A survey of styrene monomer levels in foods and plastic packaging by coupled mass spectrometry—automatic headspace gas chromatography

An extensive UK survey of styrene monomer levels in styrene based plastic packaging materials and their contained foods (133 samples) has been carried out, examining a wide range of retail foods of different brand names and including yogurts, creams, salads, coleslaws, soft cheeses, margarines, hot and cold beverages from dispensing machines, spreads, fresh and cooked meats, candied fruits, fresh strawberries, and take-away ‘fast’ foods. Analysis by headspace gas chromatography of styrene levels in the plastic containers showed levels of monomer ranging from 16 to 1300 mg kg^?1 although the majority of containers (73%) had styrene levels in the range 100–500 mg kg^?1 and only five plastic tubs had levels exceeding 1000 mg kg^?1. Analysis of the food contents of the plastic containers by automated headspace gas chromatography with single ion monitoring mass spectrometric detection showed levels of the monomer ranging from < 1 μg kg^?1 to 200 μg kg^?1, although the majority of foods (77%) had styrene levels below 10 μg kg^?1, and 26% of the total number analysed had levels below 1 μg kg^?1.     

Survey of bisphenol A and bisphenol F in canned foods.

Bisphenol A (BPA) and bisphenol F (BPF) have been determined in a range of canned foods. Sixty-two different canned foods were purchased from retail outlets in the UK from January to November 2000 and the contents extracted and analysed by GC-MS for BPA and BPF isomers. The following canned products were analysed: fish in aqueous media, 10 samples; vegetables, 10; beverages, 11; soup, 10; desserts, five; fruit, two; infant formula, four; pasta, five; and meat products, five. BPF isomers were not detected in any of the canned foods with detection limits of 0.005 mg kg(-1) for the 2,2' and 2,4' isomers and 0.01 mg kg(-1) for the 4,4' isomer. BPA was detected in 38 samples with a detection limit of 0.002 mg kg(-1). Of these, BPA was quantified in 37 canned foods at levels from 0.007 mg kg(-1), with one sample of meat containing a mean level of 0.38 mg kg(-1). All other samples contained <0.07 mg kg(-1) BPA.     

A National Australian Food Safety Telephone Survey.

A sample of 1,203 randomly selected Australian households participated in a national telephone food safety survey. All respondents were aged 18 years or over, were the main grocery buyers of the household, purchased red meat products at least once a month, and regularly prepared food in the household. There were significant gaps observed in the food safety knowledge of many respondents surveyed. Forty percent of respondents thawed raw meat at room temperature, 85% allowed cooked foods to cool at room temperature before refrigerating, and almost 70% of respondents were not aware of the correct refrigeration temperature for storage of perishable food. Almost 25% of respondents failed to identify that washing hands before handling food and during food preparation was important in reducing the risk of cross-contamination and possible foodborne illness. Seventy-five percent of the respondents recognized that there was a likelihood of foodborne illness occurring in the home, and 25% of respondents had changed their eating habits because of publicity surrounding food poisoning outbreaks. The findings raise important concerns about domestic food handling practices in Australian homes and the level of food safety knowledge in the community generally.     

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.     

Australian survey of acrylamide in carbohydrate-based foods

A method was developed and validated for the determination of acrylamide in carbohydrate-based foods. Solid-phase extraction employing a mixed-bed anion and cation exchange cartridge in series with a C18 extraction disk was used to clean-up water extracts of food samples before analysis by liquid chromatography coupled with tandem mass spectrometry detection. The limit of detection was calculated as approximately 25 μg kg^-1 and the limit of reporting was 50 μg kg^-1. The average method recovery for 84 samples from a range of matrices reporting was 99% with a relative standard deviation of 11.2%. A survey was conducted of 112 samples of carbohydrate-based foods composited from 547 products available in the Australian market. The analytical results were used in conjunction with Australian food consumption data derived from the 1995 National Nutrition Survey (NNS) to prepare preliminary dietary exposure estimates of Australians to acrylamide through only the food groups examined. Mean dietary exposure to acrylamide resulting from consumption of the foods tested, for Australians aged 2 years and above, was estimated as 22-29 µg day^-1 (equivalent to 0.4-0.5 µg kg^-1 bodyweight day^-1) and between 73 and 80 µg day^-1 (1.4 and 1.5 µg kg^-1 bodyweight day^-1) for 95th percentile consumers. Young children (2-6 years) consuming acrylamide-containing foods had a higher acrylamide exposure on a per kilogram bodyweight basis (mean 1.0-1.3 µg kg^-1 bodyweight day^-1). The estimated exposure of Australians to acrylamide is similar to that estimated for other countries.     

Determination of acrylonitrile monomer in food packaging materials and in foods

An automated headspace gas chromatographic method is described using nitrogen specific detection for the quantification of acrylonitrile monomer (AN) in acrylonitrile-butadiene-styrene (ABS) food packaging tubs and in the contained foods. For a limited number of retail foods, levels of AN in ABS tubs (ranging from 2 to 10 mg/kg) and their contents (soft margarine, butter and shortening) are reported (ranging from 0.01 to 0.05 mg/kg), the results being confirmed by mass spectrometry (low and medium resolution selected ion monitoring). The latter technique was also used to quantify the levels of AN in the coatings of retail packaging films on a range of substrates, which were found to be between <0.001 and 0.02 mg/m².     

Survey of acrylamide levels in Chinese foods

A survey of levels of acrylamide (AA) in 349 food products obtained from the Chinese market was conducted. AA was determined by an liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The limit of detection (LOD) and the limit of quantification (LOQ) of the method in four different matrices ranged from 0.8 to 10 µg kg^?1 and from 4.0 to 25 µg kg^?1, respectively. The results from this survey indicated that AA was present in all samples except drinking water and tea. AA contents in different samples varied greatly according to the raw materials and processing conditions. The highest level of AA was found in potato products, with an average level of 1467 µg kg^?1. Preliminary estimates of AA exposure and risk assessment of AA from foods in the Chinese population were performed using a combination of data obtained in the present survey and 2002 dietary consumption survey carried out in 2002 for the Chinese population. The average dietary exposure of AA was estimated to be 0.38 µg kg^?1 body weight day^?1, which is relatively low compared with the result reported by the Food and Agricultural Organization/World Health Organization (FAO/WHO). Furthermore, the margin of exposure for neurotoxicity, reproductive toxicity, and carcinogenicity of AA was calculated to be 1318, 5250, and 787, respectively.     

Survey of Listeria monocytogenes in ready-to-eat foods

The purpose of this study was to develop data on the risk of listeriosis to support a science-based strategy for addressing Listeria monocytogenes in foods in the United States. Eight categories of ready-to-eat foods were collected over 14 to 23 months from retail markets at Maryland and northern California FoodNet sites. The product categories included luncheon meats, deli salads, fresh soft "Hispanic-style" cheeses, bagged salads, blue-veined and soft mold-ripened cheeses, smoked seafood, and seafood salads. The presence and levels of L. monocytogenes in the samples were determined by rapid DNA-based assays in combination with culture methods. Of 31,705 samples tested, 577 were positive. The overall prevalence was 1.82%. with prevalences ranging from 0.17 to 4.7% among the product categories. L. monocytogenes levels in the positive samples varied from <0.3 MPN (most probable number) per g to 1.5 x 10(5) CFU/g, with 402 samples having levels of <0.3 MPN/g, 21 samples having levels of >10(2) CFU/g, and the rest of the samples having intermediate levels. No obvious trends with respect to seasonality were observed. Significant differences (P < 0.05) between the sampling sites were found, with higher prevalences for threes categories in northern California and for two categories in Maryland. Significantly (P < 0.001) higher prevalences were found for in-store-packaged samples than for manufacturer-packaged samples of luncheon meats, deli salads, and seafood salads, while 16 of the 21 samples with higher counts were manufacturer packaged. The data collected in this study help to fill gaps in the knowledge about the occurrence of L. monocytogenes in foods, and this new information should be useful in the assessment of the risk posed by L. monocytogenes to consumers.     

Metabolic disturbance of tryptophan-nicotinamide conversion pathway by putative endocrine disruptors, bisphenol A and styrene monomer

Bisphenol A, a monomer of polycarbonate plastics, disturbed the conversion pathway of the amino acid tryptophan to the vitamin nicotinamide. The conversion ratio of tryptophan to nicotinamide was reduced to 1/15 by feeding a diet containing 1% bisphenol A. A putative disturbing reaction is kynurenine-->3-hydroxykynurenine, which is catalyzed by kynurenine monohydroxylase. This is an FAD-enzyme and requires NADPH as a coenzyme. Styrene monomer (1% addition to a normal diet) did not affect the food intake or the body weight, but slightly reduced the conversion ratio of tryptophan-nicotinamide.     

HPLC法测定食品中的叶黄素含量

为了建立测定食品中的叶黄素含量的可靠方法,采用高效液相色谱法进行了测定.使用硅胶色谱柱(4.6 mm×250 mm,5μm),以环己烷∶乙酸乙酯=75∶25为流动相,检测波长445nm.该方法最低检出量1.0 mg/kg,RSD为1.2%,加标回收率为93.8%～105.6%,RSD为3.1%～4.1%.该方法简便、准确,有良好的重现性,技术参数指标符合食品理化分析的要求.     

核磁共振法测定食品中水苏糖的含量

以已知浓度的柠檬酸作为定量外标,琥珀酸和烟酰胺分别作为定量内标,建立了食品中水苏糖的核磁共振定量分析检测方法。该方法在0. 025～6. 40 g/L质量浓度范围内线性良好,相关系数R~2> 0. 999;以柠檬酸作为外标方法加标回收率为97. 91%,日内精密度与日间精密度分别为1. 65%和5. 27%;琥珀酸和烟酰胺作为内标方法加标回收率分别为101. 39%和106. 35%,日内精密度分别为1. 34%和0. 83%,日间精密度分别为0. 65%和2. 46%;对市售不同食品基质(固态、液态)中水苏糖含量进行检测,测定结果准确。与现行行业标准(QB/T 4260—2011)高效液相色谱法相比,该方法简化了样品的前处理操作,节约了时间,定量准确,对食品中水苏糖的定量检测具有更广泛的适用性。     

HPLC法测定食品中的叶黄素含量

为了测定食品中的叶黄素的含量,建立方便可靠的测定方法,采用高效液相色谱法对食品中叶黄素含量进行了测定.使用硅胶色谱柱(4.6mm×250 mm,5μm),以环己烷∶乙酸乙酯=75 ∶ 25为流动相,检测波长445nm.该方法最低检出量1.0mg/kg,RSD 为1.2%,加标回收率为93.85.6%,RSD 为3.1%～4.1%.该方法简便、准确,有良好的重现性,技术参数指标符合食品理化分析的要求.     

2018年广东省校园周边食品安全卫生调查分析

目的 调查分析2018年广东省校园周边食品的安全卫生情况。方法 在广东省全省范围内的校园周边小食杂店等经营单位的在售食品进行取样, 按照所采集样品的食品分类对应的食品安全国家标准进行检验和判定后, 对检验结果进行分析讨论。结果 本次调查采集了校园周边食品400批次, 被调查单位及生产企业所在地皆覆盖了全省21个地级市, 其中不合格批次11批次, 合格率为97.25%, 不合格食品大类为: 薯类和膨化食品(5/11)、炒货及坚果制品(4/11)、饮料(1/11)和糖果制品(1/11)4大类, 不合格项目11项次: 大肠菌群(4/11)、菌落总数(2/11)、蛋白质(1/11)和过氧化值(以脂肪计)(4/11)。结论 2018年广东省校园周边食品中薯类及膨化食品、炒货和坚果制品问题突出, 低价食品不合格率较高, 应对以上突出问题加大监管力度。     

Migration of styrene monomer, dimers and trimers from polystyrene to food simulants

Migration experiments with polystyrene were performed in two-sided contact with n-heptane and distilled water as the food simulants at temperatures of 10, 24 and 40, and 40, 60 and 90°C, respectively. The surface/volume ratios in the migration cell were set at 8.04 and 10.05 dm² l^-1 for n-heptane and distilled water, respectively. Styrene monomer, styrene dimers and styrene trimers migrating to the food simulants were determined by GC-FID analysis. Heptane fully extracted the styrene monomer and the oligomers from the polystyrene sheet, whereas in the distilled water only the migrated styrene trimers could be detected. To determine the apparent diffusion coefficient, the migration process was analysed based on Fick's law. The higher the molecular weight of the oligomers, the more significant the reduction in the diffusion coefficient. Higher molecular weight oligomers also had lower activation energy of diffusion when the temperature dependence of diffusivity was analysed by the Arrhenius equation. The diffusion coefficient of the trimers was much higher for heptane contact than for water. The activation energy of the diffusion of trimers for water contact was higher than that for heptane.     

Survey of bisphenol a diglycidyl ether (BADGE) in canned foods.

2,2-Bis(4-hydroxyphenyl)propane bis(2,3-epoxypropyl) ether (BADGE) is used in the manufacture of lacquers for coating the inside of food and beverage cans. In June 1996 the EC Scientific Committee for Food temporarily increased the specific migration limit applying to BADGE to 1 mg/kg pending consideration of additional toxicological data. In order to find out if there is migration of BADGE from can coatings into foods, a 'worst case' sampling exercise has been conducted to survey those canned foods where the propensity for migration of BADGE was judged to be highest. The foods surveyed include canned fish in oil, meat and milk and, altogether, BADGE was determined in 181 retail samples. Analysis for BADGE was conducted, in duplicate, by HPLC with fluorescence detection with confirmation of BADGE identity by GC/MS analysis using selected ion monitoring. BADGE was found at levels exceeding 1 mg/kg in seven of the 15 canned anchovy samples and five of the 22 sardine samples purchased during the period September 1995-July 1996. Infrared analysis of the can coatings provided strong evidence that the higher BADGE levels found were associated with use of PVC organosol lacquers, although in some cases cans coated with organosols gave low BADGE results. For canned sardine samples found to contain greater than 0.5 mg/kg BADGE in the total contents, a replicate can was opened and separate analyses performed on the drained fish and the oil. The results clearly showed that BADGE concentrations in the oil were about 20 times higher than in the drained fish. Further samples of canned sardines and anchovies were purchased in June/July 1997 and, in all cases, BADGE levels were found to be below 1 mg/kg. In the other retail canned foods, BADGE was not detectable (DL = 0.02 mg/kg) or detected at concentrations well below the temporary SML of 1 mg/kg.     

Survey of acrylamide in Turkish foods by an in-house validated LC-MS method.

A survey of retail Turkish foods was conducted for acrylamide using an in-house validated LC-MS method. The recoveries obtained for a variety of food matrices ranged between 81.2 and 96.8% for a spiking level of 500 ng g(-1). The limit of quantification was determined as 15-20 ng g(-1) depending on the food matrix in the basis of a signal-to-noise ratio of 5. A total of 120 food samples were analysed for acrylamide. The mean acrylamide levels in different food groups were in the order: crackers>potato chips>biscuits>cakes>baby foods>corn chips>cookies>breakfast cereals>breads>grilled vegetables>wafers>chocolates. The crumb of bread was free of acrylamide, whilst significant concentrations were found in the crust.     

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。     

Hydrocolloids in fried foods. A review

Many food ingredients and additives can be used to improve fried food, but hydrocolloids are the principal category of functional agents that have been used for the past forty years. Hydrocolloids play two main roles in fried food development. One is to form a fine ‘invisible’ coating, practically on their own, when their main purpose is to avoid excessive oil absorption during the pre-frying and frying processes. In the other, when they are added to the batter among its other ingredients, they are used to avoid oil absorption too, but they also act as viscosity control agents, improve adhesion, pick-up control and freeze-thaw stability or help to retain the crispness of the battered/breaded fried foods. This article reviews the wide range of functions that hydrocolloids perform in fried foods.