In a study published on July 16, 2016 in the peer-reviewed journal Food Control, Chiara Bignardi and colleagues from the Università degli Studi di Parma, Italy, examined the influence of ageing on the migration of degradation products and coloring agents from re-usable polycarbonate tableware allowed for food contact.
Examined food contact articles were from the same producer and were either new and never used, or used and aged between two and fourteen years. The degree of damage on the polycarbonate surface was assessed microscopically as the amount of scratches and cracks observed. Migration tests were performed for 1 hour at 40°C using 95% ethanol and isooctane as fatty food simulants. Migrating substances were identified and semi-quantified by untargeted high-resolution mass spectrometry analysis.
Several polycarbonate oligomers, with molecular weight values between 227 and 989 g/mol, were found to migrate into the examined simulants. Migrating compounds of higher molecular weight were also observed but not followed further due to an assumption that only the species below 1000 Da are of a health concern (Cavazza A., personal communication). The pattern of migrating degradation products differed between the new and the old articles. The more damaged the plastic was, the more migration of polycarbonate degradation products, including bisphenol A (BPA, CAS 80-05-7) – the monomer of polycarbonate plastics – was observed. On the other hand, the migration of putative by-products of polymerization (such as unreacted molecules), was lower in the older compared to the newer samples. Thus, the authors suggest that the ageing of polycarbonate promotes the hydrolysis of ester linkage, leading to the appearance of higher amounts of degradation products, while unreacted chains are primarily migrating from the newer products.
Coloring agents belonging to the category of solvent dyes were found to migrate from the red (solvent Red 179), the orange (solvent Yellow 184), and the yellow (solvent Yellow 232) samples. Comparing the pairs of similar samples with different ages (2013 vs. 2007, or 2014 vs. 2009), although the dye migration was detected in all samples, much higher amounts were released by the newer samples. Thus, the authors show that the new polycarbonate objects are a source of organic dyes with migration potential. This finding may require a more detailed investigation, since the national regulation of many countries prohibits the migration of organic dyes into food.
Bignardi, C. et al. (2016). “Release of non-intentionally added substances (NIAS) from food contact polycarbonate: Effect of ageing.” Food Control 71: 329-335.