ISO 7328-2008 PDF

Full title and description

ISO 7328:2008 (IDF 116:2008) — Milk‑based edible ices and ice mixes — Determination of fat content — Gravimetric method (reference method). This joint ISO/IDF standard specifies the Röse‑Gottlieb gravimetric reference procedure for measuring fat in most milk‑based edible ices, concentrated ice mixes and dried ice mixes.

Abstract

This standard defines a reference gravimetric (Röse‑Gottlieb) method for extraction and gravimetric determination of fat content in milk‑based ice cream products and mixes, includes requirements for reagents and apparatus, sample preparation, procedure, calculation, and precision (repeatability and reproducibility). It notes limitations where high levels of emulsifiers, stabilizers, egg yolk, fruit or certain combinations make the method unsuitable and points to alternative principles (e.g., Weibull‑Berntrop).

General information

• Status: Withdrawn (replaced by a later ISO/IDF standard).
• Publication date: 2008-10 (Edition 3, 2008).
• Publisher: International Organization for Standardization (ISO) in cooperation with the International Dairy Federation (IDF).
• ICS / categories: 67.100.40 — Ice cream and ice confectionery (food microbiology / dairy testing context).
• Edition / version: Edition 3 (2008).
• Number of pages: 15 pages (official English PDF length as published).

Scope

ISO 7328:2008 specifies the reference gravimetric method for determining fat content in most milk‑based edible ices and ice mixes, including concentrated and dried mixes. The method is intended as a reference procedure and is not applicable where product constituents (e.g., high levels of emulsifiers, stabilizers, thickeners, egg yolk or fruit) interfere with the Röse‑Gottlieb extraction; in such cases alternative methods are recommended.

Key topics and requirements

• Reference principle: Röse‑Gottlieb gravimetric extraction (ammonia/ethanol pre‑treatment followed by diethyl ether/petroleum ether extraction, solvent removal and weighing of extracted fat).
• Defined reagents and solvent purity requirements (e.g., hydroxyde of ammonium solution, ethanol, diethyl ether free of peroxides).
• Specified apparatus and preparation of fat‑collecting vessels and test portions.
• Procedures for sample preparation for edible ices, concentrated mixes and dried mixes, including blank tests.
• Calculation, expression of results and reporting requirements.
• Precision data: interlaboratory test results and stated repeatability and reproducibility performance.
• Limitations and guidance when the Röse‑Gottlieb method is unsuitable (references to alternative methods such as those based on the Weibull‑Berntrop principle / ISO 8262‑2).

Typical use and users

Analytical and quality control laboratories in the dairy and frozen‑dessert industry, national standards laboratories, regulatory authorities and test houses use this standard as a reference method for verification of declared fat content in ice cream and related products. It is also used during method validation, interlaboratory studies and in conformity assessment where a recognized reference procedure is required.

Related standards

ISO 7328:2008 was published as a joint ISO/IDF standard (IDF 116:2008) and has been withdrawn and replaced by ISO 23318 (IDF 249) — a broader gravimetric method for milk, dried milk products and cream (2022). Regional/EN versions (EN ISO 7328) and previous editions (ISO 7328:1999) are related. The standard also cross‑references alternative methods such as ISO 8262‑2 (Weibull‑Berntrop principle) for products unsuitable for Röse‑Gottlieb extraction.

Keywords

ice cream, edible ices, ice mixes, fat determination, gravimetric method, Röse‑Gottlieb, IDF 116, ISO 7328, dairy testing, analytical reference method.

FAQ

Q: What is this standard?

A: ISO 7328:2008 (IDF 116:2008) is a joint ISO/IDF reference standard specifying a gravimetric (Röse‑Gottlieb) method for determining fat content in milk‑based edible ices and ice mixes.

Q: What does it cover?

A: It covers reagents, apparatus, sampling and sample preparation, the extraction and gravimetric determination procedure, calculation and expression of results, precision data and limitations where the method is unsuitable.

Q: Who typically uses it?

A: Analytical and QC laboratories in the dairy and frozen‑dessert industry, national testing bodies, regulators and organizations conducting method validation or interlaboratory comparisons.

Q: Is it current or superseded?

A: ISO 7328:2008 has been withdrawn; it is superseded by ISO 23318 (IDF 249), published in 2022. Users should migrate to the later ISO/IDF standard for up‑to‑date reference procedures.

Q: Is it part of a series?

A: It is part of the family of ISO/IDF dairy analytical methods and relates to other fat‑determination standards (previously ISO 7328:1999 and related EN/ISO adoptions); it also cross‑references alternative extraction principles such as ISO 8262‑2 for specific product types.

Q: What are the key keywords?

A: ice cream, edible ices, fat content, gravimetric, Röse‑Gottlieb, milk‑based, IDF 116, analytical reference method.