On 4 and 5 April 2017, Akademie Fresenius opened the doors on their 15th International Conference "Risk Assessment of Pesticide Residues in Food" in Cologne where representatives from the European Food Safety Authority (EFSA), the industry, research institutes and the authorities in Germany, Austria and the Netherlands were engaged to speak. The European Food Safety Authority’s new Guidance Documents and performing cumulative risk assessment were just two of the topics discussed by the experts.
The level of pesticide residues found in foodstuffs produced in Ger-many and the EU rarely exceeds the limits. In 2015, only 1.1 percent of the produce examined were found to exceed the maximum residue levels. The results of the tests carried out by the Federal States of Germany, published by the Federal Office of Consumer Protection and Food Safety (BVL) in its “National Report on Residues of Plant Protection Products in Food 2015”, confirm this low level which has remained unchanged for many years. Nevertheless, the industry now faces the task of keeping the maximum residue levels (MRL) as low as possible – due to new test procedures and, last but not least, increased interest on the part of the consumer for food safety topics.
Challenges in determining pesticide residues in pollen and honey
Karsten Hohgardt of the BVL in Braunschweig reported on current problems in determining pesticide residues in pollen and honey. The most recent version of the draft of a European directive on determining maximum residue levels in honey dates back to 2009. Hohgardt regretted that the European Commission and the Member States had stopped work on these guidelines. This meant that no such guidelines had ever been officially available for conducting trials to determine residue levels in honey. Although the European Commission did actually present a moderately updated version last September, experience gained in the past has shown that the contents of the directive need to undergo a general revision, according to Hohgardt. For example, the directive contains no information regarding honey products that are already available to the consumer on the market, e.g. honeycombs and propolis resin which bees use as a sealant and produce from tree sap. Hohgardt announced that the European Commission is currently examining the possibility of achieving synergies using the results of ecotoxicological studies to determine residue levels.
Under discussion: the toxicological relevance of metabolites
Anja Friel of the European Food Safety Authority EFSA (Parma/Italy) presented the new Guidance Document on residue definition. This EFSA document provides first and foremost procedural information on how to assess the toxicological relevance of metabolites. This Guidance Document can be used to determine the metabolites that require hazard identification and characterisation and where the risks to the consumer need to be assessed.
In his role as working group lead for the “EFSA Panel on Plant Protection Products and their Residues” (PPR), Thomas Kuhl of the Federal Institute for Risk Assessment (Berlin) made a major contribution to creating the new Guidance Document. During this Akademie Fresenius conference, he devoted his full attention to the question of how to determine metabolite relevance. The principles of metabolite assessment have only very slightly changed since the 1990s. Accordingly, metabolic products that are of lesser relevance owing to their negligible quantities are seldom subjected to a toxicological assessment due to their low exposure potential. According to Kuhl, things will be different in the future. In the meantime, great progress has been made with respect to developing methods which allow the hazard potential of metabolites – such as their genotoxicity – to be better characterised, e.g. using QSAR analyses (Quantitative Structure-Activity Relationships) or the “Threshold of Toxicological Concern” (TTC) concept. Through analysing the whole spectrum of metabolites in food and all the available information on this topic, one can get away from the strict “black and white” style of thinking in the risk assessment area and open up to an approach which also takes the evidentiary value of the data and the uncertainties of the assessment into consideration.
Industry perspective on EFSA’s approach to grouping pesticides for cumulative assessment
The European Food Safety Authority has developed a new approach for grouping pesticides which is intended to smooth the path for implementing cumulative risk assessment – a procedure for assessing the risks emerging from exposure to multiple pesticide residues. The general methodology for classifying pesticides into so-called “cumulative assessment groups” – CAGs is based on determining compounds that demonstrate similar toxicological properties in a certain organ or system. To achieve this, a special software tool was developed to carry out exposure assessments for multiple pesticides. In a pilot study, consumer exposure assessments were performed for groups of pesticides which may affect the thyroid and nervous systems. In the longer term, EFSA hopes to start progressively incorporating cumulative risk assessments into its annual analysis of the chronic and acute risks that pesticides pose to consumers. This analysis uses data collected by the Member States. At this Fresenius conference, Stephanie Melching-Kollmuss of BASF (Ludwigshafen) also evaluated the CAGs from an industry perspective. From her point of view, compounds should only be grouped together based on compound-specific, adverse and human-relevant effects. A more exact toxicological characterisation would lead to smaller groups. She was also of the opinion that the number of groups should be reduced based on suitable criteria and through taking additional pathological and reproductive toxicological expertise into consideration. As the level of residue exposure is so low, the question needs to be raised as to whether effects that are only observed in animal experiments using high dosages should also be considered in the cumulative assessment process.