A03021: Migration from recycled paper and board to dry foods. Research into the factors involved, leading to practical avoidance and amelioration measures.
Wednesday 16 February 2005
This research project aims to investigate the migration of chemicals from recycled paper and board packaging into dry foods and produce guidelines for industry.
Background
The scientific problem is that the factors that control the migration of contaminants from cellulosic fibres such as recycled paper and board, are poorly understood. Recycled paper and board has found a ready outlet and is widely used for packaging dry foods. However, paper and board made from recovered fibres has less reliable purity characteristics than virgin paper because of residues that may not be removed completely. The economic and environmental benefits of paper recycling are considerable but for food packaging it is clearly problematical so long as the fundamental migration science is poorly understood.
This project has researched migration to dry foods in order to generate 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 use of recycled fibres for food packaging.
Research Approach
The project aims were realised via a group of 6 linked objectives, which were:
1. Identify the main contaminants in wastepaper feedstock and in recycled P&B
2. Determine the sorption/desorption parameters for contaminants on cellulosic fibres
3. Determine sorption/desorption parameters for P&B coated with barrier layers
4. Determine migration of actual contaminants and surrogate contaminants into dry foods and dry simulants
5. Develop and verify a mathematical model to describe and predict the migration process
6. Prepare recommendations and practical guidelines for the safe reuse of recycled fibres for packaging dry foods
Results and findings
Migration kinetics - general observations.
What was immediately clear from all the migration tests was just how rapid migration can be from paper or board (P/B) materials. There was efficient and rapid transfer. The speed of migration depended on the type of the paper or board and on the nature (molecular size and volatility) of the substance migrating.
Migration to the simulant MPPO compared with that to foodstuffs.
The rate of migration into the simulant MPPO (modified polyphenylene oxide) was nearly always greater than into dry foodstuffs. MPPO is a good simulant insofar as it is more 'severe' than food.
Effect of 'barrier' layers.
Aluminium and polyethyleneterephthalate behaved as impermeable barriers to migration under the conditions of test employed - up to 100°C. In contrast, a polyethylene (PE) coating was not a complete barrier. Rather, the PE coating caused the migration to be delayed and take longer to come to steady-state; but migration still occurred.
Modelling.
All the migration kinetics followed established scientific laws. Consequently, the experimental migration data could be fitted well by mathematical modelling.
The fact that there were no significant differences noted between the different uncoated paper/board samples tested, means that there is no obvious way to moderate the migration properties of paper or board samples by modifying their basic composition - other than to introduce a barrier layer by, for example, laminating to a plastic film.
Since migration can occur if there is direct contact between the paper/board and a powdered (or small particle size) dry food, the following options are available (individually or in combination) to keep migration within acceptable limits:
a) keep the initial content of potential migrants in the P/B within limits
- source control
- sorting
- effective cleaning
- frequent testing of batches/lots
b) use a barrier layer to prevent or slow migration
c) use recycled P/B only in indirect contact applications and/or at low temperature.
With the understanding of migration behaviour and modelling that has been gained in this project, the effectiveness of these control measures and, vice versa, relevant performance criteria for these control measures, could now be established.
Dissemination information
Final report is available from the FSA Library and Information centre. To obtain a copy, please contact the Enquiry Desk, Dr Elsie Widdowson Library and Information Services, Food Standards Agency ( tel: 020 7276 8181/8182 or email: library&info@foodstandards.gsi.gov.uk ).