On July 3, 2015 the peer-reviewed journal Analytical and Bioanalytical Chemistry published a study by Spanish researchers Elena Canellas, Paula Vera and Cristina Nerín, working at the University of Saragossa, Spain and/or the food contact materials (FCMs) supplier Samtack (Canellas et al. 2015). In their study, Canellas and colleagues were interested in the migration of non-intentionally added substances (NIAS) from the adhesive in laminated bioplastics used as FCMs. Bioplastics are sourced from renewable materials and/or they are biodegradable and/or compostable. Three different types of compostable multilayer materials were studied: (1) a polylactic acid (PLA) film, glued to paper, (2) a compostable plastic film containing PLA (ecovio®), glued to another identical piece of plastic film, and (3) a compostable plastic film containing PLA (ecovio®), glued to polyvinyl alcohol (PVA) film, glued to another piece of compostable plastic film containing PLA (ecovio®).
The adhesive used in all multimaterial FCMs was water-based and biodegradable. It was shown to contain one volatile NIAS (1,6-dioxacyclododecane-7,12-dione, no CAS available; EC number 212-291-3), 5 volatile, intentionally added constituents and several non-volatile compounds of which 4 were unidentified NIAS, likely products from the reaction between the adhesive constituents adipic acid (CAS 124-04-9) and butane-1,4-diol (CAS 110-63-4).
Migration from the multilayer FCMs was studied using Tenax® as food simulant (for dry foods), at 40°C for 10 days. Targeted analysis for the 6 identified volatile adhesive constituents, as well as for the identified non-volatile substances, was carried out. The researchers found no migration of volatile nor non-volatile adhesive constituents for multilayer 1 at limits of detection (ranging from 0.03 to 3 mg/kg food simulant), whereas migration of 2 newly formed NIAS and one other substance was observed for samples 2 and 3. Thereby, higher migration values were observed in multilayer 2, indicating that the PVA layer in sample 3 reduced (adhesive) migration.
The researchers also assessed whether the FCMs under investigation would comply with EU regulation. For some of the migrants specific migration limits (SML) exist when used in plastic FCMs, and none of the respective migrants were found at levels above their SMLs. For those migrants where no SMLs exist Canellas et al. applied the Threshold of Toxicological Concern (TTC) to assess whether the identified migrating NIAS were of concern, and found them to be below the TTC level for substances of the lowest toxicity class.
Canellas, E. et al. (2015). “UPLC–ESI-Q-TOF-MSE and GC–MS identification and quantification of non-intentionally added substances coming from biodegradable food packaging.” Analytical & Bioanalytical Chemistry.