Determination of sterigmatocystin in foods in Japan: method validation and occurrence data

ABSTRACT

A survey of the contamination of foods by sterigmatocystin (STC) was performed by an analytical method based on LC-MS/MS. STC was extracted from samples with acetonitrile/water (85/15, v/v) and then purified with immunoaffinity columns. The method was validated by a small-scale inter-laboratory study using spiked wheat samples. Mean recoveries of STC were 100.3% and 92.5% from two samples spiked at 0.5 and 5.0 µg/kg, respectively. A total of 583 samples were analysed between 2016 and 2018, and STC was detected in 19.9% of all samples at >0.05 μg/kg (limit of quantification). The foods that were contaminated by STC were wheat flour, Job’s tears products, rye flour, rice, buckwheat flour, white sorghum, barley products, azuki bean and corn flour. STC was not found in beer or wine. The occurrence of STC in domestic wheat flour (44.4%), Job’s tears products (41.7%) and rye flour (29.9%) accounted for the three highest values. The highest mean concentrations were obtained for Job’s tears products (0.3 μg/kg) and rye flour (0.3 μg/kg). The maximum contamination level was present in a sample of rye flour (7.1 μg/kg). Although the contamination levels were low, these results indicate that STC frequently contaminates Japanese retail foods. A continuous survey is required to assess exposure to STC in Japan.     

Acrylamide in deep-fried snacks of India

Acrylamide content in deep-fried snacks from 20 different production sites of South Indian province of Kerala (80 samples representing 4 important product categories) were determined using a modified high performance liquid chromatography (HPLC)–diode array detector (DAD) method. The limit of detection and the limit of quantification for this method were 1.04 and 3.17 μg/kg, respectively. The mean recoveries of acrylamide obtained by using spiked samples ranged between 90% and 103%, which shows good extraction efficiency. Acrylamide concentrations in the four groups of snacks ranged from 82.0 to 4245.6 µg/kg for potato chips, 46.2–2431.4 µg/kg for jack chips, 24.8–1959.8 µg/kg for sweet plantain chips and 14.7–1690.5 µg/kg for plantain chips. These are the most widely consumed snacks in South India, and the results revealed reasonable levels of acrylamide in these foods, which indicated the general risk of consumer exposure.     

Production of acrylamide in agricultural products by cooking

Some model studies were performed using various agricultural Products, to clarify the relation between cooking conditions and production of acrylamide (AA). Disc chips made from dried mashed potato, corn meal, wheat flour, rice flour (jyohshin-ko) and glutinous rice flour (shiratama-ko), and dried sesame (arai-goma) and dried almond were baked at 120-200 degrees C for 5-20 min, and the samples were analyzed for the levels of AA. When the samples were baked for 10 min, the highest production of AA was observed at 180-200 degrees C. When the samples were baked at 180 degrees C, AA levels in agricultural products except sesame were highest after baking for 10 min. Vegetables and fruit were baked at 220 degrees C for 5 min with a oven, high AA concentrations were found in baked potato, asparagus, pumpkin, eggplant and green gram sprouts. Concentrations of AA in potato, asparagus and green gram sprouts baked after being pre-cooked by microwave irradiation were higher than those in the products baked without being precooked. On the other hand, the precooking by boiling reduced the production of AA by baking to 1/10-1/4. Acrylamide was not found in microwaved or boiled vegetables. High free asparagine concentrations in crops tended to result in high concentrations of AA being produced by heating the agricultural products.     

Potential health hazards due to the occurrence of the mycotoxin tenuazonic acid in infant food

The mycotoxin tenuazonic acid (TA) was analyzed in different infant foods and beverages including tea infusions (fruit, herbal and fennel tea), puree infant food in jars (complementary food and side dishes) and infant cereals (for preparation of meals after addition of water or milk) by means of a stable isotope dilution assay (SIDA). The median content of TA in infant tea infusions (n = 12) was 2 μg/L, but values up to 20 μg/L were found in fennel tea infusions. In puree infant food in jars (n = 12), the median content of TA was 7 μg/kg, but higher values were detected in products containing tomato (25 μg/kg), banana and cherry (80 μg/kg) and sorghum (20 μg/kg). Infant cereals on the basis of wheat and/or oats, rice, spelt and barley (n = 4) did not contain TA in values higher than 30 μg/kg, but if sorghum was the major ingredient (n = 12), the mean content of TA was 550 μg/kg and the maximum level was 1,200 μg/kg. The European Food Safety Authority (EFSA) evaluated the toxicological potential of TA by following the threshold of toxicological concern (TTC) approach yielding a TTC value of 1,500 ng TA/kg body weight per day. Although long-term studies are needed to enlarge the database on TA contamination of sorghum-based infant food, our preliminary study points out to a tendency that the TTC value may be exceeded by infants consuming predominantly sorghum-based food. Nevertheless, further toxicity data on TA are required with high priority to assess potential health hazards.     

Acrylamide levels and dietary exposure from foods in the United States,an update based on 2011-2015 data

ABSTRACT

Acrylamide is a contaminant that can form in certain plant-based foods during high-temperature cooking. From 2011–2015, the Food and Drug Administration conducted extensive sampling and analyses of acrylamide in foods, as a follow-up to surveys from 2002–2006. We compared acrylamide occurrence data and exposure estimates based on 2011–2015 data with data and exposure estimates from 2002–2006. Acrylamide levels in selected food categories generally did not decrease significantly in 2011–2015 compared with 2002–2006. However, significant decreases in acrylamide concentrations were observed for potato chips and crackers, which may be related to the availability and use of mitigation techniques for reducing acrylamide in foods. Mean dietary intake for those 2 years and older based on 2011–2015 data was 0.36 µg/kg bw/day, comparable to the 0.44 µg/kg bw/day reported by FDA in 2006. French fries and potato products, breakfast cereal, cookies, potato chips, and crackers continue to be the greatest contributors to dietary intake of acrylamide. Infant snack foods were identified as an important contributor to acrylamide intake relative to infant jarred foods. The continued presence of acrylamide in food suggests that manufacturers and governments should continue to pursue efforts to reduce acrylamide in foods that are important contributors to acrylamide intake.     

Acrylamide in daily food in the metropolitan area of Hanoi,Vietnam

ABSTRACT

Acrylamide, a colourless and odourless crystalline solid, formed via the Maillard reaction in food, has been reported with harmful properties for humans, such as toxicity and carcinogenicity. Three hundred and four processed food samples from 17 product types, collected in Hanoi, Vietnam, were analyzed by LC-MS/MS to measure the acrylamide concentration. The limit of detection (LOD) and the limit of quantification (LOQ) of acrylamide were 1 µg Kg^?1 and 3 µg Kg^?1, respectively. Effectively, the highest acrylamide content is usually found in processed food, which is one of the primary reasons of increased acrylamide content in food. All French fried samples contained acrylamide above 500 µg kg^?1. Acrylamide concentration in non-fried noodle, vermicelli, rice noodle, ph?, dried vegetable, and rice cracker is lower than in potato chips, fried potatoes, fried cake, and fried noodles. The results could be helpful to estimate exposure and risk assessment of acrylamide in Vietnam.     

Ochratoxin A in dried vine fruits from Chinese markets

A total of 56 dried vine fruits, including 31 sultanas and 25 currants, were selected from Chinese markets in 2012. All samples were analysed for Ochratoxin A (OTA) using solid-phase extraction and high-performance liquid chromatography (HPLC) with fluorescence detection. It turned out that 58.9% of the samples were positive and the OTA amount ranged from <0.07 to 12.83 μg/kg, with a mean level of 0.99 μg/kg. Only one sample exceeded the European Union (EU) maximum level of 10 μg/kg. Meanwhile, it was shown that OTA contamination increased among north-western, northern and southern China, which showed OTA means of 0.08, 0.99 and 2.01 μg/kg, respectively. Moreover, in samples of products sold in sealed plastic bags, i.e. consumer-size packages (n = 19, mean = 0.30 μg/kg) less OTA was detected when compared with sampled bulk packages (n = 37, mean = 1.67 μg/kg). In addition, sultanas (mean = 0.92 μg/kg) had less OTA contamination than currants (mean = 1.22 μg/kg).     

Aflatoxins and ochratoxin A in flour: a survey of the Serbian retail market

This report presents data on the occurrence of aflatoxins (AF) and ochratoxin A in different types of flour marketed in Serbia. A total of 114 samples of wheat, buckwheat, rye, oat, barley, rice, millet and corn flour were collected in the period 2012–2016 and analysed using high performance liquid chromatography with fluorescence detection. Among flours other than corn, AFB1 was quantified only in rice, while ochratoxin A (OTA) was found in 29% of the samples. In corn flours the percentage of positive samples varied greatly over the years: AFB1 7.1–80.0%, OTA 30.0–40.6%, with a co-occurrence of 7.1–34.4%. Overall 5.2% of flours other than corn and 10.7% of corn flours exceeded the maximum levels (MLs) for AFB1 and/or OTA. The highest recorded levels were 8.80 μg kg^?1 of AFB1 (corn) and 23.04 μg kg^?1 of OTA (rye). Overall mean contamination levels of corn flours were 0.53 μg kg^?1 of AFB1 and 0.46 μg kg^?1 of OTA.     

Non-isoflavone phytoestrogenic compound contents of various legumes

Widely consumed legumes including chickpeas, red kidney beans, haricot beans, yellow lentils, red lentils and green lentils were analysed to determine the content of non-isoflavone phytoestrogenic compounds such as quercetin, rutin, apigenin, coumestrol and lignan (matairesinol and secoisolariciresinol). Methanolic extracts obtained by ultrasound-assisted extraction were analysed by the triple quadrupole LC–MS/MS. Red kidney beans were the best source of quercetin (603.2 ± 307.2 μg/kg) and rutin (73.4 ± 14.0 μg/kg). Apigenin and secoisolariciresinol contents were the highest in yellow lentils (18.5 ± 0.84 μg/kg) and haricot beans (451.9 ± 192.2 μg/kg), respectively. Coumestrol contents of haricot beans (18.5 ± 1.45 μg/kg) and red kidney beans (18.5 ± 1.26 μg/kg) were equal to each other, and these were determined as the highest coumestrol content values. The best sources of matairesinol occurred in green lentils (28.2 ± 0.18 μg/kg) and chickpeas (27.7 ± 1.83 μg/kg). Differences between contents of each sample of the same legume were significant and remarkable, especially for quercetin and secoisolariciresinol.     

Blockage of available lysine at different stages of infant cereal production

Determination of available lysine was used to assess the heat damage produced during the processing of cereals for infant foods. The infant cereals analysed were: wheat, 7 and 8 cereals, rice, rice–corn, rice–corn–soy and oat. Lysine losses during the toasting of flours ranged between 14 and 29%. Roller‐drying treatment caused considerable heat damage, with a 53% decrease of available lysine in roller‐dried rice–corn–soy. However, oat flour was less susceptible, with a 5% reduction in available lysine during roller‐drying. © 1999 Society of Chemical Industry     

Deoxynivalenol in wheat from the Northwestern region in China

ABSTRACT

Because of global warming and changes in farming systems, Fusarium head blight has gradually spread towards high-latitude regions such as Northwestern China. A survey was conducted to assess the prevalence and concentration of deoxynivalenol (DON) in wheat harvested during 2013 from the Shaanxi, Ningxia, Gansu, and Xinjiang provinces in China. DON concentration in 181 wheat samples was analysed by high-performance liquid chromatography combined with ultraviolet detection. Of the wheat samples, 82.9% were contaminated with DON, with a mean DON concentration of 500 μg/kg. According to the Chinese standard limits for DON, 10% of the positive samples were above the maximum limit of 1000 μg/kg. Regions with higher humidity showed higher levels of DON in the wheat samples. These results show the necessity of raising awareness of DON contamination in people from Northwestern China to protect their health from the risk of exposure to DON.     

Total mercury and methylmercury in Chinese rice and dietary exposure assessment

ABSTRACT

Total mercury levels and methylmercury levels were investigated for various grain parts (whole rice, rice husk, brown rice, polished rice, and bran) of 507 rice samples from 15 main rice-producing areas of China. The average total mercury contents in brown rice samples and polished rice samples were 4.2 and 3.3 μg/kg, respectively, the percentages exceeding the national standard limit were 0.59% and 0.39%, respectively. The average methylmercury levels were 2.9 and 2.4 μg/kg in brown rice and polished rice, respectively. The order of total mercury contents in different parts of rice was bran > brown rice > whole rice > rice husk > polished rice, and the order for methylmercury was bran > brown rice > whole rice > polished rice > rice husk. Total mercury intakes and methylmercury intakes were estimated for the Chinese population and the associated health risks were assessed.     

河北省小麦、玉米及其制品中16种真菌毒素污染水平调查与分析

目的调查分析河北省小麦、玉米及其制品中16种常见真菌毒素污染状况。方法收集河北省37份鲜(冻)玉米/玉米粒、74份玉米、玉米面制品以及240份小麦样品。样品经乙腈:水:甲酸(79:20:1, V:V:V)溶液超声离心提取后,通过同位素内标稀释法处理,采用液相色谱-串联质谱法进行检测。结果伏马毒素小麦检出8份,玉米、玉米面制品检出66份,检出范围为ND~3889.9μg/kg;玉米赤霉烯酮检出小麦检出2份,玉米、玉米面制品检出69份,检出范围为ND~323.2μg/kg;脱氧雪腐镰刀菌烯醇小麦检出122份,玉米、玉米面制品检出68份,检出范围为ND~4183.4μg/kg;3-乙酰基-脱氧雪腐镰刀菌烯醇小麦检出5份,玉米、玉米面制品检出18份;15-乙酰基-脱氧雪腐镰刀菌烯醇小麦检出12份,玉米、玉米面制品检出38份;其他毒素均为未检出。鲜(冻)玉米/玉米粒中16种真菌毒素均未检出。结论伏马毒素、玉米赤霉烯酮和脱氧雪腐镰刀菌烯醇为小麦、玉米及其制品的主要污染物,其污染状况应引起关注。     

Determination of acrylamide in roasted chestnuts and chestnut-based foods by isotope dilution HPLC-MS/MS

A collaboratively trial tested isotope dilution liquid chromatographic method with positive electrospray ionisation tandem mass spectrometry for the analysis of acrylamide in bakery ware and potato products has been extended to the determination of acrylamide in roasted chestnuts and chestnut-based foods. As chestnuts have a similar composition to potatoes, considerable amounts of acrylamide can be expected, especially in roasted chestnut products. This paper presents the concentrations of acrylamide in 31 different chestnut samples (fresh, roasted, flour, cooked, glazed) that were collected in nine European countries during 2005/2006. The influence of the roasting time on the acrylamide content was also experimentally investigated. A test portion was extracted after homogenisation with water and isotopically labelled acrylamide was added. The extract was centrifuged and the supernatant was cleaned-up in two consecutive solid phase extraction steps. The final extract was analysed by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). An HPLC column based on graphitised carbon was applied for chromatographic separation. Acrylamide concentrations in purchased roasted chestnuts were in the range of <8–1278 μg/kg whereas only low amounts (<4–159 μg/kg) were found in chestnut products. However, the median acrylamide content of the commercial roasted chestnut samples was 90 μg/kg. The influence of the roasting time on the acrylamide content in roasted chestnuts was evaluated too. As with roasted and fried potato products, the roasting time has a significant influence on the acrylamide formation. Therefore, the consumers might be exposed to significant amounts of acrylamide by eating roasted chestnuts, especially when a batch remains in the roasting vessel for too long time.     

Analysis of acrylamide by LC-MS/MS and GC-MS in processed Japanese foods.

Acrylamide concentrations in processed foods (63 samples covering 31 product types) from Japan were analysed by LC-MS/MS and GC-MS methods. The limit of detection and limit of quantification of acrylamide were 0.2 ng x ml(-1) (6 fmol) and 0.8 ng x ml(-1) (22 fmol), respectively, by LC-MS/MS, and those of 2,3-dibromopropionamide derived from acrylamide were 12 ng x ml(-1) (52 fmol) and 40 ng x ml(-1) (170 fmol), respectively, by GC-MS. Repeatability given as RSD was <5 and <15% for the LC-MS/MS and GC-MS methods, respectively. High correlation (r(2) - 0.946) was observed between values obtained by the two methods. Most potato crisps and whole potato-based fried snacks showed acrylamide concentrations >1000 microg x kg(-1). The concentrations in non-whole potato-based snacks, rice crackers processed by grilling or frying, and candied sweet potatoes were lower compared with those in the potato crisps and the whole potato-based fried snacks. One of the whole potato-based fried snacks, however, showed low acrylamide concentration (<50 microg x kg(-1)) suggesting the formation of acrylamide is strongly influenced by processing conditions. Acrylamide concentrations in instant precooked noodles and won-tons were <100 microg x kg(-1) with only one exception. Roasted barley grains for 'Mugi-cha' tea contained 200-600 microg x kg(-1) acrylamide.     

Occurrence of aflatoxins, ochratoxin A, and fumonisins in retail foods in Japan

We conducted a survey of aflatoxin B1, B2, G1, and G2, ochratoxin A, and fumonisin B1, B2, and B3 contamination in various foods on the retail market in Japan in 2004 and 2005. The mycotoxins were analyzed by high-performance liquid chromatography, liquid chromatography-mass spectrometry, or high-performance thin-layer chromatography. Aflatoxins were detected in 10 of 21 peanut butter samples; the highest concentration of aflatoxin B1 was 2.59 microg/kg. Aflatoxin contamination was not found in corn products, corn, peanuts, buckwheat flour, dried buckwheat noodles, rice, or sesame oil. Ochratoxin A was detected in oatmeal, wheat flour, rye, buckwheat flour, green coffee beans, roasted coffee beans, raisins, beer, and wine but not in rice or corn products. Ochratoxin A concentrations in contaminated samples were below 0.8 microg/kg. Fumonisins were detected in popcorn, frozen corn, corn flakes, and corn grits. The highest concentrations of fumonisins B1, B2, and B3 in these samples were 354.0, 94.0, and 64.0 microg/kg, respectively.     

Simple and Fast Determination of Acrylamide and Metabolites in Potato Chips and Grilled Asparagus by Liquid Chromatography Coupled to Mass Spectrometry

The purpose of this study was to evaluate an analytical procedure for the determination of acrylamide in different starchy foods such as potato chips and grilled asparagus. The method is based on high-performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (HPLC-QqQ-MS/MS). A solid–liquid extraction procedure, using water as extraction solvent, has been developed followed by a cleanup procedure based on solid-phase extraction (SPE) or dispersive solid-phase extraction (d-SPE). Polymeric cartridges (Oasis HLB) and aluminum oxide (Al₂O₃) were used for potato and asparagus matrices, respectively. The optimized procedures were validated, and limits of detection and quantitation were 4 and 12 μg/kg for potato chips and 2 and 5 μg/kg for grilled asparagus, respectively. Recoveries were evaluated, and good values were obtained, ranging from 90 to 117 % for potato chips and from 90 to 116 % for grilled asparagus. The method was applied to real samples, and concentrations ranged from 105 to 860 μg/kg in potato chips, whereas higher values were detected in grilled asparagus (from 292 to 1469 μg/kg). Furthermore, single-stage Orbitrap high-resolution mass spectrometry has been used for the putative identification of acrylamide-N-acetyl-S-(2-carbamoylethyl)-l-cysteine (AAMA) in urine.     

Simultaneous determination of kasugamycin and validamycin-A residues in cereals by consecutive solid-phase extraction combined with liquid chromatography–tandem mass spectrometry

Two polar aminoglycosides, kasugamycin and validamycin-A, were determined in cereals (brown rice, wheat and corn) by high-performance liquid chromatography–tandem mass spectrometry. The analytes were extracted from samples using methanol and water (70:30, v/v) at pH 5.5, purified using both a hydrophilic–hydrophobic-balanced cartridge and a strong cation-exchange cartridge, and then analysed using multiple reaction monitoring in positive electrospray ionisation mode with a special ReproSil 100 C₁₈ high-performance liquid chromatography column. This newly proposed method yielded good sensitivity and excellent chromatographic performance. The limits of quantification for kasugamycin and validamycin-A were 4.1 µg/kg and 1.0 µg/kg, respectively. The recoveries for both compounds at three fortification levels (4, 100 and 500 µg/kg for kasugamycin; 1, 10 and 100 µg/kg for validamycin-A) ranged from 75% to 110%, and the relative standard deviations were below 15%.     

Effects of variety, ripening condition and ripening stage on the quality of sulphite-free dried mango slices

The influence of cultivar and fruit ripeness on sensory properties and all-trans-β-carotene contents of dried mango slices was evaluated. Different ripeness stages, quantitatively defined by a ripening index (RPI), were generated from a single lot per cultivar by subjecting mature-green mangoes of the cultivars ‘Nam Dokmai’, ‘Kaew’, and ‘Chok Anan’ to different postharvest ripening regimes. Fruits were ripened for 2 and 3 days at 24±2 °C/45–60% relative humidity (RH) and 33±2 °C/50–70% RH, with application of calcium carbide (CaC₂) or 2-chloroethylphosphonic acid (CEPA, Ride^®) beside the control, terminating postharvest ripening when fruit firmness allowed proper peeling and slicing. After ripening, fruits were washed, peeled, sliced and subsequently dried in a conventional tray dryer at 70 °C for 8–10 h, until the water activity of the dried fruits was below 0.65. Mangoes cv. ‘Kaew’, followed by ‘Chok Anan’, were more suitable for drying than cv. ‘Nam Dokmai’ because of superior all-trans-β-carotene contents of the products. Maximum β-carotene contents of dried mango slices from cvs. ‘Chok Anan’ and ‘Kaew’ corresponded to retinol equivalents of 333–383 and 483–905 per 100 g of edible portion (dry weight), meeting daily mean requirements of vitamin A for adults according to FAO/WHO. Similar to the fresh fruit, exponential rise of all-trans-β-carotene contents with increasing fruit ripeness was also observed for the dried products of cvs. ‘Nam Dokmai’ and ‘Chok Anan’. Consistently, accelerated ripening at 33 °C, instead of 24 °C, resulted in higher all-trans-β-carotene contents of dried fruits. Both good sensory acceptance and cultivar-specific maximum all-trans-β-carotene contents of 13–16 and 20–23 mg kg^?1 usually characterised the products of ‘Nam Dokmai’ and ‘Chok Anan’ fruits with RPI levels between 3 and 4. Conversely, fruits cv. ‘Kaew’ of RPI levels above 6 generally yielded products inferior in sensory acceptance and β-carotene contents, while superior product quality was found at higher RPI levels than for the other two cultivars.     

An experimental set-up for studying acrylamide formation in potato crisps

The objective of this work was to set up lab-scale equipment for production of crisps mimicking industrial conditions. Slices of Saturna potatoes were deep-fat fried for 2-4.5 min at 160 °C. A solid phase extraction method for acrylamide from potato crisps was used, and the extraction recovery was calculated to 95%. Acrylamide was analysed using liquid chromatography tandem mass spectrometry. The relative standard deviation was below 3% for analyses performed on the same day and below 5% for inter-day analyses. The limit of quantification was estimated to be 160 μg/kg potato crisps. The colour of potato slices was determined using a digital imaging method and related to the acrylamide content. There were tendencies that L*(lightness) decreased and that that a*(redness) and b*(yellowness) increased with increasing acrylamide content. In another experiment, potatoes with different glucose levels were fried for 4 min but no significant difference in acrylamide content (2200-2800 μg/kg) was observed. The experiment was repeated after three months of storage. The levels of acrylamide increased significantly to 8200-13200 μg/kg. The potatoes had been fertilized with different levels of nitrogen, but no relation was found between the nitrogen supplied and the acrylamide content. The experimental set-up was shown to give realistic and reproducible experimental data, regarding colour, water content and acrylamide levels. It will be used together with the analytical methods as a platform for further research on the formation of acrylamide.