Approach to stochastic modelling of consumer exposure for any substance from canned foods using simulant migration data

A two-dimensional probabilistic model was constructed to estimate the short-term dietary exposure of UK consumers to any generalized migrant from coated light metal food packaging. Using three UK National Dietary and Nutrition Surveys (NDNS) comprising 4-7-day dietary surveys for different age and gender groups, actual body weights and survey years, a sample representative of the dietary consumption of the UK population was obtained comprising around 4,200 food items. Interrogation of the raw data showed that the per capita consumption of food and beverage for an adult was 2.9 kg per person day(-1), which is comparable with the US FDA value of 3.0 kg. The packaging type of each food item was assigned from the survey descriptions or by sampling from distributions based upon market share information and expert judgement. Each food item was assigned to the relevant food simulant: A (aqueous), B (acidic) or D (fatty), so that simulant migration data could be used. The exposure model was used to evaluate exposure for a given level of migration and, conversely, the level of migration that could be tolerated whilst keeping within a target threshold exposure level. As examples, migration at 10 microg dm(-2) into fatty foods only resulted in an exposure ranging from 0.06 to 0.22 microg kg(-1) body (actual) weight day(-1) depending on the scenario. The model revealed that if migration from metal coatings was only into fatty foods, migration in the range 1.83-4.95 microg dm(2) (97.5th percentile, depending on the scenario) would give an exposure of less than 1.5 microg per person day(-1). This is a toxicological threshold limit used in the USA. If migration into simulants A and B is also considered to be at the same level as that for simulant D, then the level of migration for the threshold to be reached is, not surprisingly, lower (0.64-0.87 microg dm(-2)) than that if migration were only into fatty foods. In this case, clearly the main contributors to the exposure were foodstuffs represented by simulants A and B because of their importance in the diet. These estimates are based on 4- or 7-day food diaries and chronic exposure over the long-term would be expected to be lower.

Some factors affecting the formation of furan in heated foods

Levels of furan in various foods were measured before and after heating under heating and laboratory conditions. The effect of contact with can coatings, sealing gaskets and the epoxidized oils used in gasket manufacture on furan formation was studied. The objective was to identify factors affecting furan formation. Furan present in heat-processed food samples persisted during cooking. Furan was shown to form in foods on heating, although it did not accumulate to a significant degree on heating in an open vessel. There were no interactions between foods and cans, can coatings or gaskets that had a significant influence on furan formation. Furan accumulated particularly in heat-processed canned and jarred foods because they are sealed containers that receive a considerable thermal load. Heating epoxidized oils used in sealing gaskets formed furan. At the levels used in gaskets, however, epoxidized oils should not affect the formation of furan in foods.

Dietary exposure to chemical migrants from food contact materials: a probabilistic approach

A two-dimensional probabilistic model has been developed to estimate the short-term dietary exposure of UK consumers to migrants from food packaging materials. The current EU approach uses a default scenario of assuming that all individuals are 60 kg weight and consume 1 kg of food packaged in the material of interest per day. Using four UK National Dietary and Nutrition Surveys comprising 4-7 day dietary records for different age groups and survey years, a sample representative of the UK population has been obtained consuming around 4200 different food items. Each survey provides records for around 2000 individuals and supplies detailed information on the consumption of food and data on sex, height and socio-economic status which may be used to analyse the exposure of selected groups within the community. As a result we are able to address the variation in consumption of food amongst individuals, and account for actual body weights providing a more accurate representation of the 'true' exposure. The migrants bisphenol A diglycidyl ether (BADGE), di-2-ethylhexyl adipate (DEHA) and styrene were considered as specimen compounds although the methodology employed has the flexibility to adapt to other migrants and packaging types and indeed other food contaminants. Exposure for each individual is estimated by calculating and summing the individual exposure from each item in their diet, and is repeated for all individuals in each survey to produce a distribution of exposures for the population. The packaging type of each food item is assigned by utilizing known packaging types from the database or, by sampling from a distribution based upon market share information. The parameters contributing towards the exposure from a packaged dietary item are migrant concentration and item weight. Distributions are used to represent the inherent variation and uncertainty affecting these parameters. Where data on concentrations for a particular type of food are lacking, expert judgement is used to extrapolate from available data for other food types. The model can also be run using only migration data for food simulants. In this case, concentrations expected for each of the food items are assigned based on the data for the relevant food simulant. The primary outputs of the model are distributions of estimated daily intakes for the selected population. Each distribution gives the variation across the population subject to the uncertain parameters sampled in that iteration of the model. Analysing the ensemble of distributions allows us to obtain the confidence limits around estimates for percentiles due to the uncertainties. The probabilistic approach allows sensitivity analysis to evaluate the relative importance of the input parameters and places confidence bounds on the outputs to show the effect of the uncertainties and the contribution of each food type toward the overall exposure.

Agouti Related Protein (AgRP) is Upregulated in Cushing's Syndrome

Alpha melanocyte-stimulating hormone (alpha-MSH) is an agonist at the melanocortin 3 (MC3-R) and melanocortin 4 (MC4-R) receptors. Alpha-MSH stimulates corticosterone release from rat and human adrenal cells. Patients with Cushing's syndrome have elevated levels of serum alpha-MSH. Agouti related protein (AgRP) is an endogenous antagonist at the MC3-R and MC4-R and is expressed in the rat adrenal cortex. AgRP antagonises alpha-MSH-induced corticosterone release from rat and bovine adrenal cells. This suggests that AgRP may have an inhibitory paracrine role in the adrenal gland. We measured adrenal AgRP mRNA expression and circulating AgRP in 2 patients with Cushing's syndrome and controls. Adrenal AgRP mRNA expression and plasma AgRP were higher in the patients with Cushing's syndrome compared to controls. Plasma AgRP in the patients with Cushing's syndrome following bilateral adrenalectomy and hydrocortisone replacement were similar to the levels seen in controls. Our results suggest that AgRP may have a novel inhibitory paracrine role in the human adrenal gland.

Safety assessment of food-contact paper and board using a battery of short-term toxicity tests: European union BIOSAFEPAPER project

An European Union (EU)-funded project QLK1-CT-2001-00930 (BIOSAFEPAPER) involves the development, validation and intercalibration of a short-term battery of toxicological tests for the safety assessment of food-contact paper and board. Dissemination of the results to industry, legislators (e.g. DG Consumer Protection, DG Enterprises, DG Research), standardization bodies such as CEN, and consumers will create an agreed risk evaluation procedure. The project involves pre-normative research in order to establish a set of in-vitro cytotoxicity and genotoxicity tests that will be easily adaptable to food-contact fibre-based materials and have endpoints relevant to consumer safety, including sub-lethal cellular events. These tests will be performed on samples representing actual migration conditions from food-contact paper and board with respect to different foodstuffs, and should form an experimental basis for scientifically sound recommendations for a harmonized system of risk evaluation and product testing.

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 degrees 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/dm(2)) 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/dm(2)). 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.

Test method for measuring non-visible set-off from inks and lacquers on the food-contact surface of printed packaging materials

The main objective was to develop a technique to expose spots of invisible set-off of inks and lacquers on the food-contact surface of food-packaging materials. Set-off is the unintentional transfer of components of printing inks from the outer printed surface onto the food-contact surfaces. The target sensitivity was 20 microg cm(-2) and the technique should be capable of examining large areas of printed substrate for no more than 4% coverage by set-off. These requirements equate to an ability to detect a worst-case migration potential of less than 50 microg kg(-1). Other objectives were the industrial requirements that the equipment should be inexpensive, should be easy to use by existing personnel and should preferably be non-destructive with a clear criterion for pass or fail. The approaches investigated included chemical analysis of solvent extracts, Fourier-transform infrared spectroscopy and microbeam analytical techniques, but these were found to be cumbersome and had only limited success. The objectives were achieved using an optical approach to excite and observe luminescence from invisible set-off. In model experiments, resins were applied to different substrates (plastic, paper and cartonboard). For a given resin on a given material, the key to success was to maximize the discrimination between the luminescence from the resin and that from the substrate by selecting the optimal combination of exciting wavelength and viewing goggles with selective wavelength filters. The required level of detection (20 microg cm(-2)) was achieved or exceeded for all ten resins tested on three different plastics. It was also achieved for two different papers and in all but four cases of the resins on three different cartonboards. Quantitation was achieved by the use of a calibration palette prepared using different quantities of resin spotted onto the relevant blank packaging material.

Evaluation of migration models that might be used in support of regulations for food-contact plastics

Materials and articles intended to come into contact with food must be shown to be safe because they might interact with food during processing, storage and the transportation of foodstuffs. Framework Directive 89/109/EEC and its related specific Directives provide this safety basis for the protection of the consumer against inadmissible chemical contamination from food-contact materials. Recently, the European Commission charged an international group of experts to demonstrate that migration modelling can be regarded as a valid and reliable tool to calculate 'reasonable worst-case' migration rates from the most important food-contact plastics into the European Union official food simulants. The paper summarizes the main steps followed to build up and validate a migration estimation model that can be used, for a series of plastic food-contact materials and migrants, for regulatory purposes. Analytical solutions of the diffusion equation in conjunction with an 'upper limit' equation for the migrant diffusion coefficient, D(P), and the use of 'worst case' partitioning coefficients K(P,F) were used in the migration model. The results obtained were then validated, at a confidence level of 95%, by comparison with the available experimental evidence. The successful accomplishment of the goals of this project is reflected by the fact that in Directive 2002/72/EC, the European Commission included the mathematical modelling as an alternative tool to determine migration rates for compliance purposes.

Method of test and survey of caprolactam migration into foods packaged in nylon-6

An analytical method for the determination of the nylon-6 monomer caprolactam in foods is described. The foodstuff was extracted with ethanol: water (1:2) containing capryllactam as internal standard and the extract was defatted using hexane. The extract was analysed by liquid chromatography coupled with mass spectrometry. The test method was calibrated down to 0.7 mg kg(-1). The repeatability of the method was good, with a relative standard deviation of 9% at the 15 mg kg(-1) level. The method was demonstrated to be accurate in an independent external check sample exercise. The new method was applied to the analysis of 50 retail foodstuffs packaged in nylon-6. Caprolactam was detected and confirmed in nine of the 50 food samples, in the range 2.8-13 mg kg(-1). The presence of caprolactam was indicated in a further 15 samples, in the range 0.8-11 mg kg(-1), but these samples did not meet all of the five confirmation criteria applied. All migration levels (both confirmed and unconfirmed) were below the European specific migration limit for caprolactam, which is 15 mg kg(-1). The average migration for all 50 samples, setting non-detectables at half the limit of detection, was 2.6 mg kg(-1) with a standard deviation of 3.1 mg kg(-1) (n = 50). All samples found to contain detectable levels of caprolactam migration were for applications involving heating the food in the packaging. They were packs of, for example, sausage meat for which the food would have been heat processed in the nylon casing, or they were nylon pouches for heating foods by boiling, microwaving or roasting.

Measurement uncertainty associated with overall migration testing

The results from a single laboratory that took part in a series of check-sample exercises for overall migration were used to calculate the measurement uncertainty for the overall migration methodology. The results span 10 years of proficiency testing and cover a range of plastic materials tested using a variety of time and temperature test conditions. Twelve sets of results for overall migration into olive oil and 10 sets of results for overall migration into volatile simulants were used. The measurement uncertainty associated with the determination of overall migration from plastics into olive oil was estimated as +/- 2.6 mg dm-2 for results between 1.2 and 15.4 mg dm-2. The measurement uncertainty associated with the determination of overall migration into volatile simulants was estimated as +/- 1.4 mg dm-2 for results between 2.1 and 13 mg dm-2. These estimates are within the analytical tolerances set in European Union regulations, of 3 and 2 mg dm-2, respectively. The performance of all laboratories participating in these 22 check sample exercises was also evaluated. A very large majority (93%) of the participants used official test methods, sometimes with minor modifications as stated. For the simulant olive oil, an average of 81% of laboratories (13 rounds with an average of 21 participants in each) using official methods was within the tolerance specified in regulations. For the volatile food simulants, an average of 87% of laboratories (11 rounds with an average of 38 participants in each) using official methods was within the tolerance specified. It is concluded from this evaluation of within- and between-laboratory data that the official European Standard methods for overall migration testing are suitable for the analysis of routine samples.

Chemical interactions between additives in foodstuffs: a review

This paper critically reviews the key literature on food additive-additive chemical interactions published over the last 30 years together with appropriate relevant information on food additive-food component interactions. Five main classes of food additive are included, reflecting the research effort to date: the sulfur (IV) species of preservatives, synthetic food colouring materials, nitrate and nitrite, ascorbic acid, and sorbic acid. Within each class, aspects of the chemistry (reactivity), functionality, stability, use and reactions with other specific food additives are reviewed. Where appropriate, the importance of interactions of food additives with other components of food (i.e. nutrients and non-nutrients) has been assessed and certain aspects of toxicology included. The practical outcome of this review is presented as a set of recommendations for future research in this area. The use of the data in this review is proposed as a training set to develop the framework into a diagnostic tool. This might be used ultimately for the development of a multilevel framework, operating systematically, to understand the important parameters that dictate the outcome of additive interactions.

Evaluation of some screening methods for the analysis of contaminants in recycled polyethylene terephthalate flakes

A range of different analytical techniques were used to test recycled polyethylene terephthalate (PET) flakes for potential chemical contaminants. The techniques used were headspace gas chromatography coupled to mass spectrometry (GC-MS), liquid extraction followed by GC-MS, supercritical-fluid extraction followed by GC-MS, and migration testing followed by elemental analysis using inductively coupled plasma mass spectroscopy (ICP-MS). The PET samples were 50 representative samples taken from 600 that had been collected throughout Europe and which had been screened for potential contaminants using a single technique of high-temperature GC-MS. Six of the 50 samples tested had been spiked with a selection of model contaminants, three samples were virgin PET flakes and two of the samples were from supercleaning processes. All samples were analysed 'blind' in this exercise. The qualitative results showed that most of the contaminants came from the first use, being flavour-aroma compounds from soft drinks. The quantitative analysis found concentrations under a few mg kg(-1) in the polymer, except for the spiked samples. Element migrations were low and only calcium, silicon and sodium had median migrations above 50 microg l(-1). This in-depth analysis of recycled PET flakes did not identify any significant contaminants that had not already been detected by the high-temperature static GC-MS screening method, thus demonstrating its utility.

Benzophenone in cartonboard packaging materials and the factors that influence its migration into food

Benzophenone may be present in cartonboard food-packaging materials as a residue from UV-cured inks and lacquers used to print on the packaging. It may also be present if the cartonboard is made from recycled fibres recovered from printed materials. A method has been devised to test for benzophenone in cartonboard packaging materials and to test for migration levels in foodstuffs. Packaging is extracted with solvent containing d10-benzophenone as the internal standard. Foods are extracted with solvent containing d10-benzophenone and the extract defatted using hexane. The extracts are analysed by GC-MS. For analysis of food, the limit of detection was 0.01 mg x kg(-1) and the limit of quantification was 0.05 mg x kg(-1). The calibration was linear from 0.05 to 20 mg x kg(-1). The method for food analysis was validated in-house and it also returned satisfactory results in a blind check-sample exercise organized by an independent laboratory. The methods were applied to the analysis of 350 retail samples that used printed cartonboard packaging. A total of 207 (59%) packaging samples had no significant benzophenone (<0.05 mg x dm(-2)). Seven (2%) were in the range 0.05- 0.2 mg x dm(-2), 60 (17%) were from 0.2 to 0.8 mg x dm(-2) and 76 (22%) were from 0.8 to 3.3 mg x dm(-2). A total of 71 samples were then selected at random from the 143 packaging samples that contained benzophenone, and the food itself was analysed. Benzophenone was detected in 51 (72%) of the foods. Two food samples (3%) were in the range 0.01-0.05 mg kg(-1). A total of 29 (41%) were from 0.05 to 0.5 mg kg(-1), 17 (24%) were from 0.5 to 5 mg x kg(-1) and three (4%) food samples exceeded 5 mg x kg(-1). The highest level of benzophenone in food was 7.3 mg x kg(-1) for a high-fat chocolate confectionery product packaged in direct contact with cartonboard, with room temperature storage conditions and with a high contact area:food mass ratio. When the mass fraction of benzophenone migration was calculated for the different contact and storage regimes involved, the attenuation effects of indirect contact and of low temperature storage were cumulative. Thus, there was a sixfold reduction in migration for indirect contact compared with direct contact, a sixfold reduction for chilled/frozen storage compared with ambient storage, and 40-fold reduction for the two contact conditions combined.

A study of the toxicity of five mineral hydrocarbon waxes and oils in the F344 rat, with histological examination and tissue-specific chemical characterisation of accumulated hydrocarbon material

Five food-grade mineral hydrocarbon (MHC) materials; a low melting point wax (LMPW), a synthetic wax (C80W) and three white oils (N15H, N70H and P70H) were administered orally to female Fischer-344 rats for 28 and 90 days at a dose level of 2% in the diet. Tissues were examined at autopsy for any treatment-related histopathological changes. The histology of target organs was the same as found in previous studies on LMPW and mineral oils and similar effects were also observed from feeding C80W. Chemical analysis showed no detectable levels of MHCs in urine and no discernible differences in the MHC profile in faeces extracts compared to diets. The presence of MHCs in most tissues was not always associated with observable histological changes. The notable observations were MHC material was detected in all tissues of rats fed with diets containing LMPW and C80W. The levels found ranged from 0.04 to 1.52% by weight for the LMPW and from 0.01 to 0.75% for the C80W. MHC material was detected in all samples of small intestine, heart and kidney for all groups. Only the livers from rats administered with LMPW and C80W were analysed, which were found to contain MHC material. Preferential accumulation of MHCs was in the alkane range approximately C(20)-C(35). The findings indicate that the size and the structure of individual components play a role both in determining their propensity to accumulate in different tissues and in the severity of any response that they elicit once they have accumulated. The implication of these findings are discussed in the context of specifications for 'food-grade' mineral hydrocarbons such as used as food additives. The data presented here suggests that the current specifications are not prescriptively adequate in controlling the amount of MHC material between C(25) and C(35) that can accumulate.

Method development and analysis of retail foods and beverages for carotenoid food colouring materials E160a(ii) and E160e

An analytical method using high-performance liquid chromatography with photodiode array detection was developed and applied to the determination of the permitted food colour additives beta-carotene(E160a(ii)) and beta-apo-8'-carotenal (E160e) in foods and beverages. The scope of previously reported methods has been broadened to cover a wide range of retail foods and enzymatic hydrolysis has been used in place of saponification for high-fat samples. Quantitative results (greater then 0.1 mg kg(-1)) are given for the major colour principals trans-beta-apo-8'-carotenal and trans-beta-carotene. Semiquantitative results are given for the various cis-isomers of each colorant for which authentic reference standards were not available. The method has been used successfully for the analysis of a wide range of foodstuffs with differing fat content without the need for saponification, except for moderate- to high-fat foodstuffs containing significant levels of emulsifiers, for which it was limited. The results suggest that beta-apo-8'-carotenal (E160e) does not have widespread use in the UK. None of the samples exhibited a total beta-carotene content greater than 20 mg kg(-1) and none of the high-fat samples and only one of the 17 low-fat/beverage samples contained total beta-carotene at levels less than 0.1 mg kg(-1). The total beta-carotene contents of the low-fat/beverage samples ranged from 0.4 +/- 0.03 to 8.4 i 0.71 mg kg(-1), and the total beta-carotene contents of the high-fat samples ranged from 0.1 +/- 0.01 (jelly confectionery) to 18.5 +/- 0.98 mg kg(-1) (processed cheese).

Development and application of an LC-MS method to determine possible migration of mercaptobenzothiazole, benzothiazole and related vulcanization residues from rubber used in contact with food and drink

A method was developed for the analysis of food and drink for residues of specific vulcanization accelerators used to cross-link rubber. The method was applied to the analysis of 236 samples of selected retail foodstuffs that may have been in contact with rubber during their manufacture, transport and storage. The method of analysis involved extraction of the food using acidified solvent and analysis by liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (LC-APcI-MS). The detection limit depended on the sample type and was in the range 0.005-0.043 mg kg(-1) for 2-mercaptobenzothiazole (MBT) and benzothiazole (BT). The average analytical recovery rate was 82% for MBT and 87% for BT. The analytical method was validated using a blind check sample exercise. For MBT and BT at seven different concentrations in the range 0.1-0.2 mg kg(-1), the laboratory found a mean of 91 and 90% of the expected concentrations, respectively. No trace of MBT or BT was found in any of the retail samples. It is also concluded that no sample contained significant 2-mercaptobenzothiazyl disulphide (MBTS) or N- cyclohexyl-2-benzothiazole sulphenamide (CBS). Both MBTS and CBS are important accelerators used to vulcanize rubber and they break down in foodstuffs to form MBT and BT. The absence of MBT and BT in the foodstuffs therefore also provides proof of the absence of MBTS and CBS.

Verification of the findings of acrylamide in heated foods

We report here the first confirmation of the recent Swedish findings of acrylamide in heated foods. The verification exercise used an LC-MS/MS method developed for the purpose as well as an established GCMS method for acrylamide analysis. LC-MS/MS was suitable for the direct determination of acrylamide in aqueous extracts of foods by isotope dilution mass spectrometry (IDMS) using triply deuterated acrylamide. Some food matrices were not suited to the new method and mixed-mode solid-phase extraction (SPE) was used to clean these extracts. The foods tested included UK versions of some of the key food groups analysed in Sweden. Also tested were some foods heated under home-cooking conditions. There was good agreement between the LC-MS/MS results and the GC-MS results and the levels of acrylamide found here were similar to those reported for the corresponding foods analysed in the Swedish study. The analyses confirmed that acrylamide is absent from the raw or boiled foods but present at significant levels in fried, grilled, baked and toasted foods. The highest result was 12000 microg kg(-1) acrylamide in overcooked oil-fried chips.

Survey of stable sulfur isotope ratios (34S/32S) of sulfite and sulfate in foods

A study was conducted to determine the natural abundance sulfur isotope ratios in foods containing sulphite preservatives. This involved determining (1) the accuracy and repeatability of sulfur isotope ratios measured using an elemental analyser (EA) coupled to an isotope ratio mass spectrometer (IRMS); and (2) the isotope ratios of 21 samples of commercially available S(IV) oxo-anion compounds, nine samples of S(VI) sulfate salts and the isotope ratios of the sulfate obtained by modified Monier-Williams distillation of SO(2) from 33 retail foods containing sulfite preservatives. The sulfur isotope ratio data for SO(2) recovered from foodstuffs showed a large spread of results, which suggested that the SO(2) derived from sulfite preservatives does not have a distinctive sulfur signature ratio. The range of results (3.1-52.1) overlapped with that found for a range of commercially available sulfite and sulfate reagents commonly used to preserve food (sulfites 2.5-13.7, sulfates 10.0-16.9). Whilst the variability in isotope ratios originated from the food samples themselves, evidence from the analysis of SO(2) gas suggested that isotope fractionation during dissolution, reaction and recovery was also a confounding factor.

Determination of bisphenol-type contaminants from food packaging materials in aqueous foods by solid-phase microextraction-high-performance liquid chromatography

A fast screening method consisting of off-line solid-phase microextraction coupled to HPLC and fluorescence detection, suitable for the analysis of several bisphenol derivatives and their degradation products in aqueous solution, has been developed. Detection limits of 0.7 ng ml(-1) for 2,2-bis[4-(glycidyloxy)phenyl]propane, 0.9 ng ml(-1) for bisphenol A bis(3-chloro-2-hydroxypropyl)ether, 1.1 ng ml(-1) for 2,2-bis(4-hydroxyphenyl)propane and 2.4 ng ml(-1) for bisphenol F diglycidyl ether have been achieved working in the linear range 10-500 ng ml(-1). The good analytical features achieved make the proposed method an interesting option for the direct determination of these compounds in aqueous canned food such as peas, tuna, olives, maize, artichokes or palm hearts. Both the optimization process and the results, including the analysis of real samples, are given and discussed.

Method development and analysis of retail foods for annatto food colouring material

Analytical methods for the determination of the permitted food colouring annatto (E160b) have been developed or refined to encompass the wide range of food commodity types permitted to contain it. Specific solvent extraction regimens have been used depending upon the food commodity analysed and HPLC analysis techniques coupled with spectral confirmation have been used for the determination of the major colouring components. Qualitative and quantitative data on the annatto content of 165 composite and two single retail food samples covering a wide range of foods at levels above the limit of quantification (0.1 mg kg(-1)) is reported. Quantitative results are given for the major colour principals 9'-cis-bixin, 9'-cis-norbixin and trans-bixin. Semi-quantitative results are given for the minor bixin and norbixin isomers monocis- (not 9'-), di-cis- and trans-norbixin, for which authentic reference standards were not available. Repeat analyses (n = 4-9) of 12 different types of food commodity (covering the permitted range) spiked with annatto at levels between 1.7 and 27.7 mg kg(-1) gave mean recoveries between 61 and 96%. The corresponding relative SDs (RSD) were between 2.1 and 7.9%.

A biomarker approach to measuring human dietary exposure to certain phthalate diesters

Three groups of eight volunteers were administered stable isotope-labelled phthalate diesters in a single dose and the amount of the corresponding phthalate monoesters excreted in the urine was measured. Amongst the phthalates administered were the symmetrical dibutyl-, di-2-ethyl- and diisooctyl- phthalates along with the unsymmetrical benzylbutylphthalate. The control group received no dose, the low dose group received 168-255 microg of each phthalate and the high dose group received 336 to 510 microg of each phthalate. The excreted phthalate monoesters were measured by LC-MS following hydrolysis of conjugates. The bulk of phthalate monoester was excreted in the first 24 hour period following the dose. For dibutylphthalate, 64% and 73% on a mole basis of the low, and high dose respectively was excreted as monobutylphthalate. For dioctylphthalate (sum of the 2-ethylhexyl and the isooctyl species) the yield was 14 and 12% of the low and high dose excreted as monooctylphthalate. For benzylbutylphthalate, 67% and 78% was eliminated as monobenzylphthalate and only 6% (measured for the high dose only) was eliminated as monobutylphthalate. These conversion factors can be used in future studies to assess exposure to phthalate esters via measuring urinary levels of the monoester metabolites.

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (1H-NMR) and GC-MS. NMR detected the presence of cyanoisopropyl radical residues in the plastic at 470-3400 mg/kg whereas GC-MS detected TMSN at only 65-540 mg/kg in the samples. It is concluded that the bulk of cyanoisopropyl residues detected by NMR were either polymer-bound or were the products of side-reactions of the initiator radical. The migration of TMSN itself into the food simulants 3% aqueous acetic acid, 15% aqueous ethanol, and olive oil, at 40 degrees C for 10 days, was measured using GC-MS. Migration was very low with < 1 microg/kg released from a finished article (a drinking straw) and < 5 microg/kg from resin pellets. The overall conclusions from this work are that organic residues from aids to polymerization are generally found at reassuringly low levels in plastics intended for food contact and their potential for migration to foods is correspondingly low.

Analysis of annatto (Bixa orellana) food coloring formulations. 2. Determination of aromatic hydrocarbon thermal degradation products by gas chromatography

Twenty samples of commercial annatto formulations have been analyzed for m-xylene and toluene using ambient alkaline hydrolysis, followed by solvent extraction and capillary gas chromatography. Fifteen of the samples contained <5 mg/kg toluene, four samples contained between 5 and 10 mg/kg toluene, and one sample contained 12 mg/kg toluene. The amounts found of m-xylene were 200 mg/kg (one sample), 160 mg/kg (one sample), between 30 and 88 mg/kg (four samples), between 7 and 25 mg/kg (seven samples), and <5 mg/kg (seven samples). Bixin-in-oil formulations contained the highest m-xylene concentrations and also gave the largest increase in headspace m-xylene concentration when heated in closed systems. The results are evidence for the thermal degradation of annatto during source extraction and processing, resulting in contamination by internal generation of both bixin and norbixin types with aromatic hydrocarbons. Two samples of norbixin of known production history (i. e., thermal versus nonthermal processes) were analyzed specifically to identify possible differences in their degradation component profiles. They were found to differ significantly in m-xylene content, which is consistent with their respective production histories.