Updated evaluation of the migration of styrene monomer and oligomers from polystyrene food contact materials to foods and food simulants

Due to the 2011 labelling of styrene monomer as “reasonably anticipated to be a human carcinogen” by the National Institutes of Health’s National Toxicology Program (NTP) and the controversy over whether styrene oligomers mimic the physiological effects of estrogen, an updated review of styrene monomer and oligomers in food and food contact materials (FCMs) was performed. The concentrations of styrene monomer and oligomers were determined in 24 polystyrene (PS) products and ranged from 9.3 to 3100 mg kg^–1 for the styrene monomer, 130–2900 mg kg^–1 for the sum of three styrene dimers, and 220–16,000 mg kg^–1 for the sum of six styrene trimers. Foods in contact with PS packaging had styrene monomer concentrations ranging from 2.6 to 163 ng g^–1; dimer concentrations from the limit of quantitation (LOQ) to 4.8 ng g^–1 and trimer concentrations were all below the LOQ (2 ng g^–1). Diffusion coefficients (D_p) and partition coefficients (K) were also calculated for styrene dimers and trimers. The results presented here indicate that styrene monomer concentrations in foods have not significantly changed since the 1980s and monomer concentrations in food packaging quantified in this study were all below USFDA limits. Although styrene dimers and trimers are present in higher concentrations in PS FCMs than the monomer, their migration to food is limited because of their high K values (4 × 10² to 2 × 10⁶) and their low diffusion coefficients in PS products. Additionally, diffusion coefficients calculated using USFDA-recommended food simulants and Arrhenius plots describing the temperature dependence of styrene dimers and trimers can be used in future calculations of dietary intake of the styrene oligomers.     

发泡餐盒中苯乙烯单体和低聚物的测定及迁移风险评估

目的建立聚苯乙烯发泡餐盒中苯乙烯单体和低聚物的检测方法,并对其向食品的迁移进行风险评估。方法采用二氯甲烷溶解-甲醇沉淀法提取餐盒中的苯乙烯单体和低聚物,采用气相色谱-质谱联用法测定目标物向水、酒精和脂肪食品模拟物的迁移量,通过比较各物质的估计日摄入量和毒理学安全阈值评估迁移风险。结果苯乙烯单体和低聚物在0.02~1.00 μg/mL范围内线性良好（R均大于0.99）,在餐盒及食品模拟物中的加标回收率为80.5%~101.2%,相对标准偏差为1.6%~10.5%;在5%显著性水平下各物质向脂肪食品模拟物的迁移量明显大于向水和酒精食品模拟物的迁移量 ,扩散系数为1.3×10-15~1.4×10-9 cm2/s,迁移活化能为33.5~53.3 kJ/mol;目标分析物的估计日摄入量均未超过毒理学关注阈值。结论该方法简单、可靠, 可用于测定发泡餐盒中苯乙烯单体和低聚物的含量。聚苯乙烯发泡餐盒不适合在高温条件下盛放脂肪食品。     

Migration of perfluoroalkyl acids from food packaging to food simulants

A broad range of fluorochemicals is used to impart oil and water barrier properties to paper and paperboard food packaging. Many of the fluorochemicals are applied to paper and paperboard as complex mixtures containing reaction products and by-products and unreacted starting materials. This work primarily focussed on the determination of seven perfluorocarboxylic acids (PFCAs) in two commercially available food contact papers: a di-perfluoro-alkyloxy-amino-acid and a perfluoroalkyl phosphate surfactant. In addition, the migration of the PFCAs into five food simulants from two commercial packages was evaluated. All seven PFCAs were detected in the range of 700–2220 µg kg^?1 of paper, while three perfluoroalkyl sulphonates were under the LOD. Results from migration tests showed that migration depends on paper characteristics, time and food simulant. The percentage of migration after 10 days at 40°C ranged from 4.8% to 100% for the two papers and different food simulants.     

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

ABSTRACT

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

PVC密封圈中环氧大豆油向食品模拟物迁移量的测定

建立了气相色谱-质谱法（GC-MS）对食品玻璃包装瓶盖聚氯乙烯（Polyvinyl chloride polymer,PVC）密封圈中环氧大豆油（Epoxidized soybean oil,ESBO）向食品模拟物迁移量的检测方法。以蒸馏水和橄榄油为模拟物,在40℃条件下浸泡瓶盖240h,经甲酯化和衍生化,以11,14-二环氧二十烷酸乙酯为内标物,通过测定环氧亚油酸（18∶2 2E）衍生物的含量,进而定量测定ESBO的迁移量。结果表明:ESBO在0.5⁵0.0mg/kg的浓度范围内线性关系好,R2大于0.993,回收率在92.8%¹03.9%之间,RSD为0.9%⁸.0%（n=6）,检出限（LOD）为0.2mg/kg,定量限（LOQ）为0.5mg/kg,方法精密度好,灵敏度高,定性定量准确。最后,应用其对24种不同PVC密封圈中的ESBO迁移量进行测定,水基模拟物中ESBO的迁移量符合法规EC 10/2011限量,而在油脂模拟物中测得含量在0.7⁵01.8mg/kg之间,其中7种超过了限量要求。      

Migration of aniline from polyamide cooking utensils into food simulants

Migration of aniline from polyamide cooking utensils was investigated. Aniline was found to originate from the application of black colorant in the polyamide 66 raw material. Analysis of polyamide raw material revealed an aniline concentration of 121 ± 13 mg kg^-1. The aniline concentration in a cooking utensil (turner) manufactured with 70% polyamide raw material was 82 ± 6 mg kg^-1. When testing migration from black coloured samples of turner, whisk and cooking spoon into water simulant at 100°C for 30 min, the migration levels at the third exposure were 39 ± 1, 11 ± 4 and 37 ± 4 μg dm^-2, respectively. Hence, these articles were not compliant with respect to the area-based limit for primary aromatic amines (3.33 μg dm^-2) set by European Union Directive 2002/72/EC. Repeated testing of a cooking utensil (turner) showed that approximately 100 h use at 100°C was required to reach legal (non-detectable) levels of aromatic amine migration.     

有机涂层食品接触材料中甲醛在食品模拟物中迁移规律的研究

目的 研究了有机涂层食品接触材料中毒害物质甲醛在食品模拟物中的迁移规律。方法 根据产品的实际使用条件,以食品模拟物对样品进行模拟浸泡,以乙酰丙酮分光光度法对食品模拟物中甲醛迁移量进行测定。结果 在相同的使用条件下,酸性模拟物中甲醛的迁移量最大;在接触同种食品模拟物时,甲醛的迁移量随着高压灭菌时间的延长和灭菌温度的升高而增加;货架存放时间对甲醛的迁移量无明显影响。结论 通过对甲醛迁移规律的考察,得出了有机涂层食品接触中甲醛的迁移风险。     

食品接触材料中多环芳烃在食品模拟物中的迁移规律研究

采用气相色谱-质谱联用法,对食品接触材料中多环芳烃在水、乙酸(体积分数为3%)、乙醇(体积分数为10%)和异辛烷等4种食品模拟物中的迁移规律进行了研究,研究迁移量与实验的温度、时间和模拟物属性等参数的关系。结果表明:模拟物的属性对迁移行为有显著影响,迁移量随温度的升高和时间的增加而变大。     

Migration of fluorochemical paper additives from food-contact paper into foods and food simulants

Fluorochemical-treated paper was tested to determine the amount of migration that occurs into foods and food-simulating liquids and the characteristics of the migration. Migration characteristics of fluorochemicals from paper were examined in Miglyol, butter, water, vinegar, water-ethanol solutions, emulsions and pure oil containing small amounts of emulsifiers. Additionally, microwave popcorn and chocolate spread were used to investigate migration. Results indicate that fluorochemicals paper additives do migrate to food during actual package use. For example, we found that microwave popcorn contained 3.2 fluorochemical mg kg^-1 popcorn after popping and butter contained 0.1 mg kg^-1 after 40 days at 4°C. Tests also indicate that common food-simulating liquids for migration testing and package material evaluation might not provide an accurate indication of the amount of fluorochemical that actually migrates to food. Tests show that oil containing small amounts of an emulsifier can significantly enhance migration of a fluorochemical from paper.     

Migration of antimony from PET containers into regulated EU food simulants

Antimony migration from polyethylene terephthalate (PET) containers into aqueous (distilled water, 3% acetic acid, 10% and 20% ethanol) and fatty food simulants (vegetable oil), as well as into vinegar, was studied. Test conditions were according to the recent European Regulation 10/2011 (EU, 2011). Sb migration was assayed by ICP-MS and HG-AFS. The results showed that Sb migration values ranged from 0.5 to 1.2 μg Sb/l, which are far below the maximum permissible migration value for Sb, 40 μg Sb/kg, (EU, Regulation 10/2011). Parameters as temperature and bottle re-use influence were studied. To assess toxicity, antimony speciation was performed by HPLC-ICP-MS and HG-AFS. While Sb(V) was the only species detected in aqueous simulants, an additional species (Sb–acetate complex) was measured in wine vinegar. Unlike most of the studies reported in the literature, migration tests were based on the application of the EU directive, which enables comparison and harmonisation of results.     

Migration of fluorochemical paper additives from food-contact paper into foods and food simulants

Fluorochemical-treated paper was tested to determine the amount of migration that occurs into foods and food-simulating liquids and the characteristics of the migration. Migration characteristics of fluorochemicals from paper were examined in Miglyol, butter, water, vinegar, water–ethanol solutions, emulsions and pure oil containing small amounts of emulsifiers. Additionally, microwave popcorn and chocolate spread were used to investigate migration. Results indicate that fluorochemicals paper additives do migrate to food during actual package use. For example, we found that microwave popcorn contained 3.2 fluorochemical mg kg^?1 popcorn after popping and butter contained 0.1 mg kg^?1 after 40 days at 4°C. Tests also indicate that common food-simulating liquids for migration testing and package material evaluation might not provide an accurate indication of the amount of fluorochemical that actually migrates to food. Tests show that oil containing small amounts of an emulsifier can significantly enhance migration of a fluorochemical from paper.     

Migration of Ti from nano-TiO2-polyethylene composite packaging into food simulants

An analytical method based on ICP-MS was developed for the determination of Ti in food simulants (3% (w/v) aqueous acetic acid and 50% (v/v) aqueous ethanol). The method was used to determine the migration of Ti from nano-TiO₂-PE films used for food packaging into food simulants under different temperature and migration time conditions. The maximum migration amounts into 3% (w/v) aqueous acetic acid were 1.4 ± 0.02, 6.3 ± 0.5 and 12.1 ± 0.2 μg kg^?1 at 25, 70 and 100°C, respectively, while into 50% (v/v) aqueous ethanol, the maximum migration amounts were 0.5 ± 0.1, 0.6 ± 0.03 and 2.1 ± 0.1 μg kg^?1 at 25, 70 and 100°C, respectively. Increasing the additive content in the film promoted migration of nanoparticles. The results indicated that the migration of nanoparticles might occur via dissolution from the surface and cut edges of the solid phase (film) into the liquid phase (food simulant).     

Migration of melamine from can coatings cross-linked with melamine-based resins,into food simulants and foods

Resins based on melamine-formaldehyde and related analogues such as methylolated melamine are used to cross-link coatings used inside food cans and on the metal closures of glass jars. Thirteen commercially coated cans and closures representing 80% of the European market were tested using simulants under realistic industrial heat-processing conditions for canned and jarred foods. The food simulants and the retort conditions used were 3% acetic acid for 1?h at 100°C and 10% ethanol for 1?h at 130°C. The highest migration level seen for melamine into simulant was 332?µg?kg^?1. There was no detectable migration of the melamine analogues cyanuric acid (<1?µg?kg^?1) or ammelide (<5?µg?kg^?1) from any sample. Twelve of the thirteen samples released no detectable ammeline (<5?µg?kg^?1) but the coating giving the highest release of melamine did also release ammeline at 8?µg?kg^?1 with the higher of the two process temperatures used. Migration experiments into food simulant and foods themselves were then conducted using two experimental coatings made using amino-based cross-linking resins. Coated metal panels were exposed to the food simulant 10% (v/v) aqueous ethanol and to three foodstuffs under a range of time and temperature conditions both in the laboratory and in a commercial food canning facility using proprietary time and temperature conditions. The highest migration into a food was 152?µg?kg^?1 from the first coating processed for a long time at a moderate sterilisation temperature. The highest migration into simulant was also from this coating at 220?µg?kg^?1 when processed at 134°C for 60?min, dropping to 190?µg?kg^?1 when processed at 123°C for 70?min. Migration from the second coating was quite uniformly two to three times lower under all tests. These migration results were significantly higher than the levels of melamine extractable using 95% ethanol at room temperature. The experiments show that commercial canning and retorting can be mimicked in an acceptable way using laboratory tests with an autoclave or a simple pressure cooker. The results overall show there is hydrolytic degradation of the melamine cross-linked resins to release additional melamine. There is a strong influence of the temperature of heat treatment applied with foods or simulants but only a minor influence of time of heating and only a minor influence, if any, of food/simulant acidity.     

Tailoring fatty food simulants made from solvent mixtures (1): comparison of methanol, ethanol and isopropanol behaviour with polystyrene

To investigate the use of solvent mixtures as test media replacing olive oil in migration tests, the interaction of polystyrene with mixtures composed of various amounts of tert.butyl acetate (mimicking the ester functions of oil) and of a low molecular weight alcohol (methanol, ethanol and isopropanol as inert co-solvent) was studied, using FTIR. Isopropanol, which has a lesser tendency to form hydrogen bonds in the plastic, can be used as main component of alternative fatty test media, its aggressiveness to polystyrene being tailored by adjusting the concentration of tert.butyl acetate. Concentrations below 20% seem useful on the basis of the mechanism of displacement of the alcohols.     

Distillation-extraction of styrene migrating from polystyrene containers to foods by gas chromatography

A simple, accurate and sensitive gas-liquid chromatographic method has been developed for the determination of styrene migrating from polystyrene containers into foodstuffs. an apparatus for the extraction of styrene was designed for the purpose, based on the BP apparatus for the determination of volatile oils. Styrene was extracted from foods by distillation with concurrent extraction from the distillate by n -hexane. Extraction was complete in 35 min. Hexane extracts were analysed by GC-FID using a glass column with durene as internal standard. Styrene levels in containers were from 1.7 to 192 μg g⁻¹ and in foods from 0.013 to 0.13 μg g⁻¹.     

AS和ABS塑料类食品接触材料中丙烯腈的 迁移研究

采用顶空气相色谱法,研究AS、ABS塑料食品接触中丙烯腈单体残留量与迁移量的关系和在不同迁移条件下丙烯腈在6种食品模拟物中的迁移量,并得出其迁移结论：AS塑料食品接触材料中丙烯腈迁移量要高于ABS塑料;在相同的使用时间和温度下,50%乙醇模拟物中丙烯腈的迁移量最大;在同种食品模拟物中,丙烯腈迁移量随着接触时间的延长、接触温度的升高而增加.     

PVC密封圈中环氧大豆油向食品模拟物迁移量的测定

建立了气相色谱-质谱法(GC-MS)对食品玻璃包装瓶盖聚氯乙烯(Polyvinyl chloride polymer,PVC)密封圈中环氧大豆油(Epoxidized soybean oil,ESBO)向食品模拟物迁移量的检测方法。以蒸馏水和橄榄油为模拟物,在40℃条件下浸泡瓶盖240h,经甲酯化和衍生化,以11,14-二环氧二十烷酸乙酯为内标物,通过测定环氧亚油酸(18∶2 2E)衍生物的含量,进而定量测定ESBO的迁移量。结果表明:ESBO在0.5~50.0mg/kg的浓度范围内线性关系好,R2大于0.993,回收率在92.8%~103.9%之间,RSD为0.9%~8.0%(n=6),检出限(LOD)为0.2mg/kg,定量限(LOQ)为0.5mg/kg,方法精密度好,灵敏度高,定性定量准确。最后,应用其对24种不同PVC密封圈中的ESBO迁移量进行测定,水基模拟物中ESBO的迁移量符合法规EC 10/2011限量,而在油脂模拟物中测得含量在0.7~501.8mg/kg之间,其中7种超过了限量要求。     

Migration of styrene and ethylbenzene from virgin and recycled expanded polystyrene containers and discrimination of these two kinds of polystyrene by principal component analysis

ABSTRACT

The migration of styrene and ethylbenzene from virgin and recycled expanded polystyrene (EPS) containers into isooctane was investigated using gas chromatography-mass spectrometry (GC-MS). EPS containers were in two-sided contact with isooctane at temperatures of 25 and 40°C. It was shown that recycled EPS gave greater migration ratios compared with virgin EPS, which indicated that styrene and ethylbenzene migrated more easily from recycled EPS. In addition, an analytical method to distinguish between virgin and recycled EPS containers was established by GC-MS followed by principal component analysis (PCA). The relative peak area of the identified compounds was used as input data for PCA. Distinct separation between virgin and recycled EPS was achieved on a score plot. Extension of this method to other plastics may be of great interest for recycled plastics identification.     

铝塑复合食品包装中的铝向食品模拟物的迁移研究

建立了基于电感耦合等离子体质谱法（ICP-MS）,铝塑复合食品包装中的铝向食品模拟物迁移量的测定方法。采用两种食品模拟物（3%（w/v）乙酸、水）,利用迁移机使食品模拟物与铝塑食品包装材料单面接触,在温度27±2、45、70℃下进行迁移实验,采用电感耦合等离子体质谱仪对食品模拟物中的铝元素进行测定,得出迁移规律。随着迁移时间的延长,铝的最大迁移量都在增加;在实验温度区间,随着温度的升高,铝的迁移量也随之增加至迁移平衡。本方法适合用于铝塑复合食品包装中的铝向3%（w/v）乙酸溶液和蒸馏水两种食品模拟物迁移后的检测。