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Food Additives & Contaminants: Part B: Surveillance Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tfab20

Aluminium in food and daily dietary intake estimate in Greece a

b

a

Sotirios M. Bratakos , Andriana E. Lazou , Michael S. Bratakos & Evangelos S. Lazos

c

a

Laboratory of Food Analysis, Department of Food Technology , Technological Educational Institute of Athens , Egaleo b

Laboratory of Process Analysis and Design, School of Chemical Engineering , National Technical University of Athens c

Laboratory of Food Processing, Department of Food Technology , Technological Educational Institute of Athens , Greece Accepted author version posted online: 11 Jan 2012.Published online: 01 Mar 2012.

To cite this article: Sotirios M. Bratakos , Andriana E. Lazou , Michael S. Bratakos & Evangelos S. Lazos (2012) Aluminium in food and daily dietary intake estimate in Greece, Food Additives & Contaminants: Part B: Surveillance, 5:1, 33-44, DOI: 10.1080/19393210.2012.656289 To link to this article: http://dx.doi.org/10.1080/19393210.2012.656289

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Food Additives and Contaminants: Part B Vol. 5, No. 1, March 2012, 33–44

Aluminium in food and daily dietary intake estimate in Greece Sotirios M. Bratakosa, Andriana E. Lazoub, Michael S. Bratakosa and Evangelos S. Lazosc* a

Laboratory of Food Analysis, Department of Food Technology, Technological Educational Institute of Athens, Egaleo; Laboratory of Process Analysis and Design, School of Chemical Engineering, National Technical University of Athens; c Laboratory of Food Processing, Department of Food Technology, Technological Educational Institute of Athens, Greece b

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(Received 3 September 2011; final version received 7 January 2012) Aluminium content of foods, as well as dietary aluminium intake of the Greek adult population, was determined using graphite furnace atomic absorption spectroscopy after microwave sample digestion and food consumption data. Al content ranged from 0.02 to 741.2 mg kg1, with spices, high-spice foods, cereal products, vegetables and pulses found to be high in Al. Differences in aluminium content were found between different food classes from Greece and those from some other countries. Aluminium intake of Greeks is 3.7 mg/day based on DAFNE Food Availability Databank, which uses data from the Household Budget Surveys. On the other hand, according to the per capita food consumption data collected by both national and international organisations, Al intake is 6.4 mg day1. Greek adult population has an Al intake lower than the Provisional Tolerable Weekly Intake of 7 mg kg1 body weight established by EFSA. Cereals and vegetables are the main Al contributors, providing 72.4% of daily intake. Keywords: aluminium; daily intake; foods; GFAAS

Introduction Aluminium is the most abundant metal in the earth’s crust, and hence environmental exposure to Al is unavoidable. Though no biological function had been attributed to the element, many researchers have reported that aluminium can produce toxicity to the central nervous, skeletal and hematopoietic systems, and it controversially was implicated in Alzheimer’s disease (Sjo¨gren et al. 2007; EFSA 2008). Aluminium in the food supply comes from natural sources, water used in food preparation, food ingredients and utensils used during food preparation. The primary dietary source of Al is foods and beverages, naturally existing or intentionally added (Pennington 1988; Greger 2007; EFSA 2008). Drinking water though consumed in large quantities is not considered as a serious Al contributor (WHO 1997). Aluminium leaching from Al cookware has been regarded as a serious source of Al, characterising them hazardous and/or as very serious contributors leading to high Al levels, and it has been advised not to use them especially with acidic foods (Scancar et al. 2004). However, several studies appeared reporting that Al cookware, aluminium cans, trays and Al foils are safe for cooking and as packaging materials (Ranau et al. 2001; WHO 2003). Cereals and cereal products, vegetables and beverages appeared to be among the highest Al contributors, *Corresponding author. Email: [email protected] ISSN 1939–3210 print/ISSN 1939–3229 online  2012 Taylor & Francis http://dx.doi.org/10.1080/19393210.2012.656289 http://www.tandfonline.com

while tea and some herbs and spices contain particularly high levels (Rao 1994; Cabrera et al. 2003; Fung et al. 2009). In contrast, Biego et al. (1998) reported as main Al sources milk and dairy products followed by fish and crustaceans. Other reports denote that the major dietary aluminium sources include products containing aluminium additives (grain products, processed cheese and salt), as well as several products that are naturally high in aluminium (tea, herbs and spices) (Pennington 1988; Lo´pez et al. 2000; Saiyed and Yokel 2005). Human exposure to Al through the diet and the environment has been reported to be in the range of 1 to 100 mg, whereas the daily Al dietary intake for adults has been reported to vary from 1.9 to 13 mg day1 among populations in various countries (WHO 1997). In European countries, the average dietary exposure has been estimated to be between 1.6 and 13 mg day1 from food. This range corresponds to a dietary exposure from 0.2 to 1.5 mg per kg body weight per week in a 60-kg adult (EFSA 2008). In the United States, the average daily Al intake was typically 5–10 mg (Pennington and Schoen 1995). The World Health Organisation considered that humans consumed about 30 mg of Al per day on average, through water, foods and medicines, while under certain circumstances the daily intake from food can be much higher than this average value. The Joint

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FAO/WHO Expert Committee on Food Additives has established the Provisional Tolerable Weekly Intake of 7 mg per kg body weight, which is equivalent to 60 mg day1 for an adult human (WHO 2003; EFSA 2008). It should be noted that large variations in mean dietary exposure were found among the different countries and, within a country, between different surveys. This is due to the methodology followed as well as to differences in living areas, individual dietary patterns and consumption of foods with aluminiumcontaining food additives. As some of the earlier data on the aluminium content of foods was erroneously high because of the methods used or contamination in the laboratory, graphite furnace atomic absorption spectrometry (GF AAS) could be suitable for Al determination in foods matrices. Virtually no information is available on aluminium concentration in foods in Greece. Therefore, the daily aluminium intake by Greeks is not known. The objective of this study was to determine the aluminium level in Greek foods. This information is important for assessment of the daily intake of aluminium by Greeks and will help in the development of a database on aluminium content of foods.

Materials and methods Glassware and reagents All chemicals used were of analytical and/or for AAS reagent grade. The aluminium stock solutions were prepared from Titrisol concentrates from Merck (Darmstadt, Germany). From the stock solution, standard Al solutions were prepared by dilution using 0.2% v/v nitric acid. Standard solutions were prepared with double-distilled, deionised water (DDW). DDW was also used in solution and sample preparation. To avoid contamination from detergents or other sources, all glassware and polyethylene material was treated with a 50% (v/v) HNO3 solution for 24 h and afterwards rinsed with DDW. Exhaustive cleaning of glassware material and the use of quartz, polystyrene, polyethylene and Teflon materials was very important. The digestion vessels were cleaned as the other containers. Cleaned items were stored and capped to avoid contamination from the environment.

originated from all over Greece and therefore probably representative of Greece. In addition, it should be noted that half of the population of Greece is concentrated in the Athens area. For each food item, sampling was made following international standards (Morawicki 2010) and in quantities determined by the Greek Codex of Food and Beverages (GCSL 2009). All samples were transferred to the laboratory and, depending on their nature, either were promptly analysed or were kept under refrigeration (cold or frozen at  18 C) in double polyethylene bags. Only the edible portion of foods was analysed. Vegetables were rinsed with water and stones were removed. All vegetables, fruits and cereal products were homogenised in a stainless steel blender. The meat and fish samples were freed from skin, bones and other parts not normally eaten and passed through a stainless steel grinder. Sweets and other confectionery products were homogenised by blending. All foods were processed until a uniform product was obtained. After homogenisation, samples were placed in double polyethylene bags and aliquots were removed by a plastic spoon and knife for further analysis.

Sample mineralisation Sample mineralisation was performed using a microwave acid digestion bomb (Milestone 1200 programmable, equipped with the ACM-100 automatic capping module and Teflon high-pressure vessels; Milestone, Germany). A portion of 0.2 g of the homogenised sample were weighed and transferred into digestion vessels in triplicate. To each portion, 2 mL of concentrated nitric acid, 0.5 mL of hydrogen peroxide and 1 mL of DDW were added. The microwave heating program was applied in eight steps at power/time (W/ min): 180/3, 360/3, 600/3, 0/3, 600/3, 360/3, 180/3 and 0/2. After cooling, the pressure within the digestion vessel was vented into the hood. The rupture disk, used as an inner cap, was removed very carefully, and any condensate was recombined with the resulting digest into a quartz volumetric flask. The sample digests were diluted with DDW to 20 mL. The resulting solutions therefore contained 12% (v/v) nitric acid. Digestion blanks were also prepared following the same procedure.

Aluminium determination Sampling and sample preparation The samples of food were purchased from retail stores in the Athens region. The foods chosen to perform aluminium analysis were selected on the basis of consumption data of the Hellenic Ministry of Rural Development & Foods and of the Ministry of Development. Care was taken to ensure the foods

Aluminium was determined by ETA-AAS. Samples were analysed using a Perkin-Elmer Model 3030 atomic absorption spectrometer equipped with a deuterium-lamp background corrector, an HGA-600 graphite furnace and an AS-60 autosampler. Analyses were carried out using platforms inserted into pyrolytically coated graphite tubes, and measurements

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Food Additives and Contaminants: Part B (integrated absorbance peak areas) were made by using a single-element, hollow cathode lamp. Time and temperature programs for drying, mineralisation and atomisation in the graphite furnace were assayed for a sample volume of 20 mL (Table 1). Three types of quality control samples were analysed to check the overall procedure, namely, standard reference materials Bovine Liver 1577 a and Rice flour (NIST), recoveries of aluminium added to various food samples and repeated aluminium content determination of composite samples for several food categories. The entire procedure was also carried out for all quality control samples, containing the same amount of acids and other reagents. The limit of detection (LOD) was calculated following IUPAC rules. The equation for the calibration graph was Abs ¼ 3.08  103 (Conc) þ 2.2  103 [Al, ng mL1] [r ¼ 0.9973]. The LOD was 4.03 pg (sy/x ¼ 0.004137, 3  sy/x ¼ 0.01241). The sensitivity was also checked, expressed as the amount of analyte that causes an analytical signal of 0.0044 units of absorbance.

Estimation of aluminium intake Aluminium was analysed in 170 different foods (805 samples). Per capita food consumption data used in this study were obtained by Trichopoulou and Efstathiades (1986) and Trichopoulou and Vassilakou (1995) for the years 1961–1970, 1971–1980 and 1981– 1990, respectively, by the DAFNE Food Availability Databank (http://www.hhf-greece.gr/dafnesoftweb/ Main.aspx?type ¼ multi), and by data published by Hellenic Ministry of Rural Development & Food, Eurostat, FAOSTAT data, CBI Market Information Database, FAO and Centre of Entrepreneurial and Technological Development of Epirus (KETA EPIRUS) for various food classes. In the DAFNE network, data were collected using household budget surveys, and food availability per person per day was calculated by dividing the household availability by the product of the referent time period and the mean household size (Trichopoulou and Naska 2003). An underestimation of the amount of food consumed by a Greek adult could be expected as it includes foods eaten at home while it is difficult to estimate foods consumed in restaurants and canteens. However, this survey is the most representative Greek food consumption study. Foods selected representing the same food categories were aggregated into the main food groups using the same aggregation used in the DAFNE household budget survey. The Al intake was determined by multiplying the consumption of each food by the mean Al concentration in that food item and by summing the results for all food items. The mean element levels were used in the intake calculations, because in general at an

Table 1. Instrumental conditions for aluminium determination in foods by GFAAS. Temperature-time program for graphite furnace

Step 1 2 3 4 5 6 7

(Dry)

(Ash) (Atomise) (Clean)

Temperature ( C)

Ramp time (s)

Hold time (s)

Argon flow rate (mL min1)

80 130 500 550 1100 2500 2650

5 15 10 10 10 0 1

20 10 10 10 20 4 5

300 300 300 300 300 0 300

Notes: Wavelength 309.3 nm; slit width 0.7 nm; lamp intensity 25 mA; deuterium background correction; integration time 5 s; matrix modifier 50 mg Mg(NO3)2; sample volume 20 mL; matrix modifier volume 10 mL.

international level this methodology is recognised as giving an appropriate estimate of the long-term exposure and is considered to be relevant when exposures are compared with TWI. The intake is expressed in milligrams per adult per day.

Results and discussion Quality assurance GFAAS is a useful method for Al determination in food samples after mineralisation. Microwave digestion is an advantageous mineralisation technique in terms of rapidness and completeness, and without analyte loss or contamination. The reliability of the procedure was checked by analysing the certified reference materials Rice flour 1568 a and Bovine Liver 1577 a. Values determined were close to certified values. Trueness determination, based on CRMs, ranged from 87% to 102% (Table 2). Accuracy and precision were evaluated by performing determinations on six different samples of various foods (Table 3). The average recovery result of 95.6% for spiked samples and percent relative standard deviations between replicates from 3.4% to 6.5% show that GF-AAS is an acceptable reference method for determining total Al in virtually all food sample matrices.

Aluminium content of foods Total aluminium content for various Greek foods is given in the database. A summary is shown in Table 4. High aluminium concentrations were detected in spices, spicy and aromatic herb foods, certain cereal products, vegetables and pulses. Among fresh meats, beef and chicken contained the highest aluminium

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Table 2. Trueness of aluminium in reference materials. Material

Number

Certified value (mg g1)

Measured value (mg g1)

Trueness (%)

Rice flour 1568a Bovine liver 1577a

8 8

4.4  1.0 2.0

4.60  0.20 2.15  0.18

95 93

Element Aluminium Aluminium

Note: aComposites. Table 3. Recovery and repeatability of aluminium in various food samples. Replication

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Recovery Food sample

n

Added (mg kg1)

Measured (mg kg1)

Recovered (%)

Food sample

n

Mean  SD (mg kg1)

RSD (%)

Carrot

3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3

– 0.030 0.050 – 0.030 0.050 – 0.030 0.050 – 5 10 – 5 10 – 5 10

0.248 0.277 0.299 0.092 0.121 0.142 0.073 0.104 0.122 3.80 8.35 12.98 3.06 7.54 12.36 17.31 26.42 36.28

– 96 102 – 97 100 – 103 98 – 91 91.8 – 89.6 93 – 91.2 95 95.6  4.29

Pasta

6

5.5  0.20

3.6

Bread rye

8

2.64  0.13

4.9

Raisin

8

7.34  0.25

3.4

Apple

7

0.140  0.006

4.2

Meat, beef

6

0.122  0.008

6.5

Orange juice

5

0.092  0.005

5.4

Orange juice Sunflower oil Crackers Almond Salt, table Total

Table 4. Aluminium contents of different food classes.

Food group Meat and meat products Meat, raw Fish and seafood Dairy and eggs (all) Milk and dairy products Cheese Eggs Cereals Pulses Vegetables Fruit Sweets and sugar Oils and fats Salads and sauces Nuts Spices Beverages (mg L1)

Mean (mg kg1)

Range (mg kg1)

1.33 0.43 0.62 1.56 0.63 2.50 0.63 7.10 11.26 2.34 0.37 3.54 0.32 2.82 4.08 157.00 0.52

0.05–10.30 0.05–1.70 0.07–2.20 0.07–5.90 0.07–1.60 0.12–5.90 0.52–0.74 1.40–42.25 5.85–18.70 0.07–41.10 0.02–2.00 0.43–11.10 0.03–0.91 0.06–7.97 0.21–8.76 2.50–741.2 0.01–5.30

levels, followed by beef steak, whereas pork, minced beef and lamb meat contained significantly lower levels. Data show that fresh meat contained very low

aluminium levels50.4 mg kg1. Especially, beef (including veal) and poultry, which are consumed in large quantities in Greece, showed aluminium contents of 1.4 and 0.4 mg kg1, respectively. Values5 10 mg kg1 have also been reported by Pennington (1988), Mu¨ller et al. (1998) and Turhan (2006), with offal, liver and kidney to be high in Al and raw poultry meats to contain more Al in breast than in leg meat. Al concentrations for carcass meat and poultry reported by FSA (2009) are in agreement with present findings. Higher aluminium concentrations were found in meat products such as sausages (2.2 mg kg1) and, particularly, the sample of pastourmas (8.4 mg kg1). This is due to the fact that many manufactures of meat products use ingredients such as salt, onion, garlic, pepper and various spices. Spices and herbs that are used as additives in Greek meat products contain high Al levels and could contribute to increased levels of aluminium, as in the case of pastourmas, which is heavily processed with herbs and paprika. Aluminium levels50.5 mg kg1 in bacon, ham and other meat products have been reported in Sweden (Jorhem and Haegglund 1992), Finland (Varo et al. 1980) and USA

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Food Additives and Contaminants: Part B (Sullivan et al. 1987). In most published works, sausages exhibited high Al value. Aluminium content in fresh fish samples were below 1.0 mg kg1 with an average value 0.62 mg kg1. Raw common seabream or red porgy (Pagrus pagrus) samples showed higher Al content (1.6 mg kg1) among fish species examined. Processed and preserved fish and seafood exhibited similar Al concentrations, with average values between 0.17 and 0.94 mg kg1 (range 0.14–1.10 mg kg1). Present results for canned fish were similar to those reported by Sullivan et al. (1987), MAFF (1993), Yang et al. (1994), Jorhem and Haegglund (1992), especially for trout and cod. Mu¨ller et al. (1998) were generally reported higher aluminium levels in fish species studied (1.2–5.5 mg kg1), as well as Yang et al. (1994) for canned fish and seafood. Seafood such as shrimp (Cragon vulgaris) and octopus (Octopus vulgaris), widely consumed in Greece as appetizers or tit bits, showed aluminium contents of about 0.7 mg kg1. It should be noted that differences could be attributed to the living environment of these organisms where a quantity of this metal may exist. Low Al levels were found in whole milk samples (0.09–0.13 mg kg1), followed by chocolate milk (0.72 mg kg1) and sweetened condensed milk (1.3 mg kg1) samples. The use of additives such as sugar and cocoa/chocolate with high Al content could explain the differences in Al concentration, whereas water removal by evaporation of milk could be responsible for higher Al concentration in such products (evaporated milk contained 0.24 mg kg1). In various yoghurt types, a 5 times higher aluminium level (0.48–1.1 mg kg1) compared to fresh milk was observed. This might be due to the type of packaging or milk or materials used during processing. Among the Greek cheeses, soft cheeses, like feta and anthotyros, had low Al levels (0.12–0.78 mg kg1), whereas the hard cheeses exhibited higher levels approaching 3.0 mg kg1 (mean 1.8 mg kg1). Similar aluminium concentrations (0.5–3.0 mg kg1) were reported for processed cheese in United Kingdom (MAFF 1993), as well as by Ayar et al. (2009). Deeb and Gomaa (2011) reported an extremely high Al concentration of 55.66  2.25 mg kg1 for feta cheese. However, they did not report if the samples analysed were real Greek feta cheese. According to the relevant EU legislation, only those cheeses produced in a traditional way in some areas of Greece and made from sheep milk, or from a mixture of sheep and goat’s milk of the same area, may bear the name ‘‘feta.’’ It should be noted that no additives are utilised in feta cheese production and the term feta has been a protected designation of origin (PDO) since July 2002. Among the most widely consumed imported cheeses in Greece are edam, emmental, gouda, regatto and semi-hard sliced cheese, with aluminium levels

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ranging from 2.8 to 5.3 mg kg1. High Al values have generally been reported for cheese varieties (Pennington 1988; Saiyed and Yokel 2005) containing aluminium additives (e.g. sodium aluminium phosphate, E541). Mu¨ller et al. (1998) have found slightly higher aluminium concentrations (3.4–6.4 mg kg1) than those found here, while Gonza´lez-Weller et al. (2010) reported similar values. Semi-hard cheese slices extensively used in Greece for toast, sandwich and home pizza preparation did not contain added Al. The aluminium content of whole hen’s eggs was between 0.52 and 0.74 mg kg1 (average 0.63  0.08 mg kg1). These values fall in the reported range (Pennington 1988), though higher values up to 2.1 mg kg1 FM have been reported by Mu¨ller et al. (1998). Aluminium concentrations in retail cereals and cereal products were generally less than 10 mg kg1, with mean 5.9 mg kg1. Higher Al values were found in toasted bread, rye rusks, oat, whole wheat bread and hard wheat flour. Various bread and pasta types, cake and cookies are of great importance for both consumed food quantity and energy intake. The average aluminium concentration of whole wheat bread, traditional village-type bread and white bread was 5.3 mg kg1, whereas rye bread exhibited a lower value of 3.6 mg kg1. Elevated levels were found in toasted bread (21.7 and 42.3 mg kg1). The high aluminium concentration in these samples could be attributed to the presence of permitted Al additives such as acid sodium aluminium phosphate (E541(i)) as a leavening agent in cereal foods and related products, and sodium aluminium silicate (E554) as an anticaking agent in cake mixes and dried products. Similar values for various cereals and cereal products originating from France (Leblanc et al. 2005), Belgium (Yang et al. 1994), Sweden (Jorhem and Haegglund 1992), United Kingdom (MAFF 1993; FSA 2009) and United States (Saiyed and Yokel 2005) have been reported in the past, whereas values near the higher of the range have been reported by Mu¨ller et al. (1998) in Germany. High Al concentrations in such products might be attributed to various added materials, such as eggs, yolk, currants, chocolate and Al additives. It should be noted that extremely high values of 238–2249 mg kg1 for various Egyptian breads have been reported by Iskander et al. (1990), due to origin, location and the use of dung as a fuel for bread baking. The content of cereal products depends on the processing applied, and hence some products contain little Al, whereas some other products had considerable amounts. Recently, Ekholm et al. (2007) reported Al levels in various flours similar to those found in the present work, though higher Al levels in rye (8.0 mg kg1) and other cereals (5.8–11.8 mg kg1) were found in the present study. Both higher and lower Al concentrations than those found in the

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present study in various rice types have been reported by Mu¨ller et al. (1998) and Leblanc et al. (2005), whereas Pennington (1988) reported that Al content in brown rice was 28 mg kg1. Pasta products (spaghetti, lasagne, macaroni and noodles) were found to contain aluminium in concentrations slightly lower than those reported by Varo et al. (1980) (510 mg kg1), Pennington (1988) (55 mg kg1) and Ekholm et al. (2007) (9 mg kg1). Biscuits, crackers and cookies were found to have aluminium levels55.0 mg kg1 with an average value of 2.7 mg kg1. Similar levels of aluminium in biscuits were reported by MAFF (1993), whereas Pennington (1988) reported aluminium concentrations 516.3 mg kg1 in biscuits and most cakes. The Greek cakes similarly contained aluminium levels of 5.5–8.0 mg kg1. It should be noted that a great variation in Al contents was observed as a result of the addition of various additives and materials such as cream, jam, eggs, fruits and chocolate (MAFF 1993; Saiyed and Yokel 2005; Gonza´lez-Weller et al. 2010). Pulses exhibited an aluminium content of about 11 mg kg1. Lentils were the most aluminium-rich pulse, with 14.8 mg kg1 (range 10.92–18.70 mg kg1). Also, white and red beans have significant concentrations of aluminium (11.5 mg kg1). Similar Al levels of 10 mg kg1 for pulses have been reported by Mu¨ller et al. (1998). Lower mean Al concentrations for chickpeas and lentils 3.99  3.04 mg kg1 have been reported by Gonza´lez-Weller et al. (2010), whereas Cabrera et al. (2003) reported much higher values of 6.50–30.20 mg kg1. It should be noted that Leblanc et al. (2005) reported quite lower Al concentration for pulses in France (1.08 mg kg1). For most vegetables, the Al concentrations were50.8 mg kg1. Sixty of the 127 samples (47%) showed mean Al levels lower than 0.5 mg kg1, 30 samples (24%) between 0.5 and 1.0 mg kg1 and 37 (29%) values between 1.0 and 5.6 mg kg1. Parsley exhibited the highest Al concentration, followed by celery and canned mushrooms. Since several plants can accumulate Al from soil, high Al concentrations could be expected in vegetables. Green beans, garlic (dried) and spinach had Al levels just above 1.0 mg kg1. Potato, another basic foodstuff, showed aluminium concentrations of 0.64 mg kg1; its concentration in potato chips was 2.3 mg kg1, due to salting and drying. Present findings were in good agreement with those reported by several workers (Pennington 1988; Jorhem and Haegglund 1992; MAFF 1993; Ysart et al. 2000). However, much higher values have been reported for vegetables in various countries (Soliman and Zikovsky 1999; Scancar et al. 2004; Leblanc et al. 2005; Gonza´lez-Weller et al. 2010). For fruits, mean Al concentrations ranged from50.05 to 1.5 mg kg1. It should be noted that 62% of the fruits had Al levels less than 0.20 mg kg1

and 32% of them less than 0.8 mg kg1. Watermelon exhibited the lowest, 0.05 mg kg1, and grapes the highest (1.46 mg kg1) Al content. Higher levels (0.7–3.6 mg kg1) have been reported by Mu¨ller et al. (1998), who in addition reported that most of the fruits investigated contained about 2.0 mg Al kg1. Soliman and Zikovsky (1999) reported values ranging from 0.4 (banana) to 9.6 (peaches) mg kg1. In France, Leblanc et al. (2005) reported mean values for fruits 0.41 mg kg1 fresh matter, and Ysart et al. (2000) in UK reported values for fresh fruit 0.57 mg kg1 and for fruit products 1.0 mg kg1 fresh weight. Al levels ranging from 5 mg kg1 dry matter in raspberry and orange juice to 32 mg kg1 in rosehip were reported by Ekholm et al. (2007) in Finland. Gonza´lez-Weller et al. (2010) reported values of 4.73  3.33 in apples and citrus, 32.80  33.05 in banana and 9.68  6.88 mg kg1 in other fruits (peaches, pears, plums). Aluminium concentrations in various sweets and sugar ranged from 0.95 to 7.43 mg kg1. Bee honey and milk and nuts chocolate contained higher mean Al levels (13.6 and 7.43 mg kg1, respectively). Three samples of white sugar showed Al concentrations between 1.03 and 2.86 mg kg1. Jam samples analysed contained Al levels ranging from 0.65 mg kg1 in peach jam to 3.21 mg kg1 in orange jam. Various pastries (containing chocolate, cocoa and cream) contained relatively high aluminium quantities, covering a range of 2.33–5.65 mg kg1. The elevated aluminium levels in confectionery products might be attributed to aluminium-containing additives and the use of aluminium utensils during their preparation and storage. Aluminium levels of fats and oils most frequently utilised in Greek kitchens ranged from 0.01 mg kg1 in corn oil to 0.54 mg kg1 in fresh butter. Olive oil, consumed in large quantities in Greece, showed aluminium content in the range of 0.45–0.91 mg kg1. Corn, cottonseed and sunflower oils showed aluminium concentrations of 0.07–0.45 mg kg1. FSA (2009) reported average Al concentrations of 0.27 mg kg1 in oils and fats. Pennington (1988), excluding the value for a cream substitute, noted aluminium concentrations for fats and oils in the range of 0.01 mg kg1 for corn oil to 8.0 mg kg1 for cream, whereas for salads and sauces values between 0.87 and 13 mg kg1. Leblanc et al. (2005) in France reported similarly low Al values in oils, butter and margarine, whereas Mu¨ller et al. (1998), Ayar et al. (2009) and Gonza´lez-Weller et al. (2010) reported much higher Al concentrations in margarine and butter. The elevated aluminium levels in these products may due to the spices and additives used in their production. Average aluminium content of nuts ranged from 0.48 to 8.76 mg kg1. Higher levels were measured in raisins (5.92–8.76 mg kg1), almonds (3.06–

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Food Additives and Contaminants: Part B 7.30 mg kg1) and hazelnuts (4.87–7.32 mg kg1). Roasted Greek pistachios, variety ‘‘Aeginis,’’ showed a mean aluminium value of 3.25  1.1 mg kg1. Generally, nuts have been proven a rich source of aluminium. Spices generally contain high amounts of minerals and trace elements, including aluminium. Oregano and black pepper contained the highest aluminium quantities (573.8  130.15 and 118.20  22.35 mg kg1, respectively). Despite the small quantities used, spices are significant sources of aluminium. Pennington (1988) has reported average aluminium content of spices and herbs ranging from less than 0.05 mg kg1 for salt to 2120.6 mg kg1 for thyme. Similarly such high Al levels in herbs and spices (up to 300 and 1000 mg kg1 Al, respectively) have been reported by Mu¨ller et al. (1998) and Lo´pez et al. (2000). Aluminium values for fresh and processed juice ranged from 0.03 to 0.14 mg L1, except for the fruit juice mix which showed a mean value of 0.32  0.14 mg L1. Soft drinks showed Al concentrations in the range of 0.04 to 0.12 mg L1. It was found that products packaged in aluminium cans contain 2 to 2.5 times higher Al levels. Higher mean Al concentrations in carbonated drinks and noncarbonated drinks have been reported by Gonza´lez-Weller et al. (2010), Ysart et al. (2000) and Pennington (1988), whereas Mu¨ller et al. (1998) reported values 50.7 mg Al L1 in refreshing drinks and beer. It should be noted that fruit raw material and juice processing and packaging must have an influence on Al levels. Coffee and tea infusion showed Al levels of 0.32  0.12 and 3.80  1.2 mg L1, respectively. Though Al concentrations have been reported (Pennington 1988; Mu¨ller et al. 1998) as quite high in tea leaves, the concentration in brewed tea is much lower. Fung et al. (2009) reported that tea releases 0.70–5.93 mg Al L1 during a standard infusion period. In addition, Verı´ ssimo and Gomes (2008) reported a release of 0.6 mg Al L1 in canned tea in a period of 7 months; in the case of dented canned tea, the Al level increased to 9.6 mg L1. Aluminium content in table wines was higher (0.83–2.01 mg L1) than the aluminium content in beer (0.07–0.17 mg L1), ouzo (0.32–0.50 mg L1) and brandy (0.16– 0.19 mg L1). Verı´ ssimo and Gomes (2008) reported a release of 0.14 mg Al L1 in beer in a period of 7 months. In present study, results showed that beer in aluminium cans contained on average 1.5 times more Al than in bottled beer. Tap and bottled water were found to contain very low concentrations of aluminium (0.01–0.04 mg L1). None of the samples tested exceeded the EU standard of 0.20 mg L1 as well as the JECFA provisional tolerable weekly intake (PTWI) guideline value of 0.9 mg L1 (rounded value), based on an allocation of 20% of the PTWI to drinking water and assuming a 60-kg adult drinking 2 L water per day.

39

Dietary intakes Although spices and herbs contain the highest Al concentrations, taking into account the food classes consumed by Greek population, pulses, cereal products, nuts and sweets tend to be high in aluminium, whereas fruits, oils and fats and raw meat show lower aluminium content. In Greece, according to DAFNE databank cereal products, vegetable, fruit, beverage and egg consumption decreased whereas that of fish, cheese and dairy increased (Table 5). Taking into consideration data presented by various Greek authorities and other organisations, based on statistical data on food consumption, meat, vegetable, fruit, beverage, cheese and fish consumption increased. It should be noted that some serious differences exist between the latter data and DAFNE data, as in the case of nuts. DAFNE data show that per capita nut consumption is 1.6 kg year1, while Greece is considered as the third largest producer of almonds in the EU and per capita tree nuts consumption is 17 kg year1. In addition to environmental and physiological factors, dietary intake is the most important factor. From Table 5, it is evident that the average aluminium intake of adult Greeks was 4.8, 5.5 and 5.1 mg day1 in 1961–1970, 1971–1980 and 1981–1990, respectively. The calculation of dietary intakes for these time periods was based on data concerning the mean daily availability of major food classes per capita in Greece, which were obtained from two Greek household budget surveys conducted during 1981–1982 and 1987–1988 (Trichopoulou and Efstathiades 1986; Trichopoulou and Vassilakou 1995). As some differences in per capita consumption existed between the data in DAFNE (Food Availability Databank based on Household Budget Surveys) and those presented by the Hellenic Ministry of Rural Development & Food, Eurostat, FAOSTAT data, CBI Market Information Database, FAO and Centre of Entrepreneurial and Technological Development of Epirus (KETA EPIRUS) for various food classes, aluminium intake was also calculated using the latest DAFNE data for the year 2004 and the period of 1999–2009 (Table 5). According to DAFNE data on food consumption by Greek households, the average aluminium intake of adult Greeks for the year 2004 was 3.7 mg day1, and hence a reduction in Al intake via foods could be recorded. Using consumption data reported by other authorities and organisations, for the time period of 1999–2009 the average aluminium intake of adult Greeks was 6.4 mg day1. Such differences could be found as a result of the way of per capita food consumption estimation. However, it should be noted that these values are lower compared with the Provisional Tolerable Weekly Intake of 7 mg kg1 body weight established by the Joint FAO/WHO Expert Committee on Food Additives and EFSA.

40

S.M. Bratakos et al.

Table 5. Estimated food consumption and aluminium intake in Greece, 1960–2009. Food consumption (kg/adult per year)

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Food Meat Fish Milk and milk products Cheese Eggs Cereal products Pulses Nuts Vegetables Fruit Sugar and sweets Fats and oils Beveragesd Water Total

Aluminium intake (mg/adult per year)

1961–1970a 1971–1980a 1981–1990a 2004b 1999–2009c 1961–1970 1971–1980 1981–1990 2004 1999–2009b 38.5 18.5 50.5

62.0 15.5 71.0

51.5 13.0 60.5

58 16.8 88

80.6 23 72.9

16.6 11.5 31.8

26.7 9.6 44.7

22.1 8.1 38.1

22.4 10.4 55.4

34.7 14.3 45.9

12.5 8.0 137.5 8.0 8.5 125.0 173.5 22.0 19.0 165 730

17.0 11.0 128.0 7.0 10.5 211.0 170.0 47.0 23.0 200 657

18.0 11.0 105.5 6.5 11.0 216.0 121.0 44.0 28.0 243 657

20 5 89.8 5.1 1.6 148.6 96.4 11.9 28 124.5

28.3 10.9 153 5 17 255.0 147 35 25 259 792.5

31.3 5.0 976.3 90.1 34.7 292.5 64.2 77.9 6.1 85.8 18.3 1742.1

42.5 6.9 908.8 78.8 42.8 493.7 62.9 166.4 7.4 104.0 16.4 2011.6

45.0 6.9 749.0 73.2 44.9 505.4 44.8 155.7 9.0 126.4 16.4 1845.0

50 3.2 637.6 57.4 6.5 347.7 35.7 42.1 9.0 64.7

70.7 6.9 1086.3 56.3 69.4 596.7 54.4 123.9 8.0 134.7 19.8 2322.0

1342.1

Notes: aTrichopoulou and Efstathiades (1986); Trichopoulou and Vassilakou (1995). DAFNE databank. c Eurostat, Hellenic Ministry of Rural Development & Food, FAOSTAT data, CBI Market Information Database. d Soft drinks, infusion tea and coffee, cocoa/chocolate drinks, alcoholic beverages (beer, wine, brandy, ouzo). b

Table 6. Estimation of Al dietary exposurea by the Greek adult population, 1960–2009. Dietary exposure to aluminium in mg per kg body weight per week (% contribution of total exposure) Food Meat Fish Milk and milk products Cheese Eggs Cereal products Pulses Nuts Vegetables Fruit Sugar and sweets Fats and oils Beverages Water Sum

1961–1970 0.005 0.003 0.010 0.010 0.002 0.312 0.029 0.011 0.094 0.021 0.025 0.002 0.027 0.006 0.56

(0.9) (0.6) (1.8) (1.8) (0.3) (56.1) (5.2) (2.0) (16.8) (3.7) (4.5) (0.3) (4.9) (1.0) (100)

1971–1980 0.008 0.003 0.014 0.014 0.002 0.291 0.025 0.014 0.158 0.020 0.053 0.002 0.033 0.005 0.64

(1.3) (0.5) (2.2) (2.1) (0.3) (45.2) (3.9) (2.1) (25.5) (3.1) (8.3) (0.4) (5.2) (0.8) (100)

1981–1990 0.007 0.003 0.012 0.014 0.002 0.239 0.023 0.014 0.162 0.014 0.050 0.003 0.040 0.005 0.59

(1.2) (0.4) (2.1) (2.4) (0.4) (39.7) (4.0) (2.4) (27.4) (2.4) (8.4) (0.5) (6.8) (0.9) (100)

2004 0.007 0.003 0.018 0.016 0.001 0.204 0.018 0.002 0.111 0.011 0.014 0.003 0.030

(1.6) (0.8) (4.0) (3.6) (0.2) (46.5) (4.2) (0.5) (25.4) (2.6) (3.1) (0.7) (6.8)

0.44

(100)

1999–2009 0.011 0.005 0.015 0.023 0.002 0.347 0.018 0.022 0.191 0.017 0.040 0.003 0.043 0.006 0.74

(1.5) (0.6) (2.0) (3.1) (0.3) (46.8) (2.4) (3.0) (25.7) (2.3) (5.3) (0.4) (5.8) (0.9) (100)

Note: aBased on a 60-kg adult.

According to quantitative food consumption data, the major aluminium contributors to Greek population are cereal products and vegetables corresponding to 46.7% and 25.7% of total Al intake, respectively, and to a lesser degree, beverages (5.8%) and sweets (confectionery products) (5.3%). It should be noted that tap and bottled water are not aluminium contributors as they contain low Al concentrations. Furthermore, it should be noted that the average dietary exposure to

aluminium for an adult was estimated to be 0.56, 0.64, 0.59, 0.44 and 0.74 mg per kg body weight per week, which amounted to 56, 64, 59, 44 and 74% of TWI (Table 6) for time periods of 1961–1970, 1971–1980, 1981–1990, 2004 and 1999–2009, respectively. In terms of TWI, the main dietary source of aluminium was cereal products, which contributed more than 45% of total exposure, followed by vegetables, which contributed to 25% of total exposure.

Food Additives and Contaminants: Part B

41

Table 7. Estimated dietary aluminium intake in various countries. Country Australia Canada China China, Hong Kong Finland France

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Germany

Greece Hungary India

Italy Japan Netherlands Spain (Canary) Sweden Switzerland USA

UK

Aluminium intake (mg day1)

Reference

1.6 6.17 9–12 0.60 6.7a 2.0k 4.2 2.03 1.3 (3–14 yr) 1.6 (415 yr) 7.0a 11.0c,d 8.0c,e 4.1 3.7 6.4 3.3 23 9.6–18.2i 6.6–12.5j 6.4 2.5–6.3 3.58 4.5a 3.5a 3.1b,f 10.2 13.0b,e 4.4b 2.2–8.1 8–9d 7.0e 11.8g 3.9a 2.5b,e 3.4 5.4

WHO (1997) Soliman and Zikovsky (1999) Wang et al. (1994) Wong et al. (2010) Varo et al. (1980) Ekholm et al. (2007) Biego et al. (1998) Noe¨l et al. (2003) Leblanc et al. (2005) Leblanc et al. (2005) Treier and Kluthe (1988) Treptow and Askar (1987) Treptow and Askar (1987) EFSA (2008) This study This study EFSA (2008) Rao (1994) Neelam et al. (2000) Neelam et al. (2000) Tripathi et al. (2002) Gramiccioni et al. (1996) Turconi et al. (2009) Teraoka et al. (1981) Matsuda et al. (2001) Ellen et al. (1990) Gonza´lez-Weller et al. (2010) Jorhem and Haegglund (1992) Knutti and Zimmerli (1985) Greger (2007) Pennington and Schoen (1995) Pennington and Schoen (1995) Iyengar et al. (2000) MAFF (1993) MAFF (1993) Ysart et al. (2000) FSA (2009)

Notes: aTotal Diet Study. b Duplicate diet study. c Market basket survey. d Male diets only. e Female diets only. f Mean of male and female diets. g USDIETS. i Urban population. j Rural population. k Year 2000 s, as mg/d/10 MJ.

Aluminium intake comes mainly from foods, food additives and water, as well as contamination by aluminium utensils, wrappings, containers and equipment. Although the measurements show that Al leaching occurs especially in contact with acid foods (e.g. orangeade, lemonade, cola, coffee infusion, tea infusion and beer), and leaching has been characterised as an important Al source (Verı´ ssimo and Gomes 2008; Mohammad et al. 2011), which can contribute to aluminium ingestion, the magnitude of this contribution to total Al intake is generally not of practical

importance (WHO 1997; Greger 2007; EFSA 2008). However, storage of strongly acidic or strongly salty, liquid foodstuffs in uncoated aluminium utensils should be limited in order to minimise migration. Table 7 provides information on dietary aluminium intake in several countries estimated using various methods such as total diet and duplicate diet methods, as well as consumption and compositional data. Adult daily dietary Al intake in the United Kingdom has been estimated to be 3.9 (MAFF 1993) and 3.4 mg (Ysart et al. 2000), whereas FSA (2009) reported an

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42

S.M. Bratakos et al.

increased dietary exposure to aluminium of 5.4 mg day1. In the United States, Pennington (1988) reported intakes of 9 mg day1 for teenage and adult females and 12–14 mg day1 for teenage and adult males. Furthermore, Pennington and Schoen (1995) reported aluminium exposures of adult males ranging from 8 to 9 mg day1, and that for adult females about 7 mg day1. Greger (2007) reported that most adults consume 1–10 mg Al day1 from natural sources, and that Al intake from food additives varies between 0 and 95 mg Al day1 among the North American population. In Canada, Soliman and Zikovsky (1999) reported an intake of 6.17 mg day1, a value that falls in the range reported by Greger (2007). As can be seen from this table, dietary aluminium intake by the Greek adult population based on household budget survey is similar to that in Germany (4.1 mg day1), though higher values had been reported in the past (Treptow and Askar 1987; Treier and Kluthe 1988), France (1.3–4.2 mg day1), Finland (2.0 mg day1), Italy (2.5–6.3 mg day1), Japan (3.5–4.5 mg day1), Netherlands (3.1 mg day1) and Switzerland (4.4 mg day1). Taking into account the dietary Al intake of 6.4 mg day1 estimated on the basis of per capita food consumption estimated by other authorities and organisations, it is evident that this value continues to be in the general range reported for various countries. Higher aluminium intakes have been reported in countries such as China (Wang et al. 1994; though recently a very low intake has been reported by Wong et al. 2010), India (Rao 1994; Neelam et al. 2000; Tripathi et al. 2002), Sweden (Jorhem and Haegglund 1992) and United States (Iyengar et al. 2000) (Table 7). It should be noted that the method of consumption data collection influences the accuracy of dietary exposure estimates, and this constitutes a reason for the differences found using DAFNE data and statistical data collected by other authorities. In addition, individual consumption patterns of the population are not known accurately. Hence, an underestimation of aluminium intake could be the result of using average consumption data and average aluminium concentrations of foods. Furthermore, present estimation did not include aluminium intake from other sources or food contact materials, though foods packaged in Al cans showed higher Al levels. Furthermore, it should be pointed out that the reported differences in Al intake might be partially attributed to Al content variation because of the method of its determination and the customary diets of many people in different countries, besides the method of per capita food consumption used. Moreover, it seems quite difficult for people (urban or rural population) to avoid obtain low Al amounts from diet alone (Iskander et al. 1990; Neelam et al. 2000). In addition, aluminium intake figure should include

some contribution from the Al cooking utensils, especially if acidic foods are prepared in contact with them. Contaminating aluminium due to processing, packaging or cooking may lead in an aluminium intake increase, but the real question is not the amount of aluminium in foods but the availability of the aluminium in foods and the sensitivity of some population groups to aluminium (Greger 2007). Besides this, it should be noted that Al absorption depends on the aluminium form, the presence of competing or complexing substances and pH, as well as time and concentration, which may slow and/or accelerate Al uptake and release in human body. However, it should be recognised that as Al intake could be increased because of various sources (leaching, food additives etc.) monitoring of dietary aluminium levels is needed.

Conclusions Aluminium content of Greek foods was similar to that reported for some other countries, though some differences exist. The estimated aluminium intake of 3.7 (DAFNE) and/or 6.4 mg day1 is currently regarded as lower compared with the Provisional Tolerable Weekly Intake of 7 mg kg1 body weight established by the Joint FAO/WHO Expert Committee on Food Additives and EFSA. Though spices and herbs contain the highest Al concentrations, cereal products and vegetables contribute 72.4% of the daily intake, participating with percentages of 46.7% and 25.7%, respectively. Although the number of samples of some foods examined is small, the results for the total number of 805 samples give an overall picture of the aluminium level of the Greek foods.

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