Safety assessment of the process ONDUPET, based on EREMA Basic technology, used to recycle post‐consumer PET into food contact materials

Abstract

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process ONDUPET (EU register number RECYC182), which uses the EREMA Basic technology. The input material is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post‐consumer PET containers, including no more than 5% PET from non‐food consumer applications. The flakes are heated in a continuous reactor under vacuum before being extruded. Having examined the challenge test provided, the Panel concluded that the continuous reactor (step 2, for which a challenge test was provided) is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migration of 0.15 μg/kg food, derived from the exposure scenario for toddlers when such recycled PET is used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not considered to be of safety concern when used at up to 100% for the manufacture of thermoformed trays and containers for contact with all types of foodstuffs, except drinking water, for long‐term storage at room temperature. Trays made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

1. Introduction

1.1. Background and Terms of Reference as provided by the requestor

Recycled plastic materials and articles shall only be placed on the market if the recycled plastic is from an authorised recycling process. Before a recycling process is authorised, the European Food Safety Authority (EFSA)'s opinion on its safety is required. This procedure has been established in Article 5 of Regulation (EC) No 282/20081 on recycled plastic materials intended to come into contact with foods and Articles 8 and 9 of Regulation (EC) No 1935/20042 on materials and articles intended to come into contact with food.

According to this procedure, the industry submits applications to the competent authorities of Member States, which transmit the applications to EFSA for evaluation.

In this case, EFSA received from the Agencia Española de Seguridad Alimentaria y Nutricion, Spain, an application for the evaluation of the recycling process ONDUPET, European Union (EU) register No RECYC182. The request has been listed in EFSA's register of received questions under the number EFSA‐Q‐2019‐00379. The dossier was submitted on behalf of ONDUPET, S.L., Spain.

According to Article 5 of Regulation (EC) No 282/2008 of the Commission of 27 March 2008 on recycled plastic materials intended to come into contact with foods, EFSA is required to carry out assessments of the risks originating from the migration of substances from recycled food contact plastic materials and articles into food and deliver a scientific opinion on the recycling process examined.

According to Article 4 of Regulation (EC) No 282/2008, EFSA will evaluate whether it has been demonstrated in a challenge test, or by other appropriate scientific evidence, that the recycling process is able to reduce the contamination of the plastic input to a concentration that does not pose a risk to human health. The poly(ethylene terephthalate) (PET) materials and articles used as input of the process as well as the conditions of use of the recycled PET make part of this evaluation.

2. Data and methodologies

2.1. Data

The applicant has submitted a dossier following the ‘EFSA guidelines for the submission of an application for the safety evaluation of a recycling process to produce recycled plastics intended to be used for the manufacture of materials and articles in contact with food, prior to its authorisation’ (EFSA, 2008).

Additional information was requested from the applicant during the assessment process on 06 March 2020. However, despite several requests sent by EFSA on 8 April 2020 and 6 May 2020, the applicant did not provide the additional data. A final request sent by EFSA on 19 June 2020 did also not generate a reply, and consequently, the risk assessment process was re‐started. On 29 July 2020, the applicant provided an updated petition, which was accepted as spontaneous submission of data. The Panel concluded the assessment on the basis of that data.

The following information on the recycling process was provided by the applicant and used for the evaluation:

• General information:

  • – general description,
  • – existing authorisations.

• Specific information:

  • – recycling process,
  • – characterisation of the input,
  • – determination of the decontamination efficiency of the recycling process,
  • – characterisation of the recycled plastic,
  • – intended application in contact with food,
  • – compliance with the relevant provisions on food contact materials and articles,
  • – process analysis and evaluation,
  • – operating parameters.

2.2. Methodologies

The principles followed for the evaluation are described here. The risks associated with the use of recycled plastic materials and articles in contact with food come from the possible migration of chemicals into the food in amounts that would endanger human health. The quality of the input, the efficiency of the recycling process to remove contaminants as well as the intended use of the recycled plastic are crucial points for the risk assessment (EFSA, 2008).

The criteria for the safety evaluation of a mechanical recycling process to produce recycled PET intended to be used for the manufacture of materials and articles in contact with food are described in the scientific opinion developed by the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (EFSA CEF Panel, 2011). The principle of the evaluation is to apply the decontamination 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 at 3 mg/kg PET for contaminants resulting from possible misuse. The resulting residual concentration of each surrogate contaminant in recycled PET (C_res) is compared with a modelled concentration of the surrogate contaminants in PET (C_mod). This C_mod is calculated using generally recognised conservative migration models so that the related migration does not give rise to a dietary exposure exceeding 0.0025 μg/kg body weight (bw) per day (i.e. the human exposure threshold value for chemicals with structural alerts for genotoxicity), below which the risk to human health would be negligible. If the C_res is not higher than the C_mod, the recycled PET manufactured by such a recycling process is not considered of safety concern for the defined conditions of use (EFSA CEF Panel, 2011).

The assessment was conducted in line with the principles described in the EFSA Guidance on transparency in the scientific aspects of risk assessment (EFSA, 2009) and considering the relevant guidance from the EFSA Scientific Committee.

3. Assessment

3.1. General information3

According to the applicant, the recycling process ONDUPET is intended to recycle food grade PET containers using the EREMA Basic technology. The recycled PET is intended to be used at up to 100% for sheets for thermoforming of trays/containers for food contact applications, e.g. for fruits, vegetables, cooked and uncooked meats, dairy products and desserts, for long‐term food storage at room temperature. Thermoformed trays are in general for single use. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

3.2. Description of the process

3.2.1. General description4

The recycling process ONDUPET produces recycled PET sheets and trays from PET containers from post‐consumer collection systems (kerbside and deposit systems).

The recycling process comprises the three steps below.

Input

• In step 1, the post‐consumer PET containers are processed into hot caustic washed and dried flakes. This step is performed by third parties.

Decontamination and production of recycled PET material

• In step 2, the flakes are crystallised and decontaminated under high temperature and vacuum.

• In step 3, the decontaminated flakes are extruded to produce sheets.

The operating conditions of the process have been provided to EFSA.

Sheets, the final product of the process, are checked against technical requirements, such as intrinsic viscosity, colour and black spots.

3.2.2. Characterisation of the input5

According to the applicant, the input material for the recycling process ONDUPET consists of hot caustic washed and dried flakes obtained from PET containers, previously used for food packaging, from post‐consumer collection systems (kerbside and deposit systems). A small fraction may originate from non‐food applications. According to the applicant, the proportion will be no more than 5%.

Technical data on the hot washed and dried flakes were provided, such as information on physical properties as well as residual contents of moisture, poly(vinyl chloride) (PVC), glue, polyolefins, polyamides, cellulose and metals (see Appendix A).

3.3. EREMA Basic technology

3.3.1. Description of the main steps4

The general scheme of the EREMA Basic technology, as provided by the applicant, is reported in Figure 1. The steps are:

• Decontamination in a continuous reactor (step 2):

Figure 1.

General scheme of the technology (provided by the applicant).

The flakes are continuously fed into a reactor equipped with a bottom‐mounted rotating mixing device, running under high temperature and vacuum for a predefined average residence time.

• Extrusion of the decontaminated flakes (step 3):

The flakes, continuously introduced from the previous reactor, are molten in the extruder at atmospheric pressure. The residual solid particles (e.g. paper or aluminium) are filtered out of the extruded plastic before the melt is converted into sheets.

The process is run under defined operating parameters6 of temperature, pressure and average residence time.

3.3.2. Decontamination efficiency of the recycling process7

To demonstrate the decontamination efficiency of the recycling process ONDUPET, a challenge test on step 2 was submitted to the EFSA.

PET flakes were contaminated with toluene, chlorobenzene, chloroform, methyl salicylate, phenylcyclohexane, benzophenone and methyl stearate, selected as surrogate contaminants in agreement with the EFSA guidelines (EFSA CEF Panel, 2011) and in accordance with the recommendations of the US Food and Drug Administration (FDA, 2006). The surrogates include different molecular masses and polarities to cover possible chemical classes of contaminants of concern and were demonstrated to be suitable to monitor the behaviour of PET during recycling (EFSA, 2008).

Solid surrogates (benzophenone and methyl stearate) were mixed with liquid surrogates (toluene, chlorobenzene, chloroform, methyl salicylate and phenyl cyclohexane) and admixed to 5 kg conventionally recycled8 post‐consumer PET flakes. This masterbatch was added to approximately 50 kg PET flakes and stored for 7 days at 50°C with periodical agitation. The contaminated flakes were washed and rinsed in a batch process at pilot plant scale. The concentration of surrogates in this material was determined.

The EREMA Basic technology was challenged at an industrial‐scale plant. To process a sufficiently large amount of material compatible with the high capacity of the continuous industrial plant, the reactor was initially fed with non‐contaminated flakes (white colour) and, after process conditions were stabilised, with a defined amount of contaminated flakes (green colour) and finally with a much larger quantity of non‐contaminated flakes. The flakes were continuously fed into the reactor. Samples were taken at the outlet of the reactor at regular intervals. The green flakes were separated from the white flakes and the evolution of the fraction of green flakes over time (residence time distribution curve) was determined by weighing. The green flakes were then analysed for their residual concentrations of the applied surrogates.

The Panel noted that decontamination efficiencies, calculated only on the basis of residual surrogates in the contaminated (green coloured) flakes, could be overestimated. In fact, cross‐contamination9 by transfer of contaminants from green to white flakes does occur (EFSA CEF Panel, 2011).

Therefore, to take into account cross‐contamination, some assumptions and considerations were made by the Panel:

• ‐The mass fraction of green to white flakes at various residence time points was derived from the data provided. A best‐fitting mass fraction/residence time distribution curve was used to calculate the percentage of green and white flakes at given residence times.
• ‐From the residual concentrations of surrogates in the green flakes at different residence times (provided by the applicant), a best‐fitting curve was derived and used to interpolate the residual concentrations in green flakes at different residence times.
• ‐It was assumed that cross‐contamination of surrogates from green to white flakes in the reactor occurred to the extent that the surrogate concentration in the white flakes reached 10% of the residual concentration measured in the green flakes. This percentage reflects the experience from previous evaluations.
• ‐A study was provided by the applicant. Based on the results provided as an Annex of the technical dossier and subsequently published (Welle, 2016), cross‐contamination was found at low mixing (dilution) ratios (e.g. 1:1), but the author argued that moving to higher mixing (dilution) ratios (e.g. 1:50) does not play a significant role. Therefore, the applicant requested that the 10% cross‐contamination should not apply for the industrial process ONDUPET under evaluation. However, the Panel noted that this study had some shortcomings and the conclusion that cross‐contamination was negligible was questioned due to the high detection limits of the analytical method used, as it had a major impact on calculations at a high mixing (dilution) ratio. Moreover, the Panel considered that the laboratory tests to investigate cross‐contamination were not representative of the industrial process under evaluation: different technologies (types of equipment and different operational conditions) were used, e.g. in terms of heating technique (hot gas vs. friction) and removal of contaminants from the reactor (inert gas vs. vacuum). Therefore, the study provided by the applicant allows neither to exclude cross‐contamination from the calculation of the decontamination efficiency nor to refine the previous estimate of 10%.

To take into account the cross‐contamination between green and white flakes, the evolution of the total residual surrogate content at the outlet of the continuous reactor (step 2) as a function of residence time was calculated. The amounts transferred to the white flakes (based on the assumption of 10% of the concentration measured in the green flakes) were added to those measured in the green ones, taking into account the mass fraction of green and white flakes. Correspondingly corrected concentrations of residual surrogates were compared with their initial concentrations in green flakes at the inlet of the reactor to derive the decontamination efficiencies (see Table 1).

Table 1.

Efficiency of the decontamination by the continuous reactor (step 2) in the challenge test

Surrogates	Concentrationa of surrogates before step 2 (mg/kg PET)	Concentrationb of surrogates after step 2 (mg/kg PET)	Decontamination efficiencyc (%)
Toluene	202	0.40	98.4
Chlorobenzene	361	0.76	98.3
Chloroform	291	0.48	98.6
Methyl salicylate	143	1.03	94.0
Phenylcyclohexane	364	2.31	94.7
Benzophenone	480	4.37	92.4
Methyl stearate	360	1.93	95.5

PET: poly(ethylene terephthalate).

^aInitial concentration in the contaminated PET flakes.

^bResidual concentration derived for green flakes after decontamination.

^cDecontamination efficiency of step 2 in the challenge test after correction for cross‐contamination (see text).

The decontamination efficiencies presented in Table 1 were calculated for the average residence time in the continuous reactor (step 2) in the challenge test.

The decontamination efficiency ranged from 92.4% for benzophenone up to 98.6% for chloroform.

3.4. Discussion

Considering the high temperatures used during the process, the possibility of contamination by microorganisms can be discounted. Therefore, this evaluation focuses on the chemical safety of the final product.

Technical data, such as information on physical properties and residual contents of PVC, glue, polyolefins and metals, were provided for the input materials (hot caustic washed and dried flakes, step 1). These flakes are produced from PET containers, previously used for food packaging, collected through post‐consumer collection systems. However, a small fraction may originate from non‐food applications, such as bottles for soap, mouth wash or kitchen hygiene agents. According to the applicant, the collection system and the process are managed in such a way that in the input stream, this fraction will be no more than 5%, as recommended by the EFSA CEF Panel in its ‘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’ (EFSA CEF Panel, 2011).

The process is adequately described. The washing and drying of the flakes from the collected PET containers (step 1) are conducted by third parties and, according to the applicant, this step is under control. The EREMA Basic technology comprises the continuous decontamination reactor (step 2) and extrusion (step 3). The operating parameters of temperature, pressure and residence time have been provided to EFSA.

A challenge test to measure the decontamination efficiency was conducted at industrial plant scale on the process step 2 (continuous decontamination reactor). The Panel considered that this challenge test was performed correctly according to the recommendations in the EFSA guidelines (EFSA, 2008). The reactor was operated under pressure and temperature conditions equivalent to those of the commercial process. Since a mixture of non‐contaminated (white) and contaminated (green) flakes was collected at the outlet of the reactor, the Panel calculated the decontamination efficiencies taking into account also the amount possibly transferred to the white flakes due to cross‐contamination. The Panel considered that the decontamination in the continuous reactor (step 2) was critical for the decontamination efficiency of the process. Consequently, temperature, pressure and residence time parameters of the step 2 of the process should be controlled to guarantee the performance of the decontamination (Appendix C).

The decontamination efficiencies obtained for each surrogate, ranging from 92.4% to 98.6%, have been used to calculate the residual concentrations of potential unknown contaminants in PET (C_res) according to the evaluation procedure described in the ‘Scientific opinion on the criteria to be used for safety evaluation of a mechanical recycling process to produce recycled PET’ (EFSA CEF Panel, 2011; Appendix B). By applying the decontamination percentages to the reference contamination level of 3 mg/kg PET, the C_res for the different surrogates was obtained (Table 2).

Table 2.

Decontamination efficiency from the challenge test, residual concentrations of the surrogates in the recycled PET (C_res) and calculated concentrations of the surrogates in PET (C_mod) corresponding to a modelled migration of 0.15 μg/kg food after 1 year at 25°C

Surrogates	Decontamination efficiency (%)	Cres for 100% rPET (mg/kg PET)	Cmod (mg/kg PET)
Toluene	98.4	0.05	0.13
Chlorobenzene	98.3	0.05	0.15
Chloroform	98.6	0.04	0.15
Methyl salicylate	94.0	0.18	0.20
Phenylcyclohexane	94.7	0.16	0.21
Benzophenone	92.4	0.23	0.24
Methyl stearate	95.5	0.13	0.47

PET: poly(ethylene terephthalate); rPET: recycled poly(ethylene terephthalate).

According to the evaluation principles (EFSA CEF Panel, 2011), the dietary exposure must not exceed 0.0025 μg/kg bw per day, below which the risk to human health is considered negligible. The C_res value should not exceed the modelled concentration in PET (C_mod) that could result, after 1 year at 25°C, in a migration giving rise to a dietary exposure exceeding 0.0025 μg/kg bw per day. Because the recycled PET is intended for sheets to manufacture trays and containers not used to pack water (since water could be used to prepare infant formula), the exposure scenario for toddlers has been applied. A maximum dietary exposure of 0.0025 μg/kg bw per day corresponds to a maximum migration of 0.15 μg/kg of the contaminant into the toddler's food and has been used to calculate C_mod (EFSA CEF Panel, 2011). C_res reported in Table 2 is calculated for 100% recycled PET, for which the risk to human health is demonstrated to be negligible. The relationship between the key parameters for the evaluation scheme is reported in Appendix B.

On the basis of the provided data from the challenge test and the applied conservative assumptions, the Panel considered that under the given operating conditions, the ONDUPET recycling process is able to ensure that the level of migration of unknown contaminants from the recycled PET into food is below the conservatively modelled migration of 0.15 μg/kg food. At this level, the risk to human health is considered negligible when the recycled PET is used at up to 100% to produce trays and containers intended for contact with all types of foodstuffs except drinking water.

4. Conclusions

The Panel considered that the ONDUPET recycling process using the EREMA Basic technology is adequately characterised and the critical step to decontaminate the PET is identified. Having examined the challenge test provided, the Panel concluded that temperature, pressure and residence time in the continuous reactor of step 2, which was included in the challenge test, are critical for the decontamination efficiency.

The Panel concluded that the recycling process ONDUPET is able to reduce foreseeable accidental contamination of post‐consumer food contact PET to a concentration that does not give rise to concern for a risk to human health if:

1. it is operated under conditions that are at least as severe as those applied in the challenge test used to measure the decontamination efficiency of the process;

2. the input material of the process is washed and dried post‐consumer PET flakes originating from materials and articles that have been manufactured in accordance with the EU legislation on food contact materials and no more than 5% of this PET is from non‐food consumer applications;

3. the recycled PET is used at up to 100% for the manufacture of thermoformed trays and containers for contact with all types of foodstuff except drinking water, for long‐term storage at room temperature.

The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

5. Recommendations

The Panel recommended periodic verification that the input material to be recycled originates from materials and articles that have been manufactured in accordance with the EU legislation on food contact materials and that the proportion of PET from non‐food consumer applications is no more than 5%. This adheres to good manufacturing practice and the Regulation (EC) No 282/2008, Art. 4b. Critical steps in recycling should be monitored and kept under control. In addition, supporting documentation should be available on how it is ensured that the critical steps are operated under conditions at least as severe as those in the challenge test used to measure the decontamination efficiency of the process.

Documentation provided to EFSA

1. Dossier ‘ONDUPET’. June 2019. Submitted on behalf of ONDUPET S.L., Spain.

2. Spontaneous submission of data (updated dossier ‘ONDUPET’). July 2020. Submitted on behalf of ONDUPET S.L., Spain.

Abbreviations

bw

body weight

CEF

Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids

CEP

Panel on Food Contact Materials, Enzymes and Processing Aids

C_mod

modelled concentration in PET

C_res

residual concentration in PET

PET

poly(ethylene terephthalate)

PVC

poly(vinyl chloride)

rPET

recycled poly(ethylene terephthalate)

Appendix A – Technical data of the washed flakes as provided by the applicant5

1.

Parameter	Value
Moisture max.	1.0%
Moisture variation	± 0.3%/h
Bulk density	230–850 kg/m3
Bulk density variation	± 150 kg/(m3h)
Material temperature	5–40°C
Material temperature variation	± 10°C/h
PVC max.	100 mg/kg
Glue max.	1,500 mg/kg
Polyolefins max.	100 mg/kg
Cellulose (paper, wood)	100 mg/kg
Metals max.	50 mg/kg
Polyamides max.	50 mg/kg

Appendix B – Relationship between the key parameters for the evaluation scheme (EFSA CEF Panel, 2011)

1.

*Default scenario (infant). For adults and toddlers, the migration criterion will be 0.75 and 0.15 μg/kg food, respectively. The figures are derived from the application of the human exposure threshold value of 0.0025 μg/kg bw per day applying a factor of 5 related to the overestimation of modelling.

Appendix C – Table on operational parameters (Confidential Information)10

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Suggested citation: EFSA CEP Panel (EFSA Panel on Food Contact Materials, Enzymes and Processing Aids) , Silano V, Barat Baviera JM, Bolognesi C, Chesson A, Cocconcelli PS, Crebelli R, Gott DM, Grob K, Lambré C, Mengelers M, Mortensen A, Rivière G, Steffensen I‐L, Tlustos C, Van Loveren H, Vernis L, Zorn H, Dudler V, Milana MR, Papaspyrides C, Tavares Poças MF, Volk K, Lampi E, 2020. Scientific Opinion on the safety assessment of the process ONDUPET, based on EREMA Basic technology, used to recycle post‐consumer PET into food contact materials. EFSA Journal 2020;18(10):6251, 13 pp. 10.2903/j.efsa.2020.6251