Overview
ISO 22964:2017 - "Microbiology of the food chain - Horizontal method for the detection of Cronobacter spp." - is an international standard that specifies a laboratory horizontal method for detecting Cronobacter species in food, animal feed and environmental samples in food production and handling areas. The method is intended to support food safety and microbiological testing programs by providing a harmonized, validated procedure for isolation and confirmation of Cronobacter spp.
Key technical topics and requirements
- Scope: Applicable to food products/ingredients for human consumption, animal feed and environmental samples (subject to limitations in the Introduction).
- Test principle: A staged enrichment and isolation procedure:
- Pre-enrichment in buffered peptone water (BPW) - incubate 34–38 °C for 18 ± 2 h.
- Selective enrichment in Cronobacter selective broth (CSB) - incubate 41.5 °C ± 1 °C for 24 ± 2 h.
- Plating on chromogenic Cronobacter isolation (CCI) agar - incubate at 41.5 °C ± 1 °C for 24 ± 2 h to detect typical colonies.
- Confirmation of presumptive colonies: purification (e.g., on tryptone soya agar, TSA) followed by biochemical characterization.
- Validated test portion: Method validated for 10 g (or 10 ml) test portions; smaller portions may be used if ratio to enrichment broth is maintained; larger portions require validation/verification.
- Media and reagents: Compositions and preparation are specified (see Annex B); media performance testing referenced to ISO 11133.
- Performance characteristics: The standard addresses sensitivity, specificity, limit of detection (LOD) and includes interlaboratory validation (Annex D).
- Supporting documentation: Normative diagram of procedure (Annex A), guidance for distinguishing Cronobacter from other genera (Annex C), and method validation data (Annex D).
Practical applications and who uses it
- Who uses it: Food microbiology laboratories, quality assurance/food safety teams in food manufacturers, feed producers, regulatory and public health laboratories involved in microbiological surveillance and outbreak investigations.
- Why use it:
- Standardized detection method for regulatory compliance, product release testing and environmental monitoring.
- Useful in testing powdered infant formula, dairy ingredients, dry foods, ready-to-eat products, and production environments where Cronobacter contamination is a concern.
- Harmonizes laboratory practices and supports comparability of results across labs and jurisdictions.
Related standards
- ISO 6887 (sample preparation and dilutions)
- ISO 7218 (general microbiology laboratory requirements)
- ISO 11133 (culture media preparation and performance testing)
- ISO/TS 17728 and ISO 18593 (sampling guidance for products and surfaces)
By following ISO 22964:2017, laboratories gain a validated, reproducible workflow for Cronobacter detection that integrates enrichment, chromogenic isolation (CCI agar), and biochemical confirmation - supporting robust food safety and compliance programs.
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