Migration kinetics of mineral oil hydrocarbons from recycled paperboard to dry food: monitoring of two real cases

A critical review of test methods and alternative scientific approaches to compliance and safety evaluation of paper and board for food contact

Paper and board are widely used as food contact materials. For such sensitive applications, consumer safety regarding the transfer of chemical components and contaminants to the food needs to be established. Such safety assessments are becoming increasingly challenging not only due to intentionally added substances but also non-intentionally added substances. In the European Union, compliance testing and safety evaluation of paper in food contact are largely based on national legislation and standards. The underlying tests are conventional methods, often overestimating and sometimes underestimating the migration into food. In this article, the relevant standard test methods are contrasted with currently available scientific knowledge. The scientific approaches to develop and identify suitable test methods are critically reviewed. Furthermore, theoretical predictions via mathematical modeling, with the aim to realistically simulate transfer to food, are presented and discussed in comparison with available migration studies with foods. Objectives are to (i) summarize the actual scientific knowledge in the field and draw conclusions regarding the potential and limitations of the existing test methods and (ii) identify research gaps toward a better qualitative and quantitative understanding of transport processes of volatile and non-volatile substances from paper and board into foods.

A novel approach to identify critical knowledge gaps for food safety in circular food systems

The transition from linear production towards a circular agro-food system is an important step towards increasing Europe's sustainability. This requires re-designing the food production systems, which inevitably comes with challenges as regards controlling the safety of our food, animals and the ecosystem. Where in current food production systems many food safety hazards are understood and well-managed, it is anticipated that with the transition towards circular food production systems, known hazards may re-emerge and new hazards will appear or accumulate, leading to new -and less understood- food safety risks. In this perspective paper, we present a simple, yet effective approach, to identify knowledge gaps with regard to food safety in the transition to a circular food system. An approach with five questions is proposed, derived from current food safety management approaches like HACCP. Applying this to two cases shows that risk assessment and management should emphasize more on the exposure to unexpected (with regards to its nature and its origin) hazards, as hazards might circulate and accumulate in the food production system. Five knowledge gaps became apparent: there's a need for (1) risk assessment and management to focus more on unknown hazards and mixtures of hazards, (2) more data on the occurrence of hazards in by-products, (3) better understanding the fate of hazards in the circular food production system, (4) the development of models to adequately perform risk assessments for a broad range of hazards and (5) new ways of valorization of co-products in which a safe-by-design approach should be adopted.

Current approaches and challenges of sample preparation procedures for the safety assessment of paper and cardboard food contact materials: A comprehensive review

In the European Union (EU), Regulation (EC) 1935/2004 provides a harmonized legal EU framework and sets out the general principles for safety and inertness for all Food Contact Materials (FCMs) and Food Contact Articles. From a food safety point of view, however, specific EU legislation for paper and cardboard FCMs is lacking, while at Member State level, national legislation differs among countries. More than 11,000 chemicals have been identified in all types of FCMs, most of them without any information on toxicity or migration potential from FCM to food. The present review shows a wide variability of protocols, approaches, and conditions used in scientific studies, which are difficult to compare. In this regard, procedures and conditions laid down in EU legislation for plastics and European Standards (EN protocols) may serve as a good basis for the future sample preparation procedures in the framework of paper and cardboard FCMs safety assessment. Challenges on sample preparation procedures are presented involving the interlinked steps of sample preparation, conditions used and their impact in chemical analysis and in vitro bioassay testing. Currently, there is no general consensus on the criteria for structuring, evaluating, and tuning sample preparation procedures for paper and cardboard FCMs. For this purpose, a set of modified criteria and a decision tree are proposed based on the literature. Along this, mass transfer processes occurring in paper and cardboard FCMs and parameters affecting chemical migration need to be accounted for prior to reaching general consensus on criteria for sample preparation procedures.

Survey of mineral oil hydrocarbons in Chinese commercial complementary foods for infants and young children

Recently, mineral oil hydrocarbons (MOH) in various foods have raised significant concern, especially for infants and young children due to their potential adverse health effects. Two fractions can be distinguished by certain analytical techniques, mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). The toxicological profile of MOSH and MOAH differs greatly. The toxicity of MOSH is linked with long-term accumulation of some hydrocarbons. MOAH with three to seven, non- or simple-alkylated, aromatic rings may be mutagenic and carcinogenic. However, data on the occurrence of mineral oils in commercial complementary foods for infants and young children are lacking in China. In the present study, 100 commercial food samples were collected, including 26 pureed or paste canned foods, 21 high-protein ground cereal foods (rice flour), 25 raw cereal foods (noodles), and 28 cereal-based molar sticks and biscuits. The content of MOSH and MOAH in those samples was determined by optimised sample preparation methods combined with on-line high-performance liquid chromatography coupled with gas chromatography and flame ionisation detector (HPLC-GC-FID), with a limit of quantification of 0.5 mg/kg. The results indicated that there were no MOAH detected in any of the foods, but MOSH and polyolefin oligomeric saturated hydrocarbons (POSH) existed in most of the food samples, at <0.5-23.68 mg/kg. Moreover, the data and chromatograms of the MOSH and POSH also indicated that these contaminants were closely correlated to their ingredients and manufacturers. The current study provides basic data to understand MOH exposure and consequent health impact.

Mineral oil hydrocarbons in foods: is the data reliable?

The contamination of foods with mineral oil hydrocarbons (MOH) is a serious concern, requiring in most cases tedious mitigation measures that span across the whole food supply chain. A major issue today is the significant variability of the results generated by laboratories. This study was therefore designed to achieve a deeper insight into the analytical procedures used by commercial laboratories, identifying possible gaps and suggesting improvements that will enhance the reliability of the MOH data, an important prerequisite for risk assessment. In total six different food matrices, i.e. infant formula (IF), cocoa butter, cocoa powder, biscuits, fruit-based baby food containing biscuit and roast and ground coffee were subjected to comparative inter-laboratory studies, as well as one vegetable oil analysed within the frame of a professionally conducted proficiency test. The results indicate that on some matrices with possibly low amounts of MOH contamination, the current methodologies cannot reliably conclude whether or not a food sample is indeed contaminated with mineral oils (<10 mg/kg food). Urgently needed are: (i) an aligned and fully validated sample preparation strategy tested on a range of different food matrices; (ii) a confirmation of positive flame ionisation detection (FID) results by confirmatory methods such as mass spectrometry - in line with the CEN Standard and the Joint Research Centre (JRC) Guidance Document, (iii) a more detailed root-cause analysis in the reports of laboratories through the use of mineral oil markers, and (iv) a fully validated official method for the concerned foods with a limit of application <10 mg/kg food.

Characterization of natural polymers as functional barriers for cellulose-based packaging materials

Cellulose-based packaging materials are currently the most commonly used food packaging materials due to their light weight, stability and affordable price. However, the use of recycled paper and board adds to the risk that undesirable substances migrate into the packed goods, since contaminants are not completely removed during the recycling process and can accumulate in the final product. The only available fast and practical solution that can be used to reduce the migration of these substances is the application of functional barriers in the packaging. The applied barriers are currently mostly synthetic, which either serve only a moderate barrier function and/or have the disadvantage that it is often more complex and expensive to recycle the resulting packaging material. The aim of this project is to evaluate different bio-based or biodegradable polymers with regards to their barrier properties. Due to the fact that the transport phenomena are mainly driven by (gas phase) migration, methods based on gas chromatography (GC), including GC coupled with mass spectrometry (GC-MS) and flame ionization detection (GC-FID), GC-FID coupled online with high pressure liquid chromatography (HPLC-GC-FID), and comprehensive GCxGC-MS were used to qualify and quantify the migrated substances. This use of a wide range of different methods and instruments yielded excellent results, allowing us to comprehensively characterize the biopolymers and their barrier function.

Insights into the Synergistic Biodegradation of Waste Papers Using a Combination of Thermostable Endoglucanase and Cellobiohydrolase from Chaetomium thermophilum

Enzymatic hydrolysis is considered an efficient and environmental strategy for the degradation of organic waste materials. Compared to mesophilic cellulases, thermostable cellulases with considerable activity are more advantageous in waste paper hydrolysis, particularly in terms of their participation in synergistic action. In this study, the synergistic effect of two different types of thermostable Chaetomium thermophilum cellulases, the endoglucanase CTendo45 and the cellobiohydrolase CtCel6, on five common kinds of waste papers was investigated. CtCel6 significantly enhanced the bioconversion process, and CTendo45 synergistically increased the degradation, with a maximum degree of synergistic effect of 1.67 when the mass ratio of CTendo45/CtCel6 was 5:3. The synergistic degradation products of each paper material were also determined. Additionally, the activities of CTendo45 and CtCel6 were found to be insensitive to various metals at 2 mM and 10 mM ion concentrations. This study gives an initial insight into a satisfactory synergistic effect of C. thermophilum thermostable cellulases for the hydrolysis of different paper materials, which provides a potential combination of enzymes for industrial applications, including environmentally friendly waste management and cellulosic ethanol production.

Mathematical equations combined with the MHE-GC method to study desorption kinetics of contaminants from food-package paper to air

Online sample incubation techniques are convenient, sensitive and safe, additionally, mathematical equations are applicative for other similar contaminants in paper.

Quantification of chemical contaminants in the paper and board fractions of municipal solid waste

Chemicals are used in materials as additives in order to improve the performance of the material or the production process itself. The presence of these chemicals in recyclable waste materials may potentially affect the recyclability of the materials. The addition of chemicals may vary depending on the production technology or the potential end-use of the material. Paper has been previously shown to potentially contain a large variety of chemicals. Quantitative data on the presence of chemicals in paper are necessary for appropriate waste paper management, including the recycling and re-processing of paper. However, a lack of quantitative data on the presence of chemicals in paper is evident in the literature. The aim of the present work is to quantify the presence of selected chemicals in waste paper derived from households. Samples of paper and board were collected from Danish households, including both residual and source-segregated materials, which were disposed of (e.g., through incineration) and recycled, respectively. The concentration of selected chemicals was quantified for all of the samples. The quantified chemicals included mineral oil hydrocarbons, phthalates, phenols, polychlorinated biphenyls, and selected toxic metals (Cd, Co, Cr, Cu, Ni, and Pb). The results suggest large variations in the concentration of chemicals depending on the waste paper fraction analysed. Research on the fate of chemicals in waste recycling and potential problem mitigation measures should be focused on in further studies.

Estrogenic Activity of Mineral Oil Aromatic Hydrocarbons Used in Printing Inks

The majority of printing inks are based on mineral oils (MOs) which contain complex mixtures of saturated and aromatic hydrocarbons. Consumer exposure to these oils occurs either through direct skin contacts or, more frequently, as a result of MO migration into the contents of food packaging that was made from recycled newspaper. Despite this ubiquitous and frequent exposure little is known about the potential toxicological effects, particularly with regard to the aromatic MO fractions. From a toxicological point of view the huge amount of alkylated and unsubstituted compounds therein is reason for concern as they can harbor genotoxicants as well as potential endocrine disruptors. The aim of this study was to assess both the genotoxic and estrogenic potential of MOs used in printing inks. Mineral oils with various aromatic hydrocarbon contents were tested using a battery of in vitro assays selected to address various endpoints such as estrogen-dependent cell proliferation, activation of estrogen receptor α or transcriptional induction of estrogenic target genes. In addition, the comet assay has been applied to test for genotoxicity. Out of 15 MOs tested, 10 were found to potentially act as xenoestrogens. For most of the oils the effects were clearly triggered by constituents of the aromatic hydrocarbon fraction. From 5 oils tested in the comet assay, 2 showed slight genotoxicity. Altogether it appears that MOs used in printing inks are potential endocrine disruptors and should thus be assessed carefully to what extent they might contribute to the total estrogenic burden in humans.

Waste paper for recycling: Overview and identification of potentially critical substances

Paper product manufacturing involves a variety of chemicals used either directly in paper and pulp production or in the conversion processes (i.e. printing, gluing) that follow. Due to economic and environmental initiatives, paper recycling rates continue to rise. In Europe, recycling has increased by nearly 20% within the last decade or so, reaching a level of almost 72% in 2012. With increasing recycling rates, lower quality paper fractions may be included. This may potentially lead to accumulation or un-intended spreading of chemical substances contained in paper, e.g. by introducing chemicals contained in waste paper into the recycling loop. This study provides an overview of chemicals potentially present in paper and applies a sequential hazard screening procedure based on the intrinsic hazard, physical-chemical and biodegradability characteristics of the substances. Based on the results, 51 substances were identified as potentially critical (selected mineral oils, phthalates, phenols, parabens, as well as other groups of chemicals) in relation to paper recycling. It is recommended that these substances receive more attention in waste paper.