Nanoclay migration from food packaging materials.

A recent trend is to use nanocomposites materials for food-packaging applications. Different kinds of nanoparticles are incorporated into the polymers to improve their characteristics, and, among them, nanoclay is used to improve their barrier properties to gases. In this work, the results of migration studies with different food simulants (ethanol 10% and acetic acid 3%), temperatures and times (40 ºC for 10 days and 70 ºC for 2 h) from two commercialised LDPE nanocomposite bags are presented. The migration solutions thus obtained were analysed by ICP-MS to evaluate the amount of aluminium which migrated into the solutions both in dissolved form and as a part of nanoparticles. Aluminium migration was observed for both samples with a maximum migration value of 51.65 ng cm(-)(2) for the Aisaika bags and 24.14 ng cm(-)(2) for the Debbie Meyer bags. The presence of spikes working in single-particle mode using ICP-MS indicated that part of this aluminium was present as nanoparticles. The size and morphology of the nanoclay, in both the original material and the migration solutions, was studied by scanning electron microscopy coupled to energy-dispersive X-ray diffraction (SEM-EDX). In this manner, nanoparticles of different morphologies and sizes were found to migrate into the food simulants.