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RapidREF 4323410205
Organism · Solutions
Listeria testing
Listeria monocytogenes carries the highest stakes of any organism on a ready-to-eat line — it grows at refrigeration temperature, persists in the plant environment, and a positive on a finished product is rarely a single-batch problem.
Blue-green colonies with halo · chromogenic agarWhy Listeria testing is demanding
Listeria is unusual among food pathogens because it grows at refrigeration temperature. Chilled storage, which controls most organisms, does not control this one — which is why ready-to-eat products with extended shelf life carry the strictest requirements, and why the organism is a persistent concern in dairy, chilled meats and prepared foods.
The greater operational risk is environmental. Listeria establishes itself in drains, floor junctions, and hard-to-clean equipment, and re-contaminates product from there. A finished-product positive usually indicates a harbourage site, not a one-off event, which is why environmental monitoring carries as much weight as release testing in a credible Listeria programme.
Detection is complicated by the need to distinguish L. monocytogenes from other Listeria species that share the same selective media. Chromogenic media resolve much of that, but confirmation remains the step that makes a positive defensible — and the step regulators scrutinise.
- Typical criterion
- Absence in 25 g
- Reference method
- ISO 11290-1
- Grows at
- 2–4 °C
- Culture result
- 24–48 h presumptive
Methods compared
Detection, differentiation and confirmation — where each method fits.
- Traditional · ISO 11290-1The reference standard
Two-stage selective enrichment followed by isolation on chromogenic agar, where L. monocytogenes is differentiated from other Listeria species by its opaque halo.
Time to result4–5 days - RapidEnvironmental monitoring throughput
Ready-to-use chromogenic formats sized for the volume of swabs and contact plates an environmental monitoring programme generates every week.
Time to result24–48 h - Molecular · Real-time PCRSpecies-level confirmation
Real-time PCR distinguishing L. monocytogenes from other Listeria species with high specificity — valuable when a presumptive positive is holding product.
Time to resultSame day, post-enrichment
Environmental programmes lean on throughput; release testing leans on confirmation.
Ask usProducts for Listeria testing
A selection spanning culture media, rapid formats and molecular assays. The full range is in the catalogue.
Standards & compliance
The references a Listeria programme is measured against.
- ISO 11290-1
- Horizontal method for the detection of Listeria monocytogenes and Listeria spp. — the reference workflow for food and environmental samples.
- ISO 11290-2
- The enumeration counterpart, applied where a quantitative limit rather than absence is specified.
- AOAC validation
- Rapid and molecular Listeria methods carry AOAC validation; confirm coverage for your matrix and for environmental surfaces specifically.
- SFDA
- Supplied through an SFDA-licensed establishment, aligned to Kingdom requirements for the matrices you test.
Sourced from the brands your methods are built on.
Testing for Listeria?
Tell us your matrix and how fast you need a release decision — we'll recommend the method and respond with pricing, availability and lead time.