From 1 July 2026, EU requirements for controlling Listeria monocytogenes in ready-to-eat (RTE) foods will become more demanding. The key operational shift is that compliance is no longer framed mainly at the point a product leaves the producer’s immediate control. Instead, the criteria apply to products placed on the market during their shelf life, meaning manufacturers must be able to demonstrate that safety holds until the “use by” date. This change is intended to strengthen consumer protection, particularly for vulnerable groups, given the severity of invasive listeriosis. [1]
The amended approach keeps the familiar “two-pathway” logic, but applies it more broadly across shelf life:
This distinction matters because it determines whether a business can rely primarily on growth control and validation evidence, or whether it must design for absence in 25 g as the routine benchmark through the marketed life of the product.
Historically, many RTE control strategies and release decisions were built around the concept of meeting criteria at dispatch. With the criterion now framed around products on the market during shelf life, manufacturers are under increased pressure to justify that their shelf life is realistic under foreseeable conditions—temperature control, handling, and distribution variability included. The intent, as stated in the amending regulation, is to ensure the same level of public health protection “from production to distribution” for these RTE foods. [1]
In practice, this drives deeper scrutiny of the producer’s “shelf-life safety case”: how shelf life is set, what data supports it, and how ongoing verification demonstrates that the assumptions remain true.
For products where the “not detected in 25 g” expectation applies during shelf life, end-product testing alone is rarely a sufficient risk control because Listeria contamination can be sporadic and low-level. A robust programme typically leans heavily on post-lethality hygiene control, including intensive environmental monitoring in areas where recontamination is most likely (e.g., slicing/packaging zones).
For producers aiming to operate under the 100 CFU/g route, the central requirement becomes the ability to demonstrate that growth will not take levels above the limit during shelf life. That demonstration is often built on a combination of:
Challenge testing is commonly performed according to ISO 20976-1:2019, which provides a framework for conducting microbiological challenge tests, including studies relevant to growth potential. [2]
The July 2026 change is likely to increase both the amount and structure of evidence expected in audits and investigations. Documentation typically becomes more central, because authorities may ask not only “what are your results?” but “what proves your product remains compliant at end of shelf life?”
Many manufacturers will also reassess growth-limiting interventions. Where compatible with the product, protective cultures and other hurdle concepts (formulation adjustments, packaging improvements, tighter cold-chain specifications) can strengthen the scientific justification that Listeria will not grow to unacceptable levels during shelf life. These measures are not a substitute for verification, but they can reduce reliance on narrow assumptions.
Culture-based methods remain fundamental for reference confirmation and, where needed, enumeration. EU microbiological criteria reference the ISO 11290-1 method for detection and ISO 11290-2 for enumeration. [3][4] However, in day-to-day operations, PCR-based workflows are widely used as validated alternative methods for rapid screening—typically after enrichment—because speed improves the ability to act before a situation becomes a distributed problem.
Under an “until use-by date” compliance mindset, PCR supports three practical needs:
1) Faster decision cycles (hold/release and investigations).
Shorter time-to-result helps accelerate escalation when environmental sites or product screens indicate potential loss of control, limiting the time window in which product may continue moving through the chain.
2) Sensitive screening for low-level contamination (after enrichment).
When the target is “not detected in 25 g,” detection capability at low levels matters. PCR after appropriate enrichment can be a strong fit for presence/absence screening, provided the workflow is validated for the relevant matrices and sampling plan.
3) Higher-throughput environmental monitoring and trending.
Because environmental verification is often the earliest indicator of Listeria pressure, PCR-enabled throughput can increase sampling density and improve trend visibility—useful both for preventive control and for demonstrating ongoing control in an audit-ready way.
PCR does not remove the need for a sound microbiological strategy. It works best when embedded in clear decision rules (what triggers intensified cleaning, resampling, product holds, root-cause analysis) and when positives are managed through appropriate confirmation and follow-up actions.
The July 2026 update reinforces a simple principle: for RTE foods, Listeria control must be demonstrated where it matters most — at the end of shelf life. Building that confidence typically requires stronger validation, tighter hygiene and environmental control, and faster feedback from testing. Used appropriately within a validated programme, PCR can be a practical tool to support timely decisions and robust documentation as the industry adapts to the new expectation. At Invitek Diagnostics, we are also working on expanding our molecular food safety portfolio — including a PCR assay concept designed to detect Listeria spp. with specific identification of L. monocytogenes — to support laboratories seeking efficient screening and confirmatory workflows aligned with these evolving requirements.
ISO 20976-1:2019. Microbiology of the food chain — Requirements and guidelines for conducting challenge tests of food and feed products — Part 1: Challenge tests to study the growth potential, lag time and maximum growth rate. International Organization for Standardization. (Standard landing page): https://www.iso.org/standard/67800.html
EN ISO 11290-1:2017. Microbiology of the food chain — Horizontal method for the detection and enumeration of Listeria monocytogenes and of Listeria spp. — Part 1: Detection method. International Organization for Standardization. (Standard landing page): https://www.iso.org/standard/60313.html
EN ISO 11290-2:2017. Microbiology of the food chain — Horizontal method for the detection and enumeration of Listeria monocytogenes and of Listeria spp. — Part 2: Enumeration method. International Organization for Standardization. (Standard landing page): https://www.iso.org/standard/60314.html