Overview - ISO/TS 18867:2015 (real-time PCR for Yersinia)
ISO/TS 18867:2015, Microbiology of the food chain - Polymerase chain reaction (PCR) for the detection of food‑borne pathogens, defines real‑time PCR‑based methods for detecting pathogenic strains of Yersinia enterocolitica and Yersinia pseudotuberculosis. The Technical Specification describes two horizontal methods for pathogenic bioserotypes of Y. enterocolitica and one for Y. pseudotuberculosis, applicable to food products, animal feeding stuffs and environmental samples. The PCR assays target the chromosomal ail gene and are designed for use on enriched samples, with procedures that also permit subsequent isolation of colonies.
Key topics and technical requirements
- Method principle: Sequential steps of microbial enrichment, nucleic acid extraction, probe‑based real‑time PCR amplification/detection, and optional culture isolation after PCR positivity.
- Target gene: The chromosomal ail (attachment–invasion locus) is the detection target; primer/probe sets target different ail regions for each species. (A variant of ail in Yersinia pestis can also be detected by the Y. pseudotuberculosis assay but Y. pestis is not normally food‑associated.)
- Sample scope: Designed for enrichments from foods for human consumption, animal feeds and environmental matrices.
- Reagents and media: Molecular‑grade reagents and consumables are required; specified enrichment media such as tryptone‑soya broth with yeast (TSBY) and selective media are referenced.
- Controls and interpretation: The specification requires appropriate process, extraction and PCR controls and uses Ct (cycle threshold) monitoring for detection. Isolation methods are provided for confirmation after PCR.
- Laboratory practice: Aligns with ISO best practices for sample preparation, contamination control and method validation.
Applications - who uses ISO/TS 18867:2015
- Food testing laboratories performing routine screening for food‑borne pathogens.
- Public health and reference laboratories conducting surveillance and outbreak investigation for yersiniosis.
- Food manufacturers and QA teams, especially in sectors linked to pigs/pork products, where pathogenic Y. enterocolitica is a known reservoir.
- Contract testing and environmental monitoring labs screening processing environments and animal feeds.
Practical benefits include faster, sensitive detection by real‑time PCR on enriched samples while retaining the option to culture isolates for confirmation and further characterization.
Related standards
- ISO 6887‑1 (sample preparation)
- ISO 10273 (culture‑based detection of presumptive pathogenic Y. enterocolitica)
- ISO 20837 / ISO 20838 / ISO 22119 / ISO 22174 (PCR sample prep, amplification/detection and general PCR requirements)
These referenced ISO documents define complementary requirements for PCR workflows, sample handling and method validation.
Keywords: ISO/TS 18867:2015, Yersinia enterocolitica, Yersinia pseudotuberculosis, real‑time PCR, PCR detection, food‑borne pathogens, microbiology of the food chain.