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Session 4: General reflection including the perspective of the fresh produce sector and future developments in science

In this session, two presenters reflected on the usefulness of ACROPOLIS in future developments or future needs for trade and science. The first presentations focused on the problems in the European market related to pesticide residue regulation. The second presentations focused on the usefulness of ACROPOLIS models in the perspective of developments in new toxicological testing and interpretation of results in the RISK21 project.

Axel Moehrke (Dole Fresh Fruit /Freshfel Europe) presented the views of the fresh fruit and vegetables sector on the need of trust in legislations and the role of cumulative exposure assessment to cover for multiple pesticides. The consumption of fresh produce witnessed an on-going decline over the last decade. This trend is the result of several factors, including the consumers concerns about pesticide residues, driven by scaremongering approach inspired by NGO campaign. In contrast, the fresh produce industry has never been today as conscious about its food safety responsibility adopted Good Agricultural Practice (GAP) practices certified by quality scheme. Besides, and following the harmonization of Maximum Residue Limits (MRL), the compliance with the MRL has reached a very high level in recent years.

However, the development of lab technics, the emergence of new grey areas in the legislation such as the confusion between the Acute Reference Dose and Maximum Residue Limits and the omission of cumulative risk assessment, has resulted in the use of different pesticides to cope with the different pest/fungus in agriculture. This development has introduced new uncertainties in trade and motivated a number of retailers to introduce private standards

According to the trade organizations, the ACROPOLIS project is an important new milestone to provide greater confidence in the EU regulatory process and give additional confidence for consumers in the legislative process. Axel Moehrke reminded the audience that the IT tool developed by ACROPOLIS should be for the benefit of public stakeholders in the MRL decision and recognized tool to improve food safety risk decisions.

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To conclude the presentation of this second stakeholder conference, Alan Boobis (Imperial College -UK) presented his views on the ACOPOLLIS model in future perspective in RISK 21. RISK 21 is a new discussion aiming to transform toxicological testing and risk assessment towards more mechanism based approaches. It also aims to reduce the amount of animal testing and to start the process of risk assessment based on the relevance of outcomes of exposure observations. The RISK 21 discussion started in the USA based on three reports of the National Research Council and leading scientists reviewing the developments and future needs in toxicology and risk assessment in the 21th century.

Alan Boobis highlighted the progress made in a number of areas, including QSAR and omics technology, to screen chemicals for their toxicological properties. In addition to screening tools, ‘in vitro’ testing increases the possibility of confirming toxicological profiles. New cell culture approaches were also highlighted in the lecture. Observed effects in vitro, however, cannot always be translated to toxicological effects in the human body in a straightforward manner. To complement the observations in ‘in vitro’ testing systems, PB-PK modeling, scaling factors to transform toxicodynamic information from animals to humans and a more mechanistic based pathway approach are therefore needed.

The key principles of RISK 21, as far as they relate to the ACROPOLIS achievement presented today, are among other things a well-defined problem formulation, a tiered approach to exposure estimates and a tiered approach to toxicity hazard assessment. The results of the exposure and hazard assessment are plotted in a two dimensional plot in such a way that they are understandable for non-experts. The matrix is graduated from an area of minimal concern (green = low exposure, low toxicity) to one of high concern (red - high exposure, high toxicity) Chemicals falling to the intermediate zone are of potential concern, and the need for further refinement will be context dependent, as provided in the problem formulation. For a given chemical, the matrix plot gives an immediate indication of whether refinement of the exposure estimates or of the toxicity estimates will have the greater impact on the assessment. The risk from mixtures can also be visualized in this two-dimensional plot, including the influence of uncertainty on the estimates.

According to Alan Boobis, the ACROPOLIS project has already made major contributions to the objectives of RISK 21. First of all several of the ‘in vitro’ tests and the PB-PK models provide good proof of principle of how the toxicity of mixtures can be tackled in a efficient manner. The RISK 21 tiered approach to exposure assessment ranges from simple screening methods in tier 0 to biomonitoring in tier 3. In the RISK 21 scheme, probabilistic exposure assessment is considered a tier 2 approach and the ACROPOLIS IT tool showed today that higher tier exposure assessment is becoming available in Europe in a form that is accessible to stakeholders.