Table 1.

Case scenarios for the risk assessment of nanomaterials in agriculture, feed and food (EFSA 2011)

Case	Scenario description
1. No persistence of engineered nanomaterials in preparations/formulations as marketed	For nanotechnology applications where convincing evidence is provided, demonstrating, by appropriate analytical methods that the ENM is completely degraded/solubilized to non-nanoform, the EFSA Guidance for non-nanoforms for the specific intended use should apply, and this ENM Guidance would no longer apply
2. No migration from food contact materials (i.e., no exposure)	Where evidence is provided convincingly demonstrating, by appropriate analytical methods that there is no migration, the risk assessment could be based on the information that there is no exposure to the ENM via food and therefore there is no toxicological concern
3. Complete transformation of engineered nanomaterials into a non-nanoform in the food/feed matrix before ingestion	When evidence is provided convincingly demonstrating, by appropriate analytical methods, that transformation of the ENM into a non-nanoform in the food/feed matrix is judged to be complete (i.e., non-nanoform degradation products are present) before ingestion, then EFSA Guidance for non-nanoforms for the specific intended use should apply, and this present ENM Guidance would no longer apply
4. Transformation during digestion	When evidence is provided convincingly demonstrating, by appropriate analytical methods that an ENM completely dissolves/degrades in the gastrointestinal tract, the hazard identification and hazard characterization can rely on data for the non-nanoform substance (if available) as long as the possibility of ENM absorption before the dissolution/degradation stage can be excluded. When evidence is provided convincingly demonstrating that no ENM absorption takes place a limited set of tests in general consisting of in vitro genotoxicity, in vivo local effects and/or other appropriate in vivo testing may be deemed as sufficient. The systemic toxicity profile of a dissolved ENM is likely to be similar to the soluble (ionic or molecular) form. If this is demonstrated, further testing on the ENM is not necessary. In cases where data on the non-nanoform are not available, testing of the non-nanoform is required according to the relevant EFSA Guidance for the intended use
5. Information on non-nanoform available	When information on a non-nanoform of the same substance is available and where some or all of the ENM persists in the food/feed matrix and in gastrointestinal fluids, a testing approach is recommended which is based on comparison of information on ADME, toxicity, and genotoxicity of the non-nanoform with, in first instance, ADME, repeated-dose 90-day oral toxicity study in rodents and genotoxicity information of the ENM. The purpose of comparing ADME and toxicity data from the two forms is to identify any major differences between the behavior of the non-nanoform and that of the ENM. If the differences observed indicate increased hazard, then more toxicity testing will be required on the ENM, beyond ADME, 90-day and genotoxicity tests. If the differences observed indicate less hazard then any request to waive further testing should be scientifically justified
6. No information on non-nanoform available	When information on a non-nanoform is not available and where some or all of the ENM persists in the food/feed matrix and in gastrointestinal fluids, the approach for toxicity tests on the ENM should follow the relevant EFSA guidance for the intended use with the modifications in the present guidance to take into account the nanoproperties. The ENM toxicity testing strategy provided for hazard identification and hazard characterization takes into account the nanoproperties