Overview
ISO 10272-2:2017 - "Microbiology of the food chain - Horizontal method for detection and enumeration of Campylobacter spp. - Part 2: Colony-count technique" - specifies a standardized colony-count method for enumerating thermotolerant Campylobacter spp. in the food chain. The method applies to products intended for human consumption and animal feed, environmental samples from food/feed production and handling, and primary production samples (for example animal faeces, dust and swabs). The standard is intended for properly equipped laboratories and emphasizes biosafety and skilled microbiological practice.
Key topics and technical requirements
- Scope and sample types: Enumeration of Campylobacter spp. in food, feed, environmental and primary production samples.
- Principle: Serial decimal dilutions and plating on a selective solid medium (modified Charcoal Cefoperazone Deoxycholate agar, mCCD agar), followed by incubation in a microaerobic atmosphere and colony counting.
- Incubation conditions: Plates are incubated at 41.5 °C in a controlled microaerobic atmosphere (typical composition: O2 ≈ 5% ±2, CO2 ≈ 10% ±3, optional H2 ≤10%). Plates are examined after about 44 h for presumptive colonies.
- Confirmation and identification: Suspect colonies are examined microscopically for morphology and motility, subcultured to non‑selective blood agar, and confirmed by oxidase activity and an aerobic growth test at 25 °C. Optional species identification uses biochemical or molecular tests (e.g., catalase, hippurate, indoxyl acetate assays).
- Procedure details: Test portion preparation and decimal dilutions follow ISO 6887; serial dilutions are plated (single plates in line with ISO 7218). Culture media composition and performance testing requirements are specified (see Annex B). Performance characteristics and validation data are provided (Annex C).
- Equipment: Requirements include incubators (25 °C, 37 °C, 41.5 °C), microaerobic jars or gas-mixing systems, microscopes (preferably phase contrast), sterile loops, and appropriate refrigeration.
Applications and users
Who uses ISO 10272-2:2017:
- Food and feed microbiology laboratories performing routine Campylobacter enumeration
- Food producers and processors assessing product safety and process hygiene
- Regulatory and public health laboratories for surveillance and compliance testing
- Veterinary and primary production microbiology labs testing faeces, dust, swabs, and farm environments
Practical uses:
- Establishing baseline counts and monitoring contamination trends
- Verifying hygiene controls and HACCP critical points
- Supporting epidemiology and outbreak investigations where Campylobacter contamination is suspected
Related standards (normative references)
- ISO 10272 series (other parts covering detection and method variants)
- ISO 6887 - preparation of test samples and dilutions
- ISO 7218 - general requirements for microbiological examinations
- ISO 11133 - culture media preparation, storage and performance testing
Keywords: ISO 10272-2:2017, Campylobacter enumeration, colony-count technique, mCCD agar, microaerobic incubation, food microbiology, food safety testing.