Furan in the baby-food samples purchased from the Finnish markets – Determination with SPME–GC–MS

Food Chemistry 117 (2009) 522–528

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Analytical Methods

Furan in the baby-food samples purchased from the Finnish markets – Determination with SPME–GC–MS Marika Jestoi a,*, Talvikki Järvinen a, Eila Järvenpää b, Heli Tapanainen c, Suvi Virtanen c, Kimmo Peltonen a a

Finnish Food Safety Authority (Evira), Research Department, Chemistry and Toxicology Unit, Mustialankatu 3, FI-00790 Helsinki, Finland University of Turku, Department of Biochemistry and Food Chemistry, Vatselankatu 2, FI-20014 Turku, Finland c National Institute for Health and Welfare, Nutrition Unit, P.O. Box 30, FI-00271 Helsinki, Finland b

a r t i c l e

i n f o

Article history: Received 24 September 2008 Received in revised form 20 February 2009 Accepted 12 April 2009

Keywords: Furan Baby-food Solid-phase microextraction GC–MS

a b s t r a c t A method applying solid-phase microextraction followed by gas chromatography–mass spectrometric determination was in-house validated and used to study furan concentrations in baby-food samples purchased from the Finnish markets. The validation parameters showed that the method was well applicable for the reliable analysis of furan. Furan was analysed in 21 different baby-food samples as three independent replicates. The mean levels of furan varied between 4.7 and 90.3 lg kg 1 being well in accordance with the levels reported in other studies. The mean concentrations of similar product formulas based on their ingredients were 9.2, 37.0 and 49.6 lg kg 1 for fruit-, vegetables- and meat-containing baby-foods, respectively. According to the statistical analyses, fruit-based baby-food samples had significantly lower concentrations of furan as compared to other formulas. Based on our exercise, it seems that a low margin of safety exists between the extreme worst case infant exposures and the deduced NOAEL of furan on experimental animals, particularly for a clear rodent carcinogen. Ó 2009 Elsevier Ltd. All rights reserved.

1. Introduction Chemical food safety is a topic with an increasing concern within the respective community, although due to the present risk management procedures the acute threat posed by harmful chemicals is very uncommon. Instead, more interest has been focused on the minute concentrations and consequent potential chronic symptoms. It has been postulated, that chemical contaminants found in foods (and feeds) might be aetiological factors behind several diseases (e.g. cancer), the causes of which are still greatly unknown. In addition to the environmental and agrochemical residues as well as natural toxins, contaminants produced during the food processing or storage, such as acrylamide, polycyclic aromatic hydrocarbons (PAH compounds), benzene and furan, are becoming an issue. Furan is a lipophilic contaminant, which is formed during heating process used for the manufacture of foods. Furan is an aromatic heterocyclic compound (Fig. 1) which is highly volatile with a boiling point of 31.36 °C (The Merck Index, 2006). Furan has been detected in hot-air dried, baked, fried and roasted food items, such as cereal products and coffee as well as canned or jarred prepared foods (EFSA, 2005; US FDA, 2004a; Zoller, Sager, & Reinhard, 2007). Using experimental models it has been proposed that there * Corresponding author. Tel.: +358 20 77 24431; fax: +358 20 77 24359. E-mail address: marika.jestoi@evira.fi (M. Jestoi). 0308-8146/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2009.04.029

exist multiple precursors and alternative routes for the formation of furan in foods rather that a single mechanism. Non-enzymatic browning involving reducing sugars only (Strecker degradation) or together with amino acids (Maillard reactions) has shown to produce furan and furan derivatives, the latter being important aroma compounds (Beliz, Grosch, & Schieberle, 2004). Ascorbic acid has proved to form furan through the same pyrolytic pathway than sugars even in less harsh conditions (Becalski & Seaman 2005; Limacher, Kerler, Conde-Petit, & Blank, 2007). Secondly, amino acids serine and cysteine can rearrange to form both molecular moieties needed for aldol condensation and subsequent furan formation (Perez Locas & Yaylayan, 2004). The third alternative, especially potent in prepared foods, is the formation of furan from oxidised polyunsaturated lipids, either produced via radical attack or lipoxygenase activity (Becalski & Seaman, 2005; Perez Locas & Yaylayan, 2004). However, most studies have been conducted using simple mixtures, and only few recent papers try to resolve which reactions prevail in more complicated or food systems (Limacher, Kerler, Davidek, Schmalzried, & Blank, 2008; Märk, Pollien, Lindinger, Blank, & Märk, 2006). Acute exposure effects of furan are poorly studied but can be considered of low priority as far as the food contamination is concerned. Instead, the chronic low level exposure seems to be more relevant with cancer as an endpoint. In a two-year bioassay conducted by the National Toxicology Program, furan administered by gavage to rats induced for example hepatic cholangiocarcinoma

M. Jestoi et al. / Food Chemistry 117 (2009) 522–528

O

Fig. 1. The chemical structure of furan.

and hepatocellular adenoma and carcinoma (NTP, 1993). A preliminary report from a second two-year bioassay in female mice found increased incidence and multiplicity of hepatic tumours at exposure level of 4 mg/kg bw/day exposure level (Goldsworthy et al., 2001). Furan is regarded as a possible human carcinogen (Group IIB) by the International Agency for Research on Cancer (IARC, 1995). The mode of action in furan induced carcinogenesis has two schools of thoughts: a genotoxic mode of action is supported for example by the data that metabolic activation by cytochrome P450 enzyme (CYP2E1) generates cis-2-butene-1,4-dial which has been found to irreversibly bind to proteins (Burka, Washburn, & Irwin, 1991) and nucleosides (Byrns, Predecke, & Peterson, 2002). However, genotoxic mechanism is not supported by a recently conducted in vitro and in vivo micronucleus assays (Durling, Svensson, & Abramsson-Zetterberg, 2007). Alternative hypothesises are metabolite induced cell proliferation and uncoupling of mitochondrial oxidative phosphorylation (Kedderis & Ploch, 1999; NTP, 2002). The determination of furan is very challenging due to its highly volatile nature. The most used analytical technique used to date is (automated) head-space extraction combined with gas chromatography–mass spectrometric (GC–MS) determination (e.g. Becalski et al., 2005; Hasnip, Crews, & Castle, 2006; US FDA, 2004b). Later, however, sample extraction based on solidphase microextraction (SPME) followed by GC–MS has been developed (e.g. Bianchi, Careri, Mangia, & Musci, 2006; Goldmann, Périsset, Scanlan, & Stadler, 2005). Both approaches are very convenient sample preparation techniques for head-space analyses of volatiles, as they are very simple and demand no expensive equipment for sample extraction/concentration. Both techniques also give satisfactory results, if applied correctly (Wenzl, 2008). Instead, attention should be paid to the sample storage and preparation, careful standard preparation, calibration using internal standard as well as proper quality control procedures (Wenzl, 2008). In 2007 the European Commission put out the recommendation for the monitoring of furan in different foods that have undergone heat treatment during processing. To provide competent analytical data for risk assessment, a reliable determination method is, certainly needed. The aims of this study were (i) to develop and validate an inhouse SPME–GC–MS – method for the determination of furan in baby-foods, (ii) to apply the developed method to study the concentration levels of furan in different kind of baby-food samples (fruit purées, vegetable purées and meat-containing foods) purchased from the Finnish markets, and (iii) to estimate the exposure of Finnish infants to furan based on the levels detected. 2. Materials and methods 2.1. Standards Furan (0.94 g/ml, P99%) was purchased from Fluka Chemie (Buchs, Switzerland) and deuterated furan d4 (0.99 g/ml, internal standard) was purchased from Isotec (Miamisburg, Ohio, USA). Standard solutions of 0.94 mg/ml, 0.94 and 0.094 lg/ml for furan and 1.19 mg/ml and 1.55 lg/ml for deuterated furan were prepared in methanol and stored at +4 °C.

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2.2. Chemicals Methanol was of HPLC-grade and purchased from J.T. Baker (Deventer, The Netherlands). De-ionised water was purified with a Millipore Milli-Q Plus system (Millipore, Espoo, Finland). Sodium chloride (NaCl) was of p.a (proanalysis) – grade and purchased from Merck (Darmstadt, Germany). 2.3. Samples Twenty-one different baby-food samples were purchased from the local markets in February–March 2008. The samples represented all the brands available on the markets. All brands were represented by three different product categories (if available): (i) a fruit-based, (ii) a vegetable-based and (iii) a meat–vegetable based purée packed in a glass-jar. Unfortunately, exactly corresponding samples were not available for all of the brands. The main ingredients of the baby-food samples analysed are presented in Table 1. All samples were analysed as three independent replicates originating from the same batch. The sample jars were stored unopened at +4 °C before the analysis. 2.4. Sample preparation The method used was a modification of the method of Goldmann et al. (2005). In brief, the sample was homogenised in an ice-bath, after which 2.5 g of homogenous sample was weighed into a 40 ml headspace vial (Supelco, Bellefonte, PA, USA) with a PTFE/silicone-septum. 2.5 g of ice-cold 20% NaCl was added followed by the blending of the mixture with a Polytron 1200 rodhomogenisator (Kinematica Ag, Lucerne, Switzerland). About 250 ll of MeOH and 50 ll of internal standard (deuterated furan, 1.55 lg/ml in MeOH) were added. Furan was statically extracted from the sample using SPME (CAR/PDMS-fibre, 75 lm, Supelco) at +45 °C using a magnetic stirring for 20 min. 2.5. GC–MS analysis Furan was analysed using an Agilent 6890 GC and an Agilent 5973N MS (Agilent Technologies, Palo Alto, CA, USA). The capillary column used was a 30 m  0.32 mm  20 lm HP-PLOT/Q (J&W Scientific, Folsom, CA, USA). The injection port temperature was 290 °C with injection in the splitless mode. The hold time of the injector was 1 min. Helium was used as a carrier gas with a flow rate of 2.0 ml/min. The initial GC temperature was 40 °C with a hold time of 8 min, after which the temperature was increased to 220 °C at 40 °C/min and then held for 1 min. Selected ion monitoring (SIM) was used for the detection of furan and internal standard. The ions monitored were m/z 68 and 39 and m/z 72 and 42 for furan and deuterated furan, respectively. After the extraction, the holder was removed from the head-space of the vial and the fibre immediately inserted into the injector of the GC–MS-system. The retention time of furan and deuterated furan was approximately 12.28 min. The extracted ion chromatograms for a spiked carrot-purée and a baby-food sample are presented in Fig. 2. Furan was quantified using the internal standard method. The calibration points were prepared as follows: 2.5 g of MQ-water and 2.5 g of 20% NaCl was weighed into a headspace vial. Different volumes (50–250 ll) of furan working standard solutions and a constant volume (50 ll) of internal standard working solution were added. Finally, MeOH was added to ensure that corresponding volume of solvent was added to all vials. The calibration curve covered the concentration range of 1.9–93.6 lg kg 1 furan in babyfood.

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Table 1 The different baby-food samples analysed with the ingredients and nutritional values reported by the manufacturers. All samples were analysed as three independent replicates (see text). Sample number

Manufacturer

Product

Ingredients

Protein (g/100 g)

Carbohydrates (g/ 100 g)/sugars (g/100 g)

Fat (g/ 100 g)

1

A

Carrot, water, potato

0.7

5.4/3.4

0.1

2

A

Banana, peach, water, rice flours, citron juice, vitamin C

1.1

15.2/12.1

0.01

3

A

Carrot, potato, water, bovine meat, maize oil

2.2

6.3/2.4

2.3

4 5

B B

Water, apricot, fructose, tapioca starch, vitamin C Carrot, water, potato, rice starch, rape seed oil

<0.5 0.5

15/11 7.5/2.5

<0.5 1.0

6

B

9.0/1.0

3.5

C C C

0.5 1 3

12/7 10/2 8.5/1

<0.5 1.5 3.3

10

D

Water, potato, pork meat, Apple purée, rice starch, bovine meat, onion, peas, tomato purée, wheat flours, salt Apricot, apple juice, water, mango, pineapple, tapioca starch, vitamin C Carrot, water, potato, maize, rice starch, rapeseed oil Water, potato, pork meat, carrot, peas, maize starch, onion, rapeseed oil, salt, bay, allspice Apple juice, water, apple, apricot, rice starch, vitamin C, iron

3.0

7 8 9

Carrot and potato purée Banana and peach purée Vegetables and bovine meat Apricot purée Carrot and potato purée Vegetables and meat Fruit purée Vegetable purée Meat casserole

0.2

12/6.5

0.1

11 12

D D

0.5 4

7 10

2.4 3.5

13 14 15

E E E

0.6 0.8 3.2

14/9.8 5.6 10.9

0.04 0.2 1.7

16

F

2.5

9.5/1.5

2.5

17

G

Peach, apple

0.7

11.1/8.5

0

18

G

Carrot, maize

1.1

6.2/2.2

0.7

19

G

Potato, peas, carrot, onion, water, low-fat ham, parsley

3.9

7.1/1.2

0.5

20

H

Apple, banana, water, rice flours

1.0

18.6/13.1

0.2

21

H

Carrot, water, potato, spinach, parsnip, leek

0.6

5.1/2.0

0.3

Apple and apricot purée Carrot purée Vegetables and pork meat Fruit purée Carrot purée Vegetables, rice and pork meat Organic carrot and veal meat Organic peach purée Organic carrot purée Organic vegetables and meat stew Apple and banana purée Vegetables purée

Carrot, water, rapeseed oil Water, potato, ham, carrot, peas, orange juice, rice starch, skimmed milk powder, rapeseed oil, white pepper, rosemary Apple purée, peach purée, apple juice, rice flours, vitamin C Carrot, water, rice flours Zucchini, apple juice, rice, tomato, carrot, pork meat, wheat starch, maize oil, parsley, yeast extract Water, maize, potato, carrot, veal meat, vegetable oil

2.6. Validation

3. Results

The following validation parameters were determined for the method used: specificity, recovery percent, repeatability, reproducibility, linearity, limit of detection (LOD) and limit of quantification (LOQ).

3.1. Method validation

2.7. Quality control procedures The quality control practices included the daily determination of furan concentration in a positive control sample (commercial babyfood sample) and the recovery of furan from spiked samples (selfmade carrot purée). The ion ratio (m/z 68/39) of the samples was compared to that of standards and used for further confirmation of a positive identification of furan (data not shown). 2.8. Measurement uncertainty The measurement uncertainty of the method was determined according to EURACHEM/CITAC Guidelines (2000). 2.9. Statistical analyses The results from furan analyses were subjected to statistical analyses (two-sided t-test and one-way analysis of variance (ANOVA)) using Statistix for Windows, version 7.0 (Analytical Software, Tallahassee, FL, USA). The p-values <0.05 were considered statistically significant.

The specificity of the method was determined by analysing 12 blank samples (self-made carrot purée). The analyses showed, that a signal (both at m/z 68 and 39) was recorded at the retention time of furan. Hence, the method can not be concerned as absolutely specific with respect to the common validation guidelines. The signal of blank samples was, however, taken into consideration with the calculation of LOD and LOQ (see later). According to the observations it was concluded that the method is specific for the determination of furan only when all identification parameters (detection of both ions, ion ratio corresponding to standard, correct retention time) are compatible. The repeatability was tested by analysing six replicates of spiked blank samples at three different spiking levels (Table 2). The experiment was repeated to test the in-house reproducibility. The repeatability (as well as the reproducibility) of the method was good, as the relative standard deviations (RSD) for the determinations varied between 6.3–14.3% depending on the spiking level (Table 2). The same samples were also used to determine the recovery of furan. The mean recovery was excellent, varying between 97.5% and 115.8% (depending on the spiking level). It must be noted, however, that the signal observed in the blank matrix was not taken into consideration in the calculations of recovery, which caused the mean recovery of >100% at the lowest spiking level (4.7 lg kg 1).

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a Abundance 150000

m/z 68

100000

12.28

50000 0 11.60 150000

11.80

12.00

12.20

12.40

12.60

12.80

12.40

12.60

12.80

12.40

12.60

12.80

12.40

12.60

12.80

m/z 39

100000

12.28

50000 0 11.60 150000

11.80

12.00

12.20 12.26

m/z 72

100000 50000 0 11.60 150000

11.80

12.00

12.20

m/z 42

12.26

100000 50000 0

Time-->

11.60

11.80

12.00

12.20

b Abundance 600000 400000

m/z 68 12.28

200000 0 11.60

600000

11.80

12.00

12.20

12.40

12.60

12.80

12.40

12.60

12.80

12.40

12.60

12.80

12.40

12.60

12.80

m/z 39

400000 12.28

200000 0 11.60

600000

11.80

12.00

12.20

m/z 72

400000 200000

12.26

0 11.60

600000

11.80

12.00

12.20

m/z 42

400000 200000

12.26

0

Time-->

11.60

11.80

12.00

12.20

Fig. 2. The extracted ion chromatograms for (a) a spiked carrot purée sample (28.1 lg kg

The acceptable linearity of each point of the calibration curves was tested with the method of van Trijp and Roos (1991). A toler-

1

) and (b) a baby-food sample (58.5 lg kg

1

).

ance of 100 ± 10% was accepted for the separate calibration points for good linearity. On that basis, the method can be considered as

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M. Jestoi et al. / Food Chemistry 117 (2009) 522–528

Table 2 The mean recoveries and relative standard deviations of furan determinations at three different spiking levels used. Each spiking level is represented by 12 replicates.

Mean recovery (%) RSD (%)

Spiking level 4.7 lg kg 1

Spiking level 28.1 lg kg 1

Spiking level 74.9 lg kg 1

115.8 13.2

97.5 14.3

104.7 6.3

being linear for the determination of furan in the range tested (1.9– 93.6 lg kg 1) (data not shown). LOD and LOQ for furan were calculated from the responses of the SIM signal for the ‘‘blank” matrix (n = 12). The calculated LOD (blank matrix mean response +3  standard deviation) was 1.9 lg kg 1 and the calculated LOQ (blank matrix mean response +10  standard deviation) was 4.0 lg kg 1. 3.2. Measurement uncertainty The measurement uncertainty calculated based on the systematic error (spiked samples) and random error (positive control samples) of the method is 29% (at the level of 5 lg kg 1), 23% (at the level of 25 lg kg 1) and 20% (at the level of 75 lg kg 1). 3.3. Furan in the baby-food samples All samples analysed had quantifiable amounts of furan (Table 3). The highest mean concentration (90.3 lg kg 1) was determined in sample 15 (vegetables, rice and pork meat), whereas the lowest mean concentration (4.7 lg kg 1) was observed in sample 2 (banana and peach purée). The three replicates gave very comparable results, the relative standard deviations (RSD) of the three independent measurements ranging between 1.7–31.4%. In previous studies, it has been claimed that reproducibility of the quantitative analysis of food volatiles is greatly affected by the changes in individual CAR–PDMS fibres (Mestres, Sala, Mart, Busto, & Guasch, 1999; Natera Marín, Castro Mejians, Garcia Moreno, Garcia Rowe, & Garcia Barroso, 2002), but based on our data this does not apply. The statistical analyses (two-sided t-test) showed that the concentration levels measured from a positive control sample (n = 20) did

Table 3 The concentration of furan in the baby-food samples analysed. Sample 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Jar 1 (lg kg 29.3 4.4 52.2 13.4 19.2 28.1 12.9 39.8 13.7 8.2 18.1 41.2 7.7 36.2 91.8 81.0 5.3 35.6 49.9 9.0 82.8

1

)

Jar 2 (lg kg 30.0 4.6 53.1 10.0 25.6 32.4 14.4 37.9 12.3 8.6 26.0 37.3 9.9 30.2 83.8 71.4 5.9 41.0 45.9 8.9 67.8

1

)

Jar 3 (lg kg 30.3 5.1 58.5 18.8 23.1 30.3 14.9 40.4 12.3 7.6 24.6 37.3 8.1 34.0 93.8 72.1 5.4 34.5 41.0 10.3 69.7

1

)

Mean concentration (lg kg 1)

RSD (%)

29.9 4.7 54.6 14.1 22.6 30.3 14.1 39.4 12.8 8.1 22.9 38.6 8.6 33.5 90.3 74.8 5.5 37.0 45.6 9.4 73.4

1.65 7.6 6.2 31.4 14.2 7.2 7.5 3.3 6.2 6.2 18.4 5.8 13.6 9.1 4.8 7.2 5.7 9.4 9.8 8.5 11.2

not differ significantly (t-test), although two different fibres were used in parallel. However, variation may arise when using fibres originating from different batches. This kind of problems will, however, be overcome by careful quality assurance procedures used in the analytical laboratory. The use of two fibres was practical, as this increased the laboratory efficiency remarkably, when manual injections were applied. The mean concentrations of similar product formulas based on their ingredients were 9.2, 37.0 and 49.6 lg kg 1 for fruit-, vegetables- and meat-containing baby-foods, respectively.

4. Discussion The method performance parameters determined during the inhouse validation showed that the analytical method is well applicable for the reliable determination of furan in baby-foods with limit of detection and limit of quantification suitable for the purpose. The sample analyses showed RSD of less than 20% for all other samples except sample 4, although three independent replicates were analysed. This further demonstrates that the method is repeatable for the determination of furan in baby-foods, although two different fibres from the same batch were used in parallel. In addition, the low RSD values emphasise, that only minor difference in the furan concentrations occurs in the jars prepared in the same batch. We used calibration curve prepared in water in contrary to the recommendations of Wenzl (2008). This was because the standard addition method was not found suitable as the determination was accomplished manually and therefore the suggested method would have restricted the laboratory efficiency dramatically. In addition, as the recovery of furan from the spiked samples was around 100% at all spiking levels, it is unlikely, that the matrix would affect the quantitative result. Crews, Hasnip, Roberts, and Castle (2007) compared these two different quantification methods (standard addition and calibrants prepared in solvent) and found that they both provide nearly identical results and suggested that the relative partitioning of furan and deuterated furan is not significantly affected by the nature of the sample matrix. Additionally, Limacher et al. (2007) used calibrants diluted to water to perform a reliable quantitative analysis of furan in vegetable purée. The furan concentrations in baby-food samples from the Finnish markets of our study are well in accordance with the levels determined in other studies (Becalski et al., 2005; Bianchi et al., 2006; Morehouse, Nyman, McNeal, DiNovi, & Perfetti, 2008; US FDA, 2004a; Zoller et al., 2007). Lowest concentrations have typically been found in fruit-based purées and juices, and highest in meatcontaining baby-foods. However, Zoller et al. (2007) reported low concentrations of furan (3–6 lg kg 1) in the meat-containing baby-foods, but it is noteworthy that these samples did not contain vegetables. US FDA (2004a) internet database is rather extensive, and data from years 2004–05 shows furan concentrations in fruit-based baby-foods below 8 lg kg 1, vegetables and mixed vegetables up to 112 lg kg 1 and meat containing mixed baby and toddler foods up to 90 lg kg 1. It must be noted, however, that all samples in our study represent baby-foods prepared by autoclaving in glass jars, which has been suggested to favour furan formation over other technologies used for commercial baby-food preparation and domestic practises (Roberts, Crews, Grundy, Mills, & Matthews, 2008; US FDA, 2004a; Zoller et al., 2007). Statistical analyses (ANOVA) showed that furan concentrations in baby-food samples were not significantly affected by the agricultural practise (organic/conventional) or the manufacturer whereas a significant difference was found between the recipes: the fruit-based products had significantly lower concentrations of furan as compared to vegetable- or meat-based products. As dis-

M. Jestoi et al. / Food Chemistry 117 (2009) 522–528

cussed above, same tendency has been obtained in other studies. It must be noticed that the fruit-based products with added ascorbic acid contain also organic acids. It has been reported that the formation of furan from sugars or ascorbic acid is less likely at low pH (Becalski & Seaman, 2005; Limacher et al. 2008), although Fan, Huang, and Sokorai (2008) have recently reported completely opposite findings. So it seems that the effect of pH on the formation of furan is much more complex than what has been previously suggested. Apparently preparation of autoclaved baby-food does not include process conditions of low water activity at high temperatures typical for non-enzymatic browning reactions to occur, thus more likely furan is formed through other mechanisms than Strecker degradation or Maillard reaction. Although not directly confirmed in our study, it is possible to speculate, that most potential precursors for furan in such baby-foods are polyunsaturated lipids such as polyunsaturated fatty acids and carotenoids (Becalski & Seaman, 2005; Perez Locas & Yaylayan, 2004). This is also supported by the findings of Limacher et al. (2008) and Fan et al. (2008). Based on the EFSA database on the occurrence of furan in babyfoods the concentration levels ranged from nondetectable to 112 lg kg 1 (EFSA, 2005). In our exercise the levels are well in agreement with those figures ranging from 4.7 to 90.3 lg kg 1. A consumption of 195 g/day of baby-foods (ready-to-eat or -drink) in Germany is reported (Kersting, Alexy, Sichhert-Hellert, Manz, & Schöch, 1998) which is somewhat higher than the corresponding Finnish value of 172 g/day for industrial baby-foods (Tapanainen & Virtanen, unpublished data). By using the EFSA database the German consumption level result to the exposure which range from less than 0.03 lg kg 1 bw/day to 2.9 lg kg 1 bw/day (EFSA, 2005) assuming a body weight of 7.5 kg for a 6 months old baby (Scientific Committee for Food, 1993). If we apply the mean Finnish consumption figure (172 g/day) to our data, the furan intakes in Finnish infants range from 0.8 to 15.5 lg/day resulting to exposures of 0.1 lg kg 1 bw/day and 2.1 lg kg 1 bw/day, respectively. Two extreme worst case scenarios can, however, be deduced from our data: (i) the maximum value in consumption of canned babyfoods (883 g/day) (Tapanainen & Virtanen, unpublished data) and the maximum concentration of furan detected (90.3 lg kg 1) and (ii) 95 percentile consumption of canned baby-foods (384 g/day) (Tapanainen & Virtanen, unpublished data) and the maximum concentration of furan detected (90.3 lg kg 1). These two extreme worst case scenarios gave intakes of 79.7 and 34.7 lg, respectively. National Research Council deduced as a compromise value for no observable adverse effect level (NOAEL) of furan 0.08 mg kg 1 bw/day from the lowest observed adverse effect level (LOAEL) in gavaged rats of 2 mg kg 1 bw/day by applying the benchmark dose rate as well as safety-factor approaches (NRC, 2000). If the margin of safety (MOS) is calculated by using the deduced NOAEL of 0.08 mg kg 1 bw/day (600 lg/day for 7.5 kg baby) and the extreme worst case exposure scenarios of Finnish infants, the MOS values of 7.5 and 17.3 can be derived. In the case of low exposure scenario (mean consumption of 172 g/day and furan concentration of 4.7 lg kg 1) the MOS value is 750, respectively. Based on our exercise, it seems that a low margin of safety exists between the extreme worst case infant exposures and the deduced NOAEL on experimental animals, particularly for a clear rodent carcinogen. That conclusion is in line with the conclusion EFSA (2005) derived. However, a significant reduction to the exposure scenarios is provided by the fact that at least in Finland the use of fruit-based baby-foods with low furan content (as observed in our study) is comprising a substantial proportion (mean consumption 78 g/ day, maximum consumption 488 g/day and 95 percentile consumption 197 g/day) (Tapanainen & Virtanen, unpublished data) of the consumption of total industrial baby-foods. Additionally, although a rising cancer trend among children in various organs/

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tissues in 15 European countries is reported due to the changes in lifestyle and exposure to a variety of cancer causing agents (Kaatsch et al., 2006), the authors did not observe any changes in the incidence of hepatic tumours, the clear target organ (cholangiocarcinoma, hepatocellular adenoma and carcinoma) of furan caused cancers in experimental animals (NTP, 1993). If additional safety precautions are hoped to avoid furan exposure, heating in an open can and applying occasional stirring is reported to considerably lower furan concentration in baby-food (Bianchi et al., 2006; Roberts et al., 2008; Zoller et al., 2007). Acknowledgements The authors want to thank Milla Rantala, Sanna Ylikarjula and Goran Šaric´ for their excellent technical assistance during the method development and Tiina Ritvanen for her assistance with the statistical analyses. References Becalski, A., Forsyth, D., Casey, V., Lau, B. P.-Y., Pepper, K., & Seaman, S. (2005). 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