P03-04: Safety evaluation of can's polyester coatings using and approaches

Can's internal coatings may represent a source of food contamination due to the migration of Non-Intentionally Added Substances (NIAS) from coatings into food matrix. NIAS are contaminants, degradation products, or impurities and their presence and formation are mostly unknown. Among NIAS, linear and cyclic oligoesters could possibly migrate from polyester-based coatings. Their identification and quantification are challenging due to the lack of analytical standards. In addition, there is a gap of knowledge available in the literature regarding their toxicity.The aim of this study is to evaluate the safety of a can's polyester coatings to protect consumers from chemical exposure. Five polyestercoated metal plates were extracted by acetonitrile (ACN) and ethanol-95% (EtOH) in migration cells. Samples were then concentrated and analyzed by liquid chromatography–high resolution mass spectrometry in a non-targeted way. Four cyclic oligoesters composed of tricyclodecanedimethanol (TCDDM), 1,4-butanediol (BD), and terephthalic acid (PA) were identified in all replicates: c(2BD+TCDDM+3PA), c(BD+ 2TCDDM+3PA), c(3TCDDM+3PA), c(2TCDDM+2PA). Considering TCDDM isomers and potential BD and PA isomers (1,3-butanediol and orthophthalic acid), 147 possible structural isomers were designed for four oligoesters. Several in silico predictive tools (VEGAHUB, SARAH, DEREK, Lazar, ADMETlab 2.0, Protox-II) were used to predict the mutagenicity and carcinogenicity of these molecules. All structural isomers showed negative prediction in all in silico tools for in vitro mutagenicity, and positive prediction for carcinogenicity in VEGAHUB, meaning that they can be potential tumor promotors. Lazar, ADMETlab 2.0, Protox-II also showed positive prediction for carcinogenicity for most of isomers of c(2BD+TCDDM+3PA) and c(BD+2TCDDM+3PA). Furthermore, the majority of structural isomers of four oligoesters showed 3 alerts for genotoxic carcinogenicity rule based on toxicophore rules using ADMETlab 2.0.To confirm predictive in silico alert, extracts were tested in vitro with the Cell Transformation Assay (CTA). All ACN and EtOH extracts were negative in the initiation assay of CTA, however, one of the EtOH extracts was equivocal in the promotion assay