Migration studies from paper and board food packaging materials. Part 2. Survey for residues of dialkylamino benzophenone UV-cure ink photoinitiators

Evaluating the embryotoxicity of benzophenone-based photoinitiators in stem cells and zebrafish embryos

Benzophenones (BPs) are widely used as photoinitiators (PIs) or printing inks in food packaging, which may migrate into foods. However, the toxicity information of some BP analogues, such as 4,4'-bis(diethylamino)-benzophenone (DEAB), 4-phenylbenzophenone (4-PBP), 4 (hydroxymethyl)benzophenone (4-HMBP), those are used as PIs is lacking. Developmental toxicity is a health concern associated with PIs exposure. Recently, alternative non-in vivo methods have been proposed to evaluate the concerned chemicals or better understand the modes of action of certain toxicological endpoints. In this study, using in silico methods, we predicted that BP, DEAB, 4-PBP and 4-HMBP might exhibit developmental toxicity. However, we found that only DEAB is strong embryotoxic and disturbs the early differentiation of mouse embryonic stem cells into three germ layers and cardiomyocytes. DEAB treatment also prevented cardiomyocyte differentiation in human induced pluripotent stem cells (hiPSCs) on day 10. However, BP, 4-PBP and 4-HMBP had no similar effects on cardiomyocyte differentiation on day 10. Transcriptomic analysis revealed that treatment with DEAB significantly decreased the mRNA levels of differentiation-related transcription factors SOX17 and FOXA1, in hiPSCs on day 4. Furthermore, DEAB treatment caused tail malformations and yolk sac edema in zebrafish embryos. To conclude, DEAB may be embryotoxic because it disturbs the early differentiation of stem cells. Further studies are warranted to better understand the health effects of DEAB exposure.

Occurrence, Fate, Human Exposure, and Toxicity of Commercial Photoinitiators

Photoinitiators (PIs) are a family of anthropogenic chemicals used in polymerization systems that generate active substances to initiate polymerization reactions under certain radiations. Although polymerization is considered a green method, its wide application in various commercial products, such as UV-curable inks, paints, and varnishes, has led to ubiquitous environmental issues caused by PIs. In this study, we present an overview of the current knowledge on the environmental occurrence, human exposure, and toxicity of PIs and provide suggestions for future research based on numerous available studies. The residual concentrations of PIs in commercial products, such as food packaging materials, are at microgram per gram levels. The migration of PIs from food packaging materials to foodstuffs has been confirmed by more than 100 reports of food contamination caused by PIs. Furthermore, more than 20 PIs have been detected in water, sediment, sewage sludge, and indoor dust collected from Asia, the United States, and Europe. Human internal exposure was also confirmed by the detection of PIs in serum. In addition, PIs were present in human breast milk, indicating that breastfeeding is an exposure pathway for infants. Among the most available studies, benzophenone is the dominant congener detected in the environment and humans. Toxicity studies of PIs reveal multiple toxic end points, such as carcinogenicity and endocrine-disrupting effects. Future investigations should focus on synergistic/antagonistic toxicity effects caused by PIs coexposure and metabolism/transformation pathways of newly identified PIs. Furthermore, future research should aim to develop "greener" PIs with high efficiency, low migration, and low toxicity.

Food-Borne Chemical Carcinogens and the Evidence for Human Cancer Risk

Commonly consumed foods and beverages can contain chemicals with reported carcinogenic activity in rodent models. Moreover, exposures to some of these substances have been associated with increased cancer risks in humans. Food-borne carcinogens span a range of chemical classes and can arise from natural or anthropogenic sources, as well as form endogenously. Important considerations include the mechanism(s) of action (MoA), their relevance to human biology, and the level of exposure in diet. The MoAs of carcinogens have been classified as either DNA-reactive (genotoxic), involving covalent reaction with nuclear DNA, or epigenetic, involving molecular and cellular effects other than DNA reactivity. Carcinogens are generally present in food at low levels, resulting in low daily intakes, although there are some exceptions. Carcinogens of the DNA-reactive type produce effects at lower dosages than epigenetic carcinogens. Several food-related DNA-reactive carcinogens, including aflatoxins, aristolochic acid, benzene, benzo[a]pyrene and ethylene oxide, are recognized by the International Agency for Research on Cancer (IARC) as causes of human cancer. Of the epigenetic type, the only carcinogen considered to be associated with increased cancer in humans, although not from low-level food exposure, is dioxin (TCDD). Thus, DNA-reactive carcinogens in food represent a much greater risk than epigenetic carcinogens.

Migration of Irganox 1010, Irganox 1076, and Titanium dioxide into Doogh and corresponding food simulant from laminated packaging

PURPOSE

Doogh is a famous Iranian drink based on fermented milk. Laminated film is one of the most common packaging for this beverage in Iran. So, chemical substances of the packaging may migrate to the Doogh and endanger human health.

METHOD

In this research, High-Performance Liquid Chromatography (HPLC) was used to determine the migration of Irganox 1010 and Irganox 1076 from the contact layer and inductively coupled plasma for Titanium dioxide (TiO₂) from the second layer of three-layer laminate films into Doogh and acetic acid 3% (w/v). The influence of different storage temperatures and times was investigated by evaluating the samples stored in various conditions. The morphological, thermal and mechanical properties of the film, before and after contact with food simulant were further studied.

RESULT

The highest amount of Irganox 1010 concentration of the tested samples were 0.8 ± 0.04 mg/l in acetic acid 3% (w/v), and 0.62 ± 0.04 mg/l in Doogh. The highest amount of TiO₂ concentration were 0.25 ± 0.04 mg/l in acetic acid 3% (w/v), and 0.12 ± 0.02 mg/l in Doogh. The migration of Irganox 1076 was determined, but it was not detected. The results indicated that the food simulant had no significant effect on the microstructure and thermal properties of the polymer, but it reduced the mechanical properties.

CONCLUSION

The results indicate the possible migrating of Irganox 1010 and TiO₂ through laminate packaging into Doogh in some storage conditions. Since the migration value was low, the mentioned film was proven safe for Doogh packaging, imposing no hazards on human health.

How to make the use of recycled paperboard fit for food contact? A contribution to the discussion

Recycled paperboard contains hundreds of non-evaluated or even unidentified substances that could endanger human health if they turn out to be highly toxic. It seems as unrealistic to evaluate each of them as it is to phase out the use of the problematic ones or sort out the papers and boards introducing them into the recyclate. Therefore, measures should be taken that generally reduce migration into food, such as functional barriers or functional sorbents. A general approach is used for the recycling of plastics, particularly poly(ethylene terephthalate), PET: as not every potential contaminant can be regulated, a pragmatic approach is applied, for PET mainly on the required decontamination efficiency. Criteria are required on the required efficacy of the measures to be taken. Recycled paperboard is used for various types of food contact: mostly contact is through the gas phase (evaporation and recondensation), often indirect through other layers (e.g. internal bags or for transport boxes), seldom in wetting contact. Numerous factors have to be considered. For typical folding boxes and at least strongly dominating gas phase contact, it was proposed that no more than 1% of each contaminant in the recycled paperboard should enter the food. The efficiency of the measures required to comply with this criterion depends on the application. The three main measures are reviewed with regard to this criterion: (i) internal bags with an incorporated functional barrier (successfully used for some time), (ii) a barrier layer on the internal wall of the box (for which the design of the closures might be most critical) and (iii) functional sorbents added to the paperboard (for which the sorbent capacity is critical). For transport boxes, commonly of corrugated board (quantitatively the most important use of recycled paperboard in food contact), an adjusted or different criterion is needed.

Food packaging's materials: A food safety perspective

Food packaging serves purposes of food product safety and easy handling and transport by preventing chemical contamination and enhancing shelf life, which provides convenience for consumers. Various types of materials, including plastics, glass, metals, and papers and their composites, have been used for food packaging. However, owing to consumers' increased health awareness, the significance of transferring harmful materials from packaging materials into foods is of greater concern. This review highlights the interactions of food with packaging materials and elaborates the mechanism, types, and contributing factors of migration of chemical substances from the packaging to foods. Also, various types of chemical migrants from different packaging materials with their possible impacts on food safety and human health are discussed. We conclude with a future outlook based on legislative considerations and ongoing technical contributions to optimization of food-package interactions.

Impacts of food contact chemicals on human health: a consensus statement

Food packaging is of high societal value because it conserves and protects food, makes food transportable and conveys information to consumers. It is also relevant for marketing, which is of economic significance. Other types of food contact articles, such as storage containers, processing equipment and filling lines, are also important for food production and food supply. Food contact articles are made up of one or multiple different food contact materials and consist of food contact chemicals. However, food contact chemicals transfer from all types of food contact materials and articles into food and, consequently, are taken up by humans. Here we highlight topics of concern based on scientific findings showing that food contact materials and articles are a relevant exposure pathway for known hazardous substances as well as for a plethora of toxicologically uncharacterized chemicals, both intentionally and non-intentionally added. We describe areas of certainty, like the fact that chemicals migrate from food contact articles into food, and uncertainty, for example unidentified chemicals migrating into food. Current safety assessment of food contact chemicals is ineffective at protecting human health. In addition, society is striving for waste reduction with a focus on food packaging. As a result, solutions are being developed toward reuse, recycling or alternative (non-plastic) materials. However, the critical aspect of chemical safety is often ignored. Developing solutions for improving the safety of food contact chemicals and for tackling the circular economy must include current scientific knowledge. This cannot be done in isolation but must include all relevant experts and stakeholders. Therefore, we provide an overview of areas of concern and related activities that will improve the safety of food contact articles and support a circular economy. Our aim is to initiate a broader discussion involving scientists with relevant expertise but not currently working on food contact materials, and decision makers and influencers addressing single-use food packaging due to environmental concerns. Ultimately, we aim to support science-based decision making in the interest of improving public health. Notably, reducing exposure to hazardous food contact chemicals contributes to the prevention of associated chronic diseases in the human population.

Monitoring of contaminants in recycled paperboard for food contact applications

BACKGROUND

The lack of harmonized European legislation on food packaging led the Confederation of European Paper Industries to the proposal of a voluntary Industry Guideline for the compliance of paper and board materials for food contact applications. In the present work, a previously established method for the simultaneous determination of contaminants commonly found in recycled paperboard was improved and its applicability as a quality control tool in the paper industry was also assessed. The method involves a sample pre-treatment followed by gas chromatography/mass spectrometry (GC/MS) analysis.

RESULTS

For analysis, paperboard samples were collected both from three sections of the same reel and from different reels belonging to the same production run. Results highlighted no significant differences in terms of contaminant distribution among samples, which ensured good sampling representativeness. The performance of the method was considerably improved in terms of linearity range, limits of detection and quantification (5- to 2-fold lower) by using a quadrupole GC/MS system instead of an ion trap GC/MS system.

CONCLUSION

The proposed method could offer a key strategy for analysis of benzophenone derivatives, diisopropyl naphthalene and phthalates in recycled paperboard in order to assess compliance of food packaging with the voluntary limits recommended by the Industry Guideline. © 2016 Society of Chemical Industry.

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.

Direct analysis of isopropylthioxanthone (ITX) in milk by high-performance liquid chromatography/tandem mass spectrometry

A fast screening method is presented for detecting isopropylthioxanthone (ITX) contamination in milk. The method is based on direct high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) analysis of milk samples. Sample preparation is limited to the addition of a deuterated ITX solution in acetonitrile that serves both as internal standard and to precipitate proteins. The method is highly accurate and sensitive. Isomeric specific analyses of 2-ITX and 4-ITX are possible at 6 microg/L levels with about 5% precision and accuracy. This approach has been used to check contamination in samples like milk, soy milk, baby milk, in their packaging material. Out of 37 milk samples analyzed, 16 were positive with concentrations ranging from 173-439 microg/L for 2-ITX and from <6 (lower than limit of quantification) to 25 microg/L for 4-ITX.

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 microg/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 microg/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.

Contamination of dry foods with trimethyldiphenylmethanes by migration from recycled paper and board packaging

Contamination of foods with trimethyldiphenylmethanes is reported and the origin is shown to be migration from food packaging materials of which the use of recycled carbonless copy paper was found to be the major source. This chemical is one of the solvents used in the carbonless copy paper and its presence in food and the environment has not been previously identified. In this paper we have pursued previous studies on diisopropylnaphthalenes and hydrogenated terphenyls contamination from packaging and now report the identification of this new food contaminant and present evidence of its source. Solid foods such as egg pasta, barley coffee and rice were analysed by GC/MS and a mean concentration of 18 microg/kg of trimethyldiphenylmethanes was found. Extracts from carbonless copy paper were analysed by proton NMR to characterize the trimethyldiphenylmethanes. Since trimethyldiphenylmethanes are found in solid food together with diisopropylnaphthalenes, and considering their similar chemical character, they may follow the same migration pathway as one another.

Safety assessment of paper and board food packaging: Chemical analysis and genotoxicity of possible contaminants in packaging

In order to identify potential genotoxicant(s) in recycled paperboard, samples were fractionated using multiple liquid/liquid extraction, and gel permeation chromatography, and analysed by gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry. The rec-assay was used as an indicator of genotoxicity. Genotoxicants in the recycled paperboard were identified as dehydroabietic acid (DHA) and abietic acid (AA). DHA and AA were detected in two out of five virgin products, and in all seven recycled products for food-contact use. Total amounts of DHA and AA were 240 and 990 microg/g in the virgin products and 200-990 microg/g in the recycled products. A good correlation was observed in the total amount of DHA and AA content determined in paper products and DNA-damaging activity. Moreover, genotoxic effects in paper products showed a good match with standard compounds, indicating that the genotoxic effects of these paper products was mostly attributable to DHA and AA.

Chemical analysis and genotoxicological safety assessment of paper and paperboard used for food packaging

This study presents the research on the chemical analysis and genotoxicity of 28 virgin/recycled paper products in food-contact use. In the chemical analysis, paper products were extracted by reflux with ethanol, and analyzed by gas chromatography/mass spectrometry. 4,4'-bis(dimethylamino)benzophenone (Michler's ketone: MK), 4,4'-bis(diethylamino)benzophenone (DEAB), 4-(dimethylamino)benzophenone (DMAB) and bisphenol A (BPA) were found characteristically in recycled products. Seventy-five percent of the recycled paper products contained MK (1.7-12 microg/g), 67% contained DEAB (0.64-10 micro g/g), 33% contained DMAB (0.68-0.9 microg/g) and 67% contained BPA (0.19-26 microg/g). Although, BPA was also detected in virgin paper products, the detection levels in the recycled products were ten or more times higher than those in the virgin products. The genotoxicity of paper and paperboard extracts and compounds found in them were investigated by Rec-assay and comet assay. Of the 28 products tested by Rec-assay using Bacillus subtilis, 13 possessed DNA-damaging activity. More recycled than virgin products (75% against 25%) exhibited such activity, which, of the compounds, was observed in BPA, 1,2-benzisothiazoline-3-one (BIT), 2-(thiocyanomethylthio)benzothiazole, 2,4,5,6-tetrachloro-isophthalonitrile, 2,4,6-trichlorophenol (TCP), and pentachlorophenol. The critical toxicant in one virgin paper product was concluded to be BIT. Eight samples with DNA-damaging activity were also tested by comet assay using HL-60 cells; six induced comet cells significantly (five times or higher than the control) without a decrease of viable cells. TCP, BZ, DEAB, and BIT also caused a slight increase in comet cells. In conclusion, we showed that most recycled paper products contain chemicals such as MK, DEAB, DMAB, and BPA, and possess genotoxicity. However, the levels of the chemicals in the recycled products could not explain their genotoxic effects.

Migration of Substances from Food Packaging Materials to Foods

The employment of novel food packaging materials has increased the number of occurring hazards due to the migration from packaging material to the packaged food. Although polymers have mainly monopolized the interest of migration testing and experimentation, recent studies have revealed that migration also occurs from "traditional" materials generally considered to be safe, such as paper, carton, wood, ceramic, and metal. The regulations and the directives of the EU tend to become stricter in this respect. The emphasis is on reaching a consensus in terms of food simulants and testing conditions for migration studies. Furthermore, the list of hazardous monomers, oligomers, and additives continues to augment in order to ensure that the consumer safety is in current agreement with the HACCP, which is continuously gaining ground.

Migration of surrogate contaminants in paper and paperboard into water through polyethylene coating layer

The migration of five surrogate contaminants, anthracene, benzophenone, dimethyl phthalate, methyl stearate and pentachlorophenol, from paper and paperboard into water through a polyethylene (PE) coating layer was investigated. Virgin paper and paperboard coated with PE films of 0.012 and 0.030 mm thickness were spiked evenly with standard 1-ml solutions containing 5mg of each surrogate. The spiked papers were placed in contact with the PE coating layer at 10 and 24 degrees C for 21 days. The resulting surrogate migration through the PE layer into 100ml water was measured by an analytical method developed here that used gas chromatography equipped with a flame ionization detector. Non-polar surrogates of anthracene and methyl stearate did not show any significant migration. In the case of the thin layer coating of 0.012 mm, polar water-soluble contaminants of benzophenone, dimethyl phthalate and pentachlorophenol showed an equilibrated or maximized migration after 1 day, even at a refrigerated temperature of 10 degrees C. A thick PE coating of 0.030 mm thickness delayed the progress of contaminant migration, which was also slower at lower temperature. Our results indicate that polyethylene coatings should not be seen as a complete barrier against possible contaminants in paper packaging materials under chilled or ambient conditions. Several variables such as coating thickness, temperature and suspected contaminants need to be considered to control the possible contamination risk from recycled or printed paper.

Programme on the recyclability of food-packaging materials with respect to food safety considerations: polyethylene terephthalate (PET), paper and board, and plastics covered by functional barriers

Stimulated by new ecology-driven European and national regulations, news routes of recycling waste appear on the market. Since food packages represent a large percentage of the plastics consumption and since they have a short lifetime, an important approach consists in making new packages from post-consumer used packages. On the other hand, food-packaging regulations in Europe require that packaging materials must be safe. Therefore, potential mass transfer (migration) of harmful recycling-related substances to the food must be excluded and test methods to ensure the safety-in-use of recycled materials for food packaging are needled. As a consequence of this situation, a European research project FAIR-CT98-4318, with the acronym 'Recyclability', was initiated. The project consists of three sections each focusing on a different class of recycled materials: polyethylene terephthalate (PET), paper and board, and plastics covered by functional barriers. The project consortium consists of 28 project members from 11 EU countries. In addition, the project is during its lifetime in discussion with the US Food and Drug Administrations (FDA) to consider also US FDA regulatory viewpoints and to aim, as a consequence, to harmonizable conclusions and recommendations. The paper introduces the project and presents an overview of the project work progress.

Toxicity testing and chemical analyses of recycled fibre-based paper for food contact

Food-contact materials, including paper, have to comply with a basic set of criteria concerning safety. This means that paper for food contact should not give rise to migration of components, which can endanger human health. The objectives of this pilot study were, first, to compare paper of different qualities as food-contact materials and to perform a preliminary evaluation of their suitability, from a safety point of view, and, second, to evaluate the use of different in vitro toxicity tests for screening of paper and board. Paper produced from three different categories of recycled fibres (B-D) and a raw material produced from virgin fibres (A) were obtained from industry, and extracts were examined by chemical analyses and diverse in vitro toxicity test systems. The products tested were either based on different raw materials or different treatments were applied. Paper category B was made from 40% virgin fibres, 40% unprinted cuttings from newspapers, and 20% de-inked newspapers and magazines. Paper categories C and D were based on newspapers and magazines. However, paper D was de-inked, whereas C was not. To identify constituents of the papers with a potential to migrate into foodstuff, samples of the paper products were extracted with either 99% ethanol or water. Potential migrants in the extracts were identified and semiquantified by GC-IR-MS or GC-HRMS. In parallel to the chemical analyses, a battery of four different in vitro toxicity tests with different endpoints were applied to the same extracts. (1) a cytotoxicity test using normal human skin fibroblasts. The test was based on measurements of the reduction of resazurin to resorufin by cellular redox processes and used as a screening test for acute or general toxicity; (2) a Salmonella/microsome assay (Ames test) as a screening test for mutagenic and potentially carcinogenic compounds; (3) a recombinant yeast cell bioassay as a screening test for compounds with oestrogenic activity; (4) an aryl hydrocarbon (Ah)-receptor assay (CALUX assay) as a screening test for compounds with dioxin-like activity. In addition, the papers were testedfor microbial content and, in general, the microbiological load was quite low. The following microorganisms were counted and identified on both surface and homogenized pulp samples: the total number of aerobic bacteria, the number of aerobic and anaerobic spore formers, the number of Bacillus cereus/thuringiensis, and the number of yeast and moulds. The chemical analyses showed a significantly higher amount and different composition pattern of chemicals extracted with ethanol compared with water. Analyses of the ethanol extracts showed a distinctly smaller number and lower concentrations of chemicals in extracts prepared from sample A compared with extracts of samples B-D. The compounds identified in B-D were similar, but the amounts were lower in B compared with C and D. In accordance with the chemical analyses, the water extracts were less cytotoxic than the ethanol extracts. The extract prepared from virgin fibres was less cytotoxic than the extracts prepared from paper made from recycled fibres, and extracts prepared from C was the most cytotoxic. None of the extracts showed mutagenic activity. No conclusion about the oestrogenic activity could be made, because all extracts were cytotoxic to the test organism (yeast cells). Ethanol extracts of A and B showed a negligible positive response in the Ah-receptor assay at the highest nontoxic concentration, whereas C and D showed a more pronounced effect with C being the most potent. A comparable weak effect of water extracts of samples B-D was observed, too. However, the active compound(s) was not identified by chemical analyses.

Analysis of food packaging UV inks for chemicals with potential to migrate into food simulants

Ultraviolet (UV) inks are an alternative formulation system to the more usual paste or liquid inks (oils or solvents based) that dry mainly by evaporation or penetration into the printed substrate. Based on acrylic acid chemistry, UV inks dry (the exact term is 'curing') by the chemical process of photopolymerization. Their composition (acrylate monomers and oligomers together with photo-initiators) exposed to UV emission lamps on the printing press units enable the transformation of the freshly printed ink layer into a tack-free film. For UV inks intendedfor primary food packaging, special care has to be paid to potential migrating species like small photo-initiator molecules and acrylate monomers not cross-linked in the formed network. The paper presents chromatographic methods to ascertain the level of ink ingredients potentially available to migrate into food simulants (migration tests). GC/MS was employed to quantify the levels of photo-initiators or acrylic esters (acrylates).

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.

Migration studies from paper and board food packaging materials. Part 2. Survey for residues of dialkylamino benzophenone UV-cure ink photoinitiators

A survey of retail samples was conducted in two phases with 50 general paper and board food contact materials and articles analysed in 1992, and 121 samples, specifically of printed cartonboard, analysed in 1995. Packaging samples were extracted with ethanol containing 0.4% triethylamine. The extracts were analysed using high performance liquid chromatography (HPLC) and the presence of 4,4'-bis (dimethylamino) benzophenone (Michler's ketone, MK) and 4,4'-bis (diethylamino)-benzophenone (DEAB) confirmed using gas chromatography coupled to mass spectroscopy (GC-MS). The limits of detection for MK and DEAB in packaging were 0.05 mg/kg and 0.1-0.2 mg/kg respectively. In the first phase, MK was detected in 24% of the 50 samples at concentrations of 0.06-3.9 mg/kg paper. DEAB was detected in 12% of samples (0.1-0.2 mg/kg). In the second phase, 26% of the 121 cartonboard samples contained detectable MK (0.1-1.6 mg/kg) and 4% contained DEAB (0.2-0.7 mg/kg). Residues of the monoamine 4-(dimethylamino)benzophenone (DMAB) were found in 10% of the 1992 samples (0.1-0.6 mg/ kg). DMAB was not surveyed in 1995. These levels are too low to indicate the use of these cure agents for printing the packages. Rather, the most likely origin is from the use of recycled fibres. For three samples where the highest concentration of MK was detected, the food was analysed by GC-MS after extraction and clean-up. There was no measurable migration of MK at a detection limit of 2 micrograms/kg food. It is concluded, therefore, that the concentrations of MK present in the packaging samples analysed are unlikely to pose a risk to human health.