SAFETY EVALUATION OF FOOD CONTACT PAPER AND BOARD USING CHEMICAL TESTS AND IN VITRO BIOASSAYS - THE ROLE OF KNOWN AND UNKNOWN SUBSTANCES

International audience; In vitro toxicological tests has have been proposed as an approach to complement the chemical safety assessment of food contact materials, particularly those with a complex or unknown chemical composition such as paper and board. An EU 5th framework program project “BIOSAFEPAPER – Application of bioassays for safety assessment of paper and board for food contact” specially focused on the application of biotests to paper and board. The project included both chemical characterization and toxicological testing of a representative number of paper and board extracts prepared according to the proposed end use (wet, fatty and dry food contact). Among the concerns addressed in the project wereraised regarding the applicability of in vitro tests are the effects of interference of the extractables on the outcome of the cytotoxicity and genotoxicity tests applied and the role of known compounds present in paper and boardchemically complex materials such as paper and board, either as constituents or contaminants.. In order to answer these questions, a series of experiments were performed to assess the role of, natural substances (wood extracts, resin acids), some additives (diisopropylnaphthalene, phthalates, acrylamide, fluorescent whitening agents) and contaminants (2,4-diaminotoluene, benzoa(a)pyrene) in the toxicological profile of paper and board. These substances were individually tested or used to spike actual paper and board extracts. The toxic concentrations of diisopropylnaphthalenes and phthalates , were compared with those actually detected in paper and board extracts showing conspicuous toxicity. According to the results of the spiking experiments the extracts did not affect the toxicity of tested chemicals, nor was there any significant metabolic intereference in the cases where two compounds were used in tests involving xenobiotic metabolism by the target cells. While the identified substances apparently have a role in the cytotoxicity of some of the project samples, their presence does not explain the total toxicological profile of the extracts. In conclusion, biotesting can have a role in the safety assessment of chemically complex materials in detecting potentially harmful activities not predictable by the chemical analysis alone.