In an article published online on August 9, 2021, in the peer-reviewed journal Food Additives & Contaminants: Part A, Edoardo Galbiati and colleagues from the NutriFOODchem Research Group, Ghent University, Belgium, reported on a hazard prioritization of chemicals used in printing inks and adhesives in plastic food contact materials (FCMs).
To prioritize hazardous substances, the researchers first compiled an inventory of chemicals intentionally used in printing inks and adhesives of plastic FCMs by reviewing scientific publications and regulatory documents including the Swiss Ordinance Annex 10 on materials and articles in contact with food. Subsequently, they performed several steps to exclude substances not considered relevant such as chemicals without a CAS number, chemicals with a molecular weight above 1000 Dalton, and according to selected criteria based on the Threshold of Toxicological Concern (TTC) concept. For the remaining chemicals, Galbiati et al. performed hazard prioritization by comparing them to the Candidate List of substances of very high concern (SVHC) for authorization under the REACH regulation (FPF reported), to the SIN list (FPF reported), the Rapid Alert System for Food and Feed (RASFF) portal, and a list of substances used in printed paper and board FCMs published by Van Bossuyt et al. (FPF reported). When toxicity data was absent or scarce, the scientists followed the TCC approach to predict the chemical’s toxicity based on the chemicals’ structural information and estimated exposure level. Any of the substances present on the SVHC or SIN lists, in Van Bossuyt et al., in a notification from the RASFF portal, or with a Structural Alert (S.A.) for genotoxic carcinogenicity were considered as high priority. Chemicals classified as Cramer Class III or a S.A. for non-genotoxic carcinogenicity were ranked as medium priority. High and medium priority substances were presented to five experts from industry and academia to gain their opinion whether the chemical is “relevant or not for further investigation with respect to its migration from inks and adhesives used in food contact materials.”
The initial inventory Galbiati and co-authors compiled listed 7413 substances that are known to be used in printing inks and adhesives applied to plastic food packaging. According to the study results, most of them have not been evaluated for their toxicity, highlighting “the gap between the required safety assessment and the reality.” Driven by that fact and due to the high number of substances used in printing inks and adhesives, the scientists performed a prioritization in order to identify the substances of highest concern that need to be addressed first in risk assessments. After filtering according to the above-mentioned steps, 2331 of the chemicals were retained. Of these, 57 were present in the SVCH list, 141 in the SIN list, 96 in the publication by Van Bossuyt, and 35 notified by RASFF. Together with the 389 substances with a S.A. for genotoxic carcinogenicity, this made up a total of 636 unique high priority substances. Another 1024 chemicals were classified as medium priority substances including 818 Cramer class III chemicals, and 206 with a S.A. for non-genotoxic carcinogenicity. The experts evaluated 1660 of the high and medium priority substances and considered 696 relevant “for further investigation with respect to its migration from inks and adhesives used in food contact materials” which were classified as ‘very high priority substances’. Galbiati and colleagues propose that their strategy “can be further developed in order to provide a useful tool to European authorities and national risk assessors for the prioritisation of the evaluation of an extensive group of FCMs substances.”
The Food Packaging Forum’s Food Contact Chemicals database (FCCdb) lists intentionally added food contact chemicals including a set of 608 substances prioritized for further assessment and substitution. Another recently published research study reported on phthalates migrating from adhesive labels into fruits and vegetables (FPF reported), and printing inks have previously been identified as priority products by the US state of Washington due concerns that they release polychlorinated biphenyls (PCBs, FPF reported). While there is no specific regulation for printing inks used in FCMs under European community law, in Switzerland a positive list for printing inks has been in force since 2010, having undergone updates since then (FPF reported and here). While Switzerland lists more than 5000 substances for use in printing inks, only a few have been evaluated toxicologically.
Reference
Galbiati, E. et al. (2021). “Hazard prioritisation of substances in printing inks and adhesives applied to plastic.” Food Additives & Contaminants: Part A. DOI: 10.1080/19440049.2021.1954701
