In September 2025, the European Food Safety Authority (EFSA) released the technical report "Outcomes of the Peer Review Meeting on Common Issues Related to Physicochemical Properties and Analytical Methods of Pesticides", which serves as a crucial wake-up call for enterprises seeking to enter the EU pesticide market. This report systematically collates the core discussions of the 29th Pesticide Peer Review Meeting (held on November 22-23, 2023), focusing on high-frequency issues in key areas such as active substance identification, impurity profiles, and more. As the core scientific assessment body for EU pesticide active substance approval, EFSA's conclusions directly determine whether a substance can be approved for entry into the EU market, making this report an invaluable guide for enterprises to avoid registration risks.

The EU's approval process for pesticide active substances is renowned for its scientific rigor, and EFSA's peer review stands as the core checkpoint within this process. The common issues included in this report all stem from high-frequency controversial points in actual registration processes, accurately targeting the "pain points" of enterprise applications. Among these, the following four key issues are particularly noteworthy, and their conclusions provide a clear operational framework for enterprise applications.

Active Substance Re-evaluation: Full-chain Control of New Relevant Impurities

The identification of new "relevant impurities" during the re-evaluation of active substances is a common challenging issue for enterprises. During this meeting, member states focused on two core questions: Must other manufacturers of the active substance prove that these newly identified relevant impurities are absent from their products? And must formulators provide validated analytical methods for determining these new relevant impurities in their formulated products?

EFSA's conclusion provides a clear answer: the control of relevant impurities covers the entire chain. On one hand, all active substance manufacturers must test for such impurities in the technical material; on the other hand, formulators must also submit validated analytical methods at the formulation level. This requirement reflects the EU's strict control over pesticide safety — if an enterprise fails to provide a qualified testing method, it will be directly classified as a data gap, which in turn affects the conclusion and progress of the re-evaluation. This means that enterprises need to establish a dynamic impurity monitoring mechanism during the re-evaluation phase to proactively anticipate potential impurity risks.

Raw Material Management: Core Compliance Requirements for Supplier Changes

In the registration of active substances, the identity information (name, CAS number, structural formula), purity, and commercial availability of raw materials are essential application materials. However, during the re-evaluation or TE assessment phase, the compliance handling of raw material supplier changes has become a frequent confusion for enterprises: Is it necessary to conduct a new TE assessment, or is it sufficient to only provide the new supplier's MSDS?

EFSA clearly rejected the simplistic approach of "only providing MSDS", pointing out that MSDS is not an official data requirement and cannot meet the needs of comprehensive assessment. Although the handling methods vary among member states, the meeting reached a key consensus: regardless of whether the supplier changes, the technical material must always comply with the reference specifications. This conclusion provides enterprises with a clear operational guideline — when changing suppliers, the core work should focus on ensuring the consistency of technical material specifications, rather than relying on informal materials such as MSDS. Additional verification data should be supplemented when necessary.

Production Process: Multi-dimensional Assessment Logic for CMR Substance Relevance Determination

The use of CMR substances (carcinogenic, mutagenic, and reproductive toxic substances) in the production process and the determination of their relevance as impurities have long been the focus of reviews. The core question is: Should such substances be regarded as relevant impurities and included in specifications?

The meeting presented differentiated assessment perspectives: If the CMR substance is a raw material, some member states accept theoretical explanations based on the production process; if it can be sufficiently demonstrated that the substance cannot be present in the technical material, additional analytical data is not required. If the CMR substance is a solvent, some member states use a threshold of 1 g/kg — if batch analysis results show the content is below this value, it should not be regarded as a relevant impurity. However, other member states insist that once a CMR substance is detected in the technical material, it should be treated as a relevant impurity regardless of its content. Some member states have proposed more refined standards: if the detection result is below the LOD (Limit of Detection), it may not be included in the technical specifications; but if it falls between the LOD and LOQ (Limit of Quantitation), it should be included in the specifications.

The final consensus broke the reliance on single test data: the determination of whether an impurity is a relevant impurity ultimately requires a comprehensive judgment based on toxicological and ecotoxicological assessment results, rather than solely relying on analytical test data. This requires enterprises to not only retain test data when using CMR substances but also establish a multi-dimensional risk assessment system to provide sufficient basis for the determination of impurity relevance.

Formulation Authorization: Packaging-related Risk Control for Storage Stability

In the storage stability study of formulations, two issues repeatedly arise: Is packaging deformation acceptable? Can test results from small/medium-sized packages (such as 1 L, 20 L) be extrapolated to larger packages?

Regarding packaging deformation, some member states have put forward clear requirements: applicants should provide photos of product packaging in the application materials to facilitate the assessment of packaging size and potential bulging. Regarding the extrapolation of packaging sizes, most member states recognize the "worst-case scenario" attribute of small packages — due to their higher surface area-to-volume ratio, extrapolating test results to larger packages has a scientific basis, and research literature in the field of food contact materials can also be referenced to support the argument. However, some member states have put forward higher requirements, requiring enterprises to explain how to ensure product uniformity under large packaging, safe transfer operations for users, and container recycling methods.

EFSA specifically pointed out that the current guidance documents do not fully cover these scenarios and may be updated in the future. This reminds enterprises to proactively strengthen the detailed management of storage stability studies, especially packaging-related risk control, while closely monitoring updates to guidance documents.

Conclusion: Building a Solid Compliance Foundation with a Problem-oriented Approach

EFSA's newly released report on common issues essentially represents a concentrated manifestation of the EU's pesticide evaluation logic — a full-chain compliance requirement centered on science and targeted at risk control. For pesticide enterprises planning to enter or already deeply engaged in the EU market, this report is not only a collation of past review controversies but also a "pitfall-avoidance guide" for future applications. Enterprises need to take these common issues as a guide to establish a more refined compliance system in key links such as active substance impurity control, raw material management, CMR substance risk assessment, and formulation storage stability. Only in this way can they improve the approval rate in the EU's strict approval process and lay a solid foundation for market access.