Overview
ISO 24223:2021 - Cheese - Guidance on sample preparation for physical and chemical testing provides practical guidance for preparing cheese samples (fresh, (semi)soft, (semi)hard, processed and whey cheese) for laboratory analysis. It covers the steps taken after sampling according to ISO 707 | IDF 50 and before method‑specific analytical procedures, including instrumental analysis. The standard emphasizes representative subsampling, contamination avoidance and preservation of analytes (noting that volatile substances, minor components or allergens may require extra precautions).
Key topics and requirements
- Scope & purpose: Guidance for sample preparation for physical and chemical testing of various cheese types, ensuring samples are representative and suitable for subsequent analytical methods.
- Sample receipt and commingling: Options to individually prepare partial samples or commingle and thoroughly mix before grinding/blending.
- Cheese‑specific pre‑preparation:
- Cheese in liquid (brine, oil, governing liquid): drain via sieve; brined cheese-place on absorbent paper or sieve 20–30 s at 18–22 °C; cheese in oil-drain 3–5 min and dab excess oil.
- Blue‑veined and cheeses with inclusions: take complete angular slices to reflect distribution of moulds or additives.
- Fresh cheeses with whey separation: thoroughly mix curd and whey before preparation.
- Removal of non‑edible or non‑target parts: Remove coatings, rinds or non‑edible parts as normally discarded before consumption; retain edible outer layers when relevant.
- Cutting, grinding and blending:
- Use clean, dry tools that do not alter sample composition (knives, peeling devices, grinders, blenders).
- Grinding machines should avoid undue heat; example aperture sizes 1.2–2.0 mm may suit hard/semi‑hard cheeses.
- Blending or sieving techniques to remove excessive liquids (oil, whey, brine).
- Containers and storage: Use opaque, inert containers (glass, stainless steel, polypropylene) with secure closures; avoid materials/conditions that affect results.
- Reporting: Record preparatory steps, conditions and any deviations that may affect analyses.
Applications
ISO 24223:2021 is used to ensure consistent, reproducible sample preparation for:
- Chemical composition testing (moisture, fat, protein, salt)
- Instrumental analyses (spectrometry, chromatographic preps)
- Physical testing (texture, rheology)
- Specialized analyses where sample handling can affect target analytes
Who should use this standard
- Food testing laboratories and quality control teams in dairy processing
- Regulatory and food safety authorities performing official cheese testing
- Researchers conducting compositional or instrumental cheese analyses
- Producers and auditors establishing standard operating procedures for sampling and sample preparation
Related standards
- ISO 707 | IDF 50 - Sampling of milk and milk products (reference for initial sampling)
- Method‑specific analytical standards referenced in ISO 24223:2021 (listed as References [2]–[22] in the document)
Keywords: ISO 24223:2021, cheese sample preparation, physical and chemical testing, cheese testing guidance, ISO 707, sample grinding, rind removal, dairy laboratory procedures.
