Scientific Opinion on the criteria to be used for safety evaluation of a mechanical recycling process to produce recycled PET intended to be used for manufacture of materials and articles in contact with food

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Article
Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids
EFSA Journal
EFSA Journal 2011;9(7):2184 [25 pp.].
doi
10.2903/j.efsa.2011.2184
Panel members at the time of adoption
Arturo Anadón, Mona-Lise Binderup, Wilfried Bursch, Laurence Castle, Riccardo Crebelli, Karl-Heinz Engel, Roland Franz, Nathalie Gontard, Thomas Haertlé, Trine Husøy, Klaus-Dieter Jany, Catherine Leclercq, Jean-Claude Lhuguenot, Wim Mennes, Maria Rosaria Milana, Karla Pfaff, Kettil Svensson, Fidel Toldrá, Rosemary Waring, Detlef Wölfle
Acknowledgements

The Panel wishes to thank the members of the Working Group on Recycling process for the preparation of this opinion: Laurence Castle, Vincent Dudler, R. Franz, Nathalie Gontard, Eugenia Lampi, Maria Rosaria Milana, Cristina Nérin, Constantine Papaspyrides, Karla Pfaff, and EFSA’s staff members Eric Barthelemy and Dimitrios Spyropoulos for the support provided to this EFSA scientific output. R. Franz participated as hearing expert to answer to questions and to provide comments on the draft opinion.

Possible conflict of interest
One member of the Panel, Roland Franz declared an interest as his Institute has submitted applications for the evaluation of recycling processes. This was considered as a conflict of interest and he was requested to leave the room during discussion and adoption of the opinion.
Type
Opinion of the Scientific Committee/Scientific Panel
On request from
CEF Panel
Question Number
EFSA-Q-2010-01501
Adopted
6 July 2011
Published
20 July 2011
Affiliation
European Food Safety Authority (EFSA), Parma, Italy
Note
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Abstract

This scientific opinion of EFSA deals with the criteria to be used for safety evaluation of a recycling process to produce recycled PET intended to be used for manufacture of materials and articles in contact with food.
The principle of the evaluation is to apply the cleaning efficiency of a recycling technology or process, obtained from a challenge test with surrogate contaminants, to a reference contamination level for post consumer PET, conservatively set a 3 mg/kg PET for a contaminant resulting from possible misuse. The resulting residual concentration of each contaminant in recycled PET (Cres) is then compared to a modelled concentration in PET (Cmod). This Cmod is calculated using generally recognized conservative migration models such that the related migration does not give rise to a dietary exposure exceeding 0.0025 μg/kg bw/day, the human exposure threshold value for chemicals with structural alerts raising concern for potential genotoxicity, below which the risk to human health would be negligible.
The default scenario, when the recycled PET is intended for general use, is that of an infant weighing 5 kg and consuming every day 0.75 l of water coming from a water bottle manufactured from 100% recycled PET. According to this scenario, it can be derived that the highest concentration of a substance in water that would ensure that the dietary exposure of 0.0025 µg/kg bw/day is not exceeded, is 0.017 μg/kg food. Taking into account that generally agreed diffusion modelling overestimates migration by at least 5 times, a calculated migration less than 0.1 µg/kg in food would satisfy the above criterion for the default exposure scenario. In the case of the other exposure scenarios for adults and toddlers, the relevant migration criterion will accordingly be 0.75 and 0.15 µg/kg food.
Therefore if a recycling process is able to reduce an input reference contamination of 3 mg/kg PET to a Cres not higher than a Cmod corresponding to the relevant migration criterion, the potential dietary exposure cannot be higher than 0.0025 µg/kg bw/day and recycled PET manufactured with such recycling process is not considered of safety concern.
The Panel considered appropriate that the proportion of PET from non-food consumer applications should be no more than 5% in the input to be recycled.

Summary

Following the publication of the Regulation (EC) No 282/2008 of the Commission of 27 March 2008 on recycled plastic materials intended to come into contact with foods and the relevant EFSA Guidelines on submission of a dossier for safety evaluation by the EFSA, many dossiers have been submitted to EFSA for evaluation dealing with recycling processes for polyethylene terephthalate (PET) food contact materials.

These processes use as an input post consumer PET to produce recycled PET intended for food contact applications.

The CEF Panel is currently evaluating these PET recycling processes and has developed criteria specific to this type of plastic which are used during the evaluation process. For the sake of transparency and in order to inform all stakeholders on the considerations followed for the risk assessment of PET recycling processes, the CEF Panel considers that these criteria should be published. Thus, the scientific opinion describes the risk assessment approach used by the Panel and provides arithmetic values for the criteria specific to the evaluation of recycling processes for PET intended to be used in food contact materials.

The underlying principle of the evaluation is to apply the cleaning efficiency of a recycling technology or process to a reference contamination level for post consumer PET. The resulting residual concentration in recycled PET (Cres) is then compared to a modelled concentration in PET (Cmod). This Cmod is calculated using generally recognized conservative migration models such that the related migration cannot give rise to a dietary exposure exceeding the threshold below which the risk to human health would be negligible.

The decontamination efficiency of the recycling process is determined by means of especially designed challenge tests using sets of surrogate contaminants. These surrogates are substances with different molecular weights and polarities representative of possible chemical classes of contaminants of concern. The surrogates are added at exaggeratedly high levels in the plastic PET input to be recycled. Their initial concentration and their final concentration, after the recycling process, is determined analytically. The decontamination efficiency is expressed as percentage of reduction of a surrogate present in the decontaminated PET compared to its initial level before it entered the process.

The establishment of a reference contamination level for an unknown contaminant potentially present in the input of a PET recycling process is based on experimental data of an EU survey. In this survey performed in the framework of a European project thousands of collected PET bottles were examined. Post-use residual substances were identified as food related substances (limonene, up to 20 mg/kg - average 2.9 mg/kg PET) and plastic related substances (adipates, phthalates, erucamide dioctyl adipate up to 0.5 mg/kg ). Rare cases of bottles misused by the consumers (i.e. refilled with organic solvents) were identified and the highest level in the misused PET bottles was for toluene (6750 mg/kg PET). An incidence of 0.03-0.04 % of misused bottles was estimated. Based on these figures, it was estimated that as a worst case the contamination of the recycling PET feedstock with toluene would have been ranging from 1.4 to 2.7 mg/kg PET. Thus, the evaluation criterion to be used as the reference contamination level for misuse for individual substances in the input of a PET recycling process is set at 3 mg/kg PET, corresponding to the highest figure obtained from the experimental data. Results from another survey in the USA and from theoretical considerations on the nature and sorption of the possible misuse contaminants support the conservatism of this value.

It is impossible to predict the identity of contaminants potentially present in post consumer PET used as input of a recycling process and to ensure that they are not genotoxic. Therefore, a level of a dietary exposure which can be considered of negligible risk to human health must take into account this possibility, too.

As a pragmatic approach, the Panel considers that this dietary exposure should be below 0.0025 μg/kg bw/day for an unknown contaminant possibly present. This is the human exposure threshold value for chemicals with structural alerts raising concern for potential genotoxicity. Generally, this threshold value is low enough to address concern over all toxicological effects. Thus, it is ensured that any unknown contaminant possibly present is treated in a conservative way.

As regards the exposure scenario, the Panel considers that the most conservative scenario is that of an infant weighing 5 kg and consuming every day 0.75 l of water (WHO, 2003) coming from a water bottle manufactured from 100% recycled PET. From this figure, it can be derived that the highest concentration of a substance in water that would ensure that the dietary exposure of 0.0025 µg/kg bw/day is not exceeded is 0.017 μg/kg food. This scenario is applied as default when the recycled PET is intended for general use.

The Panel noted that for other categories of the population, toddlers and adults, due to the lower food consumption per kg bw, the respective concentrations in food would be higher and that other exposure scenarios can be formulated.

Taking into account the overestimation of migration by the generally agreed diffusion modelling, a calculated migration less than 0.1 µg/kg in food would satisfy the above criterion for the default exposure scenario. In the case of the other exposure scenarios for adults and toddlers, the relevant migration criterion will accordingly be 0.75 and 0.15 µg/kg food respectively.

The Panel considers that if a recycling process is able to reduce an input reference contamination of 3 mg/kg PET to a Cres not higher than a Cmod corresponding to the relevant migration criterion, the potential dietary exposure cannot be higher than 0.0025 µg/kg bw/day. Recycled PET manufactured with such recycling process is therefore not considered of safety concern.

In collection systems of post consumer PET, a percentage of containers used for non-food applications such as containers for mouthwash, detergents, shampoos, household cleaning products, medicines, garden chemicals and DIY “Do It Yourself “/home improvement products (e.g. paint removers, furniture polish) can be present. The contamination can originate from the presence of PET non compliant with the current EC Regulation on plastics in contact with foodstuffs or from the sorption of the chemicals from the non-food product. As a pre-requisite, the Panel considers that input based on containers coming from non-food uses should not be intentionally used. The Panel considered appropriate that the proportion of PET from non-food consumer applications should be no more than 5% in the input to be recycled.

In the case the above conditions are not fulfilled, the petitioner must provide further information to prove the safety of the process.

The Panel considers that the control of the pre-established and appropriate specifications of the input in the frame of a process management under good manufacturing practices (GMP) is mandatory to ensure the compliance of the recycled product with the requirements set out in the safety evaluation.

Keywords
Food contact materials, Plastics, Poly(ethylene terephthalate), PET, Recycling process, Evaluation, Safety
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Number of Pages
25