ISO 21527-1-2008 PDF

Full title and description

ISO 21527-1:2008 — Microbiology of food and animal feeding stuffs — Horizontal method for the enumeration of yeasts and moulds — Part 1: Colony count technique in products with water activity greater than 0.95. A horizontal colony‑count method intended for routine enumeration of viable yeasts and moulds in high‑moisture food and feed matrices (eggs, meat, most dairy products, fruits, vegetables, fresh pastes, etc.).

Abstract

ISO 21527-1:2008 specifies procedures for preparation, dilution, inoculation, incubation and colony counting to determine viable yeast and mould counts in products having water activity (a_w) greater than 0.95. The method uses selective mycological media (typical: DRBC or equivalent), surface inoculation (spread plates), incubation at 25 °C ± 1 °C and counting after an established incubation period. The standard excludes enumeration of mould spores, identification of fungal species and mycotoxin analysis, and is not suitable for certain heat‑resistant fungi found in some canned/bottled products.

General information

• Status: Published (international standard).
• Publication date: July 2008 (Edition 1). Confirmed by systematic review in 2018; marked for revision in subsequent reviews.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 07.100.30 — Food microbiology.
• Edition / version: 1 (2008).
• Number of pages: 8 pages.

Scope

Provides a horizontal colony‑count technique for enumeration of viable yeasts and moulds in food and animal feeding stuffs with water activity greater than 0.95. The standard covers sample preparation, choice of diluent, inoculation (surface/spread), recommended selective media and incubation conditions for reliable colony counts. It does not cover enumeration of mould spores, species identification, mycotoxin testing or enumeration of specific heat‑resistant or otherwise atypical fungi (for which other methods may be required).

Key topics and requirements

• Principle: surface inoculation (spread plate) of selective medium and colony counting to report CFU per g or mL.
• Sample handling and diluent: recommended use of appropriate sterile diluent (commonly 0.1% peptone water) and defined procedures for preparing suspensions and decimal dilutions.
• Selective media: guidance for use of media suitable for high‑moisture products (commonly DRBC or equivalent formulations) with optional antibiotics to suppress bacteria.
• Incubation conditions: aerobic incubation at 25 °C ± 1 °C with a typical incubation period (counting after the specified days — standard practice is to incubate around five days, with optional short exposure to diffuse daylight if required for colony development).
• Counting and calculation: selection of countable plates, separate counting of yeasts and molds when necessary, and conversion to CFU per unit using dilution factors.
• Limitations and exclusions: does not enumerate mould spores, is not intended for heat‑resistant fungi in canned/bottled products, and does not address species identification or mycotoxin testing.
• Referenced laboratory quality practice: aligns with sample‑preparation and lab quality standards (for example, ISO guidance on microbiological sample handling and culture media quality).

Typical use and users

Used by food‑testing laboratories, contract testing services, quality control teams in food and feed manufacturing (meat, dairy, produce, ready‑to‑eat), regulatory agencies and auditors for routine monitoring of yeast and mould loads, shelf‑life assessment and spoilage investigations in high‑moisture products.

Related standards

ISO 21527-1 is part of the ISO 21527 series; the principal related document is ISO 21527-2:2008 (Part 2 — methods for products with water activity ≤ 0.95). It is commonly used alongside general microbiology standards and laboratory practice documents such as the ISO 6887 series (sample preparation), ISO 7218 (general requirements for microbiological examinations) and ISO/TS 11133 (culture media — performance and quality control). National/adopted variants and companion method standards (EN/ISO versions) may also exist.

Keywords

yeasts, moulds, molds, enumeration, colony count, DRBC, a_w, water activity, food microbiology, ISO 21527, colony count technique, high‑moisture foods

FAQ

Q: What is this standard?

A: ISO 21527-1:2008 is an international standard specifying a horizontal colony‑count method for enumeration of viable yeasts and moulds in food and animal feeding stuffs with water activity greater than 0.95.

Q: What does it cover?

A: It covers sampling suspension/dilution, surface inoculation on selective media, incubation at 25 °C ± 1 °C, colony counting and calculation of CFU per gram or millilitre for high‑moisture products. It excludes mould spore counts, species identification and mycotoxin testing.

Q: Who typically uses it?

A: Food and feed microbiology laboratories, quality control and R&D teams in food manufacturers, contract testing labs and regulatory bodies performing routine yeast and mould enumeration and spoilage monitoring in high‑moisture products.

Q: Is it current or superseded?

A: The 2008 edition is the published and widely used version. It was subject to ISO systematic review (confirmed in 2018) and has been referenced for revision activity; users should check with their national standards body or ISO for the very latest status if they require evidence of any subsequent revision or replacement.

Q: Is it part of a series?

A: Yes — ISO 21527 comprises at least two parts. Part 1 (this standard) covers products with a_w > 0.95; ISO 21527-2:2008 covers products with a_w ≤ 0.95. Revision work on the series has been planned or undertaken at committee level.

Q: What are the key keywords?

A: Yeasts; moulds (molds); enumeration; colony count; DRBC; water activity; food microbiology; ISO 21527; incubation 25 °C; high‑moisture foods.