Analysis of Naturally Occurring Fluoride in Commercial Teas and Estimation of Its Daily Intake through Tea Consumption

The aim of this study was to determine the levels of fluoride in commercial teas and to estimate the contribution of tea consumption to the fluoride recommended daily allowance. A total of 558 tea products in 6 categories, green tea, black tea, oolong tea, pu'er tea, white tea, and reprocessed tea, were collected in the period from 2010 to 2013. The levels of fluoride in infusions of these teas were determined by a fluoride‐ion selective electrode. The mean fluoride level in all of the tea samples was 85.16 mg/kg. For each category of tea, the mean fluoride levels were 63.04, 99.74, 52.19, 101.67, 159.78, and 110.54 mg/kg for green tea, black tea, white tea, pu'er tea, oolong tea, and reprocessed tea, respectively. The fluoride content of tea from 4 tea zones in descending order were Southern tea zone (111.39 mg/kg) > Southwest tea zone (78.78 mg/kg) > Jiangnan tea zone (71.73 mg/kg) > Jiangbei tea zone (64.63 mg/kg). These areas produced teas with lower fluoride levels than available foreign‐produced tea (161.11 mg/kg). The mean chronic daily intake (CDI) was 0.02 mg/(kg?day) or 1.27 mg/kg. Generally, consuming tea from these 6 categories does not result in the intake of excessive amounts of fluoride for the general population.     

Dietary Intake of Fluoride in the United Kingdom and Fluoride Content of Some Foodstuffs

Using samples from the Total Diet Study, the average dietary intake per person of fluoride in the United Kingdom is estimated to be 1.82 mg day^?1. Beverages account for 71% of the total dietary intake and tea contributes most to the intake from the beverages group. Above-average consumption of tea, as recorded in Great Britain, could result in fluoride intakes as high as 8.9 mg day^?1. It is estimated that tap water containing 1 mg litre^?1 of fluoride could increase normal dietary intakes by 54%. Individual foods have been analysed and the results show that tea infusions and foods containing skin or bone have higher fluoride concentrations than other foods. Concentrations as high as 44 mg kg^?1 were found in the tail meat of krill, and a sample of mechanically deboned meat contained 2.8 mg kg^?1 fluoride. Samples of flour, bread, vegetables, meat and fish products and infant foods generally contained less than 1 mg kg^?1 of fluoride. Soft drinks from an area with a fluoridated water supply had a higher fluoride concentration than samples taken from an area with unfluoridated water.     

The oral nitrate and nitrite intake in The Netherlands: evaluation of the results obtained by HPIC analysis of duplicate 24-hour diet samples collected in 1994.

In spring and autumn of 1994 duplicates of 24-h diets were collected from 123 respondents. One of the goals of this study was to determine the amount of nitrite and nitrate in the duplicates of 24-h diets to establish the oral daily intake of these analytes. For this purpose an HPIC/UV method for the determination of nitrate and nitrite in duplicate diets was developed and validated. The sample preparation procedure was derived from the in-house method used for the determination of nitrate and nitrite in human blood plasma. The sample is diluted with water, deproteinized with Carrez reagent, followed by chromatographic clean-up on an SPE C18-column. Both the nitrate and the nitrite results are quantitative. The recovery for nitrite was on average 104% (n = 21, spiking levels: 0.84-95 mg/kg) and for nitrate on average 103% (N = 21, spiking levels: 1.8-404 mg/kg). Samples of duplicates of 24-h diets were analysed according to the method developed. The median intake of nitrite calculated from the samples collected in spring 1994 was 0.6 mg/person day (range < 0.1-6.1 mg/person/day). For the samples collected in autumn 1994 these figures were < 0.2 mg/person/day (range < 0.1-16 mg/person/day). The mean intake of nitrate was 73 mg/person/day (range 7-322 mg/person/day) in spring 1994 and 87 mg/person/day (range 1-310 mg/person/day) in autumn 1994. The overall mean intake of nitrate in 1994 was 80 mg/person/day. The daily intake for nitrate was higher than that found in the duplicate diet study carried out in 1984/1985, when an average daily intake of 52 mg/person was measured. The intake of nitrite was also higher than found in the duplicate diets collected in 1984/1985. The findings of the study are discussed in the context of the ADI for nitrate and nitrite as well as the outcome of other recent European intake studies.     

Fluoride in teas of different types and forms and the exposure of humans to fluoride with tea and diet

Human exposure to the fluoride (F) from commercial teas was assessed. The efficacy of the F leaching was determined from the total F (F_t) contents in the teas (53–435 mg/kg) and the F concentrations in tea infusions (0.31–3.55 mg/l of free F available to human organism). Both were determined with a fluoride ion selective electrode. The efficacies of F leaching from the green, oolong and black teas were 55–90% with continuous, and 74–100% by repeated infusions, and were not affected by the type or the manufactured form. Lower efficacies were observed from Pu’erh teas, 21–38% with continuous, and 37–59% by repeated infusions. The daily intake of F with daily consumption of five cups of tea can represent 9–101% of the adequate intake (AI) for an adult person with 70 kg, and with tea and diet 25–173% of the AI in non-fluoridated and 35–210% of AI in fluoridated areas. The upper limits of these intakes can be already associated with a risk of developing F-related adverse effects.     

Human exposure assessment of fluoride from tea (Camellia sinensis L.): A UK based issue?

Fluoride concentrations in UK tea, including the leading supermarket economy labelled products, were determined. Fluoride ranged from 93 to 820 mg/kg in the products and 0.43 to 8.85 mg/L in the infusions. The UK supermarket economy teas contained elevated fluoride, ranging from 3.60 to 7.96 mg/L in a 2 minute brewing infusion, comparable to Chinese brick tea, indicating the use of mature leaves in their manufacture. Considering the dietary reference intake (DRI) of 4 mg/day of fluoride for an adult consuming 1 L of tea, prepared from an economy tea, containing 6.0 mg/L fluoride, 75–120% of the DRI fluoride is available for absorption by the human system in the presence of food, increasing to 150% when fasting. Excess fluoride in the diet can lead to detrimental health effects such as fluorosis of the teeth and skeletal fluorosis and consuming economy branded tea will lead to exposure.     

Safety evaluation on fluoride content in black tea

Fluoride content in black tea in various commodities, packages, and preparation processess was assayed and its safety evaluated. A fluoride ion selective electrode method was used to determine the fluoride content in 20 tea samples, in various black tea commodities, namely stick-shaped, granular, and canned or bottled tea beverage, originally produced in India, Sri Lanka, China, Japan and UK, and milk–tea after addition of milk and sugar. The fluoride content of 5 stick-shaped black teas was 96.9–148 mg/kg, that of 8 granular black tea was 139–223 mg/kg, and that of 3 canned or bottled beverage black tea beverages was 0.70–0.96 mg/l, respectively. Neither the bagged black tea paper nor the addition of milk and sugar affected the ionic fluoride level within the tea. These results suggest that, for heavy black tea drinkers, the fluoride intake in areas with drinking water fluoridation, and also other probable sources of fluoride, may approach or reach the level of risk from chronic fluoride intoxication.     

Caffeine intake and its sources: A review of national representative studies

Aim of this review is to summarize current daily caffeine intake of children, adolescents, and adults, and trends in caffeine intake over the past decade. A literature search was conducted (1997–2015) which yielded 18 reports on nationally representative studies, describing caffeine consumption of over 275,000 children, adolescents and adults. The data revealed that mean total daily caffeine intake in children, adolescents, and adults is below caffeine intake recommendations such as those stated by Health Canada (2.5 mg/kg bw/day for children and adolescents, and 400 mg/day for adults) and the European Food Safety Authority, EFSA (3 mg/kg bw/day for children and adolescents, and 400 mg/day for adults). Total daily caffeine intake has remained stable in the last 10–15 years, and coffee, tea and soft drinks are the most important caffeine sources. Across all age groups, energy drinks contribute little to total caffeine intake. The highest potential for reducing daily caffeine intake is by limiting coffee consumption, and in some countries and age groups, by reducing tea and soft drink consumption.     

Japan Flavour and Fragrance Materials Association’s (JFFMA) safety assessment of food-flavouring substances uniquely used in Japan that belong to the class of aliphatic primary alcohols,aldehydes, carboxylic acids,acetals and esters containing additional oxygenated functional groups

ABSTRACT

We performed a safety evaluation using the procedure devised by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) of the following four flavouring substances that belong to the class of ‘aliphatic primary alcohols, aldehydes, carboxylic acids, acetals, and esters containing additional oxygenated functional groups’ and are uniquely used in Japan: butyl butyrylacetate, ethyl 2-hydroxy-4-methylpentanoate, 3-hydroxyhexanoic acid and methyl hydroxyacetate. Although no genotoxicity study data were found in the published literature, none of the four substances had chemical structural alerts predicting genotoxicity. All four substances were categorised as class I by using Cramer’s classification. The estimated daily intake of each of the four substances was determined to be 0.007–2.9 μg/person/day by using the maximised survey-derived intake method and based on the annual production data in Japan in 2001, 2005 and 2010, and was determined to be 0.250–600.0 μg/person/day by using the single-portion exposure technique and based on average-use levels in standard portion sizes of flavoured foods. Both of these estimated daily intake ranges were below the threshold of toxicological concern for class I substances, which is 1800 μg/person/day. Although no information from in vitro and in vivo toxicity studies for the four substances was available, these substances were judged to raise no safety concerns at the current levels of intake.     

Aluminium and fluoride in hospital daily diets and in teas

The levels of aluminium and fluoride have been determined in hospital daily diets including breakfast, dinner and supper, as well as in black teas and herbal teas purchased from the local market. In tea, aluminium was determined directly in a sample solution by atomic absorption spectroscopy using nitrous oxide and an acetylene flame. For analysis of the hospital diet, samples containing lower levels of aluminium were analysed using a spectrophotometric method which measured aluminium in the form of a 8-hydroxyquinoline complex. Decomposition of the samples was achieved using a mixture of concentrated acids [nitric (HNO₃), perchloric (HClO₄) and sulphuric (H₂SO₄)] in platinum dishes. Fluoride was assayed by spectrophotometry using a microdiffusion procedure with a mixture of concentrated HClO₄ and silver sulphate, trace amounts of the released fluoride [as hydrogen fluoride (HF)] were trapped on the alkaline surface of a Petri dish and then determined in the form of an alizarin-fluoride complex. The mean level of aluminium found in hospital daily diets amounted to 21.3±12.3 mg and the mean level of fluoride was 1.38±1.12 mg per adult person. In the 16 samples of commercially available brands of black teas, the levels of aluminium and fluroide ranged from 445 to 1552 ppm (mean=897±264 ppm) and from 30 to 340 ppm (mean 141±85 ppm), respectively. In six herbal teas, the mean levels of aluminium and fluoride were lower, and amounted to 218.9±150.7 ppm and 6.0±6.9 ppm, respectively. This study has shown that concern about a high intake of aluminium and fluoride from these foods is unfounded.     

低氟砖茶与传统砖茶品质的比较分析

为满足国家标准规定砖茶允许含氟量≤300mg/kg的要求,选用一芽四五叶原料生产低氟砖茶（氟含量285mg/kg）,以传统砖茶（氟含量850mg/kg）为对照,分别进行了感官品质、主要成分及儿茶素和氨基酸组分比较分析。结果表明:低氟砖茶感官品质优于传统砖茶;低氟砖茶主要成分水浸出物、茶多酚、可溶性糖、咖啡碱、茶黄素、茶红素、茶褐素比传统砖茶增加了48.33%、79.22%、44.44%、89.55%、42.86%、26.28%、42.96%;氨基酸组分除甲硫氨酸和脯氨酸外,其他氨基酸高于传统砖茶,儿茶素组分除L-CG外,其他儿茶素含量高于传统砖茶。结果显示通过提高原料嫩度生产低氟砖茶是可行的。      

Daily dietary intake of fluoride by Slovenian Military based on analysis of total fluorine in total diet samples using fluoride ion selective electrode

The purpose of this study was to develop an analytical procedure for determination of the amount of total fluoride in total diet samples, including drinking water and beverages. Samples were taken by the duplicate portion technique and decomposed by alkali carbonate fusion using KNaCO₃, and the amount of fluoride in solution was determined by fluoride ion selective electrode using the multiple known addition technique. The mean amount of total fluoride determined in 20 total diet samples obtained from the Slovenian Military was 1.84 ± 0.70 mg/kg on a dry matter basis. Accordingly the estimated daily intake was 1.50 ± 0.56 mg.     

Determination of brominated flame retardants and brominated dioxins in fish collected from three regions of Japan

The concentrations of brominated dioxins which are polybrominated dibenzo-p-dioxins/polybrominated dibenzofurans (PBDD/DFs) and mono-bromo polychlorinated dibenzo-p-dioxins/dibenzofurans, polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA) were investigated in a total of 45 fish samples collected from three regions in Japan. In the brominated dioxins, 1,2,3,4,6,7,8-heptabromodibenzofuran (HpBDF) was the most abundant congener, and it was found in seven fish samples at 0.10-25.6 pg/g wet weight (ww). The highest concentration of 1,2,3,4,6,7,8-HpBDF was found in the pike eel. Regarding other congeners, 2,3,7,8-tetrabromodibenzo-p-dioxin was detected in the sea bream at 0.02 pg/g ww, and 2,3,7,8-tetrabromodibenzofuran was detected in the conger eel at 0.03 pg/g ww. 3-Bromo-2,7,8-trichlorodibenzofuran was detected in the Sardinella zunasi and the conger eel at 0.01 pg/g ww and 0.02 pg/g ww, respectively. Using toxic equivalency factors of chlorinated dioxins, we calculated the PBDD/DFs concentrations of these fish samples at 0.001-0.256 pg TEQ/g ww. PBDEs were detected in all of the fish samples. The concentrations of total PBDEs were 0.01-2.88 ng/g ww. The seerfish and the yellowtail containd PBDEs in high concentrations. The most dominant congener in most of the fish was 2,2',4,4'-tetrabromo diphenyl ether. TBBPA was detected in 29 fish samples at 0.01-0.11 ng/g ww. The mean level of TBBPA was about one-tenth or less of the total level of PBDEs. A good correlation was obtained between total PBDEs and fat content. On the other hand, no correlation was obtained between TBBPA and fat content. The daily intakes from fish were estimated to be 0.58 ng/kg body weight (bw)/day for total PBDEs, 0.03 ng/kg bw/day for TBBPA, and 0.01 pg TEQ/kg bw/day for brominated dioxins in the case assuming that the average bw of a Japanese adult person is 50 kg and that the average fish consumption is 82 g/day. For PBDEs, the provisionally calculated value was much less than the lowest observed adverse effect level value (1 mg/kg bw/day). For brominated dioxins, the daily intake was at a very low level compared with the Japanese daily intake of polychlorinated dioxins from fish. Even if the value of PBDD/DFs is added to the amount of chlorinated dioxin exposure, it was estimated that it is less than the tolerable daily intake (4 pg TEQ/kg bw/day) in Japan.     

Quercetin,luteolin, apigenin and kaempferol contents of some foods

Quercetin, luteolin, apigenin and kaempferol contents of Urtica sp., Rosa cannina (rosehip), Salvia officinalis (sage), Tilia platyphyllos (linden flower), black tea, Daucus carota L. spp sativus (violet carrot juice), grape molasses, honey and tarhana were determined by HPLC with UV detection. Consumption of the samples was assessed using a food frequency questionnaire method. One hundred healthy volunteers were asked to state the number of times on average per day, week or month they consumed each item over the last 6 months. Quercetin was determined in all samples except honey, whereas luteolin was determined only in sage. Kaempferol was determined in black tea, linden flower and honey samples, and apigenin was determined in honey and Urtica sp. Quercetin intake by the consumption of tea, linden flower, sage rosehip, violet carrot juice, grape molasses, tarhana and juice of Urtica sp. were estimated as 4.2–25, 2.6, 3.3, and 2.0 μg/day, 1.67 mg/day, 1.70 mg/day, 1.78 mg/month and 21.75–65.25 μg/month, respectively. Luteolin intake by the consumption of sage was estimated as 1.32 μg/day. Apigenin intakes by the consumption of honey and juice of Urtica sp. were estimated as 2.34 mg/day and 3.58–10.73 mg/month, respectively. Kaempferol intakes of the participants from tea, linden flower and honey were estimated as 13.2–79.2, 13.56 and 190 μg/day respectively. ©     

Polycyclic aromatic hydrocarbon levels and risk assessment for food from service facilities in Korea

ABSTRACT

In this study, levels of benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene (BaP), dibenzo[a,h]anthracene, benzo[g,h,i]perylene and indeno[1,2,3-c,d]pyrene in 412 food items collected from food service facilities in Korea were analysed. The concentrations of the eight polycyclic aromatic hydrocarbons (PAHs) ranged 0.13–0.48 μg/kg. The concentrations of benzo[a]pyrene in all food samples were <1 μg/kg, which is the lowest maximum limit in foods regulated by European Union legislation. PAH contents were employed to conduct exposure and risk assessment. The chronic daily intake of PAHs from 412 food samples was 5.48 × 10^–6-4.70 ×x 10^–4 µg-TEQ_BaP/kg/day with margins of exposure of 1.04 × 10⁹-1.16 × 10¹¹.     

Aflatoxin M1 and B1 in Colombian milk powder and estimated risk exposure

ABSTRACT

Aflatoxin M₁ (AFM₁) and aflatoxin B₁ (AFB₁) were determined in 51 milk powder samples purchased from different grocery stores located in the Caribbean region of Colombia. Analysis was conducted using QuEChERS extraction and high-performance liquid chromatography with fluorescence detection. Results from the analytical method showed recovery ranges from 65% to 110% and relative standard deviations lower than 20%. AFM₁ was detected in 100% of the milk samples (0.20–1.19 µg/kg) and 55% exceeded the maximum level in milk (0.5 µg/kg) set by the Colombian and European regulations. AFB₁ was not detected in any of the analysed samples. Considering the measured contamination the maximum AFM₁ level that can be ingested by consumption of milk powder is 0.007–0.013 µg/person/day. These values are above the average dietary intake estimated in Latin America according to the Joint FAO/WHO Expert Committee, which is 0.0035 µg/person/day.     

The lead, cadmium and mercury concentrations in muscle, liver and kidney from Finnish pigs and cattle during 1987-1988

The lead, cadmium and mercury concentrations in muscle, liver and kidney from Finnish pigs and cattle were determined. The average wet weight lead concentrations in pig muscle, liver and kidney were 15 micrograms/kg, 38 micrograms/kg and 40 micrograms/kg, respectively. The corresponding concentrations for cattle were 13 micrograms/kg, 57 micrograms/kg and 110 micrograms/kg. The average wet weight cadmium concentrations were 1.5 micrograms/kg, 28 micrograms/kg and 170 micrograms/kg (pigs) and 1.3 micrograms/kg, 61 micrograms/kg and 350 micrograms/kg (cattle). The corresponding mercury concentrations were 11 micrograms/kg, 12 micrograms/kg and 14 micrograms/kg (pigs) and 11 micrograms/kg, 12 micrograms/kg and 15 micrograms/kg (cattle). The average concentrations were at or above the detection limit of the metal in question. According to the results obtained by the National Veterinary Institute, the cadmium concentration in pigs and cattle has decreased during the period 1973-1988. The provisional tolerable daily intake of lead/person (60 kg), recommended by GEMS/Food, is 0.43 mg. According to the results for lead levels in these products in Finland, a daily intake of 29 kg pig muscle, 33 kg cattle muscle, 11 kg pig liver, 8 kg cattle liver, 11 kg pig kidney or 4 kg cattle kidney would be required to reach this norm. The corresponding provisional tolerable daily intake of cadmium/person (60 kg) is 0.06 mg and is equivalent to 40 kg pig muscle, 46 kg cattle muscle, 2 kg pig liver, 1 kg cattle liver, 0.4 kg pig kidney and 0.2 kg cattle kidney. The validity of the methods was tested four times a year using spiked check samples.     

Total and acid-soluble fluoride content of infant cereals, beverages and biscuits from Brazil

Total fluoride (TF) and HCl 0.01 M ('gastric juice')-soluble fluoride (SF) were analysed in infant foods, beverages and calcium-rich biscuits. Samples were divided into seven categories: children cereals (A), chocolate-flavoured milk (B), soy beverages (C), filled biscuits (D), non-filled biscuits (E), wafer biscuits (F) and corn starch biscuits (G). Mean TF concentrations ± SD (amplitude, unit µg F ml^-1 or µg F g^-1) were: (A) 4.25 ± 3.04 (0.20 - 7.84, n = 6); (B) 0.34 ± 0.47 (0.05-1.27, n = 6); (C) 0.15 ± 0.07 (0.09-0.29, n = 8); (D) 8.44 ± 1.76 (7.65-10.47, n = 4); (E) 12.41 ± 1.15 (10.69-13.68, n = 4); (F) 0.35 ± 0 (0.34-0.36, n = 4) and (G) 7.77 ± 1.12 (6.86-8.68, n = 2). Five samples of cereals, one sample of chocolate-flavoured milk and 10 samples of biscuits were analysed for SF. In cereals analysed for SF, all fluoride was soluble, while for the chocolate-flavoured milk, approximately 50% of TF was soluble. Regarding the biscuits analysed for SF approximately 20% of TF was soluble. It was observed that some of the cereals and beverages, and most of the biscuits analysed, might be important contributors to total daily fluoride intake. When consumed just once per day, cereals and beverages might supply up to 25% of the maximum recommended daily fluoride intake (0.07 mg F kg^-1 body weight) for a 2-year-old child (12 kg). For the filled, non-filled and corn starch biscuits, when 3, 32 or 20 units of them, respectively, are consumed just once per day, they may supply up to 16% of the maximum recommended daily fluoride intake. However, only approximately 25% of fluoride absorption occurs from the stomach and 75% from the small intestine. Therefore, a higher fluoride bioavailability is possible.     

Comparison of PCDD/F and dl-PCB levels in Turkish foodstuffs: industrial versus rural,local versus supermarket products,and assessment of dietary intake

Polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) and dioxin-like and non-dioxin-like (indicator) polychlorinated biphenyls (PCBs) were monitored in various foodstuffs of animal origin and edible oil samples obtained from two different cities in Turkey both rural and industrial. Total dioxin+dioxin-like PCBs and indicator PCB concentrations of pooled samples ranged 0.20–4.19 pg World Health Organization-Toxic Equivalency (WHO-TEQ)₍₁₉₉₈₎/g fat and 57.2–1710 pg/g fat, respectively. The dominant congeners were 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD, 2,3,7,8-TCDD and PCB126. Dietary intake of dioxin+dioxin-like PCBs and indicator PCBs from fish, dairy products, edible oil, egg and meat was 0.509 pg WHO-TEQ₁₉₉₈/kg bw (body weight)/day and 839 pg/kg bw/day in Afyon and 0.588 pg WHO-TEQ₁₉₉₈/ kg bw/day and 1070 pg/kg bw/day in Kocaeli, respectively. The major contributors to total exposure were dairy products and fish. Despite the unexplained high contamination level in an individual egg sample from Kocaeli, average concentration levels in Turkey, even in industrialized regions, were low compared to reported concentrations in Western Europe. Exposure levels were well below the tolerable daily intake (TDI) of 2 pg WHO-TEQ₁₉₉₈/kg body weight.     

Market Survey and Risk Assessment for Trace Metals in Edible Fungi and the Substrate Role in Accumulation of Heavy Metals

Levels of cadmium (Cd), arsenic (As), mercury (Hg), lead (Pb), iron (Fe), and zinc (Zn) were investigated in 285 samples of 9 species of edible fungi (Lentinus edodes, Auricularia auricula, Pleurotus ostreatus, Tremella fuciformis, Flammulina velutipes, Agrocybe chaxinggu, Armillaria mellea, Agaricus bisporus, and Pholiota nameko), which were collected from markets in Beijing, China. In addition, edible fungi and culture substrates were collected from 7 cultivation bases to examine the role of the substrate in trace metal accumulation. Trace metal concentrations were determined on a dry weight basis. Data showed that all the edible fungi contained trace metals, the levels of which varied among species, and there were significant positive correlations between trace metal (Cd, Pb, and As) concentrations in mushrooms and their substrates. The concentrations of Cd, As, Hg, Pb, Fe, and Zn in the tested fungi ranged from 0.005 to 13.8 mg/kg, nd to 1.62 mg/kg, nd to 0.506 mg/kg, 0.011 to 22.1 mg/kg, 46.3 to 2514 mg/kg, and 14.6 to 289 mg/kg, respectively. In general, concentrations of Cd, As, Hg, Pb, Fe, and Zn were relatively high in L. edodes, whereas Tremella fuciformis and P. nameko had relatively low levels of trace metals. Furthermore, the estimated weekly intake of trace metals was calculated and compared with the WHO/FAO provisional tolerable weekly intake. The estimated weekly intake of Cd, As, Hg, Pb, Fe, and Zn from consuming edible fungi was lower than the provisional tolerable weekly intake.     

A hierarchical Bayesian approach for risk assessment of melamine in infant formula based on cases of related nephrolithiasis in children

Although the 2008 outbreak of nephrolithiasis in children due to melamine-contaminated infant formula has subsided, it remains uncertain whether the present tolerable daily intake (TDI) of melamine provides sufficient protection for young children. To conduct a safety assessment for melamine in infant formula, we established a dose–response relationship based on 13 nephrolithiasis cases selected from 932 children, all of whom were under 5 years of age and had potentially been exposed to contaminated milk in China or Taiwan. According to the children's exposure history, distributions of individual daily melamine intake (mg/kg?BW/day) were reconstructed using Monte Carlo simulations to account for uncertainties in exposure duration and melamine concentrations in the contaminated milk. Based on the simulated individual average daily intake (AVDI) of melamine, subjects were further classified into four separate AVDI groups: high, medium, low and a reference group. A statistical logistic model was then fitted for the dose–response relationship between nephrolithiasis incidence and daily melamine intakes using Markov chain Monte Carlo (MCMC) simulations. Based on the background exposure, spontaneous rate, and mode of action (MOA) of nephrolithiasis in children, the simulated lower bounds of the 95% CIs daily melamine intake ranged from 0.008 to 0.03?mg/kg?BW/day corresponding to an additional risks of 0.1% is proposed as a plausible TDI, which is approximately an order lower than the current WHO-suggested TDI level of 0.2?mg/kg?BW/day. More stringent regulations on melamine levels in infant formula should be considered to protect young children fully.