In Vitro Genotoxicity/Mutagenicity Testing of Food Packaging

To ensure the safe use of packaging materials and food contact materials, genotoxicity assessment is one of the requirements of regulatory agencies around the globe. Thus, it is essential to carry out preliminary tests to clarify this possible mechanism. The Salmonella/mammalian-microsome mutagenicity test, widely known as the Ames test, is a rapid, relatively simple procedure for testing chemicals for mutagenicity as well as for offering provision for the metabolism of otherwise nonmutagenic chemicals to their potentially DNA-reactive forms. However, a single test is not sufficient to detect all relevant genotoxic mechanisms in tumorigenesis. Thus, in order to complement the results in the Ames test and to contribute to the elucidation of the effects, ensuring their use or not, mutagenicity at the chromosomal level must also be evaluated. In the micronucleus (MN) assay, chromosomal damages induced by chemical products are evaluated. The MN is expressed in dividing cultured cells because fragments from damaged chromosomes or whole chromosomes that lag during anaphase become enveloped by nuclear membrane, independently from the main nucleus during telophase, prior to cell division. Together, these tests detect the most relevant events for the multistep process of malignancy, that is, gene mutations, clastogenicity, and aneugenicity. Detailed descriptions of the protocols used for detection of point mutations and chromosomal damage induced by food packaging in vitro are given in this chapter.