Characterisation of Elastomers as Food Contact Materials-Part 1: Quantification of Extractable Compounds, Swelling of Elastomers in Food Simulants and Release of Elements.

Elastomers are not a uniform class of materials but comprise a broad spectrum of chemically different polymers. Sealing gaskets, gloves, teats, conveyor belts and tubing are examples of elastomers being used as food contact materials (FCMs). Ten elastomer samples were evaluated with respect to the content of extractable compounds, migration of substances into ethanolic food simulants, swelling in food simulants and release of elements in different food simulants. The number of extractable substances <1000 Da was determined by comprehensive two-dimensional gas chromatography coupled with flame ionisation detection (GC × GC-FID) analysis of tetrahydrofuran (THF) extracts. The number of signals ranged from 61 (a thermoplastic elastomer (TPE)) to 690 (a natural rubber/styrene-butadiene-rubber blend (NR/SBR)). As for risk assessment, the decisive factor is which substances reach the food. The extent of substances that migrate into ethanolic food simulants was investigated. Elastomer FCMs can be the source of food contamination with heavy metals. Notably, contamination with lead was detected in some samples investigated in this study. It was shown that food simulants harbour the potential to morphologically alter or even disintegrate elastomeric materials. The results presented here highlight the importance to carefully choose the elastomer type for the intended use as FCMs as not every application may prove safe for consumers.

Exposure to acrylamide from home-cooked food: fried potatoes (rösti) in Switzerland as an example.

There is a significant lack of data on acrylamide in food which is prepared domestically, as obtaining samples of food cooked in people's homes is more complex than taking samples from shops. Rösti is a fried potato dish, which can be a significant contributor to acrylamide exposure, particularly in the German speaking areas of Switzerland. A set of 71 samples was collected from people who cooked the dish at home. The average acrylamide content was 709 µg/kg. Based on a food frequency questionnaire and on a Swiss national food survey the results enabled the determination of the exposure of the population to acrylamide through home-made rösti. The values for an exposure estimate to acrylamide from rösti are 7.8 µg/day for the whole population (including rösti eaters and non-eaters) and 27.2 µg/day for predominantly rösti consumers participating in this study.

Epoxidation for the analysis of the mineral oil aromatic hydrocarbons in food. An update.

On-line coupled high performance liquid chromatography-gas chromatography-flame ionization detection (HPLC-GC-FID) used for determining mineral oil aromatic hydrocarbons (MOAH) in foods, particularly in certain oils and fats, may be disturbed by interfering olefins present as natural food components or resulting from raffination of the oils and fats. While some interference can be coped with by disregarding their peaks, others overload GC to the extent of obscuring the MOAH or form humps which need to be distinguished from the hump formed by the MOAH. In the latter cases, it is necessary to remove these interferences prior to HPLC-GC analysis. So far, epoxidation of the olefins to increase their retention time beyond that of the MOAH in HPLC is the best method available, though imperfect by causing some loss of MOAH and sometimes incomplete removal of the interference. Two methods are re-evaluated; preference is given to a slightly modified version of that proposed by Nestola and Schmidt. The performances are comparable: the losses of MOAH are similar and with both methods not all interfering olefins may be removed from refined edible oils. However, the Nestola/Schmidt method has practical advantages, the main ones being that no cooling is necessary and no solvent needs to be evaporated, which facilitates automation. Potential residual interferences must be recognized and subtracted, which can be by the characteristics of the hump they form in HPLC-GC-FID, by GCxGC-FID or by GCxGC-MS using characteristic mass fragments.

Advantages of comprehensive two-dimensional gas chromatography for comprehensive analysis of potential migrants from food contact materials.

All substances migrating from food contact materials (FCMs), such as packagings, into food must be safe. This presupposes comprehensive analysis of all constituents potentially reaching a concentration in food that may be of toxicological concern. There is no single technique meeting this task and usually several need to be combined. In many cases, comprehensive two-dimensional gas chromatography (GCxGC) is the best technique available to start with. It provides high resolution and an overview in well-structured plots, grouping similar substances in a manner facilitating identifications. Further, flame ionization detection (FID) enables approximate quantitation without standards, and electron impact (EI) fragmentation in mass spectrometry (MS) provides access to large libraries for identification. GC is limited in amenable molecular mass, but the characterization of the lower mass constituents is usually helpful also for the identification of higher mass ones by techniques like HPLC-MS. The scope of this paper is to advocate the use of GCxGC for comprehensive migrate analysis, based on advantages illustrated by examples.

Activated carbon added to recycled paperboard to prevent migration into food: approach for determining efficacy, and first results.

Catcherboard MB12® from Smurfit Kappa is a recycled paperboard incorporating activated carbon to reduce the release of contaminants into food. An approach is proposed to determine the efficacy of the activated carbon. Sorption into activated carbon increases the concentration ratio paperboard/food (distribution coefficient) and reduces the migration rate, i.e. prolongs the time for equilibration. Using silicone paper as food simulant, the concentration ratio was increased by a factor of at least 1000 compared to recycled paperboard without activated carbon, which is sufficient to meet the 1% criterion proposed for barriers. Sorbents have limited capacity. A load with in total 4000 mg surrogate substances/kg paperboard (in addition to the material from the paperboard) exceeded the capacity: concentration ratios were reduced and the release of paperboard constituents increased. Capacity is consumed by constituents from the printing inks and the packed food. Total amounts of substances in dry foods of sufficient volatility to potentially migrate into the paperboard through the gas phase at ambient temperature were determined by GC-FID. For the large majority of the dry foods, these amounts were clearly below the capacity limit even under the exaggerated assumption of total transfer. Migration of mineral oil hydrocarbons into cat food over up to 1 year was not detectable at 1 mg/kg. It is concluded that recycled paperboard with activated carbon is promising for respecting the 1% criterion stipulated for functional barriers to avoid food contamination from recycled paperboard.

Recycled paperboard with a barrier layer for food contact: set-off during stacking or reeling. Analytical method and preliminary results.

The use of recycled paperboard for packaging dry foods is in the interest of sustainability of resources, but in most applications, the food must be protected against contamination, such as by a functional barrier on the internal surface of the paperboard box. After application, the paperboard is usually stacked or reeled before making boxes. During this period, the food-contact surface of the barrier layer is in contact with the outer side of the paperboard, which may result in set-off and subsequent contamination of food. A method is described for the determination of this path of migration, based on the taped format also used for the measurement of the barrier efficiency. Recycled paperboard containing the three surrogate substances n-heptadecane, 4-methyl benzophenone and dipropyl phthalate was taped to the food-contact side of the barrier layer. Pressure onto the test packs did not seem to be a relevant parameter. After periods of interest, a piece of the paperboard with the barrier layer was extracted and analysed for the surrogate substances. Another piece may be brought into contact with silicone paper to simulate the transfer to food. After 2 weeks at 60°C (simulating about 1 year at 25°C), set-off and the transfer to the silicone paper exceeded 1% for all barrier materials tested, but after 6 weeks at 40°C (around half a year at 25°C), set-off remained below 1% for all barrier layers except a multilayer with polyethylene on the food-contact surface. The preliminary conclusion is that set-off should be taken seriously, but may be kept low enough to provide sufficient protection of the packed food.

Update of on-line coupled liquid chromatography - gas chromatography for the analysis of mineral oil hydrocarbons in foods and cosmetics.

On-line coupled high performance liquid chromatography-gas chromatography-flame ionization detection (HPLC-GC-FID) is the most widely used method for the analysis of mineral oil hydrocarbons in food, food contact materials, tissues and cosmetics. With comprehensive two-dimensional gas chromatography (GCxGC), a tool became available for better establishing the elution sequence of the various types of hydrocarbons from the HPLC column used for isolating the mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). The performance of a heavily used HPLC column with reduced retention for MOAH was investigated to improve the robustness of the method. Updates are recommended that render the MOSH/MOAH separation less dependent of the state of the HPLC column and more correct in cases of highly refined mineral oil products of high molecular mass. Cyclohexyl cyclohexane (Cycy), used as internal standard, turned out to be eluted slightly after cholestane (Cho); apparently the size exclusion effect predominates the extra retention by ring number on the 60Å pore size silica gel. Hence, Cycy can be used to determine the end of the MOSH fraction. Long chain alkyl benzenes were eluted earlier than tri-tert. butyl benzene (Tbb). It is proposed to start the MOAH transfer immediately after the MOSH fraction and use a gradient causing breakthrough of dichloromethane (visible in the UV chromatogram) at a time suitable to elute perylene (Per) at the end of the fraction. In this way, a decrease in retention power of the HPLC column can be tolerated without adjustment of the MOAH fraction until some MOAH start being eluted into the MOSH fraction. This critical point can be checked either with di(2-ethylhexyl) benzene (DEHB) as a marker or the HPLC-UV chromatogram. Finally, based on new findings in rats and human tissues, it is recommended to integrate the MOSH and MOAH up to the retention time of the n-alkane C40.

Leaching of plasticizers from polyvinylchloride perfusion lines by different lipid emulsions for premature infants under clinical conditions.

Plasticizers migrate from polyvinylchloride (PVC) infusion systems into lipid emulsions. The aim of this study was to investigate the leaching of different plasticizers from PVC perfusion lines by a selection of lipid emulsions under clinical conditions. Seven PVC perfusion lines with an equal length of 150cm and three internal diameters were perfused with three lipid emulsions: Intralipid® 20%, ClinOleic® 20% and SMOFlipid® 20%, mimicking clinical conditions. The concentrations of the plasticizers were measured directly in the emulsions by gas chromatography - mass spectrometry. Of the four plasticizers examined in this study, di (2-ethylhexyl) phthalate (DEHP) leached the most and was found, on average, at 46.5µg/ml in the emulsions - around one order of magnitude higher than the other plasticizers. This study demonstrates that the leaching of DEHP by lipid emulsions in conditions of total parenteral nutrition is many times higher than should be accepted and higher when compared to the other plasticizers. There was no significant difference in leaching of plasticizers in relation to the type of lipid emulsion. The influence of tube diameter on the leaching rate of plasticizers should be taken into account especially in particular exposed patients.

Survey on plasticizers currently found in PVC toys on the Swiss market: Banned phthalates are only a minor concern.

Plasticizers in toys are a recurring source of criticism and concern, as consumers feel they may endanger the health of their children. Most of the information available in literature concerns the presence or absence of certain phthalic acid ester plasticizers. Very little information can be found in the public domain with respect to the actually used plasticizers at a given time and place. In this paper, we present the plasticizer composition of 118 samples from 88 polyvinyl chloride toys found on the Swiss market in autumn 2015. Bis(2-ethylhexyl) terephthalate (DEHT) was by far the most frequent main plasticizer in the analyzed samples, which is a change when compared to the plasticizers found in toys and child care articles in 2007. Furthermore, the data show that the banned phthalates in toys are only a minor concern. The occurrence, however, is not evenly distributed between importers. If a toy is not designed to be sold on the European market by the manufacturer, it seems to be more likely to contain a banned phthalic acid ester.

Mineral oil saturated hydrocarbons (MOSH) in female Fischer 344 rats; accumulation of wax components; implications for risk assessment.

Female Fischer 344 rats were exposed to three MOSH mixtures: oils largely below and above C25 (S-C25 and L-C25) and a 1:1 mixture of L-C25 with a wax; doses of 400, 1000 and 4000mg/kg feed were administered during 120days. MOSH were determined by on-line HPLC-GC-FID in liver, spleen, adipose tissue and the carcass. The composition of the hydrocarbons accumulated in the tissues was further analyzed by comprehensive two-dimensional GC (GC×GC). MOSH in the mass range of C26-30 were more strongly accumulated than those between C20-25, which does not support the present classification of MOSH differentiating at n-C25 for risk assessment. Compared to the total of the MOSH, n-alkanes and n-alkyl monocyclic naphthenes were generally enriched in adipose tissue. In liver and spleen, n-alkanes up to C25 were eliminated, but strongly accumulated at around C30. Based on this profile, poor solubility and the melting points, it is hypothesized that crystallization protects these wax components against metabolism and elimination. In the liver, relative retention of n-alkanes decreased again beyond C30, accentuated at high exposure, suggesting reduced absorption. Compared to the animal data, accumulation of n-alkanes from food sources, such as apples, into human tissues seems low, perhaps because of low absorption due to their presence in crystalline form. A series of dominant isoalkanes, accumulated in all tissues analyzed, was characterized, though without proposing a structure. Implications on present regulation of white mineral oil products are discussed.

Accumulation of mineral oil saturated hydrocarbons (MOSH) in female Fischer 344 rats: Comparison with human data and consequences for risk assessment.

Female Fischer 344 rats were orally exposed to a mixture of mineral oil saturated hydrocarbons (MOSH) of broad molecular mass range at doses of 40, 400 and 4000mg/kg feed. Amounts and compositions of the MOSH were analyzed in liver, spleen, adipose tissue and the carcass after exposure during 30, 60, 90 and 120d as well as after 90d exposure followed by 30d depuration. At 40mg/kg in the feed, after 30d of exposure, 10.9% of the ingested MOSH were recovered from the animal body; after 90d plus 30d depuration it was 3.9%. In liver and spleen, the maximum retention in terms of molecular mass (simulated distillation) was at n-C29; in adipose tissue and carcass it was at n-C15/16. The differentiation between MOSH below and above n-C25 (Class I versus Class II and III oils), used for present regulation, is not supported by the present data on accumulation; structural characteristics seem more pertinent than molecular mass. Concentrations in the tissues increased far less than proportionally with the dose, rendering linear extrapolation to low doses questionable. No steady state was reached after 120d. In fact, comparing with the concentrations in human tissues at the estimated exposure, extrapolation from animal experiments seems to grossly underestimate human internal exposure. Comprehensive two-dimensional gas chromatography (GCxGC) was used to characterize the MOSH residues in the tissues with the aim of identifying the most strongly accumulated types. In the liver and spleen, the highly branched hydrocarbons dominated, whereas in the adipose tissue it was the n-alkanes and species with main n-alkyl moieties. Strong MOSH accumulation is not of concern per se, but the safety at the high concentrations in human tissues needs to be re-evaluated, possibly taking into account also end points other than granuloma formation.

Required barrier efficiency of internal bags against the migration from recycled paperboard packaging into food: a benchmark.

The use of recycled paperboard and corrugated board for food packaging is in the interest of the sustainability of resources, but in most applications the food must be protected against contamination from these materials, such as by an internal bag with a functional barrier. Producers of packaging need a specification to find the most suitable and economical barrier for a given application, and the customer needs the confidence that a solution offered to him is adequate. An accurate determination of the barrier efficiency is not possible due to the large number of migrants, most of which have not been evaluated or not even identified. Hence the specification must be based on assumptions and verifiable by a simple test. The proposed benchmark presumes that the migration of all non-evaluated or even unknown substances in recycled paperboard will remain below 0.01 mg kg(-1) food, the conventional detection limit, if their transfer does not exceed 1% of the content in the paperboard. Some substances, such as mineral oil or fatty acids, will exceed the 0.01 mg kg(-1) limit, but they are known, evaluated and of no concern at the reduced migration. Since the critical substances must be assumed to be unknown, the criterion of the 1% migration is tested with three surrogate substances of similar volatility and covering a broad range of polarity. The cornerstones of the method are specified.

Analysis of saturated and aromatic hydrocarbons migrating from a polyolefin-based hot-melt adhesive into food.

Hot-melt adhesives are widely utilised to glue cardboard boxes used as food packaging material. They have to comply with the requirements of Article 3 of the European Framework Regulation for food contact materials (1935/2004). The hot melt raw materials analysed mainly consisted of paraffinic waxes, hydrocarbon resins and polyolefins. The hydrocarbon resins, functioning as tackifiers, were the predominant source of hydrocarbons of sufficient volatility to migrate into dry foods: the 18 hydrocarbon resins analysed contained 8.2-118 g kg(-1) saturated and up to 59 g kg(-1) aromatic hydrocarbons eluted from GC between n-C16 and n-C24, substantially more than the paraffinic waxes and the polyolefins. These tackfier resins, especially the oligomers ≤ C24, have been characterised structurally by GC×GC-MS and (1)H-NMR spectroscopy. Migration into food was estimated using a simulating system with polenta as food simulant, which was verified by the analysis of a commercial risotto rice sample packed in a virgin fibre folding box sealed with a hot melt. About 0.5-1.5% of the potentially migrating substances (between n-C16 and n-C24) of a hot melt were found to be transferred into food under storage conditions, which can result in a food contamination in the order of 1 mg kg(-1) food (depending on the amount of potentially migrating substances from the hot melt, the hot melt surface, amount of food, contact time etc.). Migrates from hot melts are easily mistaken for mineral oil hydrocarbons from recycled cardboard.

Acrylamide in a fried potato dish (rösti) from restaurants in Zurich, Switzerland.

Rösti, a fried potato product, is a large contributor to acrylamide exposure locally in Switzerland. A survey of 55 dishes prepared by 51 restaurants in the city of Zurich showed that the average rösti contained 702 µg/kg acrylamide. By analysing the content of reducing sugars in the potatoes used for frying, it is shown that with simple measures, the exposure to acrylamide could easily be reduced by factor 2 or more, while even improving the culinary experience. Though rösti is a typical dish in the German-speaking areas in Switzerland, the result may be of general interest for fried potato products which are popular in large areas of Central Europe.

Argentation high performance liquid chromatography on-line coupled to gas chromatography for the analysis of monounsaturated polyolefin oligomers in packaging materials and foods.

Multidimensional chromatography based on two-dimensional high performance liquid chromatography on-line coupled to gas chromatography (on-line HPLC-HPLC-GC) enables the separate analysis of saturated, monounsaturated and aromatic hydrocarbons in packaging materials like polyolefins or paperboard and their migrates into foods. Since normal-phase HPLC on silica gel did not preseparate saturated from monounsaturated hydrocarbons, a separation step on a normal-phase HPLC column treated in the laboratory with an optimized amount of silver nitrate was added. The preparation of this HPLC column and the instrumental set-up are described, followed by examples showing the potential of the method. In a preliminary investigation of 11 polyolefin granulates for food contact up to 40% monounsaturated hydrocarbons among the oligomers C16-35 were determined.

Mineral oil in human tissues, part II: characterization of the accumulated hydrocarbons by comprehensive two-dimensional gas chromatography.

Mineral oil hydrocarbons are by far the largest contaminant in the human body. Their composition differs from that in the mineral oils humans are exposed to, and varies also between different tissues of the same individual. Using the presently best technique for characterizing the composition of mineral oil hydrocarbons, comprehensive two-dimensional gas chromatography (GC×GC), the hydrocarbons in human tissues were compared to those of various mineral oils. This provided information about the strongly accumulated species and might give hints on the flow path through the human body. The selectivity of accumulation is probably also of interest for the risk assessment of synthetic hydrocarbons (polyolefins). GC×GC grouped the MOSH into classes of n-alkanes, paraffins with a low degree of branching, multibranched paraffins and naphthenes (alkylated cyclic hydrocarbons) with 1-4 rings. Metabolic elimination was observed for constituents of all these classes, but was selective within each class. The MOSH in the subcutaneous abdominal fat tissues and the mesenteric lymph nodes (MLN) had almost the same composition and included the distinct signals observed in mineral oil, though in reduced amounts relative to the cloud of unresolved hydrocarbons. The MOSH in the liver and the spleen were different from those in the MLN and fat tissue, but again with largely identical composition for a given individual. Virtually all constituents forming distinct signals were eliminated, leaving an unresolved residue of highly isomerized hydrocarbons.

Migration by 'direct' or 'indirect' food contact? 'Dry' and 'wetting' foods? Experimental data for 'touching' contact of dry foods with paper and board.

Food contact is characterised in various terms, all of which are somewhat ill-defined. This work investigated the simplification that migration from food contact materials into dry food virtually exclusively proceeds through the gas phase, which would imply that the migration of essentially non-volatile components is negligible. It is shown here that this is not necessarily appropriate: for newspaper printed with an ink based on essentially non-volatile polyalphaolefins (PAO) as the main solvent, the migration into polenta and a baking mix reached 64% and 66% respectively of the content in the paper in merely 20 days at ambient temperature. Migration of involatile substances into dry foods implies diffusion through the paper to the small contact points. It depended on particle size, as this determines the density of the contacts. The diffusion rates within the food contact material and the food, including the transfer from one particle to the next, are other determining factors. This leaves the question whether such migration can be modelled or tested in a systematic manner (simulation), or whether it needs to be determined on a case-by-case basis.

Comprehensive two-dimensional gas chromatography for characterizing mineral oils in foods and distinguishing them from synthetic hydrocarbons.

Many foods are contaminated by hydrocarbons of mineral oil or synthetic origin. High performance liquid chromatography on-line coupled with gas chromatography and flame ionization detection (HPLC-GC-FID) is a powerful tool for the quantitative determination, but it would often be desirable to obtain more information about the type of hydrocarbons in order to identify the source of the contamination and specify pertinent legislation. Comprehensive two-dimensional gas chromatography (GC×GC) is shown to produce plots distinguishing mineral oil saturated hydrocarbons (MOSH) from polymer oligomeric saturated hydrocarbons (POSH) and characterizing the degree of raffination of a mineral oil. The first dimension separation occurred on a phenyl methyl polysiloxane, the second on a dimethyl polysiloxane. Mass spectrometry (MS) was used for identification, FID for quantitative determination. This shows the substantial advances in chromatography to characterize complex hydrocarbon mixtures even as contaminants in food.

Mineral oil in human tissues, Part I: concentrations and molecular mass distributions.

Of 37 subjects aged 25-91 y (mean 67 y), mineral oil hydrocarbons were measured in subcutaneous abdominal fat tissue, mesenteric lymph nodes (MLN), spleen, liver and lung, for some of them also in kidney, heart and brain. No mineral oil aromatic hydrocarbons (MOAH) were detected. The mean concentration of mineral oil saturated hydrocarbons (MOSH) in the mesenteric lymph nodes was 223 mg/kg, in liver 131 mg/kg, in fat tissue 130 mg/kg, in spleen 93 mg/kg and in lung 12 mg/kg. They were clearly lower in kidney, heart and brain. The maxima, found in MLN and spleen, were 1390 and 1400 mg/kg, respectively. For a quarter of the subjects a total amount of MOSH in the body above 5 g was calculated. The MOSH composition in the fat tissue and the MLN appeared virtually identical and varied little between the subjects. It was centered on the n-alkanes C23-C24, ranged from C16 to C35 and included hydrocarbons of plant origin. The MOSH in spleen and liver had almost the same composition for a given subject, but varied somewhat between subjects. They were centered between C25 and C27, ranged from C18 to beyond C45 and were without hydrocarbons of plant origin. Part of the MOSH seem to be strongly accumulated, resulting in far higher concentrations in human tissues related to exposure than observed in shorter term animal experiments. The composition of the accumulated MOSH does not support that Class I mineral oils, sometimes termed "food grade", are less accumulated in the human body than Class II and III oils, which questions the present classification.

Assurance of safety of recycled paperboard for food packaging through comprehensive analysis of potential migrants is unrealistic.

A method for determining potentially health-relevant components in paperboard used for packaging dry foods as comprehensively as technically feasible was applied to a sample of recycled paperboard. The task was specified by a detection limit in food of 0.01mg/kg, from which a detection limit of 0.1mg/kg in paperboard was derived. Extracts from the paperboard were preseparated into seven fractions by high performance liquid chromatography (HPLC) and transferred on-line to gas chromatography with flame ionization detection (GC-FID). The chromatograms visualize the high complexity of the material that may migrate into foods at toxicologically potentially relevant concentrations. Since only a minority of the substances was also detectable in fresh fiber board, most must have originated from chemicals used in the paper and board fed into the recycling process. Significant variability between recycled paperboards of four manufacturers was observed because of varying feedstocks. Using comprehensive two-dimensional GC (GC×GC) with time of flight mass spectrometry (TOF-MS), more than 250 substances were counted that probably exceeded the detection limit and were probably of sufficient volatility for migration into dry food. It is concluded in three main messages to risk managers: (i) since most potential migrants have not been adequately evaluated, many not even identified, the safety required by Article 3 of EU Regulation 1935/2004 has not been ensured; (ii) the number of substances potentially migrating into food above 0.01mg/kg is too large to realistically be brought under control; (iii) a barrier reducing the migration into food by a factor of 100 over the life time of a product would keep the migration of all except a few well known substances below 0.01mg/kg in food.