Standards for Detection and Enumeration of Listeria monocytogenes and Listeria spp. in the food chain
The International Organization for Standardization (ISO) published the revised EN ISO 11290-1 and EN ISO 11290-2 standards in 2017. Part 1 specifies a horizontal method for the detection of Listeria monocytogenes and Listeria spp., while Part 2 describes the enumeration of these organisms in food, animal feed, and environmental samples.
Section Overview
- EN ISO 11290-1:2017 Summary
- Listeria monocytogenes and Listeria spp. Detection Steps as per EN ISO 11290-1:2017
- Key Points of EN ISO 11290-2:2017
- Enumeration Steps for Listeria monocytogenes and Listeria spp. as per EN ISO 11290-2:2017
- Compliance with EN ISO 11290:2017 Requirements
- Ordering Information
The revised edition of Part 1 cancels and replaces the first edition (EN ISO 11290-1:1996) and incorporates Amendment 1 from 2004. Similarly, Part 2 cancels and replaces the first edition (EN ISO 11290-2:1998) and incorporates Amendment 1 from 2004. Compared to the previous edition, the main changes in the revised EN ISO 11290:2017 are considered significant.
Notably, the scope in both Parts 1 and 2 has been expanded to include the detection and enumeration of Listeria spp. as well. Learn more in our Listeria: Surviving Bacteria article.
EN ISO 11290-1:2017 Summary
- Scope extended to include Listeria spp. detection. The title has changed accordingly.
- Primary enrichment in half-Fraser broth: incubation changed to 25 h ± 1 h.
- Secondary enrichment in Fraser broth updated to 24 h ± 2 h.
- Enriched half-Fraser and Fraser broths may be refrigerated before transfer or isolation on selective agar for max. 72 h.
- Incubated isolation plates can be refrigerated for a maximum of two days before reading.
- Microscopic confirmation aspect is optional in the case of use of agar specific for pathogenic Listeria spp.
- CAMP and catalase tests are optional.
- New performance characteristics included.
Listeria monocytogenes and Listeria spp. Detection Steps as per EN ISO 11290-1:2017
Day 2 - Selective enrichment
0.1 mL of culture + 10 mL Fraser broth
24 h ± 2 h • 37 °C ± 1 °C
Day 3 - Plating out
Streak from both primary AND secondary enrichments onto:
1. Listeria selective agar acc. Ottaviani and Agosti 24 h ± 2 h • 37 °C ± 1 °C and additionally 24 h ± 2 h • 37 °C ± 1 °C
2. 2ndselective agar of choice (e.g. PALCAM agar, Oxford agar), Incubate as specified by the manufacturer
Day 4 - Confirmation step
Test 1 typical colony. If negative, test 4 additional marked colonies.
Streak onto non-selective agar (e.g. Nutrient agar) 24 h ± 3 h • 37 °C - 1 °C
Day 5 & 6 - Expression of result
Follow confirmation procedures for L. monocytogenes
Follow confirmation procedures for Listeria spp.
Expression of results
Key Points of EN ISO 11290-2:2017
- Primary suspension with buffered peptone water, half-Fraser with or without supplements, and all appropriate dilutions are referred to in ISO 6887.
- Resuscitation step (incubation of initial suspension of sample 1 h ± 5 min at 20 °C ± 2 °C) deleted.
- Microscopic aspect, CAMP and catalase tests are optional.
- Enumeration of Listeria spp. is included in the scope. Title is changed accordingly.
As a worldwide leading provider of a broad range of dehydrated granulated and ready-to-use culture media for food, beverages and water microbiology, we closely track and support the development of relevant standards to ensure consumer confidence and safety.
Our GranuCult® granulated media, Readybag® pre-weighed granulated media in ready-to-use bags, ReadyPlate™, and ReadyTube® ready-to-use media are all compliant with EN ISO 11133:2014. All information regarding compliance with additional reference standards are displayed on the product label and in the technical information available on our website.
Enumeration Steps for Listeria monocytogenes and Listeria spp. as per EN ISO 11290-2:2017
Day 2 - Plating-out
Surface inoculate onto Listeria selective agar acc. Ottaviani and Agosti.
Incubate 24 h ± 2 h and additional 24 h ± 2 h at 37 °C ± 1 °C
Enumerate presumptive L.monocytogenes and / or Listeria spp.
Day 3 - Confirmation
Test 1 Colony from each dilution.
Streak onto non-selective agar (e.g. Nutrient agar)
24 h ± 3 h • 37 °C - 1 °C
Day 4 & 5 - Expression of result
Follow confirmation procedures for L. monocytogenes.
Follow confirmation procedures for Listeria spp.
Calculate and report results for L. monocytogenes and/or Listeria spp
Compliance with EN ISO 11290:2017 Requirements
We have implemented all the requirements described in both Part 1 and Part 2 of the revised EN ISO 11290:2017. These standards provide a comprehensive framework for the detection and enumeration of Listeria monocytogenes and Listeria spp. in food, animal feed, and environmental samples, ensuring the safety and quality of products throughout the food chain.
By adhering to these rigorous standards, we validate our commitment to maintaining high levels of food safety and regulatory compliance. Our GranuCult™ Granulated Culture Media is specifically designed to facilitate these testing processes, providing reliable results that meet the latest industry requirements. For more information on our products and how they align with ISO 11290:2017, please visit GranuCult™ Granulated Culture Media.
The revised EN ISO 11290:2017 outlines specific culture media and accessories that are now available for order.
Ordering Information
Other pack sizes available
* 5 kg, 25 kg
** 5 kg
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