Overview
EN ISO 11290-2:2017/A1:2026 is an amendment to the established international standard focusing on the enumeration of Listeria monocytogenes and Listeria spp. in the food chain. This amendment, adopted by CEN, introduces essential updates regarding the storage of samples before analysis and revises the control strains used in performance testing of culture media and reagents. These changes are designed to further harmonize methods in food microbiology, ensuring consistent, accurate testing outcomes for laboratories and producers worldwide.
Key Topics
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Sample Storage Before Analysis
The amendment introduces detailed guidance on the storage of food and feed samples prior to analysis. Key aspects include:
- Chilled perishable foods should be stored between 2°C and 8°C, with examination ideally upon receipt or within 8 hours. Under certain conditions, this period may extend to 24 hours.
- Any deviations or extended storage must be justified and documented in the laboratory’s test report.
- Reference to related standards such as ISO 7218 for storage of low-moisture and frozen products, and ISO/TS 17728 and ISO 18593 for sampling protocols.
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Updated Control Strain for Performance Testing
- The amendment replaces the reference strain Listeria monocytogenes WDCM 00109 with WDCM 00231 for specified performance testing procedures.
- The change applies to quality assurance of both culture media and reagents, in line with test methods described in ISO 11133 and referenced tables.
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Performance Testing of Culture Media and Reagents
- Continues to require performance characteristics such as productivity, specificity, and selectivity, as outlined in ISO 11133.
- Lists appropriate positive and negative control strains for key confirmation tests, with specific criteria for each type of media or reagent.
Applications
EN ISO 11290-2:2017/A1:2026 is of high practical value to:
- Food Producers and Processors: Ensures that testing for Listeria monocytogenes and Listeria spp. meets harmonized international requirements, supporting food safety and regulatory compliance.
- Testing Laboratories: Provides clear procedures for the storage of test samples, usage of updated control strains, and rigorous performance criteria, supporting reliable, reproducible results.
- Food Safety Auditors and Inspectors: Offers standardized methods useful for verifying compliance with legal and industry requirements regarding Listeria monitoring in food products and processing environments.
- Quality Assurance Managers: Supports robust quality systems by introducing uniform protocols for performance validation of culture media and reagents.
By adopting these amendments, stakeholders in the food supply chain can enhance their detection and enumeration of Listeria, minimize false results, and maintain high standards of food hygiene management.
Related Standards
For comprehensive application, this amendment should be used in conjunction with:
- ISO 11290-2:2017 – Original standard for the enumeration method of Listeria monocytogenes and Listeria spp.
- ISO 7218 – General guidance on microbiological laboratory sample management and sample storage.
- ISO/TS 17728 – Sampling techniques for food and feed products.
- ISO 18593 – Surface sampling of food processing environments.
- ISO 11133 – Preparation, production, storage, and performance testing of culture media.
Summary
EN ISO 11290-2:2017/A1:2026 strengthens the detection and enumeration methodology for Listeria species in the food chain by refining sample storage procedures and updating performance testing requirements. Implementation of this amendment enhances laboratory reliability, supports food safety, and aligns with international best practices critical for food industry stakeholders.
