Development and validation of analytical methods for ethyl carbamate in various fermented foods

The aim of this work was to develop and validate analytical methods for ethyl carbamate (EC) in various food matrices. Column chromatography was used for the analysis of EC in kimchi, a fermented soybean paste (doenjang), a fermented fish product (jeotgal), yoghurt, bread, and cheese. To remove the fat in the bread and cheese, a Florisil cartridge was selected. The volume of dichloromethane in the chromatography column was optimised to 60 mL for the kimchi, cheese, and fermented soybean paste. For the bread, jeotgal, and yoghurt, the best recovery rate was found by using 100 mL of dichloromethane. For the accurate analysis of EC in the vinegar, 150 mL of dichloromethane and a neutralisation process (pH = 8.0) were required. In the standard curve of EC, satisfactory linearity (R² = 0.998) was shown. The limit of quantification (LOQ) was 10 ng/mL and the recovery rates ranged from 76.9% to 118.1%. Intra- and inter-assay precision ranged from 3.5% to 34.2% and 3.8% to 41.9%, respectively.     

Bisphenol A in domestic and imported canned foods in Japan

Bisphenol A (BPA) concentrations were surveyed in 100 domestic and 60 imported canned foods purchased from the Japanese market in 2011–12. BPA was extracted from the canned foods, derivatised by ethylation and analysed using GC-MS. In the domestic canned foods, the maximum and average BPA concentrations were 30 and 3.4 ng g^?1, respectively, while in the imported canned foods they were 390 and 57 ng g^?1, respectively. The BPA level in the domestic canned foods was significantly lower than that in the imported canned foods. Based on these results, the intakes of BPA from the domestic and imported canned foods in Japan were estimated as 644 ng person^?1 day^?1. The Japanese BPA intake was the second lowest following New Zealand, although imported canned foods increased. It was sufficiently lower than the tolerable daily intake of EFSA and the USEPA. The drastic reduction of BPA in the domestic canned foods should be due to the ‘BPA reduced cans’ that Japanese can manufacturers had developed in the late 1990s and became widely used in Japan.     

Are Chileans exposed to dietary furan?

Chilean consumer preferences include foods that may contain considerable amounts of furan, a potential human carcinogen. However, there is no information regarding dietary exposure to furan in Chile. Thus, the objective of this work was to determine the Chilean exposure to dietary furan. To accomplish this objective, the furan concentration of 14 types of commercial foods processed at high temperature were analysed based on a modified headspace-GC/MS (HS-GC/MS) method in which the limits of detection for different food matrices ranged from 0.01 to 0.6 ng g^?1. In addition, a risk assessment was made with exposure estimates based on dietary data from national studies on different age groups (9-month-old babies, school children, adults and elderly people). Of the food items surveyed “American”-type coffee (espresso coffee plus hot water) obtained from automatic coffee machine (936 ng g^?1) and low moisture starchy products like crisps and “soda”-type crackers showed the highest furan concentrations (259 and 91 ng g^?1, respectively). Furthermore, furan was also found in samples of breakfast cereals (approximately 20 ng g^?1), jarred fruit baby foods (8.5 ng g^?1) and orange juice (7.0 ng g^?1). School children (aged 9–13 years) represented the highest intake of furan (about 500 ng kg^?1_bw day^?1), with margins of exposure of 2479 and 2411, respectively, which points to a possible public health risk.     

Ethyl carbamate in fermented foods and beverages: dietary exposure of the Hong Kong population in 2007–2008

To evaluate the potential public health risk of ethyl carbamate (EC), EC exposure from fermented foods and beverages for Hong Kong population was estimated. In 276 samples analysed, EC was detected (limit of detection (LOD) at 0.4?µg?kg^?1) in 202 samples (73%), with higher levels in fermented red bean curd (150–650?µg?kg^?1) and yellow wine (140–390?µg?kg^?1), while low or non-detected (ND) in preserved vegetables (ND–10?µg?kg^?1) and fermented tea (ND–15?µg?kg^?1). The estimated dietary exposure from all fermented foods and beverages was 8.27?ng?kg^?1?bw?day^?1, while exposure excluding alcoholic beverages was 5.42?ng?kg^?1?bw?day^?1, with calculated margins of exposure (MOEs) at 3.6?×?10⁴ and 5.5?×?10⁴ respectively. The risk of adverse health effects was low for the average population but higher (MOE?of?10³) for high consumers of alcoholic beverages especially habitual drinkers of alcoholic types with high EC contents.     

Measurement of ampicillin residue levels in chicken eggs during and after medicated feed administration by LC-MS/MS

A simple and sensitive LC-MS/MS method was developed and validated for the determination of ampicillin (ABPC) in chicken eggs. Residues were extracted by reverse-phase solid-phase extraction. Chromatographic separation was performed using a reverse-phase column with an elution gradient. The limits of detection and quantification were 0.01 and 0.1 ng g^?1, respectively. For the 0.1–50 ng g^?1 concentration range, mean recovery and accuracy values were 93.9–98.5% and 100.2–118.0%, respectively. ABPC residue concentrations in eggs before, during and after 7 days of medicated feeding of maximum dosage (40 mg kg^?1 body weight day^?1) of ABPC were determined with the LC-MS/MS method. The maximum concentration of ABPC in eggs was 3.6 ± 1.7 ng g^?1 (mean ± SD) on the last day of the administration period. Residue concentrations of ABPC in eggs during and after ABPC administration were not over the Japanese maximum residue limit of 0.01 mg kg^?1.     

Furan in commercial baby foods from the Spanish market: estimation of daily intake and risk assessment

ABSTRACT

The occurrence of furan in commercial baby food samples from the Spanish market was evaluated using an automated headspace solid-phase microextraction method coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS). A total of 76 baby food samples including infant formula, baby cereals, fruit in cans and/or jars, vegetables, meat, and fish, were surveyed for furan content. The lowest concentration of this compound was found in infant formula (<0.02–0.33 ng ml^?1), and cereal-based food (0.15–2.1 ng g^?1) while baby food containing fish showed the highest concentrations (19–84 ng g^?1). Following recommendation of the European Food Safety Authority (EFSA), the effect on furan content was evaluated of consumer home preparation of foods, heating and handling. Furan concentrations were reduced by up to 35% when samples were heated in a dish using microwave oven and by up to 53% when a hot water bath was used. Finally, we estimated the furan intake from baby food consumption (0.002–1.18 µg kg^?1 body weight day^?1) and we calculated the margin of exposure (MOE) from samples as purchased and also after home preparation of the food. For infant formula and cereal baby foods, the MOEs (26,278–412,776) indicated no infant health concern or priority, while for meat and fish-based baby foods the values pointed to a potential public health risk, even considering the furan losses during preparation at home.     

Determination of oxytetracycline residue in shrimp using a portable time-resolved analyzer and HPLC�CMS/MS validation

Oxytetracycline residue in shrimp muscle was determined using a portable time-resolved analyzer. After extraction in EDTA-metaphosphoric acid and filtration, the analyte was cleaned up using hydrophilic-lipophilic balance cartridges. Europium-sensitized luminescence (ESL) was measured at ??_ex = 385 nm and ??_em = 620 nm. Recoveries were 80.3 and 79.7% at 100 ng g^?1 and 2 ??g g^?1, respectively. The signal intensity was linear (r ² ?? 0.996) in each decade in the 5?C5,000 ng g^?1 range. Averaged relative standard deviation was ~2% and limit of detection was 8.3 ng g^?1. This instrument-method combination enabled sensitive in-situ quantification of OTC residue in shrimp. The ESL results were validated by HPLC?CMS/MS.     

Assessment of the dietary intake of propylene glycol in the Korean population

An improved method for the analysis of propylene glycol (PG) in foods using a gas chromatography-flame ionisation detector (GC-FID), with confirmation by GC-MS, was validated by measuring several analytical parameters. The PG concentrations in 1073 products available in Korean markets were determined. PG was detected in 74.1% of the samples, in a concentration range from the limit of detection (n.d., 0.39 μg ml^?1) to 12,819.9 mg kg^?1. The Korea National Health and Nutrition Examination Survey (KNHANES) 2011–2013 reported the mean intake levels of PG from all sources by the general population and consumers were 26.3 mg day^?1 (0.52 mg kg^?1 day^?1) and 34.3 mg day^?1 (0.67 mg kg^?1 day^?1), respectively. The 95th percentile intake levels of the general population and consumers were 123.6 mg day^?1 (2.39 mg kg^?1 day^?1) and 146.3 mg day^?1 (2.86 mg kg^?1 day^?1), respectively. In all groups of the general population, breads were the main contributors to the total PG intake. These reports provide a current perspective on the daily intake of PG in the Korean population.     

Assessment of caffeine intake in the Korean population

An improved method for the analysis of caffeine in foods by HPLC was validated by measuring several analytical parameters. The caffeine contents of 1202 products available from Korean markets were analysed. A consumption study was conducted by using data from the Korea National Health and Nutrition Examination Survey (KNHANES), 2010–12, to estimate the caffeine intakes of the Korean population. The mean intakes of caffeine from all sources in the general population and consumers were 67.8 and 102.6 mg day^?1 for all age groups, respectively. The 95th percentile intakes of the general population and consumers were 250.7 and 313.7 mg day^?1, respectively. In those aged 30–49 years, the caffeine intakes of the general population and consumers were highest at 25.5% (101.8 mg kg^?1 day^?1) and 36.6% (0.9 mg kg^?1 day^?1), respectively, compared with the maximum recommended daily intake (400 mg day^?1) for adults. In the general population, the main contributors to the total caffeine intake were carbonated beverage for the younger age groups and coffee for the adults. These data provide a current perspective on caffeine intake in the Korean population.     

Risk assessment of dietary exposure to tryptamine for the Austrian population

ABSTRACT

Tryptamine acts as a neuromodulator and vasoactive agent in the human body. Dose–response data on dietary tryptamine are scarce and neither a toxicological threshold value nor tolerable levels in foods have been established so far. This paper reviews dose–response characteristics and toxicological effects of tryptamine as well as tryptamine contents in food, estimates dietary exposure of Austrian consumers, and calculates risk-based maximum tolerable limits for food categories. A dose without effect of 8 mg kg^?1 body weight day^?1 was derived from literature data. Dietary exposure via fish/seafood, beer, cheese and meat products was estimated for Austrian schoolchildren, female and male consumers, based on 543 food samples analysed in Austria 2010–15 and on food consumption data from 2008. Even worst-case estimates based on very high tryptamine contents reported in the literature did not exceed 5.9 mg kg^?1 body weight day^?1, and thus were below the dose without effect. Maximum tolerable levels for food commodities were calculated for high-consumption scenarios (95th percentile of female Austrian consumers). For fresh/cooked fish, preserved fish, cheese, raw sausage, condiments, sauerkraut and fermented tofu, maximum tolerable levels were 1650, 3200, 2840, 4800, 14,120, 1740 and 2400 mg kg^?1, respectively. For beer, the maximum tolerable limit of 65 mg kg^?1 included an uncertainty factor of 10. None of the Austrian occurrence data exceeded these levels (in fact, only 3.3% of samples demonstrated measurable amounts of tryptamine), and just one report was found in the literature on a raw fish sample exceeding the respective tolerable level. In sum, dietary intake of tryptamine should not cause adverse health effects in healthy individuals. The assessment did not take into account the combined effects of simultaneously ingested biogenic amines, and increased susceptibility to tryptamine, e.g., due to reduced monoamine oxidase activity.     

Quantification of ethyl carbamate in soy sauce consumed in Korea and estimated daily intakes by age

To estimate the daily intake of ethyl carbamate (EC, a possible human carcinogen) from soy sauce consumed in Korea, 136 soy sauce samples were collected from various regions and analysed by gas chromatography/selected ion mode mass spectrometry (GC/SIM‐MS). The distribution of EC varied significantly among samples, ranging from not detected to 128.9 µg kg^?1, with the highest level in Japanese‐style soy sauce. Based on individual intakes in the Complementary Report on 1998 National Health and Nutrition Survey and EC contents analysed in the present study, the contribution of soy sauce to EC intake was estimated by multiplying the mean concentration of EC by individual soy sauce intake data. Daily intakes of EC kg^?1 body weight by high consumers were particularly high in age groups 1–2 years (78.59 ng), 3–6 years (86.37 ng), 50–64 years (86.24 ng) and ≥ 65 years (76.86 ng). Based on a benchmark dose confidence limit (BMDL) of 0.3 mg EC kg^?1 body weight day^?1, the margin of exposure (MOE) calculated from the daily intake of EC in soy sauce for high consumers ranged from 3488 to 7317, which is of concern. Daily EC intakes are likely to be exceeded in groups who consume other fermented foods as well as alcoholic beverages. Copyright © 2006 Society of Chemical Industry     

A survey of bisphenol A and other bisphenol analogues in foodstuffs from nine cities in China

Bisphenol A (BPA) is a high-production-volume chemical that is widely used in polycarbonate plastics and epoxy food-can coatings. Following several studies that have reported adverse effects of BPA over the past decade, other bisphenol analogues, such as bisphenol F (BPF), bisphenol S (BPS), bisphenol AF (BPAF), and bisphenol B (BPB), have been gradually developed as substitutes for BPA in several applications. Nevertheless, few studies have reported on the occurrence of compounds other than BPA in foodstuffs. In this study, 289 food samples (13 categories: cereals and cereal products, meat and meat products, fish and seafood, eggs, milk and milk products, bean products, fruits, vegetables, cookies/snacks, beverages, cooking oils, condiments, and others), collected from nine cities in China, were analysed for eight bisphenol analogues using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). BPA and BPF were found widely in foodstuffs at concentrations ranging from below the limit of quantitation (LOQ) to 299 ng g^–1 (mean = 4.94 ng g^–1) and from below the LOQ to 623 ng g^–1 (mean = 2.50 ng g^–1), fresh weight, respectively. The highest total concentrations of bisphenols (∑BPs: sum of eight bisphenols) were found in the category of vegetables that included canned products (mean = 27.0 ng g^–1), followed by fish and seafood (16.5 ng g^–1) and beverages (15.6 ng g^–1). ∑BP concentrations (mean = 2–3 ng g^–1) in milk and milk products, cooking oils, and eggs were low. Food samples sold in metallic cans contained higher mean ∑BP concentrations (56.9 ng g^–1) in comparison with those packaged in glass (0.43 ng g^–1), paper (11.9 ng g^–1), or plastic (6.40 ng g^–1). The daily dietary intakes of bisphenols were estimated, based on the mean concentrations measured and daily consumption rates of foods, to be 646 and 664 ng kg^–1 bw day^–1 for men and women, respectively.     

Aflatoxin M1 in raw,UHT milk and dairy products in Sicily (Italy)

A survey on 73 milk samples from different animal breeds and 24 dairy products samples from Sicily, Italy, was carried out for the presence of aflatoxin M₁ (AFM1) by LC-fluorescence detection after immunoaffinity cleanup. AFM1 was detected in 48% and 42% of the milk and dairy samples at concentration ranges between <5.0–16.0 and <5.0–18.0 ng L^?1, respectively. Within the raw milk samples, 92% had an AFM1 content below 5.0 ng L^?1, in 7% of the cases it was in the range 5.0–10.0 ng L^?1 and 1% was contaminated between 10.0 and 20.0 ng L^?1. For the dairy products, ultra-high-temperature treated (UHT) milk, milk cream and cheese, the incidence was 42%, of which 83% contained less than 5.0 ng L^?1 and 17% contained 10.0–20.0 ng L^?1 AFM1. The levels of contamination found justify continuous monitoring for public health and to reduce consumer exposure.     

Blood,breast milk and urine: potential biomarkers of exposure and estimated daily intake of ochratoxin A: a review

The purposes of this review are to study potential biomarkers of exposure for ochratoxin A (OTA) in biological fluids (blood, urine and breast milk) for the period 2005–14, calculate the estimated daily intake (EDI) of OTA by using database consumption for the Spanish population, and, finally, to correlate OTA levels detected in blood and EDI values calculated from food products. The values of OTA detected in potential biomarkers of exposure for blood, breast milk and urine ranged from 0.15 to 18.0, from 0.002 to 13.1, and from 0.013 to 0.2 ng ml^–1, respectively. The calculated EDI for OTA in plasma ranged from 0.15 to 26 ng kg^–1 bw day^–1, higher than that obtained in urine (0.017–0.4 ng kg^–1 bw day^–1). All these values are correlated with the range of EDI for OTA calculated from food products: 0.0001–25.2 ng kg^–1 bw day^–1.     

Optimization of Headspace Single-Drop Microextraction Coupled with Gas Chromatography–Mass Spectrometry for Determining Volatile Oxidation Compounds in Mayonnaise by Response Surface Methodology

In this assay, headspace single-drop microextraction (HS-SDME) coupled with gas chromatography–mass spectrometry (GC–MS) as a simple, low-cost and rapid method has been developed and validated for determining volatile oxidation compounds including hexanal and heptanal in mayonnaise. The main microextraction variables affecting the HS-SDME procedure such as extraction temperature and time, stirring rate, and amount of NaCl were optimized by response surface methodology employing a central composite design. Obtained results demonstrated that higher yield of extracted analytes could be achieved under the following optimal conditions: extraction temperature of 45 °C, extraction time of 16 min, stirring rate at 700 rpm, and addition of 2 g NaCl. The optimized HS-SDME/GC–MS method was validated for oxidized mayonnaise samples (50 °C/48 h) by calculating analytical parameters (linearity, precision, accuracy, and sensitivity). Good linearity (R ²?>?0.99) was observed by plotting calibration curves of extracted hexanal and heptanal over the concentration range of 0.025–10 μg g^?1, and the repeatability of the method, expressed as relative standard deviation, were found to be 4.04 % for hexanal and 3.68 % for heptanal (n?=?7). After the microextraction process of spiked mayonnaise sample, high levels of relative recovery were obtained for hexanal (107.33 %) and heptanal (91.43 %). The detection limits were 0.008 ng g^?1 and 0.021 ng g^?1 for hexanal and heptanal, respectively, while quantification limits of hexanal and heptanal were calculated to be 0.027 ng g^?1 and 0.071 ng g^?1, respectively. The possibility of the HS-SDME followed GC–MS to determine and quantify volatile oxidation compounds such as hexanal and heptanal was confirmed by analyzing commercial fresh mayonnaise stored at 4 and 25 °C during 3 months.     

Fusarium species identification and fumonisin production in maize kernels from Shandong Province,China, from 2012 to 2014

A total of 225 maize kernel samples were collected from Shandong Province in China from 2012 to 2014 and analysed for contamination with Fusarium spp. and fumonisins (FBs) using molecular methods and high-performance liquid chromatography with fluorescence detection. The results showed that the average incidences of Fusarium spp. in 2012, 2013 and 2014 were 23.3%, 37.1% and 36.5%, respectively, Fusarium verticillioides being the predominant species. In 2012, the average contamination level of FBs was 3071 ng g^?1, which was higher than that in 2014 (2913 ng g^?1) and 2013 (2072 ng g^?1). Of all samples, 13% and 19% had FB contamination levels higher than 2000 and 4000 ng g^?1, which are the maximum limits as set by the Food and Drug Administration of the United States and the European Commission, respectively. Therefore, efforts should be taken to minimise the potential risk of FBs to the health of humans and animals.     

Survey of furan in heat processed foods by headspace gas chromatography/mass spectrometry and estimated adult exposure

Furan is a suspected human carcinogen that is formed in some processed foods at low ng per g levels. Recent improvements in analytical methodology and scientific instrumentation have made it possible to accurately measure the amount of furan in a wide variety of foods. Results from analysis of more than 300 processed foods are presented. Furan was found at levels ranging from non-detectable (LOD, 0.2–0.9 ng g^?1) to over 100 ng g^?1. Exposure estimates for several adult food types were calculated, with brewed coffee being the major source of furan in the adult diet (0.15 µg kg^?1 body weight day^?1). Estimates of mean exposure to furan for different subpopulations were calculated. For consumers 2 years and older, the intake is estimated to be about 0.2 µg kg^?1 body weight day^?1.     

Occurrence of 13 volatile organic compounds in foods from the Canadian total diet study

Volatile organic compounds (VOCs) are ubiquitous in the environment due to evaporation and incomplete combustion of fuels, use of consumer and personal care products, etc. and they can accumulate in foods. Some VOCs in foods can also be formed during food processing and preparation and migrate from food packaging. In this pilot study, a GC-MS method based on headspace solid-phase microextraction (SPME) was validated and used to analyse selected individual foods which can be consumed directly and 153 different total diet composite food samples for 13 VOCs. Vinyl chloride was not detected in any of the 153 composite food samples, while the other 12 VOCs were detected at various frequencies, with m-xylene being the most frequently detected (in 151 of the 153 samples), followed by toluene (145), 1,3,5-trimethylbenzene (140), ethylbenzene (139), styrene (133), 1,2,4-trimethylbenzene (122), benzene (96), p-dichlorobenzene (95), n-butylbenzene (55), chloroform (45), naphthalene (45) and trichloroethylene (31). Concentrations of the 12 VOCs in most of the food composite samples were low, with the 90th percentiles from 1.6 ng g^–1 for n-butylbenzene to 20 ng g^–1 for toluene. However, some VOCs were detected at higher levels with maxima, for example, of 948 ng g^–1 for m-xylene and 320 ng g^–1 for ethylbenzene in chewing gum, 207 ng g^–1 for styrene and 157 ng g^–1 for toluene in herbs and spices. VOCs were detected at higher levels in most of the individual food items than their corresponding composite samples, for example, the average chloroform concentration in the individual canned soft drinks was 20 ng g^–1 compared with 3.0 ng g^–1 in their composite, and the average toluene concentration in the individual canned citrus juice was 96 ng g^–1 compared with 0.68 ng g^–1 in their composite. Thus, for determination of VOCs in foods which can be consumed directly, their individual food items should be analysed whenever possible for accurate exposure assessment.     

Simultaneous Determination of Seven Polycyclic Aromatic Hydrocarbons in Coffee Samples Using Effective Microwave-Assisted Extraction and Microextraction Method Followed by Gas Chromatography-Mass Spectrometry and Method Optimization Using Central Composite Design

In this research, for the first attempt, we successfully determined seven polycyclic aromatic hydrocarbons (PAHs) in various coffee samples using microwave-assisted extraction and dispersive liquid-liquid microextraction (MAE-DLLME) coupled with gas chromatography-mass spectrometry (GC-MS). The effects of most important variables in microextraction step were investigated and optimized using response surface methodology (RSM) based on central composite design. The calibration curves were linear in the range of 1–200 ng g^?1, with a correlation coefficient (R ²) higher than 0.989. Limits of detection were obtained between 0.1 and 0.3 ng g^?1. The relative standard deviations (RSD%) for seven repeated analysis were less than 8% for all PAH compounds at a concentration of 10 ng g^?1. Relative recoveries were obtained 88.1–101.3%. The satisfactory results obtained by the proposed method and the comparison of these results with previous methods demonstrated that the MAE-DLLME-GC-MS is an accurate, rapid, and reliable sample-pretreatment method with low consumption of the organic solvent.     

Assessment of dietary phytoestrogen intake via plant-derived foods in China

The potential influence of dietary phytoestrogen exposure on human health during different life phases including early childhood is a matter of scientific debate. In order to improve the risk–benefit assessment of exposure to dietary phytoestrogen, reliable and age-stratified exposure data are desirable. For contributing to the database on phytoestrogen exposure, in the present study plant-derived foods from the Chinese market were analysed by LC-MS/MS for their contents of phytoestrogens, including daidzein, genistein, secoisolariciresinol, glycitein and coumestrol. The analytical data showed the presence of phytoestrogens in a concentration range of less than 0.1 to about 50 μg g^?1. Dietary intake was assessed on the basis of average food intake data obtained from interviewing 1000 randomly selected people with the help of food frequency questionnaires. Based on the overall population sampled, the average total phytoestrogen intake was estimated at 232 μg kg^?1 day^?1. Genistein contributed to about 66%, secoisolariciresinol and glycitein to about 10% each, and daidzein to about 7% of the overall intake. Coumestrol was present only in trace amounts. Age-related exposure assessment indicated that pre-pubertal children (aged 0–14 years) were exposed at the highest level with an average total phytoestrogen intake of 621 μg kg^?1 day^?1. The substantially higher average exposure of children as compared with adults should trigger further research into the potential health effects of early life exposure to phytoestrogen.