FAIR-CT98-4318 Programme on the recyclability of food packaging materials with respect to food safety considerations-polyethylene terephthalate and cellulosic fibres

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FAIR Area 1.2 - Green Chemicals and Polymers Chain : Packaging : Paper/Pulp

	Proposal No:	FAIR-CT98-4318
	Date Prepared:	November 1999
	Source:	Launch Report March 1999

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Launch Report March 1999

Summary

Although not directly a 'non-food' profect. The following will be of interest to those working in the area of bio-degradable packaging materials. Stimulated by new regulations, new routes of recycling waste appear on the market. Since food packages represent a large percentage of the plastics consumption, and since they have a short lifetime, an important approach consists in making new packages from post-consumer used packages. Food packaging regulations in Europe require that the packaging materials must not cause mass transfer (migration) of harmful substances to the food. Considerable scientific progress has been made in understanding and modelling the transfer of adventitious hazardous substances from recycled plastics into foodstuffs. Most of this knowledge has been elaborated within the recently finished EU project AIR-CT93-1014. One of the main conclusions of this project was that PET as a low diffusivity plastic and is the most promising polymer for reuse as a food packaging material. Nevertheless, the practical translation of this progress into innovative industrial solutions is still awaited. One of the reasons has typical European character and can be substantiated by the fact that the European legal requirements in this respect are not yet clearly and uniformly defined. As a consequence, economic and generally recognised test methods are not available so far. With respect to PET, there is clearly an obvious reason for the industrial hesitation in launching advanced food packaging applications. In the whole chain of knowledge on diffusion and migration into and out of PET - which allows for instance to correlate a known initial concentration in the plastic with the resulting time- dependent concentration in a foodstuff - there remains one missing link: This is the still open but highly important question of the nature and concentration of actual contaminants found in re-collected PET. Filling up this gap with analytical data relevant for the whole of Europe, and then linking this statistical picture with the available knowledge on PET diffusion behaviour, would enable to draw scientifically sound and convincing conclusions about the safety of reusing PET.

With respect to recovered paper and board as food packaging materials, the situation is practically the reverse of that described for plastics above. Considerable work has focused on the compositional analysis of virgin and recycled fibres to identify contaminants which could potentially be harmful to the consumer. However, little systematic work has been focused on the interactions of such substances between paper/board fibres and foodstuffs, and taking also polymeric coatings and plastic layers on paper and board into account. Again, as with the PET situation, there is a missing link in the chain of knowledge about the migration from cellulosic fibres which needs to be made to achieve analogous goals as mentioned above for recycled PET and to enter new pathways in the enormous food packaging market of paper and board. This topic gains automatically even more importance since it is the clear intention of the European Commission services, now nearing completion of food contact plastics regulations, to bring also paper and board within the scope of specific European regulations on food contact materials.

The objectives of the project are (i) to facilitate industrial innovation and to harmonise legislative enforcement of new environmental packaging requirements stemming from the Directive 94/62/EEC on packaging and packaging waste, by (ii): Drawing up a statistical overview of the nature and extent of contaminants in PET recovered from the food packaging market, in order to establish an evaluation platform for the quality and safety-in-use of recycled PET plastics for food packaging and (iii) Generating a scientific understanding of the physico-chemical behaviour of chemical contaminants on paper and board fibres as a basis for safety evaluation and definition of criteria for the appropriate reuse of recycled fibres for food packaging. Another option to reuse recycled plastics and which is very attractive from the point of view of food safety can be seen in the use of a functional barrier, which is a layer of virgin polymer placed between the recycled material and the food. The functional barrier (FB) plays the role of a protective layer. Theoretically, during the time of diffusion in FB no detectable diffusion occurs in food. The diffusion kinetics of the migrant have a consequence on official methods to control migration. With monolayer materials, migration increases linearly with the square root of time of contact in an initial period. The situation is different for multilayer materials. No migration occurring during lag time, migration testing (including storage of packaging since processing) have to be longer than this period. The measurement of pollutant migration at 1 0 days (test actually applied) may have no significance and new test strategies may be necessary.

The overall aim of the project is to overcome the current hesitation and inhibitions to innovation felt by many SME companies who want to produce new and environmentally-friendly food packaging but who cannot operate in an uncertain legislative framework. Simultaneously, practical recommendations and guidance to the Commission for appropriate legislation on recycled materials will be offered.

Overall objectives

The aim of the project is to overcome the current hesitation and inhibitions to innovation felt by many SME companies who want to produce new and environmentally-friendly food packaging but who cannot operate in an uncertain legislative framework. This project aim should be achieved by generating more know- ledge and methodologies with respect to the safe reuse of recycled PET and cellulosic fibres as well as the applicability of functional barrier layers for protection against recycled materials. Simultaneously, practical recommendations and guidance to the Commission for appropriate legislation on recycled materials will be offered. By doing this, the project will promote the competitiveness of European industry in comparison to US firms which already benefit from legally applicable FDA regulations. Finally, in order to achieve solutions agreeable between European and US-FDA regulatory systems, the project foresees an informal and partial experimental involvement of the US-FDA's laboratory for "Safety evaluation of indirect food additives".

To meet the project aims, the following overall objectives are placed in the project:

• To facilitate industrial innovation and to harmonise legislative enforcement of new environmental packaging requirements stemming from the Directive 94/62/EEC on packaging and packaging waste, by:
• Drawing up a statistical overview of the nature and extent of contaminants in polyethylene terephthalate (PET) recovered from the food packaging market, in order to establish an evaluation platform for the quality and safety-in-use of recycled PET plastics for food packaging.
• Generating a scientific understanding of the physico-chemical behaviour of chemical contaminants on paper and board fibres as a basis for safety evaluation and definition of criteria for the appropriate reuse of recycled fibres for food packaging.
• Generating an advanced scientific understanding and modelling of the physico-chemical behaviour of chemical contaminants in recycled plastics layers buried by functional barrier polymers as a basis for safety evaluation and definition of criteria for the appropriate functional barrier protection design against recycled plastics for food packaging.
• Proposing practical recommendations for appropriate legislation on recycled materials and economic test procedures including predictive tools for the evaluation and safety- optimised design of recycled material-based food packaging applications.

State of the art

Food packaging regulations in Europe require that the packaging materials must not cause mass transfer (migration) of harmful substances to the food. Considerable scientific progress has been made in understanding and modelling the diffusion and migration of adventitious hazardous substances from recycled plastics into foodstuffs in direct or indirect contact with the food. Most of this knowledge has been elaborated within the recently finished EU project AIR-CT93-1014. One of the main conclusions of this project was that PET is a low diffusivity plastic and is the most promising polymer for reuse as a food packaging material Furthermore, from the project's results and taking the existing FDA's position into account, for the first time in Europe an attempt has been made within an ILSI Europe expert group to draft corresponding guidelines and recommendations for the safe reuse of plastics for food packaging.

Nevertheless, the practical translation of this progress into innovative industrial solutions is still awaited. One of the reasons has typical European character and can be substantiated by the fact that the European legal requirements in this respect are not yet clearly and uniformly defined. As a consequence, the second reason is the lack of economic and generally recognised test methods. SME companies in particular cannot afford and/or are not capable to undertake alone the work- load and costs related to the specific test programmes and research work which is needed here. It must be noted that due to a lack of knowledge the currently proposed test approaches are too conservative and pose therefore a much too high cost burden on the shoulders of interested companies.

With respect to PET, although being the most promising candidate plastic for recycling, there is clearly an obvious reason for the industrial hesitation in launching advanced food packaging applications. In the whole chain of know- ledge on diffusion and migration into and out of PET - which allows for instance to correlate a known initial concentration in the plastic with the resulting time-dependent concentration in a foodstuff - there remains one missing link:

This is the still open but highly important question of the nature and concentration of actual contaminants found in collected PET such as that originating from soft drink bottles. Filling up this gap with analytical data relevant for the whole of Europe, and then linking this statistical picture with the available knowledge on PET diffusion behaviour, would enable us to draw scientifically sound and convincing conclusions about the safety of reusing PET. This in turn would allow us to derive the appropriate test conditions and methods for industry to use and for recommending to the Commission for future regulations. These methods will offer for the first time the possibility of being not too exaggerated and over-challenging - which is presently necessary as a precaution due to the current lack of knowledge - but being practical and economical whilst safe-guarding the consumer at the same time.

With respect to recovered paper and board as food packaging materials, the situation is practically the reverse of that described for plastics above. Considerable work has focused on the compositional analysis of virgin and recycled fibres to identify contaminants which could potentially be harmful to the consumer. How- ever, little systematic work has been focused on the interactions of such substances between paper/board fibres and foodstuffs, and taking also polymeric coatings and plastic layers on paper and board into account. Again, as with the PET situation, there is a missing link in the chain of knowledge about the migration from cellulosic fibres which needs to be made to achieve analogous goals as mentioned above for recycled PET and to enter new pathways in the enormous food packaging market of paper and board. This topic gains automatically even more importance since it is the clear intention of the European Commission services, now nearing completion of food contact plastics regulations, to bring also paper and board within the scope of specific European regulations on food contact materials. For this reason 'a paper and board task force was invited recently by the Commission to meet together for a first discussion to identify the state of the art in this field. The outcome of this meeting which was laid down in the corresponding minutes, confirms clearly what has been stated above. Another argument for the obvious necessity in carrying out the proposed systematic research work is the fact that within Europe there exist different opinions on the reusability of recycled fibres. Whereas some European countries are more in favour of the reuse, other countries have strong reservations in this respect and clearly prefer virgin fibres. The reason for that is evidently: the existing gap of physico-chemical knowledge about the correlation of a contaminants concentration on cellulosic fibre with its extent of migration into foodstuffs.

With respect to the safe use of functional barrier further knowledge is necessary to draw final conclusions on suitable test approaches inclusively predicative mathematical modelling. Project progress will be reported periodically on the project homepage: http://www.ivv.fhg.de/fair/index.html

Objectives

To achieve the overall aims the following specific objectives and research goals are placed in the 3 project sections:

Task 1 (PET) related objectives of section 1 are:

• To establish a statistical European overview of the nature and extent of contaminants in polyethylene terephthalate (PET) materials recovered from the food packaging market.
• To apply these statistics to existing diffusion and migration models, i.e. to model and predict the average and maximum occurring exposure of the consumer to recycling-related contaminants transferred to foodstuffs when packed with recycled PET.
• -Make a general evaluation of the safety-in- use of recycled PET plastics for food packaging so thereby establish criteria for the test conditions to be used in so-called challenge tests (examination of the cleansing effect for contaminants in PET) and minimum requirements in cleansing efficiencies of recycling processes.
• To provide a recognition test for the presence of recycled PET in food packages.

Task 2 (P&B) related objectives of section 2 are-.

• A literature review of contaminants on recycled fibres, with a limited experimental verification.
• To select a set of model contaminants or surrogates which are representative in terms of chemical structures and physical properties for the above mentioned contaminants found in actual practice.
• To investigate systematically the physico-chemical behaviour of the selected set of surrogate contaminants on paper and board, including coated P&B, in contact with food- stuffs and food simulants thus producing a fundamental set of data about their adsorption on and mobility from P&B into food.
• With the aid of the data set from the 6th objective and using existing knowledge, to develop a physico-mathematical model describing mass transport processes from P&B into food taking also permeation processes through polymer layers or coatings into account. The model should be designed such that it will be generally applicable to any type of chemical and such that it describes mass transfer as a worse case situation.
• To give an evaluation of the safety-in-use of recycled paper and board fibres and a definition of criteria for the appropriate reuse of recycled fibres for food packaging.
• To draw conclusions on test strategies not only for recycled P&B fibres but also for virgin P&B food contact articles to assist the currently ongoing regulatory decision-making process in Europe.

Task 3 (FB) related objectives of section 3 are:

• Develop a screening procedure of barrier properties of different polymers likely to behave as functional barrier
• Propose a set of surrogates
• Elaborate testing procedures for functional barriers and multilayer materials
• Develop tools based on predictive, validated approaches, allowing optimisation of the material, and reducing to the extent possible the need for testing
• Elaborate proposals for evaluating processes with functional barriers by national or federal authorities and guidelines for industry

Research tasks

In order to meet the project objectives, the three project sections are composed of 17 sub- tasks as presented below:

Task 1 PET

• Statistical Europe-wide PET sampling
• Identification of the most appropriate-analytical technique for PET analysis
• Chemical analysis to establishing the statistical overview on recycled PET contamination
• Evaluation and interpretation of the statistical data
• Modelling of contaminant transfer into food
• Definition of material and process criteria to ensure consumer safety

Task 2 Paper & Board

• Literature review of contaminants on recycled fibres and limited experimental confirmation
• Definition of surrogates contaminants and P&B test samples
• Systematic interaction studies
• Adsorption isotherms using plain P&B
• Adsorption isotherms and permeation tests using coated P&B
• Mass transfer into foods and/or food simulants
• Development and verification of a physico-mathematical model
• Definition of criteria for the safe reuse of recycled fibres for food packaging
• Conclusions on test strategies for recycled P&B fibres intended for contact with food

Task 3 Functional Barrier

• Selection of surrogates
• Diffusion in model materials
• Diffusion during processing
• Migration / Extraction
• Modelling
• Process and test new materials
• Guidelines to industry, recommendations and proposals to Commission