Overview
EN ISO 21528-1:2017 - Microbiology of the food chain: Horizontal method for the detection and enumeration of Enterobacteriaceae (Part 1: Detection) - specifies a standardized, enrichment-based laboratory method to detect Enterobacteriaceae in foods, animal feed and related environmental samples. The standard is intended for use when target organisms may require resuscitation by enrichment and when expected counts are below 100 CFU per g or mL. The document also warns that the method can show substantial variability (see Clause 11) and that testing should be done in properly equipped labs by skilled microbiologists.
Key topics and requirements
- Scope of application: Products for human consumption, animal feeding stuffs, and environmental samples from primary production, food processing and handling areas.
- Detection principle: Enrichment in a non-selective medium to resuscitate stressed Enterobacteriaceae, followed by isolation, selection and biochemical confirmation.
- Enrichment and confirmation: The 2017 revision standardizes enrichment in buffered peptone water (BPW) and confirmation in Glucose OF medium (change noted from earlier editions).
- Enumeration option: Enumeration by Most Probable Number (MPN) after incubation in liquid medium is described in Annex A (informative).
- Performance and variability: Clause 11 covers precision, sensitivity and specificity; users should note the method’s susceptibility to variability and apply quality assurance accordingly.
- Safety and laboratory competence: Testing must be performed in appropriate lab facilities under trained personnel with safe disposal of incubated materials.
- Documentation: Procedures for sampling, test portion preparation, incubation, colony selection, subculturing and biochemical confirmation tests are defined; Annexes list media, reagents and validation guidance.
Applications
- Routine screening for Enterobacteriaceae as indicators of hygiene and potential contamination in:
- Raw and processed foods
- Animal feed
- Environmental swabs from production, handling and storage areas
- Food safety monitoring, supplier verification and HACCP-related testing
- Method validation and quality control of culture media and laboratory procedures
Who should use this standard
- Food and feed microbiology laboratories (public and private)
- Quality assurance and food safety teams in manufacturing and processing
- Regulatory and inspection authorities performing compliance testing
- Test method developers and standardization bodies referencing horizontal methods
Related standards
- Other parts of the ISO 21528 series (enumeration and complementary methods) - see the ISO website for the complete list and cross-references.
Keywords: EN ISO 21528-1:2017, Enterobacteriaceae detection, food microbiology standard, enrichment method, MPN enumeration, food safety testing.
