UPDATE  2007-07-04

 

Project closing conference, Baveno, 27-28 September 2006

The JRC organised the closing conference of the project in Baveno. The event gathered 140 participants from both the EU as well as Norway, Switzerland, US, Japan, Thailand etc.

The objective of the project was to develop a normative predictive tool to assess safety of food contact materials. The data obtained allowed to validate migration models on real foodstuffs both for compliance as worst case or refined for exposure assessment. The results also showed aspects of food chemistry that can influence migration, and initiated a new area of public risk perception specific to food contact materials safety.

These systematic kinetics studies have a direct impact on Directive 85/572/EC on correspondence factors of foodstuffs and food simulants. The results obtained also show an impact on 2002/72/EC on allowing the use of mathematical modelling. The data is used to validate the current diffusion model for further applications. In cunjunction with statistical data obtained from food consumption and plastics packaging surveys realistic estimations or worse-case exposure can predicted.

In addition the project shows an impact on risk assessment from systematic kinetics of migration related to real foods in different conditions for exposure assessment (EFSA), as well on standardisation (CEN) from the development of methods in foodstuffs.

For a download of the presentations in PDF format in a single ZIP-package, click here.


Project progress in Y2:

The core research work within the second project year laid on the study of physico-chemical parameters (WP 3), physico-chemical food specifications (WP 4) and most important on the development and verification of the migration model. Milestone 3 could be reached by establishing a basic migration model.

In the second reporting period a large number of time dependent migration data were generated representing the experimental fundament for the development of the advanced migration model accounting for the mass transfer and partitioning processes associated with real foodstuffs. In a first step a basic migration model was established accounting for the diffusion process in the plastic material, the partitioning between plastic material and food as well as the diffusion process in the foodstuff (D/K/D diffusion model). By means of the basic migration model the experimental data generated in the first and second reporting period were evaluated.

The evaluation procedure relies on the known release of the migrants from the plastic material as part of the previous EU-project ["Certified Reference Materials" EU-project contract G6RD-CTG2000-00411] and delivers a first set of physical constants characterising the diffusion properties of the foods and the partitioning behaviour of the migrants between the plastic materials and foods. At the actual stage the diffusion properties of the foods are expressed as apparent diffusion coefficients and will we subjected in the next reporting period to a refinement procedure in terms of consideration of further mass transfer processes taking place in the foods, which have influence on the overall time scale of migration. Main focus for the further work is on one hand side the validation of the physical constants derived from time dependent migration data by use of the concentration profiles and on the other hand side the establishment of the final reliable migration model making use were indicated of worst case and simplification assumptions. Deliverable D6 represents the state-of-the-art report on current migration models for food simulants combined with a rational on how to proceed with actual foodstuffs.

As already mentioned most of the analytical methods for determining model migrants in the three representative foods (orange juice, minced turkey or chicken breast and gouda cheese) were finished and a collection of these methods written in CEN format was compiled.
The hypothesis that these methods would be applicable to other foods (23 different kinds of foods) involved in the project can already be confirmed and methods seem to work successfully with most of foods analysed until now. However, the compilation of methods (Deliverable 2) should be considered as a living document that will be improved step by step during the project. It was agreed in the project consortium that this compilation should be published as a compendium of useful analytical methods for determination of food packaging migrants in foodstuffs.

The main effort during the second reporting period was the generation of the bulk of the kinetic migration experiments with foods. Numerous kinetic measurements have further been carried out.
Using the selected representative model migrants such as octene, styrene and limonene as volatiles as well as bisphenol A (BPA), diphenyl butadiene (DPBD) and triclosan as less volatile substances time dependent concentration profiles in the food along the migration direction from the source into the inner food compartments have been measured. In parallel, on an independent second experimental approach kinetic migration experiments have been carried with these model migrants and using defined migrant releasing plastic materials in contact with foodstuffs. For this purpose a LDPE foil of 450 µm thickness was produced which acts as controlled migrant release source of selected model compounds for the migration tests. To achieve suitable and well defined concentrations in the release film, appropriate impregnation methods delivering a homogenously impregnated "migration source" had to be established. Concerning BPA, however, it was postulated this substance not very soluble in the chosen LDPE-film. As a consequence the aim for further research work is to try and overcome the homogeneity problem by carrying out experiments using a different film (plasticised PVC).

The interactive implementation work involving as an essential consumer science point of view the question of consumer acceptance of modelling for food packaging safety evaluation will further be carried out by establishing an informative leaflet accompanying the questionnaire respectively of an oral instruction of the customer before filling out the questionnaire. Each of the or selected participants will then organise a limited polling in his country by finding a focus group via newspaper or other advertisement or similar.

Project progress in Y1:

The major objectives for the reporting Y1 period were related to establishing the appropriate frame conditions for the experimental core work of this project:
More specifically, it was necessary to define a list of plastics materials and chemical substances which serve as release reservoirs and model compounds for the comprehensive migration studies in contact with foods in the experimental core work. In this respect, the project benefits the specified or pre-certified character of the reference plastic materials from the EU project “Specific Migration“ (contract no°G6RD-CTG2000-00411) which can serve as the most suitable test and reference materials which are currently available. On the other hand, a list of foodstuffs representing approximately  15 – 20   food groups with respect to such physical-chemical properties which can be expected to influence the behaviour of food with respect to mobility of migrants and sorption properties for the uptake of migrants was to be established. This list, however, should also be harmonised considerations in relations to the actual food consumptional market situation and consumer protection standpoint (which foodstuffs are most frequently consumed and deserve therefore consideration at higher priority). Moreover, and in relation to this sample definition phase it was essential to establish the analytical and experimental conditions for the project core work. More specifically, it was necessary to develop appropriate analytical methods for the quantitative determination of the selected model chemicals in the chosen foodstuffs and to establish the experimental design for the comprehensive migration test programme in which those physical-chemical parameters will be derived which are needed to establish the intended theoretical migration model as a basis for exposure calculations.

Concerning test samples and model chemicals, a total of 5 plastics films and 18 chemical substances serving as model migrants have been defined such that the selected model migrants cover a representative molecular weight range as well as a range of chemical groupings and polarities, with polar water soluble substances  and unpolar water insoluble substances. In addition, the model migrants represent typical substances present in packaging materials such as residual monomers or additives or contaminants.

For the selection of foodstuffs, two different main aspects were taken into account for the final selection of the foodstuffs list. First, a physical-chemical classification was made considering major food parameters which might influence the migration behaviour. Then a consumption data and market related classification of food groups was made and considered for further modification of the food list. In addition further consideration was given to socioeconomic and cultural factors as well as the impact of changing demographics in Europe, concept of healthy eating and other, including analytical problems with the test migrants or the relevance of a packed food for its migration potential. As a result, a final and representative list of 23 foodstuffs/food groups could be established as a solid basis to meet the projects requirement of having finally selected at least 15-20 foodstuffs for the experimental core work. The selected foods were divided into three main categories:
1.    Aqueous and acidic foods
2.    Fatty foods
3.    Dry foods

As a consequence the related project milestone M1 has been taken. The selection criteria and justification of test materials and foods are described in a comprehensive document, the project deliverable D1.

With regard to the already mentioned experimental core work the start-up phase to generate the scientific/technical fundament has been successfully completed. More specifically, the development of the needed analytical methods is finalised for the first three model food types cheese, orange juice and meat (low fat) and a compendium of the methods written in a CEN like standard format is available and will be ttached to this report. The related deliverable D2 is currently in preparation and will be delivered in time during the Y2 reporting period for being mounted publicly available on the project website. With respect to the migration test programme,  appropriate test conditions were defined and the needed experimental design has been established. Two special cell designs have been developed for this purpose and considerable efforts have been made to allow investigation of concentration profiles of the selected test migrants in (semi)solid foods. Numerous measurements have been carried out so far which demonstrate the workability of the applied systems, but it would be too premature to draw any further conclusions at this moment. In conclusion, from the current state of progress, also milestone M2 has been taken, which means: the necessary analytical tools as well as the experimental design is now available for being applied in the further project work.

Concerning the establishment of the migration model, the physical and chemical complexity of real foodstuffs compared to food simulants needs to be considered. A document describing the state of the art in migration modelling in contact with food simulants and giving perspectives how to proceed with food was delivered with project deliverable D6.