitonides, acetylation to phytosteryl (steryl) acetates, determination of the melting point of the steryl acetates and microscopic examination of crystal form following reconversion to sterols. The method is intended to indicate the presence of vegetable-derived sterols (phytosterols) in milk fat.

General information

• Status: Withdrawn.
• Publication date: December 1976 (edition 1).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 67.100.10 (Milk and processed milk products).
• Edition / version: Edition 1 (1976).
• Number of pages: 5 pages.

Core bibliographic and lifecycle information as recorded by ISO.

Scope

The standard applies to laboratory detection of vegetable fat adulteration in milk fat by chemical conversion and microscopic/thermal examination of sterol derivatives. It is a qualitative detection method intended for routine laboratory screening rather than quantitative determination; it complements reference methods (for example, gas–liquid chromatography of sterols). The standard text describes sample preparation, reagents, preparation of steryl digitonides, acetylation, melting-point determination and microscopic examination steps.

Key topics and requirements

• Preparation of steryl digitonides from the fat sample (saponification and precipitation).
• Acetylation of steryl digitonides to generate steryl (phytosteryl) acetates.
• Determination of melting point of steryl acetates as an indicator of phytosterol presence.
• Microscopic examination of crystals after saponification/reconversion to sterols to confirm crystal morphology consistent with vegetable sterols.
• Use as a screening/qualitative detection method to indicate presence of vegetable fat in milk fat; complementary to chromatographic reference methods.

Typical use and users

Food testing laboratories, dairy industry quality/control departments, regulatory food-control authorities and standards bodies use this type of method as a screening test for adulteration of milk fat by vegetable fats/oils. The procedure is suitable where quick laboratory screening is needed and may be followed up by chromatographic reference methods when confirmation or quantification is required.

Related standards

ISO 3595:1976 is related to other ISO/IDF/AOAC methods for detection of vegetable fat in milk fat, notably ISO 3594:1976 (Milk fat — Detection of vegetable fat by gas‑liquid chromatography of sterols, reference method). Both standards were issued in 1976 and have subsequently been withdrawn; the chromatographic method has historically been treated as a reference/confirmatory technique to complement phytosteryl-acetate screening. Additional related methods and later techniques for fatty‑acid/sterol analysis are available in subsequent standards and analytical literature.

Keywords

milk fat; vegetable fat detection; phytosteryl acetate; steryl digitonide; sterols; saponification; melting point; microscopic examination; dairy analysis; adulteration screening.

FAQ

Q: What is this standard?

A: ISO 3595:1976 is an International Standard titled "Milk fat — Detection of vegetable fat by the phytosteryl acetate test" that specifies a laboratory screening test to detect vegetable fat in milk fat.

Q: What does it cover?

A: It covers a qualitative laboratory procedure based on conversion of sterols to steryl acetates, melting-point determination of those acetates, and microscopic examination of crystals after reconversion — all used to indicate the presence of phytosterols from vegetable fats in milk fat.

Q: Who typically uses it?

A: Food and dairy testing laboratories, quality control teams in the dairy industry, and food regulatory laboratories use this method for screening milk fat samples for vegetable‑fat adulteration; positive or ambiguous results are typically confirmed by chromatographic reference methods.

Q: Is it current or superseded?

A: ISO 3595:1976 is recorded as Withdrawn by ISO. It is not a current active ISO standard; complementary reference methods (for example ISO 3594:1976) and later analytical developments have been used historically, and laboratories now commonly rely on chromatographic and modern instrumental techniques for confirmation. Users should consult national or current international methods for up-to-date, validated procedures.

Q: Is it part of a series?

A: The document sits within ISO/TC 34/SC 5 (Milk and milk products) work and is historically linked with ISO 3594:1976 (the reference gas‑liquid chromatography method) and other standards on analysis of animal and vegetable fats and oils. It was issued alongside related dairy analysis standards in the 1970s.

Q: What are the key keywords?

A: Key keywords are milk fat, vegetable fat, phytosteryl acetate, sterols, adulteration detection, saponification, melting point, microscopy.