Overview
EN ISO 11290-2:2017 (ISO 11290-2:2017) is a CEN/ISO horizontal standard for the enumeration of Listeria monocytogenes and Listeria spp. in the food chain. It specifies a laboratory method for counting L. monocytogenes and other Listeria species in food and feed products and in environmental samples taken from food production and handling areas. This second edition (2017) replaces the 1998 edition and harmonizes procedures used across EU member bodies.
Key Topics
- Scope and applicability: Enumeration of L. monocytogenes and Listeria spp. in products intended for human consumption, animal feed, and environmental monitoring in food facilities.
- Principle of the method: Horizontal enumeration based on initial sample suspension, surface plating, incubation and confirmation of characteristic colonies.
- Sample handling: Test portion selection, preparation of initial suspension and serial dilutions (referenced to ISO 6887 guidance for diluents).
- Culture media & reagents: Composition and preparation are covered (see normative annexes); appropriate media for selective plating are specified.
- Incubation and colony counting: Conditions for incubation and procedures for enumeration of characteristic colonies are defined.
- Confirmation procedures: Selection of colonies for confirmation and workflows to confirm L. monocytogenes and Listeria spp. - note that microscopy, catalase and CAMP tests are optional in this edition.
- Method performance: Validation, repeatability and reproducibility characteristics are included; results reporting and quality assurance requirements are defined.
- Laboratory safety: Explicit warning on protecting laboratory personnel when handling potential Listeria cultures.
Applications and Users
Who uses EN ISO 11290-2:2017:
- Food and feed microbiology laboratories performing routine testing for Listeria enumeration.
- Quality assurance and food safety teams in food manufacturers and processors.
- Regulatory and inspection bodies assessing compliance with food safety criteria.
- Environmental monitoring programs in food production and handling facilities.
Practical applications:
- Routine enumeration to support product safety release decisions.
- Environmental monitoring to assess hygiene and contamination control.
- Validation and verification of sanitation and process controls.
- Supporting investigations of contamination sources in production environments.
Related Standards
- EN ISO 11290-1 - detection (presence/absence) method for Listeria (complements Part 2 enumeration).
- ISO 6887 (all parts) - preparation of test samples, initial suspension and diluents.
- Other national or sector-specific methods may be used where justified, but harmonization with ISO 11290 series is encouraged.
Keywords: EN ISO 11290-2:2017, ISO 11290-2, Listeria monocytogenes enumeration, Listeria spp., food microbiology standard, food safety testing, CEN.
