Overview
ISO 22174:2024 - Microbiology of the food chain - Polymerase chain reaction (PCR) for the detection and quantification of microorganisms - General requirements and definitions - specifies general requirements and standardized definitions for in vitro amplification of nucleic acids (DNA and RNA) applied to food‑chain testing. The second edition (2024) replaces earlier related standards and sets minimum requirements to ensure comparable, reproducible PCR results across different laboratories. The scope covers detection and quantification of microorganisms and viruses in products for human consumption, animal feed, environmental samples in food/feed production and handling, and samples from primary production.
Key topics and technical requirements
- Terminology and definitions for PCR/RT‑PCR, qPCR and dPCR to harmonize reporting and interpretation (Clause 3).
- Sample handling: guidance on laboratory samples, test portions, sampling, transport, storage and test sample preparation (Clauses 4–6).
- Nucleic acid preparation: extraction, purification, assessment of nucleic acid quality/quantity and strategies to prevent amplification from dead cells (Clause 6).
- Amplification and detection: PCR/RT‑PCR workflows, amplicon detection and confirmation methods (Clauses 7–8).
- Controls and quality assurance: description of required internal, external and no‑template controls and expanded content on control reactions for robust assays (Clause 12.2.2).
- Laboratory environment and flows: layout, contamination control, cleaning and environmental monitoring for nucleic acid contamination (Clause 9).
- Reagents, equipment and consumables: expectations for validated materials, thermal cycler performance (reference to ISO 20836) and digital PCR (dPCR) requirements now included.
- Data analysis, evaluation and reporting: qualitative and quantitative evaluation procedures plus test report content (Clause 12.2–12.4).
- Performance, validation and verification: clauses on method performance characteristics and requirements for validation and verification of PCR‑based methods (Clauses 13–14).
Practical applications
- Routine and confirmatory testing of pathogens (bacteria, viruses, fungi) in food and feed safety programs.
- Environmental monitoring during food production and processing to detect contamination sources.
- Quantitative microbial risk assessment using qPCR or digital PCR (dPCR) for copy‑number determination.
- Development, validation and verification of PCR assays, kits and laboratory workflows.
Who should use ISO 22174:2024
- Food and feed microbiology laboratories and testing service providers
- Public health and regulatory agencies overseeing food safety
- Test kit and assay developers, instrument manufacturers (qPCR, dPCR)
- Quality managers responsible for laboratory accreditation and method validation
Related standards
- ISO 6887 (sample preparation)
- ISO 7218 (general microbiology laboratory requirements)
- ISO 20836 (thermal performance of cyclers)
Keywords: ISO 22174:2024, PCR, qPCR, dPCR, microbiology of the food chain, nucleic acid extraction, validation, laboratory contamination control, food safety testing.