EFSA publish scientific opinion on genotoxicity testing strategies applicable to food and feed assessment

For an adequate evaluation of the genotoxic potential of a chemical substance, different end-points (i.e. induction of gene mutations, structural and numerical chromosomal alterations) need to be assessed, as each of these events have been implicated in carcinogenesis and heritable diseases. Adequate coverage of these end-points can only be obtained by the use of more than one test system, as no individual test can simultaneously provide information on all these end-points. 

The Scientific Committee has therefore recommended a revision to the in vitro test battery as the first step in testing, with a bacterial reverse mutation test (OECD 471) and in vitro mammalian cell micronucleus (OECD 487) test.  The addition of the in vitro mammalian gene mutation cell test in the basic battery significantly increases the ability of the test battery to produce “misleading” positive results (i.e. specificity [in this context the ability to correctly  identify non-carcinogens]) with no substantial gain in the test battery to detect “real” positives (i.e. sensitivity [in this context the ability to correctly identify genotoxic carcinogens]).  Therefore, the in vitro mammalian gene mutation test has been omitted from the in vitro test battery.

If all in vitro endpoints are clearly negative in adequately conducted tests, then it can be concluded with reasonable certainty that the substance has no genotoxic potential, without the need to undertake in vivo testing (there are of course exceptions to this rule).

If you require further information on genotoxicity testing strategies or on any other regulatory matters please contact JSC at +44(0)1423 520245 or enquiries@jsci.co.uk