Frank Welle

Dr. Frank Welle

Fraunhofer IVV
orcid

Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2011 in Resources, Conservation and Recycling
Verified
Journal Article
Closed access
Frank WelleFrank Welle
Frank Welle

1 July 2021 in Sustainability
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Journal Article
Open access
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EPElisabeth Pinter
Elisabeth Pinter
Frank WelleFrank Welle
Frank Welle
Elisa MayrhoferElisa Mayrhofer
Elisa Mayrhofer
APAndreas Pechhacker
Andreas Pechhacker
LMLukas Motloch
Lukas Motloch
Manfred TackerManfred Tacker
Manfred Tacker
With the European Green Deal, the importance of recycled products and materials has increased. Specifically, for PET bottles, a high content of recycled material (rPET) is demanded by the industry and consumers. This study was carried out in a lab environment replicating real-life industrial processes, to investigate the possible impacts on rPET quality over eleven recycling loops, aiming to use high amounts of rPET repetitively. A cycle included extrusion, solid state polycondensation (SSP), a second extrusion to simulate bottle production, hot wash and a drying step. 75% rPET and 25% virgin PET were extruded in eleven cycles to simulate a recycling and production process. Samples underwent chemical, physical and biological analysis. The quality of the rPET material was not adversely affected. Parameters such as coloring, intrinsic viscosity, concentration of critical chemicals and presence of mutagenic contaminants could be positively assessed. The quality of the produced material was likely influenced by the input material’s high standard. A closed loop PET bottle recycling process using an rPET content of up to 75% was possible when following the proposed process, indicating that this level of recycled content can be maintained indefinitely without compromising quality.

19 November 2018 in Food Additives & Contaminants: Part A
Verified
Journal Article
Closed access
Frank WelleFrank Welle
Frank Welle
Roland FranzRoland Franz
Roland Franz
Microplastics have been ubiquitously found and identified in aquatic and terrestrial environments for several years. Due to their occurrence in the oceans, microplastics were also found and characterised in seafood products and in other foods and beverages such as beer, honey and table salt. Very recently, microplastic particles were also determined in bottled mineral water. The objective of this publication is to present and discuss a compilation of the currently available literature data on microplastics in bottled mineral water. The related oral exposure of the consumer from substances present in microplastics and from the plastics particles themselves is estimated and toxicological arguments for and considerations on risk assessment from the consumption of bottled mineral water containing microplastics are presented. Exposure estimations based on the reported microplastic amounts found in mineral water and the assumption of total mass transfer of small molecules like additives and oligomers present in the plastic would not raise a safety concern. Available toxicokinetic data suggests that marginal fraction of the ingested low amount of microplastics can be absorbed, if at all, the conclusion is very likely that the reported amounts present in bottled mineral water do not raise a safety concern for the consumer. Considering the use of plastic materials in our daily life, occurrence of microplastics in beverages is likely a minor exposure pathway for plastic particles. Due to recent progress in analytical methods and the public discussion on plastics marine litter, public concern about eating and drinking microplastics with food, and related safety issues was raised. However, a better data basis for exposure estimates and risk assessment would be very helpful to better accommodate consumer concerns. The intention of this paper is to deliver a contribution to this topic taking the bottled mineral water as a case example.

21 December 2010 in Food Additives & Contaminants: Part A
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Journal Article
Closed access
Frank WelleFrank Welle
Frank Welle
Roland FranzRoland Franz
Roland Franz
Plastics bottles made from polyethylene terephthalate (PET) are increasingly used for soft drinks, mineral water, juices and beer. In this study a literature review is presented concerning antimony levels found both in PET materials as well as in foods and food simulants. On the other hand, 67 PET samples from the European bottle market were investigated for their residual antimony concentrations. A mean value of 224 ± 32 mg kg−1 was found, the median was 220 mg kg−1. Diffusion coefficients for antimony in PET bottle materials were experimentally determined at different temperature between 105 and 150°C. From these data, the activation energy of diffusion for antimony species from the PET bottle wall into beverages and food simulants was calculated. The obtained value of 189 kJ mol−1 was found to be in good agreement with published data on PET microwave trays (184 kJ mol−1). Based on these results, the migration of antimony into beverages was predicted by mathematical migration modelling for different surface/volume ratios and antimony bottle wall concentrations. The results were compared with literature data as well as international legal limits and guidelines values for drinking water and the migration limit set from food packaging legislation. It was concluded that antimony levels in beverages due to migration from PET bottles manufactured according to the state of the art can never reach or exceed the European-specific migration limit of 40 µg kg−1. Maximum migration levels caused by room-temperature storage even after 3 years will never be essentially higher than 2.5 µg kg−1 and in any case will be below the European limit of 5 µg kg−1 for drinking water. The results of this study confirm that the exposure of the consumer by antimony migration from PET bottles into beverages and even into edible oils reaches approximately 1% of the current tolerable daily intake (TDI) established by World Health Organisation (WHO). Having substantiated such low antimony levels in PET-bottled beverages, the often addressed question on oestrogenic effects caused by antimony from PET bottles appears to be groundless.

12 January 2022 in Sustainability
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Journal Article
Open access
PDF file
Roland FranzRoland Franz
Roland Franz
Frank WelleFrank Welle
Frank Welle
The European strategy for plastics, as part of the EU’s circular economy action plan, should support the reduction in plastic waste. One key element in this action plan is the improvement of the economics and quality of recycled plastics. In addition, an important goal is that by 2030, all plastics packaging placed on the EU market must either be reusable or can be recycled in a cost-effective manner. This means that, at the end, a closed-loop recycling of food packaging materials should be established. However, the use of recyclates must not result in less severe preventive consumer protection of food packaging materials. This may lead to a conservative evaluation of authorities on post-consumer recyclates in food packaging applications. On the other hand, over-conservatism might over-protect the consumer and generate insurmountable barriers to the application of post-consumer recyclates for food packaging and, hence, counteract the targets of circular economy. The objective of this review is to provide an insight into the evaluation of post-consumer recyclates applied in direct contact to food. Safety assessment criteria as developed by the European Food Safety Authority EFSA will be presented, explained, and critically discussed.

1 March 2004 in Food Additives & Contaminants
Verified
Journal Article
Closed access
Roland FranzRoland Franz
Roland Franz
AMA. Mauer
A. Mauer
Frank WelleFrank Welle
Frank Welle
Typical contamination and the frequency of misuse of poly(ethylene terephthalate) (PET) bottles are crucial parameters in the risk assessment of post-consumer recycled (PCR) PET intended for bottle-to-bottle recycling for direct food contact applications. Owing to the fact that misuse of PET bottles is a rare event, sustainable knowledge about the average concentration of hazardous compounds in PCR PET is accessible only by the screening of large numbers of samples. In order to establish average levels of contaminants in PET source materials for recycling, PET flakes from commercial washing plants (689 samples), reprocessed pellets (38) and super-clean pellets (217) were collected from 12 European countries between 1997 and 2001. Analysis of these materials by headspace gas chromatography revealed average and maximum levels in PCR PET of 18.6 and 86.0 mg kg−1 for acetaldehyde and 2.9 and 20 mg kg−1 for limonene, respectively. Acetaldehyde and limonene are typical compounds derived from PET itself and from prior PET bottle contents (flavouring components), respectively. Maximum levels in PCR PET of real contaminants such as misuse chemicals like solvents ranged from 1.4 to 2.7 mg kg−1, and statistically were shown to result from 0.03 to 0.04% of recollected PET bottles that had been misused. Based on a principal component analysis of the experimental data, the impact of the recollecting system and the European Union Member State where the post-consumer PET bottles had been collected on the nature and extent of adventitious contaminants was not significant. Under consideration of the cleaning efficiency of super-clean processes as well as migration from the bottle wall into food, it can be concluded that the consumer will be exposed at maximum to levels <50 ng total misuse chemicals day−1. Therefore, PCR PET materials and articles produced by modern super-clean technologies can be considered to be safe in direct food applications in the same way as virgin food-grade PET.