A recent report from Food Technology Intelligence takes a closer a look at the important issue of the impact of migrating contaminants and additives in processed foods.
Across Europe, there are limits on recycling PET (polyethylene terephthalate) paper, board and composite materials that are used in food packaging applications because European legal requirements for their re-use may not be clearly defined. There has been a lack of knowledge on how additives and contaminants migrate from the recycled materials into food, which under current EU laws is prohibited. For this reason, the food industry has not been willing to use recycled materials.
In previous research, a group of scientists at the Fraunhofer Institut fur Verfahrenstechnik und Verpackung in Germany focused on the migration and recycling of packaging materials. Now they are trying to document the nature and extent of contamination in PET recovered from packaged products. The researchers are now aiming to generate a knowledge base covering the migration of contaminants and additives from reused paper and board packaging materials into foods.
The scientists will also investigate the use of functional barriers between the recycled material and products. Functional barriers are a function of several parameters. For organic molecules, PET is an excellent diffusion barrier that prevents any measurable migration of substances. But what is crucial is whether the barrier is efficient under applied packaging and storage conditions.
PET is an excellent material for packaging food. It has a low diffusivity and is the most promising polymer for recycling. It is mostly used for bottles and cups and is recycled by sorting, grinding, washing and drying. However, PET used in food contact applications must be further cleansed to eliminate the transfer of undesirable elements.
Contaminants and possible migrants of concern in recycled paper and board include chemical trace elements, waxes, fluorescent whitening agents and dyes, sizing agents, organochlorine substances, plasticizers, aromatic hydrocarbons, volatile organic compounds, curing and grease-proofing agents, amines, biocides and surfactants.
Investigators analysed 900 samples from European PET recyclers. By far the greatest portion of contaminants found in conventionally reprocessed PET were soft drink flavour components originating from first bottle use. These components were usually found in post-consumer PET samples in minute amounts - in the low ppm range. A few low-molecular-weight components were found at very low levels as PET unspecific compounds in trace amounts - lower than 0.5 ppm. Super-clean processed PET, however, was indistinguishable from virgin food-grade PET.
In order to investigate the migration behaviour of paper and board packaging materials, experimental studies were run using 12 model contaminants and 15 samples. The results of these studies, including the total and specific migration into the foods or food simulants, are to be published during the spring or summer 2003. The final report is also to include experiments and new data on the effects of functional barriers.
Further information on this research project can be obtained from Roland Franz, Fraunhofer Institut fur Verfahrenstechnik und Verpackung, by emailing: roland.franz@ivv.fraunhofer.de.