Use of Tenax® films to demonstrate the migration of chemical contaminants from cardboard into dry food

ABSTRACT

Contaminants in food packaging are a challenge of our time since the packaging material itself has been found to represent a source of food contamination through the migration of substances from it. Before first use, packaging materials destined for the packaging of dry foods can be evaluated by performing migration experiments with the simulant for dry foods, Tenax®. This simulant is commercially available as a powder that is more difficult to handle during the migration experiments. This paper reports the development of a Tenax film. The film can be applied to the cardboard surface to conduct the migration test. After the migration is completed, the film can be easily extracted to determine the concentration of the contaminants in the film. Finally, the performance of the Tenax film was compared with the conventional Tenax powder for the evaluation of 15 model migrants.     

Model studies of migration from paper and board into fruit and vegetables and into Tenax™ as a food simulant

Four samples of paper and board (P/B) of a type used for packaging dry foods were subjected to migration tests using mushrooms, apples, potatoes and bananas, and using the polymeric powder Tenax? as a food simulant. The P/B samples contained only low levels of diisopropylnaphthalene (DiPN) and diisobutyl phthalate (DiBP) and so the experiments were conducted after impregnating the P/B with added model substances. These were o-xylene, acetophenone, dodecane, benzophenone, DiPN and DiBP. Migration levels depended strongly on the nature of the substance and on the nature of the food and much less on the characteristics of the P/B, except insofar as they affected the contact area – flexible papers giving more extensive contact with the food than thick rigid board. Migration into Tenax? was at least a factor of 10 higher than migration into the fresh fruit and vegetables. The food samples were placed in contact with the P/B and then overwrapped loosely with aluminium foil and so this correction factor will tend to be conservative compared with a more open storage of the packed foods. Washing, peeling or cooking the fruits and vegetables after contact with the P/B had a surprisingly small effect on contaminant levels in general, and no one processing step was effective in giving a significant reduction of all the types of chemicals studied. This was because either they had penetrated into the food (so resisting peeling), or were not freely water-soluble (so resisting washing) or were not particularly volatile (so resisting loss by evaporation during cooking).     

Mineral oil migration from paper-based packaging into food,investigated by means of food simulants and model substances

ABSTRACT

Mineral oil hydrocarbons (MOH) are known to be mixtures of non-identified substances, which can migrate from, inter alia, recycled food packaging into food products. Such substances may have carcinogenic potential, which leads to a need to avoid their migration into food. In this article, we investigate the possible use of food simulants and model substances to simplify migration approaches. Tenax and Sorb-Star were chosen as simulant media. To stage the action of known components as a replacement for the migration of MOH, 16 single substances, including n-alkanes and aromatic compounds, were used. Kinetic studies were carried out at a maximum of 60°C with contact times of up to 14 days in touching contact with a medium or in gas-phase transfer to it. The results demonstrated that migration was predominantly a function of temperature, time and contact type, but it was also dependant on the molecular weight and polarity of the substances. Due to their low polarity, alkanes showed higher migration to the lipophilic food simulants than did pure aromatics without alkylation. Additionally, alkylated aromatics represent mineral oil aromatic hydrocarbons (MOAH) more realistically. In contrast to Tenax in the gas-phase transition, Tenax in touching contact may lead to overestimated values at higher temperatures. Migration values for Sorb-Star are in similar regions for both contact types. However, the values of the touching contact experiments were slightly higher than those of the gas-phase transfer. The results for Sorb-Star and Tenax with transport solely over the gas phase are also in good agreement. Sorb-Star generally represents an optimal simulant for chunky foods, whereas Tenax seems a good simulant for food types with a high contact surface. Temperatures up to 40°C are appropriate for most types of migration experiments, whereas 60°C should only be used as an option for experiments with Sorb-Star.     

Potential migration of Diisopropyl naphthalenes from recycled paperboard packaging into dry foods

The results of a study of the potential migration of diisopropyl naphthalenes (DIPN) from recycled paperboard packaging into some types of dry solid foodstuffs are reported. Paperboard diskettes containing different DIPN concentrations were prepared and put into contact with four types of dry solid foodstuffs, having high specific surface areas and different lipid contents. At regular intervals the DIPN content in the foods was determined. Two migration mechanisms have been proposed and verified. The first one relates to the direct contact existing between paperboard and foodstuff. The second one refers to the indirect contact between paperboard and food, controlled by an air space created above the paperboard into which the DIPN has diffused. Both mechanisms occurred and the migration depended on different factors: the contact time, the characteristics of the foodstuffs and the DIPN content in the cellulose-based matrix. However, only very low levels of contamination in the foodstuffs occurred in migration. As a consequence, this report also considers possible limitations which could be applied to the content of carbonless copy paper in packaging paperboard formulations.     

Kinetic migration of isothiazolinone biocides from paper packaging to Tenax and Porapak

Migration investigations were carried out on paper packaging materials in contact with solid food simulants. The aim was to investigate the migration behaviour of a series of isothiazolinone biocides (2-methyl-3-isothiazolinone (MI), 1,2-benzisothiazolinone (BIT) and 2-octyl-3-isothiazolinone (OIT)) as potential contaminants in paper materials, at varying temperatures and migration times, for the food simulants Tenax and Porapak. Based on the migration results, Tenax was found to be a good food simulant, and was more suitable than Porapak at high temperature. Petri dishes were found to be suitable for use as migration cells when the compounds to be evaluated were non-volatile. The amount of migration gradually increased with time and increasing temperature, finally reaching a steady value. When the temperature was higher than the boiling point of OIT, the migration rate decreased because of volatilization. The maximum migration rates were 3.4% for MI, 2.2% for BIT and 10.6% for OIT at high temperature (≥100 °C). Two kinds of paper packaging for food were tested with the method that was developed. OIT in the papers migrated into the food simulants but the amount that migrated was less than 0.14 μg kg(-1).     

A study on the migration of organic pollutants from recycled paperboard packaging materials to solid food matrices

Paper and board are widely used as food packaging materials, mainly for disposable products. As public interest in conservation of natural resources has accelerated in the past several years, the use of recycled paper and board has increased. Recycled fiber materials can be used in certain limits as food contact materials. The safety of recycled fiber-based materials for food contact applications is largely dictated by the ability of post-consumer contaminants to be absorbed into recycled materials and later released by the packaging material and trapped on the food. The present work was undertaken with the aim of investigating the physicochemical behavior of selected model contaminants on paper and board, in contact with foodstuffs thus producing a fundamental set of data about their mobility from recycled paper and board into foods. More specifically, the kinetics of migration of selected model contaminants (surrogates) from contaminated recycled paper packaging samples into dry foodstuffs with different fat content was studied using a method based on solvent extraction and GC-FID quantification. Results showed the ability of selected contaminants of various types and various volatilities to potentially transfer to dry foods. The proportion of substances migrated to food was strongly dependent on the nature of the paper samples, fat content of the food, chemical nature and volatility of the migrant. The highest level of migration of organic pollutants was observed for the substrate with the highest fat content. Furthermore, it is shown that contact time and temperature have a significant effect on migration of model contaminants into foods.     

Migration of dehydroabietic and abietic acids from paper and paperboard food packaging into food-simulating solvents and Tenax TA

An investigation was undertaken to establish the concentration in paper products of dehydroabietic (DHA) and abietic (AA) resin acids, present in rosin, which are major toxicants of pulp- and paper-mill effluent. Their migration was studied from paper and paperboard products into various food-simulating solvents and the substitute fatty food simulant Tenax TA (modified polyphenylene oxide). DHA and AA were detected in five of 10 virgin paper products and in all 10 recycled paperboard products for food-contact use at concentrations of 14-500 and 110-1200 µg/g, respectively. In virgin paper products, the highest migration was into 95% ethanol or heptane, with negligible or no migration into other solvents. In recycled paperboard products, migration was highest into 95% ethanol, but was also observed into 20% ethanol, water and heptane. Migration to Tenax TA was also observed and the migration level increased with time. The maximum migration levels of DHA and AA into food simulants were 0.853 and 3.14 µg/g, respectively. The results suggest that, in the worst case, the daily intake of DHA and AA from paper and paperboard products was 50 times lower than the tolerable daily intake of rosin.     

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

Mineral oil hydrocarbons present in printing inks and recycled paper migrate from paper-based food packaging to foods primarily through the gas phase. Migration from two commercial products packed in recycled paperboard, i.e. muesli and egg pasta, was monitored up to the end of their shelf life (1 year) to study the influence of time, storage conditions, food packaging structure and temperature. Mineral oil saturated and aromatic hydrocarbons (MOSH and MOAH, respectively), and diisopropyl naphthalenes (DIPN) were monitored using online HPLC-GC/FID. Storage conditions were: free standing, shelved, and packed in transport boxes of corrugated board, to represent domestic, supermarket and warehouse storage, respectively. Migration to food whose packs were kept in transport boxes was the highest, especially after prolonged storage, followed by shelved and free-standing packs. Tested temperatures were representative of refrigeration, room temperature, storage in summer months and accelerated migration testing. Migration was strongly influenced by temperature: for egg pasta directly packed in paperboard, around 30 mg kg^?1 of MOSH migrated in 8 months at 20°C, but in only 1week at 40°C. Muesli was contained into an internal polyethylene bag, which firstly adsorbed hydrocarbons and later released them partly towards the food. Differently, the external polypropylene bag, containing pasta and recycled paper tray, strongly limited the migration towards the atmosphere and gave rise to the highest level of food contamination. Tests at increased temperatures not only accelerated migration, but also widened the migration of hydrocarbons to higher molecular masses, highlighting thus a difficult interpretation of data from accelerated simulation.     

Determination of primary aromatic amines in cold water extract of coloured paper napkin samples by liquid chromatography-tandem mass spectrometry

The aim of this study was the optimisation of a multi-analyte method for the analysis of primary aromatic amines (PAAs) from napkins in order to support official controls and food safety. We developed a UHPLC-MS/MS method for the simultaneous determination of 36 toxicologically relevant PAAs for paper and board. Good regression coefficients of the calibration curves in a range of 0.992–0.999 and reproducibilities in a range of 2.3–15% were obtained. Limits of detections (LODs) were in the range of 0.03–1.4 µg l^–1 and recoveries were in a range of 21–110% for all the amines. A total of 93 coloured paper napkin samples from different European countries were bought and extracted with water to determine the PAAs. The results showed that 42 of 93 samples contained at least one PAA. More than half of the detected PAAs are considered as toxic, carcinogenic or probably carcinogenic to humans by the International Agency for Research on Cancer (IARC), or are classified as such in the European Union legislation on chemicals. Summed concentrations of PAAs in seven samples were higher than 10 µg l^–1, the limit of summed PAA in the European Union plastic food contact material regulation. Also, eight PAAs, classified as Category 1A and 1B carcinogen in the European Union legislation of chemicals, were detected at concentrations higher than 2 µg l^–1, exceeding the limit proposed by the Federal Institute for Risk Assessment in Germany. Aniline (n = 14) was most frequently present in higher concentrations followed by o-toluidine, o-anisidine, 2,4-dimethylaniline and 4-aminoazobenzene. Red, orange, yellow and multicoloured paper napkins contained the highest concentrations of total PAAs (> 10 µg l^–1). Although the European Union has not harmonised the legislation of paper and board materials and, thus, there is no specific migration limit for PAAs from paper napkins, the present study showed that coloured paper napkins can contain toxic and carcinogenic PAAs at concentrations that are relevant for monitoring.     

Exploring the sensitivity of the zone of inhibition test for leachable biocides from paper and board food contact materials, and improvements thereof

The zone of inhibition method to test the release of biocides from paper and board food contact materials was evaluated. The method tests the paper by placing a small specimen directly onto culture plates of Bacillus subtilis and Aspergillus niger. The principle is that any extractable biocide will diffuse from the paper into the surrounding nutrient medium and so inhibit growth of the microorganism in the vicinity. The test was found to have insufficient sensitivity for assuring food safety, where detection limits for migration at or below the mg l(-1) (parts per million) level are needed. Also, the test does not mimic the actual or foreseeable conditions of use since most paper/board materials are not intended for direct contact with an aqueous medium for up to 3 days at 30°C (B. subtilis) or 25°C (A. niger), which are the incubation conditions used. The sensitivity of the test was increased approximately 100-fold by preparing a concentrated extract of the paper to be tested and applying this extract to the assay via a blank paper carrier. This was done using methanol as a good solvent for most biocides, as a proof of principle. Other solvents or food simulants could be used to mimic the conditions of use intended for the particular paper/board samples under examination, e.g. contact with dry, fatty, aqueous or acidic foods, hot or cold. Twenty-four plain (unconverted) paper and board samples and 100 food packaging samples were evaluated using the modified procedure. The results revealed that the method has been developed to the stage where background cytotoxic action of normal paper constituents gives a weak response. Unlike the original method, therefore, the modified method with its improved sensitivity and the facility to link with the intended food contact conditions may be considered a suitable bioassay screening test to complement chemical analysis of paper/board for composition and migration.     

基于剖析图法的瓦楞纸箱尺寸设计

采用剖析图法计算瓦楞纸箱制造尺寸。由瓦楞纸板压痕原理出发,通过测量已知制造尺寸的FEFCO 0200瓦楞纸箱样品的内、外尺寸,计算出压痕内转移量、外转移量。以FEFCO 0421为例,绘制出包含已知尺寸和待求制造尺寸的横向局部剖析图和纵向局部剖析图。通过分析剖析图及包装造型图,分别由内尺寸或外尺寸计算出瓦楞纸箱制造尺寸,并绘制出包装结构设计图。剖析图法计算瓦楞纸箱制造尺寸,不受瓦楞纸板楞型和瓦楞纸箱箱型的影响,不仅适用于瓦楞纸箱尺寸设计,包括超微瓦楞纸箱和极大瓦楞纸箱,还适用于瓦楞纸板制造的家具、展示架等其他瓦楞纸板产品的尺寸设计。     

Migration of inorganic contaminants into dry food from packaging made from recycled paper and board.

A radiotracer method was applied to the measurement of inorganic contaminants migrating into food. The method was applied to the study of 10 samples of recycled paper and board. The only elements detected in the static migration test were zinc and iron, at concentrations close to the detection limit. Samples of rice, oats, custard powder, mushrooms and fries showed that traces of these elements had migrated from the packaging. The migration was limited to less than 1%, with the exception of the mushrooms, where the decomposition of the food had resulted in a 12.5% transfer of zinc from the mushroom bag after 8 days, equivalent to migration of 0.022 mg dm(-2). Shaking had no effect on migration, except in one case of custard powder where migration occurred at a level equivalent to 0.002 mg dm(-2). The maximum migration determined in the present study was 4.8 microg zinc and 2.6 microg iron, which is negligible when compared with the recommended daily intakes of 15 and 14 mg, respectively. When Tenax was tested as a food simulant, no zinc was detected (< 0.001 mg dm(-2)), although slight migration (0.001 mg dm(-2)) occurred into food.     

Survey of the migration of melamine and formaldehyde from melamine food contact articles available on the UK market

The migration of melamine and formaldehyde, monomers used in the production of melamine-ware food contact articles, has been determined from 50 retail articles purchased in the UK. The food simulant 3% aqueous acetic acid was used as this is the most aggressive simulant towards melamine plastics. The test conditions used were repeated exposure to the simulant for 2 hours at 70°C, since the articles were all intended for general use including contact with hot foods and beverages. Melamine migrated from 43 of the 50 samples tested and formaldehyde migrated from all 50 samples. Directive 2002/72/EC specifies migration limits for both of these monomers in foods and food simulants. Melamine is restricted by a specific migration limit (SML) of 30 mg/kg (equivalent to 5 mg/dm²) and formaldehyde, along with hexamethylenetetramine expressed as formaldehyde, is restricted by a total (T) SML(T) of 15 mg/kg (equivalent to 2.5 mg/dm²). In all cases the migration of melamine was much lower than the SML for this monomer. The migration of formaldehyde exceeded the SML(T) for 5 of the 50 samples tested. The failure to comply with the SML(T) was accompanied by a number of visible surface effects including discolouration and/or pitting of the simulant contact surface and cracking of the articles. Similar surface effects were observed when one of the samples was exposed to fruit juice which confirmed the suitability of the exposure conditions and 3% acetic acid as a simulant for the articles tested. The ratio of specific migration to overall migration was consistent with, but did not prove, the hypothesis that high formaldehyde migration could be due to the use of excessive hexamethylenetetramine in the polymer formulation. All illegal products were voluntarily removed from the market by the product suppliers.     

卷烟箱循环利用现状及优化对策——以贵州中烟为例

为了积极响应绿色包装、循环经济的要求,对卷烟箱的循环利用现状进行研究和探讨。以贵州中烟A厂烟箱实际循环利用的情况为依据,从挑选标准、循环利用次数、回收模式等多方面进行了定性分析,对回收过程中烟箱质量进行了定量分析,并据此在优化回收烟箱处理方面提出了相应对策。研究发现烟箱在回收4次时,烟箱质量缺陷突显,同时力学性能显著下降,回收烟箱质量缺陷中摇盖下垂和箱体破损远高于其他缺陷。结论提出了相应的五个方面的优化对策:(1)完善回收烟箱标准;(2)优化回收烟箱处理;(3)提高烟箱通用性;(4)提高烟箱质量;(5)优化烟箱循环利用模式。     

Migration of mineral oil from party plates of recycled paperboard into foods: 1. Is recycled paperboard fit for the purpose? 2. Adequate testing procedure

Party plates made of recycled paperboard with a polyolefin film on the food contact surface (more often polypropylene than polyethylene) were tested for migration of mineral oil into various foods applying reasonable worst case conditions. The worst case was identified as a slice of fried meat placed onto the plate while hot and allowed to cool for 1?h. As it caused the acceptable daily intake (ADI) specified by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) to be exceeded, it is concluded that recycled paperboard is generally acceptable for party plates only when separated from the food by a functional barrier. Migration data obtained with oil as simulant at 70°C was compared to the migration into foods. A contact time of 30?min was found to reasonably cover the worst case determined in food.     

Migration of mineral oil from party plates of recycled paperboard into foods: 1. Is recycled paperboard fit for the purpose? 2. Adequate testing procedure

Party plates made of recycled paperboard with a polyolefin film on the food contact surface (more often polypropylene than polyethylene) were tested for migration of mineral oil into various foods applying reasonable worst case conditions. The worst case was identified as a slice of fried meat placed onto the plate while hot and allowed to cool for 1 h. As it caused the acceptable daily intake (ADI) specified by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) to be exceeded, it is concluded that recycled paperboard is generally acceptable for party plates only when separated from the food by a functional barrier. Migration data obtained with oil as simulant at 70°C was compared to the migration into foods. A contact time of 30 min was found to reasonably cover the worst case determined in food.     

Migration of photoinitiators from cardboard into dry food: evaluation of Tenax® as a food simulant

Photoinitiators are widely used to cure ink on packaging materials used in food applications such as cardboards for the packaging of dry foods. Conventional migration testing for long-term storage at ambient temperature with Tenax^® was applied to paperboard for the following photoinitiators: benzophenone (BP), 4,4?-bis(diethylamino)benzophenone (DEAB), 2-chloro-9H-thioxanthen-9-one (CTX), 1-chloro-4-propoxy-9H-thioxanthen-9-one (CPTX), 4-(dimethylamino)benzophenone (DMBP), 2-ethylanthraquinone (EA), 2-ethylhexyl-4-dimethylaminobenzoate (EDB), ethyl-4-dimethylaminobenzoate (EDMAB), 4-hydroxybenzophenone (4-HBP), 2-hydroxy-4-methoxybenzophenone (HMBP), 2-hydroxy-4?-(2-hydroxyethoxy)-2-methylpropiophenone (HMMP), 2-isopropyl-9H-thioxanthen-9-one (ITX), 4-methylbenzophenone (MBP) and Michler’s ketone (MK). Test conditions (10 days at 60°C) were according to Regulation (EU) No. 10/2011 and showed different migration patterns for the different photoinitiators. The results were compared with the migration in cereals after a storage of 6 months at room temperature. The simulation with Tenax at 60°C overestimated actual migration in cereals up to a maximum of 92%. In addition, the effect of a lower contact temperature and the impact of the Tenax pore size were investigated. Analogous simulation performed with rice instead of Tenax resulted in insufficiently low migration rates, showing Tenax is a much stronger adsorbent than rice and cereals.     

Migration kinetics of four photo-initiators from paper food packaging to solid food simulants

ABSTRACT

The migration behaviour of four photo-initiators (BP, EHA, MBP and Irgacure 907) was studied by ‘printing’ onto four different food-packaging materials (Kraft paper, white cardboard, Polyethylene (PE)-coated paper and composite paper) and tracking movement into the food simulant: Tenax-TA (porous polymer 2,6-diphenyl furan resin). The results indicated that the migration of the photo-initiators was related to the molecular weight and log K_o/w of each photo-initiator. At different temperatures, the migration rates of the photo-initiators were different in papers with different thicknesses. The amount of each photo-initiator found in the food was closely related to the food matrix. The Weibull model was used to predict the migration load into the food simulants by calculating the parameters τ and β and determining the relationship of the two parameters with temperature and paper thickness. The established Weibull model was then used to predict the migration of each photo-initiator with respect to different foods. A two-parameter Weibull model fitted the actual situation, with some deviation from the actual migration amount.     

Comparison of the migration of melamine from melamine-formaldehyde plastics ('melaware') into various food simulants and foods themselves

A variety of melaware articles were tested for the migration of melamine into the food simulant 3% w/v acetic acid as a benchmark, and into other food simulants, beverages and foods for comparison. The results indicate that the acidity of the food simulant plays a role in promoting migration, but not by as much as might have been anticipated, since 3% acetic acid gave migration values about double those obtained using water under the same time and temperature test conditions. In contrast, migration into the fatty food simulant olive oil was not detectable and at least 20-fold lower than with the aqueous food simulants. This was expected given the solubility properties of melamine and the characteristics of the melaware plastic. Migration levels into hot acidic beverages (apple juice, tomato juice, red-fruit tea and black coffee) were rather similar to the acetic acid simulant when the same time and temperature test conditions are used, e.g. 2 h at 70°C. However, migration levels into foods that were placed hot into melaware articles and then allowed to cool on standing were much lower (6-14 times lower) than if pre-heated food was placed into the articles and then maintained (artificially) at that high temperature in the same way that a controlled time-temperature test using simulants would be conducted. This very strong influence of time and especially temperature was manifest in the effects seen of microwave heating of food or beverage in the melaware articles. Here, despite the short duration of hot contact, migration levels were similar to simulants used for longer periods, e.g. 70°C for 2 h. This is rationalized in terms of the peak temperature achieved on microwave heating, which may exceed 70°C, counterbalancing the shorter time period held hot. There was also evidence that when using melaware utensils in boiling liquids, as for stovetop use of spatulas, the boiling action of circulating food/simulant can have an additional effect in promoting surface erosion, increasing the plastic decomposition and so elevating the melamine release.     

Test procedures for obtaining representative extracts suitable for reliable in vitro toxicity assessment of paper and board intended for food contact

This paper describes the use of a suite of extraction procedures applicable to the assessment of the in vitro toxicity of paper/board samples intended for food-contact applications. The sample is extracted with ethanol, water, or exposed to modified polyphenylene oxide (Tenax®) for fatty, non-fatty and dry food applications, respectively. The water extracts are directly suitable for safety assessment using in vitro bioassays. The ethanol extracts of the paper/board and of the exposed Tenax require pre-concentration to give acceptable sensitivity. This is because the in vitro bioassays can tolerate only a small percentage of added organic solvent before the solvent itself inhibits. The extraction procedures have been selected such that they mimic the foreseeable conditions of use with foods and that they are also fully compatible with the battery of in vitro biological assays for the safety assessment of the total migrate. The application of the extraction protocols is illustrated by the results for one of the many paper/board samples provided by the BIOSAFEPAPER project industrial platform members. The assessment indicated that this sample should not be considered as suitable for use with fatty foodstuffs but was suitable for dry and non-fatty foods. Information subsequently received from the manufacturer revealed that this was a non-food-grade product included in the project to test the capabilities of the bioassay procedures. The selection criteria for the test conditions and the suite of methods developed have been prepared in Comité Européen de Normalisation (CEN) format and is currently being progressed by CEN/TC172 as a European Standard.