Migration behaviour of silicone moulds in contact with different foodstuffs

Various foodstuffs were prepared in silicone baking moulds and analyzed for siloxane migration using a previously developed and validated ¹H-NMR method. Meat loaf significantly exceeded the overall migration limit of 60 mg kg^?1 (10 mg sdm^?1) in the first and third experiment. The highest siloxane migration found in a meat loaf after preparation in a commercial mould was 177 mg kg^?1. In contrast, milk-based food showed very low or non-detectable migration (<2.4 mg kg^?1), even containing high fat levels. Similar results were achieved using 50% ethanol as the simulant for milk-based products, as defined in the Plastics Directive 2007/19/EEC. After solvent extraction of the moulds in simulating long-term usage, no further migration into the food was detectable, indicating that there is no significant formation of low molecular weight, potentially migrating siloxanes from the elastomer. During repeated usage, the moulds showed a high uptake of fat: up to 8.0 g fat per kg elastomer. Proper tempering of the moulds had a major influence on the migration properties of siloxanes into different foodstuffs. Non-tempered moulds with a high level of volatile organic compounds (1.1%) were shown to have considerably higher migration than the equivalent tempered moulds.     

Diffusion behaviour of additives in polypropylene in correlation with polymer properties

The migration behaviour of polymer additives in 17 polypropylene (PP) samples is described. These samples cover the major types of PP used in food packaging. The diffusion coefficients of additives with relatively small molecular masses, M _r = 136 (limonene), as well as the migration of typical antioxidants used in PP up to M _r = 1178 (IRGANOX 1010), were measured at different temperatures. In addition, the diffusion data and percentages of xylene-soluble fractions were correlated. This enables a prediction of the migration behaviour of a PP sample by testing its ‘isotactic index’ with xylene. The results clearly indicate that PP can be subdivided, from the migration point of view, into the monophasic homopolymer (h-PP), the monophasic random copolymer (r-PP), and the heterophasic copolymer (heco-PP). The diffusion coefficients for r-PP are at least one order of magnitude higher than those of h-PP and comparable with the values for heco-PP. Upper limits for the diffusion values can be calculated based on the safety margin required by consumer protection laws.     

Study of the partition coefficients Kp/f of seven model migrants from LDPE polymer in contact with food simulants

This study evaluated the influence of parameters such as temperature and type of low-density polyethylene (LDPE) film on the log K_p/f values of seven model migrants in food simulants. Two different types of LDPE films contaminated by extrusion and immersion were placed in contact with three food simulants including 20% ethanol, 50% ethanol and olive oil under several time–temperature conditions. Results suggest that most log K_p/f values are little affected by these parameters in this study. In addition, the relation between log K_p/f and log P_o/w was established for each food simulant and regression lines, as well as correlation coefficients, were calculated. Correlations were compared with data from real foodstuffs. Data presented in this study could be valuable in assigning certain foods to particular food simulants as well as predicting the mass transfer of potential migrants into different types of food or food simulants, avoiding tedious and expensive laboratory analysis. The results could be especially useful for regulatory agencies as well as for the food industry.     

Determination of diffusion and partition coefficients of model migrants by direct contact and vapour phase transfer from low-density polyethylene films into cake

The aim of the present study was to determine the migration kinetics of one photoinitiator, benzophenone, and two optical brighteners, Uvitex OB and 1,4-diphenyl-1,3-butadiene (DPBD), from low-density polyethylene (LDPE) films into cake. Transfer was assessed by both direct contact and also the vapour phase.

To perform the migration tests by direct contact, plastic films enriched with the additives were placed between two cake slices. To evaluate the migration through the gas phase, cake and the fortified LDPE film were placed with no direct contact in a glass container that was hermetically closed. Samples were stored at different time–temperature conditions.

Target compounds were extracted from the films with ethanol (70°C, 24 h) and analysed by HPLC-DAD. Relevant parameters such as partition and diffusion coefficients between food and plastic film were calculated. The Arrhenius equation was applied to estimate the diffusion coefficient at any temperature.

The data indicate that migration of benzophenone occurs in a significant extent into cake by both direct contact and through the gas phase (no direct contact). Conversely, very little migration occurred for Uvitex OB by direct contact and none through the gas phase. Results for benzophenone suggest that migration through the gas phase should be considered when evaluating migration from food packaging materials into food.     

Development of an in-house method for the incorporation of model migrants in polyethylene films and determination of diffusion constants in food

Two methods were tested and compared for the additivation of low density polyethylene (LDPE). The aim was to obtain highly contaminated plastic films to enable the study of migration (diffusion and partition phenomena). One of the methods involved immersion of low density polyethylene (LDPE) films in a concentrated solution of the selected substances. The other method involved achieving close contact of plastic films with a polyethylene wax contaminated with the selected compounds. The PE-wax method provided better results as regards the final concentration and homogeneity of the contaminants in the plastic films (deviations between replicates for each plastic film was lower than 10% for both migrants tested). This method was therefore considered suitable for preparing a homogeneous additive release system. Finally, to test the applicability of the method, concentration profiles were studied in chocolate spread placed in contact with the contaminated films, and diffusion coefficients were estimated in this foodstuff. Estimated diffusion coefficients were 4.6 × 10⁻⁰⁷ cm²/s for DPBD and 3.2 × 10⁻⁰⁷ cm²/s for triclosan in the same conditions.     

Survey of counterfeit melamine tableware available on the market in Thailand,and its migration

A simple measurement of sample density by adopting the principles of buoyancy could help screen counterfeit melamine ware if the density was below 1.50?g?cm^?3. However, samples with a density exceeding 1.50?g?cm^?3 were not necessarily made from melamine formaldehyde. FTIR analysis showed that all counterfeit products were made of urea formaldehyde and coated on the food-contact side with melamine formaldehyde, a tactic probably intended to cover up the true product features. The overall migration of real and counterfeit melamine samples complied with both European Union and Thai regulations, as the exposure layers in both cases were melamine formaldehyde. Formaldehyde migration failed to comply with Thai standards, but this was not the case for European Union standards. However, the results showed a significant inconsistency between individual items of the same brand and between individual exposures of the same test specimen. This indicated the inherent inhomogeneity between individual items, which mainly resulted from the manufacturing process: for instance, insufficient temperature and time to obtain complete polycondensation of monomers. Therefore, it is recommended that constant surveillance be conducted on melamine articles available in the marketplace in terms of quality and safety.     

液相色谱串联质谱法检测一次性纸杯中全氟辛酸和全氟辛烷磺酸的迁移量

目的 建立液相色谱串联质谱法检测一次性纸杯中全氟辛酸、全氟辛烷磺酸向食品模拟物中的迁移量。方法 待测样品经前处理后, 通过C18色谱柱进行分离, 以乙腈-水为流动相进行梯度洗脱、流速 0.2 mL/min、柱温为30 ℃、进样量2 μL, 由三重四级杆质谱进行定性和定量分析。结果 全氟辛酸和全氟辛烷磺酸在0.1~2.0 ng/mL范围内线性关系良好, 相关系数均≥0.999; 低、中、高3个添加水平的平均加标回收为81.27%~97.12%; 相对标准偏差为2.9%~7.4%。应用建立的方法对一次性纸杯进行模拟迁移试验, 初步得到了这2种物质在不同模拟状态下的迁移量。结论 该方法选择性强、灵敏性和准确度高, 适用于一次性纸杯中全氟辛酸和全氟辛烷磺酸的确证和定量分析。     

Migration of antimony from PET trays into food simulant and food: determination of Arrhenius parameters and comparison of predicted and measured migration data

Migration experiments with small sheets cut out from ovenable PET trays were performed in two-sided contact with 3% acetic acid as food simulant at various temperatures. The fraction of diffusible antimony (Sb) was estimated to be 62% in the PET sample under study. Apparent diffusion coefficients of Sb in PET trays were determined experimentally. Measurement of migration between 20 and 150°C yielded a linear Arrhenius plot over a wide temperature range from which the activation energy (E _a) of 188?±?36?kJ?mol^?1 and the pre-exponential factor (D ₀) of 3.6?×?10¹⁴?cm²?s^?1 were determined for diffusing Sb species. E _a was similar to previously reported values for PET bottles obtained with a different experimental approach. E _a and D ₀ were applied as model parameters in migration modelling software for predicting the Sb transfer in real food. Ready meals intended for preparation in a baking oven were heated in the PET trays under study and the actual Sb migration into the food phase was measured by isotope dilution ICP-MS. It was shown that the predictive modelling reproduces correctly experimental data.     

Occurrence of phthalates in different food matrices: A systematic review of the main sources of contamination and potential risks

This systematic review aimed to investigate the occurrence of phthalates (phthalic acid esters [PAEs]) in different food matrices, as well as report the main sources of PAEs in food, the potential risks to the population, and the factors that influence its migration from food contact materials (FCMs) to food. Nineteen PAEs were identified, including di-(2-ehtylhexyl) phthalate (DEHP), dibutyl-phthalate (DBP), benzylbutyl phthalate (BBP), diisononyl phthalate (DINP), and diisodecyl phthalate (DIDP) in fruits and vegetables, milk and dairy products, cereals, meat, fish, fat and oils, snacks, condiments and sauces, miscellaneous, and baby food. Fifty-seven values of PAEs were above the legal limits of countries. DEHP is the PAE with the highest incidence, with maximum concentrations above the specific migration limit (SML) for milk and dairy products, oils and fats, fish, cereals, condiments and sauces, meat, and fruits and vegetables. The risk of exceeding the tolerable daily intake (TDI) was high for DEHP and DBP in fish, fat and oils, cereals, and milk and dairy products for children and adults. Fat and oils are the most critical food for DEHP, DBP, BBP, and DINP. Comparing the estimated daily intake (EDI) with the TDI, there was a risk for “milk and dairy products” in adults and for “cereal and cereal products” in children concerning DEHP. “Cereal and cereal products” presented a risk in children and adults concerning DBP. The “fat and oils” category presented a risk in children and adults about DBP and DINP. Temperature, contact time between food and the FCM, fat percent, and acidity positively correlate with the PAE's migration. The contamination occurs in many steps of the production chain.     

Advances in green solvents for production of polysaccharide-based packaging films: Insights of ionic liquids and deep eutectic solvents

The problems with plastic materials and the good film-forming properties of polysaccharides motivated research in the development of polysaccharide-based films. In the last 5 years, there has been an explosion of publications on using green solvents, including ionic liquids (ILs), and deep eutectic solvents (DESs) as candidates to substitute the conventional solvents/plasticizers for preparations of desired polysaccharide-based films. This review summarizes related properties and recovery of ILs and DESs, a series of green preparation strategies (including pretreatment solvents/reaction media, ILs/DESs as components, extraction solvents of bioactive compounds added into films), and inherent properties of polysaccharide-based films with/without ILs and DESs. Major reported advantages of these new solvents are high dissolving capacity of certain ILs/DESs for polysaccharides (i.e., up to 30 wt% for cellulose) and better plasticizing ability than traditional plasticizers. In addition, they frequently display intrinsic antioxidant and antibacterial activities that facilitate ILs/DESs applications in the processing of polysaccharide-based films (especially active food packaging films). ILs/DESs in the film could also be further recycled by water or ethanol/methanol treatment followed by drying/evaporation. One particularly promising approach is to use bioactive cholinium-based ILs and DESs with good safety and plasticizing ability to improve the functional properties of prepared films. Whole extracts by ILs/DESs from various byproducts can also be directly used in films without separation/polishing of compounds from the extracting agents. Scaling-up, including costs and environmental footprint, as well as the safety and applications in real foods of polysaccharide-based film with ILs/DESs (extracts) deserves more studies.     

The specific diffusion behaviour in paper and migration modelling from recycled board into dry foodstuffs

Recycled board plays an important role in food packaging, but the great variety of organic impurities must be considered as potential food contaminants. The diffusion behaviour of the impurities is significantly different from that in plastic materials. The two-layer concept for paper and board introduced recently is now treated in more detail. In the rate-determining surface region the diffusion coefficients of the n-alkanes in the homologous series with 15–35 carbon atoms decrease proportionally as their vapour pressures. This leads to a different equation of the diffusion coefficients in comparison with that for the core layer. Different polarities of the migrants have additional influences on the diffusion due to their interactions with the fibre matrix. A new analytical method for the quantification of aromatic impurities has previously been developed. Based on this method and on the described diffusion behaviour, a migration model for specific and global mass transfer of impurities from recycled board into dry food and food simulants is given.     

纸塑包装中PCBs的迁移模型及效果评价

多氯联苯化合物种类繁多,无法逐一进行冗长的迁移试验,迁移模型不仅可以简化迁移研究,而且概括性强,适用范围广。文章基于"有限包装-有限食品"模型,考虑纸层与塑料层间的扩散系数,忽略其间分配系数的差异,建立迁移预测模型。并以Brandsch模型估算扩散系数,以定义式粗算分配系数,并分析迁移试验值与模拟预测情况的差异。对比结果显示,试验值变化的整体趋势与模型预测结果相符。迁移量均随着时间的延长而增加,且平衡时的迁移量随着温度的升高而加大,大多预测值明显略高于试验值。     

Tea brewed in traditional metallic teapots as a significant source of lead,nickel and other chemical elements

An environmental inquiry conducted by the Brussels Inter-communal Laboratory of Chemistry and Bacteriology (BILCB) has revealed that in 2000?a traditional metallic teapot caused in Brussels lead intoxication among a family of Morocco origin. Following this case study of lead poisoning and subsequent preliminary results carried out by the BILCB, which confirmed the dangerousness of this kind of item, samples of traditional metallic teapots were collected from North African groceries in Brussels by the Institute of Public Health (IPH) in collaboration with the BILCB and the Federal Agency for the Safety of the Food Chain (FASFC). Aluminium, copper, iron, nickel, lead and zinc were analysed to identify metals with a potential to migrate into tea solutions. Simulants (natural tea, tea acidified with citric acid and citric acid) were brewed in those teapots in order to identify the leaching potential of migration at boiling point temperature for different contact periods. Multi-elementary analysis was carried out by inductively coupled plasma-atomic emission spectrometry (ICP-AES). It was concluded that the concentrations of those leached metals depend on the nature of the migration liquids, the type of teapots and the contact periods. Most teapots showed a high level of toxic metals in leachates for lead and to a less extent for nickel, which can contribute significantly to the risk of serious poisoning. A comparison of the results with the toxicological reference values was done. The teapots were withdrawn from the market by the FASFC.     

Migration of model contaminants from PET bottles: influence of temperature, food simulant and functional barrier

To simulate post-consumer recycled plastics, selected model contaminants were incorporated into PET bottles using a time saving method. Migration into 3% acetic acid, a cola-type beverage and 95% ethanol was followed during 1 year of storage at 20 and 40°C. Aroma compounds previously found in post-consumer PET material were used as model contaminants. Benzaldehyde was found to migrate to the highest extent. Storage at 40°C affected the bottle material and this might be one reason for the high migration values of these bottles. Migration into ethanol was up to 20 times higher than into 3% acetic acid or a cola-type beverage. Bottles with a functional barrier resisted migration into food simulants even when filled with 95% ethanol and stored for 1 year at 40°C. Differential scanning calorimetry measurements showed that ethanol was interacting with the plastic material. This resulted in a lower glass transition temperature of bottles stored with ethanol compared with bottles stored empty or with other food simulants.     

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.     

Uncertainty and sensitivity analysis: Mathematical model of coupled heat and mass transfer for a contact baking process

Similar to other processes, the modelling of heat and mass transfer during food processing involves uncertainty in the values of input parameters (heat and mass transfer coefficients, evaporation rate parameters, thermo-physical properties, initial and boundary conditions) which leads to uncertainty in the model predictions. The aim of the current paper is to address this uncertainty challenge in the modelling of food production processes using a combination of uncertainty and sensitivity analysis, where the uncertainty analysis and global sensitivity analysis were applied to a heat and mass transfer model of a contact baking process. The Monte Carlo procedure was applied for propagating uncertainty in the input parameters to uncertainty in the model predictions. Monte Carlo simulations and the least squares method were used in the sensitivity analysis: for each model output, a linear regression model was constructed and the standardized regression coefficients (SRCs) and R² were computed. The effect of input parameters on model predictions was calculated, and the relative impact of the parameters on each of the outputs was ranked. Results of the uncertainty and sensitivity analysis can be used to prioritize future experimental efforts, as discussed for the contact baking process.     

Near infrared reflectance analysis of oil concentration in an emulsion: A study of oil and water migrations in a mayonnaise-based salad

Equations were derived for estimating the oil concentration in mayonnaise containing 11–75% (w/w) oil in mayonnaise-based salads by measurements of absorption using a near infrared scanning spectrometer (Neotec 6350 Research Composition Analyzer). The precision of the predictions averaged from two or three equations was better than ±1.0% at an oil concentration of 40% (w/w). The use of the method is demonstrated by its application to a study of the migration of oil and water in coleslaw during the first 6h after production.     

Determination of aroma compound diffusion in model food systems: Comparison of macroscopic and microscopic methodologies

Diffusion properties at macroscopic and microscopic scales for three aroma compounds (in solution and gel systems) were characterized using three different methodologies: the diffusion cell and the Volatile Air Stripping Kinetic methods for the determination of apparent diffusion coefficients and the pulsed-field-gradient Nuclear Magnetic Resonance method for the determination of self-diffusion coefficients. The accuracy of the methods was established by comparing ethyl hexanoate diffusion coefficient in water or D₂O solution and in 1%-agar gel system at 25 and 30 °C. The robustness of the three methodologies was also investigated in 1%-iota-carrageenan system with different NaCl content leading to gel strengthening.     

Transport phenomena in a model cheese: The influence of the charge and shape of solutes on diffusion

During cheese ripening, microorganisms grow as immobilized colonies, metabolizing substrates present in the matrix and generating products from enzymatic reactions. Local factors that limit the rates of diffusion, either within the general cheese matrix or near the colonies, may influence the metabolic activity of the bacteria during ripening, affecting the final quality of the cheese. The objective of this study was to determine the diffusion coefficients of solutes as a function of their different physicochemical characteristics (size, charge, and shape) in an ultrafiltrate (UF) model cheese (based on ultrafiltered milk) to enable better understanding of the ripening mechanisms. Diffusion coefficients of fluorescein isothiocyanate (FITC)-dextrans (4 kDa to 2 MDa) and FITC-labeled dairy proteins (α-lactalbumin, β-lactoglobulin, and BSA) were measured using the technique of fluorescence recovery after photobleaching (FRAP). This study showed that macromolecules up to 2 MDa and proteins could diffuse through the UF model cheese. The larger FITC-dextrans were not more hindered by the structure of the UF model cheese compared with the smaller ones. Any decrease in the diffusion coefficients of solutes was related only to their hydrodynamic radii. The FITC-dextran diffusion data were fitted to an obstruction model, resulting in a constant obstruction factor (k ~0.42). Diffusion in the model cheese was sensitive to the physicochemical characteristics of the solute. The FITC-dairy proteins studied (rigid and negatively charged molecules) were hindered to a greater degree than the FITC-dextrans (flexible and charge-neutral molecules) in the UF model cheese. The existence of steric and electrostatic interactions between the protein matrix of the UF model cheese and the FITC-dairy proteins could explain the decrease in diffusion compared with FITC-dextrans.