T-2 and HT-2 toxins in cereals and cereal-based products in South Korea

A total of 214 samples, consisting of brown rice, barley, mixed grains, corn, wheat and wheat flour were analysed for T-2 and HT-2 toxins using high-performance liquid chromatography with fluorescence detection. Recovery and repeatability were 79.9%–107.5% and 4.9%–14.5% for T-2, and 74.0%–106.1% and 5.0%–17.9% for HT-2, respectively. T-2 toxin was detected in 11 (5.1%) of all samples. The highest incidence was found in corn (21.7%) followed by mixed grains and brown rice. Mean of all samples was 1.5–4.1?µg?kg^?1, the maximum level being 41.5?µg?kg^?1 in corn. HT-2 toxin was detected in 126 (58.9%) of all samples, and the mean values were 26.4–59.2?µg?kg^?1. The estimated daily intakes for the sum of T-2 and HT-2 toxins were 2.56, 3.22, 2.53, 0.03, 0.01 and 2.45?ng (kg?bw)^?1?day^?1 in brown rice, barley, mixed grains, corn, wheat and wheat flour, respectively.     

Elements in rice on the Swedish market: Part 2. Chromium,copper, iron,manganese, platinum,rubidium, selenium and zinc

A survey of the levels of some essential and non-essential trace elements in different types of rice available on the Swedish retail market was carried out in 2001–03. The types of rice included long and short grain, brown, white, and parboiled white. The mean levels found were: chromium (Cr)?=?0.008 mg kg^?1, copper (Cu)?=?1.9 mg kg^?1, iron (Fe)?=?4.7 mg kg^?1, manganese (Mn)?=?16 mg kg^?1, platinum (Pt)?<?0.0003 mg kg^?1, rubidium (Rb)?=?3.3 mg kg^?1, selenium (Se) =0.1 mg kg^?1; and zinc (Zn)?=?15 mg kg^?1. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for the determination of Pt, Rb, and Se, after acid digestion. All other elements were determined using atomic absorption spectrometry (AAS) after dry ashing. Intake calculations were performed and it was concluded that rice may contribute considerably to the daily requirements of the essential elements Cu, Fe, Mn, Se, and Zn if rice consumption is high. The levels of some elements, e.g. Fe and Mn, were significantly higher in brown compared with white rice.     

Ultrasound-Assisted Extraction Followed by Solid-Phase Extraction Followed by Dispersive Liquid–Liquid Microextraction for the Sensitive Determination of Diazinon and Chlorpyrifos in Rice

Selectivity of solid-phase extraction (SPE) was combined with the concentration power of dispersive liquid–liquid microextraction (DLLME) to obtain a sensitive, low solvent consumption method for high-performance liquid chromatography determination of diazinon and chlorpyrifos in rice. In this method, rice samples were extracted by ultrasound-assisted extraction followed by SPE. Then, the SPE eluent was used as a disperser solvent in the next dispersive liquid-liquid microextraction step for further purification and enrichment of diazinon and chlorpyrifos. Under the optimal conditions, the linear range was from 5.0 to 250 μg kg^?1 for diazinon and from 2.5 to 250 μg kg^?1 for chlorpyrifos. Limits of detection of diazinon and chlorpyrifos were 1.5 and 0.7 μg kg^?1, respectively. Limits of quantitation of diazinon and chlorpyrifos were 5.5 and 3.0 μg kg^?1, respectively. The precisions and recoveries also were investigated by spiking 10 μg kg^?1 concentration in rice. The recoveries obtained were over 90 % with relative standard deviation (RSD%) below 9.0 %. The new approach was utilized to successfully detect trace amounts of diazinon and chlorpyrifos in different Iranian rice samples.     

Total mercury in milled rice and brown rice from China and health risk evaluation

Total mercury (THg) levels in 440 pairs of milled rice samples and brown rice samples from 15 major rice grain-producing provinces of China were measured and the associated health risk via rice consumption for different age categories of Chinese population was also assessed. THg contents were measured by a direct mercury analyser and the limit of detection (LOD) was 1.5 μg kg^?1. The THg levels for milled rice samples and brown rice samples varied from non-detected to 17.8 μg kg^?1 and 1.5 to 25.4 μg kg^?1, respectively, with a mean level of 3.4 μg kg^?1 and 4.9 μg kg^?1, respectively. The THg levels in all milled and brown rice samples were generally low, except three brown rice samples having concentrations above the legally set value for cereals (20 μg kg^?1 Hg). THg intakes for different age categories were estimated according to THg content and corresponding rice consumption and the associated health risk was evaluated by the corresponding provisional tolerable weekly intake (PTWI) for THg (5.0 μg kg^?1 bw week^?1), which was established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The 50th percentile of the THg intakes via milled rice and brown rice consumption for different age categories was in the range 0.09–0.19 μg kg^?1 bw week^?1 and 0.14–0.27 μg kg^?1 bw week^?1, respectively, well below the PTWI, suggesting that the associated health risk is relatively low. However, the 99.9th percentile of the THg intakes for 2–4-year-old children amounted up to 20.6% of the PTWI (milled rice) and 29.5% of the PTWI (brown rice), which deserves attention.     

Nitrate and nitrite levels in commonly consumed vegetables in Hong Kong

Levels of nitrate and nitrite in 73 different vegetables, a total of 708 individual samples grouped into leafy, legumes, root and tuber, and fruiting vegetables, which are traded mainly in Hong Kong, were measured. Where available, five samples of each vegetable type were purchased from different commercial outlets during the winter of 2008 and summer of 2009. Levels of nitrate and nitrite were determined by ion chromatography and flow injection analysis, respectively. Nitrate and nitrite levels of all samples ranged <4–6300 and <0.8–9.0 mg?kg^?1, respectively. Nitrate concentrations for the different groups, in descending order, were leafy?>?root and tuber?>?fruiting and legume vegetables. More than 80% of vegetables had mean nitrate concentrations less than 2000?mg?kg^?1, but mean nitrate concentrations of three types of leafy vegetables, namely Chinese spinach, Shanghai cabbage and Chinese white cabbage, were >3500?mg?kg^?1. On the other hand, nitrite concentrations were generally low –?<1?mg?kg^?1 on average. Nitrate in vegetables (i.e. Chinese flowering cabbage, Chinese spinach and celery) can be reduced significantly (12–31%) after blanching for 1–3?min, but not after soaking.     

Distribution of aflatoxins in shelling and milling fractions of naturally contaminated rice

The objective of this study was to determine the distribution of an economically important class of mycotoxins, the aflatoxins, in rice milling fractions. Rice plants grown under field production conditions are frequently infected with types of pathogenic fungi that produce toxic metabolites (mycotoxins). Paddy (seeds) rice from healthy plants in the field was collected and stored on a farm under humid, poorly ventilated conditions. Samples were milled into four fractions (hulls, brown rice, bran and white rice) and analysed for aflatoxins (B₁, B₂, G₁ and G₂) using a validated method. Rice fractions from healthy plants, which contained low levels of aflatoxins (less than 1?µg?kg^?1), were used to determine the efficiency of the extraction method. Seeds stored under poor conditions were found to be contaminated with aflatoxins B₁ and B₂ as were the fractions. The sums of AFB₁ and AFB₂ in stored paddy rice, hulls, brown rice, bran and white rice were 141, 39, 158, 367 and 56?µg?kg^?1, respectively. The ratio of aflatoxin B₁ and B₂ was about 10?:?1. AFG₁ and AFG₂ were less than 1?µg?kg^?1. Thus, brown rice contained 92.9% of the aflatoxins in paddy rice, whereas white rice contained only 27.9%.     

Genotypic variation of iron partitioning in rice grain

The present study investigates the variation of Fe concentration and partitioning in different grain tissues, particularly in the endosperm (white rice) among different rice cultivars from diverse genetic backgrounds. Iron concentration ranged from 10 to 20 mg kg^?1 in brown rice and 3–11 mg kg^?1 in white rice. Iron concentration in white rice was not correlated with that in brown rice. Polishing removed 25–84% of Fe from the brown rice, resulting in a low Fe concentration in the white rice and changed the ranking order for Fe concentration among the cultivars tested. Total Fe content in the whole grain including husk (r = 0.28, NS) and total Fe content in brown rice (r = 0.09, NS) was not significantly correlated with Fe concentration in white rice. Iron content in white rice was found to vary between 0.05 and 0.2 µg grain^?1 among cultivars tested, with the highest Fe content in cv. Sakha. Iron concentration in white rice was negatively correlated with total Fe content in the bran fraction, which is lost during the polishing process to produce white rice from brown rice (r = ? 0.82**). The partitioning of Fe between the endosperm and bran seemed to play a key role in achieving high Fe concentration in the white rice. The surface cell layers of the caryopsis appeared to be the main resistance of Fe partitioning into the endosperm (white rice) as there was a significantly negative correlation between Fe concentration in the white rice and Fe content in the bran, which is lost during the polishing process. Copyright © 2007 Society of Chemical Industry     

Elements in rice from the Swedish market: 1. Cadmium,lead and arsenic (total and inorganic)

A survey of the levels of cadmium, lead and arsenic in different types of rice available on the Swedish retail market was carried out in 2001–03. The types of rice included long and short grain, brown, white, and parboiled white rice. The mean levels found were as follows: total As: 0.20 mg kg^?1, inorganic As: 0.11 mg kg^?1; Cd: 0.024 mg kg^?1; and Pb: 0.004 mg kg^?1. ICP-MS was used for the determination of As (total and inorganic) after acid digestion. Lead and cadmium were determined using graphite furnace atomic absorption spectrometry (GFAAS) after dry ashing. In countries where rice is a staple food, it may represent a significant contribution in relation to the provisional tolerable weekly intake for Cd and inorganic As.     

Isotope dilution-GC-MS/MS analysis of 16 polycyclic aromatic hydrocarbons in selected medicinal herbs used as health food additives

Medicinal herbs have a very important role in health protection and disease control, and have been used in health foods. Polycyclic aromatic hydrocarbons (PAHs) have carcinogenic, biological and mutagenic effects. In this paper, the content of 16?PAHs as representative contaminants in nine Chinese medicinal herbs, as additives for health foods, was investigated in order to ensure food safety from this source. A highly sensitive isotope dilution-gas chromatography-tandem mass spectrometry (ID-GC-MS/MS) method combined with gel permeation chromatography (GPC) and solid-phase extraction (SPE) was developed. Calibration curves showed good linearity for all PAHs (R ^2?>?0.999), and the limit of quantification (LOQ) ranged from 0.42 to 2.7?µg?kg^?1. Average recoveries for these compounds were in the range of 52.5–117%, 52.6–119% and 81.4–108% at the concentrations of 10, 50 and 250?µg?kg^?1 with RSD of 1.8–15%, 0.9–15% and 1.0–15%, respectively. The proposed method was used for the analysis of nine Chinese medicinal herbs. Total levels of PAHs varied from 98.2?µg?kg^?1 (cassia seed) to 2245?µg?kg^?1 (eucommia bark). The highest level was found for phenanthrene (Phe) in liquorice root (631.3?µg?kg^?1), indigowoad leaf (551.0?µg?kg^?1), rose flower (435.2?µg?kg^?1) and eucommia bark (432.3?µg?kg^?1). The proposed method could provide a useful basis for safety monitoring of herbs and risk management for PAHs in the health food industry.     

Determination of seven pyrethroid pesticide residues in vegetables by gas chromatography using carboxylated multi-walled carbon nanotubes as dispersion solid phase extraction sorbent

ABSTRACT

A novel carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) dispersive solid phase extraction (d-SPE) method combined with gas chromatography (GC) with an electron capture detector (ECD) was developed for the determination of seven pyrethroid pesticides in cucumber, spinach, eggplant, tomato and carrot. We optimised d-SPE conditions including the type and volume of the extractant, the type and amount of the sorbent, and shaking time. Under the optimal conditions, the linear range was from 2.0 to 2000 μg kg^?1. The recoveries were from 88.5% to 108.2%, with the corresponding RSDs <6%, correlation coefficients 0.9987–0.9998, LOD 0.5–2.9 μg kg^?1 and LOQ 1.5–9.7 μg kg^?1. The proposed method is simple, fast, and safe, with high recovery and sensitivity, and is applicable to analysis of pyrethroid pesticides in vegetable samples.     

Elemental composition of commercial sea cucumbers (holothurians)

Toxic and essential elements in 11 different sea cucumber species were determined and compared with daily intake recommendations and maximum allowed levels. The contents of macro-elements contents in dried sea cucumber samples were found to be 25,000–152,000?mg?kg^–1 for Na, 4000–8600?mg?kg^?1 for Mg, 1100–5200?mg?kg^?1 for K, 15,000–68,000?mg?kg^?1 and 36,300–251,000?mg?kg^?1 for Cl. Trace element concentrations in dried sea cucumber samples were found to be 11–100?mg?kg^?1 for Zn, 41–660?mg?kg^?1 for Fe, 3–74?mg?kg^?1 for Cu, 1.1–16?mg?kg^?1 for Mn, 1.4–3.7?mg?kg^?1 for Se, 1.1–9.6?mg?kg^?1 for Cr, and 0.3–5.1?mg?kg^?1 for Ni. All sea cucumber species were rich sources of Na, Cl, Mg, Ca, Fe, Cu, Se and Cr for human consumption. Regarding contaminants, As, Cd and Pb concentrations in dried sea cucumbers were in the ranges of 1.1–6.1, 0.03–0.06 and 0.11–0.69?mg?kg^?1, respectively. Moreover, Hg values of 11 sea cucumbers were below the detection limit (0.01?mg?kg^?1).     

Immunochromatography for the rapid determination of cadmium concentrations in wheat grain and eggplant

BACKGROUND: A simple and quick on‐site test for trace levels of cadmium (Cd) in food is needed because of the human toxicity of this heavy metal. We developed an immunochromatography kit which uses the antigen‐antibody complex reaction between the Cd–ethylenediaminetetraacetic acid (Cd–EDTA) complex and an anti‐Cd–EDTA antibody. We previously reported the successful use of this kit to determine Cd concentrations in brown rice with respect to the international standard: 0.4 mg kg^?1. Here, we measured, using this immunochromatography kit, Cd concentrations in crops with lower international standards than rice. RESULTS: Cadmium extracted with 0.1 mol L^?1 HCl from wheat grain and fresh eggplant was purified sufficiently using an ion‐exchange column treatment. Appropriate HCl extraction rates and dilution rates for the column eluate were selected; Cd concentrations in wheat grain and fresh eggplant were determined successfully by immunochromatography with respect to the international standards of 0.2 mg kg^?1 and 0.05 mg kg^?1 fresh weight, respectively. CONCLUSION: Approximate Cd concentrations in wheat grain and fresh eggplant can be monitored easily and quickly by this method at locations where facilities for acid digestion and precision analysis are not available. Copyright © 2011 Society of Chemical Industry     

Survey on the occurrence of aflatoxins in rice from different provinces of Iran

Aflatoxins were surveyed in 256 rice samples taken from retail markets in different provinces of Iran during October 2007 and July 2008. A methanol/water (80?:?20,?v/v) mixture and an aflatoxin immunoaffinity column (IAC) were used for extraction and clean-up. Mycotoxins were determined using HPLC with fluorescence detection and post-column derivatization using a photo-ionization cell. Levels of contamination ranged 0.0–5.8?ng?g^?1 (mean, 1.4?ng?g^?1) and 0.1–6.3?ng?g^?1 (mean, 1.6?ng?g^?1) for AFB1 and total aflatoxins, respectively. AFB1 was detected in almost all samples. Results showed that 55 samples (21.5%) were contaminated with more than 2?µg?kg^?1 of AFB1, while seven samples (2.7 %) contained more than 4?µg?kg^?1 total aflatoxins. The calculated probable daily intake of AFB1 from rice for Iranians ranged 1.4–5.8?ng AFB1 per kg body weight per day for average consumers and, hence. exceeding the estimated provisional maximum tolerable daily intake.     

Analysis of isothiazolinone biocides in paper for food packaging by ultra-high-performance liquid chromatography–tandem mass spectrometry

A novel and simple method to detect isothiazolinone-type biocides (2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BIT) and 2-octyl-3-isothiazolinone (OIT)) in paper used for food packaging by ultrasonic extraction coupled with UPLC-MS/MS was developed. Parameters affecting process efficiency such as extraction solvents, UPLC mobile phase, gradient elution procedure and MS/MS conditions were studied to optimise the operating conditions. Using the optimised gradient elution procedure, the retention time was less than 6?min. The limits of detection (LODs) were found to be between 0.001 and 0.010?mg?kg^?1, which was validated using actual concentrations. After diluting the standard solution with a blank matrix, the linear calibration curve ranges were 0.002–1.000?mg?kg^?1 for BIT and OIT, 0.005–1.000?mg?kg^?1 for MI, and 0.020–1.000?mg?kg^?1 for CMI, with correlation coefficients higher than 0.9985 (n?=?6). A good level of precision with a mean recovery greater than 81.3% and a relative standard deviation (RSD) less than 6.2% were also obtained. A methodology has been proposed for the analysis of isothiazolinones in paper.     

Predicted dietary intake of selenium by the general adult population in Belgium

The total selenium content of about 800 food products purchased in Belgium was determined and combined with food records to determine the nutritional selenium status of Belgian people. The largest selenium concentrations (>1?mg?kg^?1) were found in Brazil nuts and offal, of which the consumption is limited. Usually consumed food groups with the highest selenium concentrations were fish and shellfish (0.2–0.9?mg?kg^?1), eggs, poultry meat, cheese, mushrooms and pasta (approximately 0.2?mg?kg^?1). The mean dietary selenium intake was calculated to be 60?µg?day^?1, which is at the lower end but within the range recommended by the Superior Health Council in Belgium (60–70?µg?day^?1), and adequate according to the 55?µg?day^?1 recommended by the Scientific Committee on Food (SCF) of the European Commission. The major sources of selenium intake are meat and meat products (31%), fish and shellfish (20%), pasta and rice (12%), and bread and breakfast cereals (11%).     

A Highly Sensitive Method for the Determination of Thiophanate Methyl,Cyromazine, and Their Metabolites in Edible Fungi by Ultra-Performance Liquid Chromatography Using Accelerated Solvent Extraction and Cleanup with Solid-Phase Extraction

A highly sensitive ultra-performance liquid chromatographic method with diode-array detection was developed for residue determination of thiophanate methyl (TM), cyromazine (CYR), and their metabolites, carbendazim (MBC) and melamine (MEL). Edible fungi samples were treated using accelerated solvent extraction (ASE) followed by cleanup with solid-phase extraction (SPE). Under optimized conditions, good linearity was achieved with a correlation coefficient (r ²) of ≥0.9998. The limit of quantification was 0.36, 0.24, 0.4, and 0.5 μg kg^?1 for MEL, CYR, MBC, and TM, respectively. The intra- and interday precisions (in terms of the relative standard deviation (RSD)) of the four analytes were in the range of 2.3–4.5 and 3.1–6.3 %, respectively. The recoveries for TM, MBC, CYR, and MEL in four edible fungi samples at three spiked levels of 0.6, 6, and 20 μg kg^?1 for TM and MBC and 0.4, 4, and 20 μg kg^?1 for CYR and MEL were in the range of 82–105 % with RSDs below 5.6 %. The proposed method can be used for the routine determination of CYR and MEL in edible fungi with high sensitivity and accuracy as well as low consumption of reagents.     

Dietary risk assessment of organophosphorus and dithiocarbamate pesticides in a total diet study at a Brazilian university restaurant

In this study ready-to-eat food samples were collected in the production line of the university restaurant of the University of Brasilia, Brazil, which serves non-vegetarian and vegetarian meals daily. Samples were analysed for the presence of ten organophosphorus insecticides (OPs) by GC/FPD, after extraction with ethyl acetate and anhydrous sodium sulfate (LOQ?=?0.002?mg?kg^–1), and for dithiocarbamate fungicides, as CS₂, using the spectrophotometric method (LOQ?=?0.05?mg?kg^?1). About 43% of the 175 samples analysed contained at least one OP compound at levels up to 1.83?mg?kg^?1. Methamidophos was the compound most detected (37.7%), present in most of the soup, soybean and salad samples. No OP residues were found in fruit juice, beans and bran rice samples. The cumulative acute intake of OPs was estimated using methamidophos and acephate as index compounds (IC). The total cumulative intake represented 9.1% and 47.7% of the methamidophos ARfD for the non-vegetarian and vegetarian diets, respectively. When acephate was used as IC, the total intakes represented 20.7% and 116% of the ARfD for the non-vegetarian and vegetarian diets, respectively. Dithiocarbamates were detected in 70% of the 177 samples analysed, at levels up to 0.51?mg?kg^?1 CS₂; all salad samples were positive and no residues were found in fruit juice. The chronic intake of dithiocarbamates represented 8.6 and 8.9% of the ADI (mancozeb) for the vegetarian and non vegetarian diets, respectively.     

Chemical composition and toxic trace element composition of some Nigerian edible wild mushrooms

Two essential amino acids (methionine and tryptophan); anti‐nutritional factors (tannin and trypsin inhibitor) and toxic elements (Pb, Cd, Ni, As, Hg and Cr) were determined spectrophotometrically from five edible wild mushrooms. The tryptophan content was between 1.00 and 1.82 g (100 g)^?1 but methionine was low at 0.26–1.38 g (100 g)^?1. Tannin content was high (30.3–40.0 mg g^?1) but trypsin inhibitor was low (22.0–39.5 TIU g^?1). Trace elements analysis reviled Pb (0.34–5.06 mg kg^?1) to be the highest of all the trace elements. Cd was (0.06–1.70 mg kg^?1), Ni (0.26–2.08 mg kg^?1), As (0.17–0.92 mg kg^?1), Hg (0.01–0.05 mg kg^?1) and Cr (0.04–0.22 mg kg^?1). These mushrooms are nutritious but must be well processed to eliminate or at least reduce the levels of tannin and Pb to improve their nutritional values.     

Validation and quantification of neonicotinoid insecticide residues in rice whole grain and rice straw using LC-MS/MS

An efficient analytical method was developed and validated using a modified QuEChERS method and LC-MS/MS for the detection and quantification of neonicotinoid insecticide residues in rice whole grain and rice straw. The samples were extracted using acetonitrile and cleaned up by dispersive solid-phase extraction. Validation based on five fortification levels showed good recoveries of neonicotinoids ranging from 75% to 116 % and 60% to 105 % for rice whole grain and straw, respectively. The precision ranged between 3% and 17 %, and 2% and 10 % for grain and straw, respectively. The limit of detection was from 0.007 to 0.0084 mg kg^?1 and 0.005 to 0.15 mg kg^?1 and the limit of quantification was in the range of 0.024–0.028 mg kg^?1 and 0.016–0.051 mg kg^?1 for rice whole grain and rice straw, respectively. Monitoring of farm gate samples indicated that, out of 24 samples, 1 rice whole grain sample was contaminated with thiamethoxam residues (0.07 mg kg^?1).     

A new,direct analytical method using LC-MS/MS for fatty acid esters of 3-chloro-1,2-propanediol (3-MCPD esters) in edible oils

A new, direct analytical method for the determination of 3-chloro-1,2-propanediol fatty acid esters (3-MCPD esters) was developed. The targeted 3-MCPD esters included five types of monoester and 20 types of diester. Samples (oils and fats) were dissolved in a mixture of tert-butyl methyl ether and ethyl acetate (4:1), purified using two solid-phase extraction (SPE) cartridges (C₁₈ and silica), then analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Five monoesters and five diesters with the same fatty acid group could be separated and quantified. Pairs of 3-MCPD diesters carrying the same two different fatty acid groups, but at reversed positions (sn-1 and sn-2), could not be separated and so were expressed as a sum of both compounds. The limits of quantification (LOQs) were estimated to be between 0.02 to 0.08?mg?kg^?1, depending on the types of 3-MCPD ester. Repeatability expressed as relative standard deviation (RSD_r%) varied from 5.5% to 25.5%. The new method was shown to be applicable to various commercial edible oils and showed levels of 3-MCPD esters varying from 0.58 to 25.35?mg?kg^?1. The levels of mono- and diesters ranged from 0.10 to 0.69?mg?kg^?1 and from 0.06 to 16?mg?kg^?1, respectively.