An EFSA Scientific Committee has been considering how to harmonise strategies for evaluating genotoxicity when assessing the safety of chemicals in food and animal feed. For an adequate evaluation of genotoxic potential, different end-points need to be assessed (notably, the induction of gene mutation and alterations to chromosome structure and number), and the Committee recommended a step-wise approach to the assessment process, starting with an Ames test (bacterial mutation assay) and in vitro mammalian cell micronucleus test. It was suggested that where “all in vitro end-points are clearly negative in adequately conducted tests, then it can be concluded with reasonable certainty that the substance has no genotoxic potential” (a decision on whether to proceed to in vivo testing under such circumstances should be considered on a case-by-case basis, using a documented weight-of-evidence approach). In cases where there were inconclusive, contradictory or equivocal results from in vitro studies, it was noted that further in vitro tests might resolve outstanding issues, while in cases where there were positive in vitro results, the Committee felt that all relevant data should be considered (including data on bioavailability and metabolism, and structural and read-across information) before decisions were made on follow-up (in vivo) studies. If in vivo testing was deemed necessary, EFSA proposed the in vivo micronucleus test, in vivo Comet assay or transgenic rodent assay (depending on the in vitro results, and any target organs and tissues identified).

[European Food Safety Authority (2011). EFSA Scientific Committee; Draft Scientific opinion on genotoxicity testing strategies applicable in food and feed safety assessment. Endorsed for public consultation on 5 April 2011. Visit online.] {187597}

The above item was taken from the June 2011 issue of Toxicology and Regulatory News which is sent automatically to members of bibra (click here for more details).

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