The evaluation of toxicity and mutagenicity of various drinking waters in the human blood lymphocytes (HULYs) in vitro

Evaluation of the Suitability of Mammalian In Vitro Assays to Assess the Genotoxic Potential of Food Contact Materials

Background: Non-targeted screening of food contact materials (FCM) for non-intentionally added substances (NIAS) reveals a great number of unknown and unidentified substances present at low concentrations. In the absence of toxicological data, the application of the threshold of toxicological concern (TTC) or of EU Regulation 10/2011 requires methods able to fulfill safety threshold criteria. In this review, mammalian in vitro genotoxicity assays are analyzed for their ability to detect DNA-damaging substances at limits of biological detection (LOBD) corresponding to the appropriate safety thresholds. Results: The ability of the assays to detect genotoxic effects varies greatly between substance classes. Especially for direct-acting mutagens, the assays lacked the ability to detect most DNA reactive substances below the threshold of 10 ppb, making them unsuitable to pick up potential genotoxicants present in FCM migrates. However, suitability for the detection of chromosomal damage or investigation of other modes of action makes them a complementary tool as part of a standard test battery aimed at giving additional information to ensure safety. Conclusion: improvements are necessary to comply with regulatory thresholds to consider mammalian genotoxicity in vitro assays to assess FCM safety.

In Vitro Toxicity Testing of Food Contact Materials: State-of-the-Art and Future Challenges

Currently, toxicological testing of food contact materials (FCMs) is focused on single substances and their genotoxicity. However, people are exposed to mixtures of chemicals migrating from food contact articles (FCAs) into food, and toxic effects other than genotoxic damage may also be relevant. Since FCMs can be made of more than 8 thousand substances, assessing them one-by-one is very resource-consuming. Moreover, finished FCAs usually contain non-intentionally added substances (NIAS). NIAS toxicity can only be tested if a substance's chemical identity is known and if it is available as a pure chemical. Often, this is not the case. Nonetheless, regulations require safety assessments for all substances migrating from FCAs, including NIAS, hence new approaches to meet this legal obligation are needed. Testing the overall migrate or extract from an FCM/FCA is an option. Ideally, such an assessment would be performed by means of in vitro bioassays, as they are rapid and cost-effective. Here, we review the studies using in vitro bioassays to test toxicity of FCMs/FCAs. Three main categories of in vitro assays that have been applied include assays for cytotoxicity, genotoxicity, and endocrine disruption potential. In addition, we reviewed studies with small multicellular animal-based bioassays. Our overview shows that in vitro testing of FCMs is in principle feasible. We discuss future research needs and FCM-specific challenges. Sample preparation procedures need to be optimized and standardized. Further, the array of in vitro tests should be expanded to include those of highest relevance for the most prevalent human diseases of concern.

Use of bioassays to assess hazard of food contact material extracts: State of the art

This review focuses on the use of in vitro bioassays for the hazard assessment of food contact materials (FCM) as a relevant strategy, in complement to analytical methods. FCM may transfer constituents to foods, not always detected by analytical chemistry, resulting in low but measurable human exposures. Testing FCM extracts with bioassays represents the biological response of a combination of substances, able to be released from the finished materials. Furthermore, this approach is particularly useful regarding the current risk assessment challenges with unpredicted/unidentified non-intentionally added substances (NIAS) that can be leached from the FCM in the food. Bioassays applied to assess hazard of different FCM types are described for, to date, the toxicological endpoints able to be expressed at low levels; cytotoxicity, genotoxicity and endocrine disruption potential. The bioassay strengths and relative key points needed to correctly use and improve the performance of bioassays for an additional FCM risk assessment is developed. This review compiles studies showing that combining both chemical and toxicological analyses presents a very promising and pragmatic tool for identifying new undesirable NIAS (not predicted) which can represent a great part of the migrating substances and/or "cocktail effect".

Chemical compounds and toxicological assessments of drinking water stored in polyethylene terephthalate (PET) bottles: A source of controversy reviewed

A declaration of conformity according to European regulation No. 10/2011 is required to ensure the safety of plastic materials in contact with foodstuffs. This regulation established a positive list of substances that are authorized for use in plastic materials. Some compounds are subject to restrictions and/or specifications according to their toxicological data. Despite this, the analysis of PET reveals some non-intentionally added substances (NIAS) produced by authorized initial reactants and additives. Genotoxic and estrogenic activities in PET-bottled water have been reported. Chemical mixtures in bottled water have been suggested as the source of these toxicological effects. Furthermore, sample preparation techniques, such as solid-phase extraction (SPE), to extract estrogen-like compounds in bottled water are controversial. It has been suggested that inappropriate extraction methods and sample treatment may result in false-negative or positive responses when testing water extracts in bioassays. There is therefore a need to combine chemical analysis with bioassays to carry out hazard assessments. Formaldehyde, acetaldehyde and antimony are clearly related to migration from PET into water. However, several studies have shown other theoretically unexpected substances in bottled water. The origin of these compounds has not been clearly established (PET container, cap-sealing resins, background contamination, water processing steps, NIAS, recycled PET, etc.). Here, we surveyed toxicological studies on PET-bottled water and chemical compounds that may be present therein. Our literature review shows that contradictory results for PET-bottled water have been reported, and differences can be explained by the wide variety of analytical methods, bioassays and exposure conditions employed.