Potential Migration of ε-Caprolactam to Water and Wine as Affected by Transportation and Storage

Under normal sealing and storage conditions, Nylon-6, poly-caprolactam-based plastic laminates may release impurities to packaged foods and liquids and the application of heat for cooking often increases the rate of migration. Epsiloncaprolactam is one of the main contaminates found to migrate from a Nylon-6 polycaprolactam plastic film. The objectives of this study were to determine the effects of solvent, transportation and storage time on the migration of ε-caprolactam from a Nylon6-based lidding material into water or a white wine substitute (12% ethanol). Polypropylene plastic cups were filled, sealed, packaged, stacked and exposed to a simulated 3-day cross-country shipment. Cups were sampled with or without simulated shipment after 0, 7, 14 and 28 days at 20.6°C. Epsilon-caprolactam was determined using a GC equipped with FID and a Restek Rtx 1301 megabore column. Results of the study indicated migration of ε-caprolactam into containers at the time of sealing with significantly higher levels (4.42 ppm average) occurring in cups containing 12% ethanol vs. water (0.01 ppm average). After the cups were sealed, neither simulated crosscountry shipment nor storage increased levels of ε-caprolactam in either solvent. The results indicate that wine sealed in packages lined with Nylon-6-based plastic could contain significant amounts of ε-caprolactam. However, it is not understood how the alcohol, whether as liquid or vapor, interacted with the lidding material to increase migration at the time of sealing. No delamination of the polypropylene layer in the lidding material was observed after sealing. Future research needs to be conducted to study the effects of alcohol, alcohol vapor, sealing time and temperature on εcaprolactam migration.