Listeria in ready-to-eat food: from 1 July 2026 “not detected in 25 g” throughout the shelf-life unless the producer shows that 100 cfu/g will not be exceeded — the EURL Lm has updated its guidance on challenge tests
On 26 February 2026 the EU Reference Laboratory for Listeria monocytogenes (EURL Lm) published an amendment to its technical guidance on challenge tests and durability studies for ready-to-eat foods. The document supports the application of Regulation (EU) 2024/2895, which from 1 July 2026 extends the “not detected in 25 g” criterion to products placed on the market throughout their shelf-life where the producer cannot show that 100 cfu/g will not be exceeded.
- Regulation 2024/2895 amended item 1.2 of Annex I to Regulation (EC) No 2073/2005 (ready-to-eat foods able to support the growth of L. monocytogenes, other than those intended for infants and for special medical purposes). Where the producer cannot demonstrate to the competent authority that 100 cfu/g will not be exceeded throughout the shelf-life, the criterion “not detected in 25 g” (n = 5, c = 0; EN ISO 11290-1) applies to products placed on the market during their entire shelf-life — previously it applied only before the food left the producer’s immediate control.
- The EURL Lm guidance (version 4, amendment 1) is to be read together with EN ISO 20976-1 and the DG SANTE guidance document; the amendment updates the reference to the new version of the DG SANTE document of December 2025, replaces the annex with the recommended set of strains by a reference to a separate report and corrects the formula in section 6.2.2.7.
- Challenge test assessing the growth potential: at least 3 batches (recommended from different production days), a mixture of L. monocytogenes strains, inoculation at about 100 cfu/g (range 50–200 cfu/g) within 2 days of production, and a standard deviation of the day-0 results below 0.3 log10 cfu/g. Storage reflects the cold chain — by default, where no data are available, 7 °C at the manufacturer and at retail and 10 °C at the consumer.
- The growth potential Δ is the difference between the highest result from at least 4 sampling points and the day-0 mean; Δ ≤ 0.5 log10 means the food does not support growth (category 1.3), Δ > 0.5 log10 that it does (category 1.2). According to the guidance, durability studies on naturally contaminated products are not recommended for validating the shelf-life — they are more appropriate for verifying it.