Overview
ISO/TS 17919:2013 - "Microbiology of the food chain - PCR for the detection of food‑borne pathogens - Detection of botulinum type A, B, E and F neurotoxin‑producing clostridia" - specifies a horizontal molecular method for detecting genes encoding botulinum neurotoxins (BoNT A, B, E, F) in food, feed and environmental samples. The method targets the causative organisms (clostridia carrying BoNT genes) via polymerase chain reaction (PCR). Importantly, the standard detects the presence of toxin genes and not the toxins themselves; a positive PCR result does not necessarily indicate active toxin in the sample.
Key topics and technical requirements
- Principle and workflow: consecutive steps of microbial enrichment, nucleic‑acid extraction, PCR amplification, detection of PCR products and confirmation. Real‑time PCR integrates amplification and detection.
- Microbial enrichment: non‑selective enrichment in tryptone–peptone–glucose–yeast extract (TPGY) broth under anaerobic conditions, with buffered variants for acidic foods. Composition and preparation of media are specified.
- Nucleic acid extraction: procedures to separate cells, lyse and purify DNA suitable for PCR.
- Amplification and detection: protocols for conventional PCR with gel electrophoresis and for real‑time PCR assays; annexes describe multiplex agarose‑gel assays (Annex B) and real‑time PCR assays (Annex C).
- Confirmation: identity of PCR amplicons must be confirmed by sequencing, hybridization, restriction analysis or equivalent.
- Reagents, equipment and sampling: guidance on analytical grade reagents, culture media (ISO 11133), dedicated molecular‑biology consumables and laboratory equipment.
- Quality and compliance: normative references include ISO 20837, ISO 20838, ISO 22174 and ISO 6887; these define sample preparation, amplification/detection requirements and general PCR method definitions.
- Intellectual property: the document notes possible patent claims (e.g., Applied Biosystems) relevant to assay elements.
Applications
- Screening of food products (finished goods and ingredients) for BoNT‑gene carrying clostridia.
- Testing of animal feed and environmental samples (processing environments, raw materials).
- Outbreak investigation, surveillance and risk assessment for botulism hazards in the food chain.
- Method development and validation in diagnostic and regulatory laboratories.
Who should use this standard
- Food microbiology laboratories and public‑health diagnostic labs.
- Regulatory agencies and food safety authorities.
- Food and feed manufacturers with in‑house testing or quality control units.
- Researchers developing PCR assays for Clostridium botulinum and related organisms.
Related standards (select)
- ISO 20837 - sample preparation for qualitative PCR detection.
- ISO 20838 - amplification and detection requirements for qualitative PCR.
- ISO 22174 - general PCR requirements and definitions.
- ISO 6887‑1, ISO 11133 - sample preparation and culture media production.
Keywords: ISO/TS 17919:2013, PCR, botulinum, Clostridia, botulinum neurotoxin, food safety, microbiology of the food chain, real‑time PCR, enrichment, nucleic acid extraction.