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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
Colour additives in snack foods consumed by primary school children in Hong Kong a
b
b
Kris Yuet-Wan Lok , Wai-Yuen Chung , Iris F.F. Benzie & Jean Woo
a
a
Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, China b
Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hong Kong, China Published online: 17 Aug 2010.
To cite this article: Kris Yuet-Wan Lok , Wai-Yuen Chung , Iris F.F. Benzie & Jean Woo (2010) Colour additives in snack foods consumed by primary school children in Hong Kong, Food Additives & Contaminants: Part B: Surveillance, 3:3, 148-155, DOI: 10.1080/19393210.2010.509815 To link to this article: http://dx.doi.org/10.1080/19393210.2010.509815
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Food Additives and Contaminants: Part B Vol. 3, No. 3, September 2010, 148–155
Colour additives in snack foods consumed by primary school children in Hong Kong Kris Yuet-Wan Loka*, Wai-Yuen Chungb, Iris F.F. Benzieb and Jean Wooa a
Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, China; bDepartment of Health Technology and Informatics, Hong Kong Polytechnic University, Hong Kong, China
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(Received 11 February 2010; final version received 17 July 2010) The objective of the present study was to assess synthetic colours in common snack foods consumed by children and the accuracy of labelling. Dietary exposure to synthetic colours was estimated using food frequency questionnaire data obtained from primary school children in Hong Kong. The concentration of synthetic colours in food items consumed was determined by HPLC with photodiode array detection. Dietary exposure to synthetic colours for an average primary school student was considerably lower than the acceptable daily intake for their age. Estimates fell below the maximum acceptable daily intake established by the Food and Agriculture Organization/World Health Organization (FAO/WHO) and European Food Safety Authority (ESFA). However, data from HPLC analyses showed that several synthetic colours, which were labelled as being present in the food, were not detected and vice versa. Keywords: snack products; additives, general
Introduction Consumer-awareness about the contents of food is largely dependent on labelling information. However, many consumers find this information to be confusing and misleading. Therefore, there is demand for clarification of what the common terms used really mean (Bailey 2002). Additives are ingredients which are not usually regarded or used as foods themselves but which are used in or on food to affect its keeping qualities, appearance, taste, texture or to assist in processing. Providing better information about the ingredients and additives in processed food is an important public health tool. Food labelling is an important communication channel whereby consumers can obtain specific information on individual food products. However, the public is unaware of the realities of the food industry and the techniques and process that operate within it. Consumers express high levels of concern about the use of additives in food, fearing unknown long-term health problems. In particular, consumers tend to have a negative opinion of ‘‘E numbers’’ (colour additives) as these have been anecdotally linked to behavioural changes in children. The most common food colour additive discussed is tartrazine (E102), a synthetic food colorant which has been identified to provoke certain conditions such as asthma, eczema, urticaria and migraine (Rowe et al. 1994). Behavioural changes, such as hyperactivity, restlessness and sleep disturbance, are associated with the ingestion of tartrazine in
*Corresponding author. Email: [email protected] ISSN 1939–3210 print/ISSN 1939–3229 online ß 2010 Taylor & Francis DOI: 10.1080/19393210.2010.509815 http://www.informaworld.com
some children. (Metcalfe et al. 2003). A recent randomised, double blind, placebo-controlled crossover trial from the UK tested whether combinations of artificial food colours affect children’s behaviour. It was found that ingestion of seven food additives could lower a child’s IQ by up to five points (McCann et al. 2007). Evidence has shown also that children may be more susceptible than adults to certain synthetic colours, and their exposure and consumption are often greater than those of adults (Goldman 2000). Lacking local data on the levels of synthetic colours in children’s food items, dietary estimates could not be determined and the associated health risks to the local population were not clear. A study of synthetic colours in children’s snack foods was, therefore, needed to examine the situation locally. In addition, we also examined whether foods are labelled clearly, so that consumers may know precisely what they and their children are consuming. We undertook HPLC analysis of various commercial snack foods containing synthetic colours (E numbers), correlated the results with information on labels and compared typical estimated intakes in local children to the acceptable daily intake (ADI). These are based on toxicological studies on experimental animals and human clinical studies on experimental animals and human clinical studies, repeatedly determined and evaluated by Food and Agricultural Organization (FAO) and World Health Organization (WHO) (Downham et al. 2000).
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Materials and methods
Chemicals
Experimental
Tartrazine, quinoline yellow WS, sunset yellow FCF, amaranth, allura red AC, indigo carmine, lissamine green B, chromotrope FB, new coccine, hydrochloric acid, ammonium acetate and ammonium hydroxide were purchased from Sigma (Sigma-Aldrich Co, St. Louis, MO, USA); erythrosine B, acid red 1 and erioglaucine disodium from IL USA (International Laboratory Limited, San Bruno, CA, USA); acetonitrile and methanol (both HiPerSolv Chromanorm) from BDH (VWR International Ltd, Poole, UK). Water was of Milli-Q quality (18.2 M cm).
Food diary (7 day) and food frequency questionnaire (FFQ) A total of 164 children aged 8–9 years from eight primary schools in Shatin, Hong Kong, were interviewed individually. These schools were selected based on convenience. Before conducting the field survey, food items containing synthetic colours (about 300 food items) were obtained from different supermarkets in Hong Kong. These food items were grouped into nine categories: biscuits, crisps, drinks, desserts, sweets, ice cream, jam, cakes and miscellaneous snacks. Photographs of collected food items were prepared for use during the interview. The food frequency questionnaire was designed to obtain information needed for the assessment of the intake of synthetic colours in these foods by the 8–9year-old children over the course of 1 year. The questionnaire consisted of the following sections: identification, school information, parental education and income information. Child’s height and weight were measured to the nearest 0.1 cm and kg, respectively (Seca, Model 220, Germany), and an un-weighed food diary of foods consumed during 7 days (including one weekend) was kept. From the results of the FFQ, a total of 87 food items were identified as being commonly consumed by the children, and these were analyzed for their content of 11 synthetic colours (Table 1). All foods were purchased in Hong Kong, testing the same type of food items from different origins, including China, Hong Kong, Japan, Malaysia, Europe and USA. Dry food items (e.g. biscuits) were stored at room temperature until tested; perishable goods (e.g. sausage) were stored at 4 C until tested (which was within 1 week), and ice cream was stored at 20 C until tested. Each food was extracted and tested once only. Careful note was taken of synthetic colours and E labelling on the food packaging.
Table 1. Common name and E number of synthetic food colours tested. Synthetic colorants Tartrazine Quinoline Yellow WS Sunset Yellow FCF Chromotrope FB Amaranth New Coccine Erythrosine B Allura Red AC Indigo Carmine Erioglaucine Disodium Lissamine Green B
E number
Colourant classes
E102 E104 E110 E122 E123 E124 E127 E129 E132 E133 E142
Azo compound Chinophthalon derivative Azo compound Azo compound Azo compound Azo compound Xanthenes Azo compound Indigo colorants Triarylmethane group Triarylmethane group
Testing methods Purity of standards Since the synthetic dyes purchased for use as reference materials for identification and measurement were not in pure form, the dye content of each was determined as described by Walford (1980). A 0.010 g (10 mg) portion of a synthetic dye (colour standard) was accurately weighed and dissolved in 10.0 ml of water. Then, 200 ml (or a lesser but known amount for those with stronger absorption) of the solution was diluted to 10.0 ml with 0.02% w/v ammonium acetate. Each solution was then scanned and measured on a DU 730 Life Science UV–Vis spectrophotometer (Beckman Coulter Inc., Fullerton, CA, USA).
Calibration of the HPLC assay All dyes assayed were water-soluble. Standard stock solutions of concentrations from 0.5 to 2 mg ml1, depending on their absorptivity, were prepared in water. Although the HPLC conditions used were found to be able to resolve all the dyes (E142 and E133 eluted closely and could not be distinguished well) in one run, it was preferable to perform two sets of calibrations in case the sample peaks were very large and broad. E133 (maximum absorption at 628 nm) has another minor absorption near 409 nm, which is absent for E142. Therefore, when both E133 and E142 (seldom used together for efficient colour blending) are present, the simplest way is to quantify the total (E133 and E142) amount first at 635 nm (for E142) as usual, followed by re-quantifying the same sample extract again at 409 nm with E133 calibrated alone. The difference between the amounts of the sample measured at 635 and 409 nm will then be the result for E142 in the sample. This design achieved wellseparated peaks of synthetic dyes. Two sets of synthetic dyes for routine calibration were made from the standard stock solutions, with one solution containing nine synthetic dyes (E102, E110, E122, E124, E127, E129, E132 and E133) and the other containing the remaining three synthetic dyes
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(E104, E123 and E142), all in water. In this way, the calibration of the two synthetic dyes with overlapping chromatograms (E142 and E133) were separated. These two composite dye solutions, as stock solutions of mixed standards, were stored at 4 C for a maximum of 1 month. For daily calibration, another two sets of working standards were then prepared by first diluting each stock solution of mixed stock standard 1 in 10 in 0.02 M ammonium acetate, followed by further dilution with 0.02 M ammonium acetate to give two sets of calibrated solutions, each set containing five concentrations (working standard) of each synthetic dye. Finally, to each working standard, an equal volume of methanol was added so that all the standards were dissolved in a 0.02 M ammonium acetate/methanol solution (1 : 1, v/v). All these working standards were kept at 4 C and made fresh weekly. A 10 ml sample of each working standard was injected into the HPLC system.
Food sample analysis A total of 87 foodstuffs were analyzed for 11 synthetic colours (Table 1). Foods were grouped into the following categories: crisps (potato chips), biscuits, drinks, desserts, sweets, ice cream, jam, cakes and miscellaneous snacks.
Extraction of colour additives Synthetic colours from foods were extracted with a solution prepared from methanol diluted with an equal volume of 0.02 M ammonium acetate (i.e. 1 : 1, v/v) containing a few drops of 10% aqueous ammonium hydroxide. This solution, as mentioned in Limson (1986), was used to re-dissolve dried extract for HPLC injection. All measured dyes were checked and found to dissolve in the extracting solution. Solid, hard samples were ground and blended with a mini-blender (Philips, Domestic Appliances and Personal Care B.V., Drachten, The Netherlands), whereas solid, soft (jellylike) or sticky samples were just cut into small pieces. In general, 5.0 g of a sample was weighed and thoroughly vortexed for 1 min with about 10 ml of the extracting solution in a 50 ml centrifuge tube. The mixture was sonicated for 5 min, followed by 1 min vigorously manual shaking and then centrifuged for 5 min at 2500 rpm and room temperature (20 C). The top liquid layer was pipette out to a 50 ml volumetric flask. The extraction procedures were repeated three more times, unless all solids (such as sweets) had solubilised, each with 10 ml of the extracting solution. The combined extract was finally made up to 50.0 ml, mixed thoroughly and 1 ml of the final extract was taken and centrifuged for 10 min at 13,000 rpm and room temperature. Then, 50 ml of the top clear
centrifugate was identified by HPLC using photodiode array (PDA) detection. Similarly, for drinks or liquid samples, 5.0 g of sample was weighed directly into a 50 ml volumetric flask and made up to mark with the extracting solution. Then, 1 ml of the solution was centrifuged for 10 min at 13,000 rpm and room temperature; 50 ml from the top clear supernatant was injected.
Determination of extracted colour additives The HPLC system comprised a Waters Alliance 2695 Separation Module (Waters Corp., Milford, MA, USA) and a Waters 996 photo-diode Array detector (Waters Corp.). The analytical column was a Phenomenex Luna after 5 m C18(2), 250 4.6 mm column (Phenomenex, Torrance, CA, USA) guarded by a Waters Symmetry after 5 m C18, 20 3.9 mm Sentry guard column (Waters Corp.). The instruments and columns were at room temperature and a flow-rate of 1.0 ml min1, but the autosampler was set at 4 C, except for jelly-like extract where room temperature was used. Two mobile phases were used, 0.02 M ammonium acetate at pH 7.8 (solvent A) and 90% acetonitrile/10% 0.02 M ammonium acetate (v/v) at final pH 7.8 (solvent B). Table 2 showed the program for the gradient elution. The detection (Table 3) chosen for each synthetic colorant was the maximum absorption of the corresponding standard scanned by the PDA detector. Each testing sample was gradient-eluted with solvent A decreasing linearly from 85 to 57% and solvent B increasing linearly from 15 to 43% in 13 min, washed with solvent A (100%) for 2 min and finally equilibrated in the initial condition (A 85%, B 15%) for 4 min. Therefore, each run only lasted for 19 min. The detected wavelengths (nm) for E numbers were 426 (E102), 414 (E104), 482 (E110), 515 (E122), 523 (E123), 505 (E124), 530 (E127), 509 (E129), 613 (E132), 628 (E133) and 635 (E142). Studies of recovery were also attempted to assess recoveries from sampled food by spiking a solution of five typical synthetic dyes (E102, E110, E124, E129, E133) that commonly existed in the Table 2. Gradient program – 19 min per run at 1.0 ml min1. Time (min) 0 13 13.1 15.0 15.1 19.0
Solvent A (%)
Solvent B (%)
Curve
85 57 100 100 85 85
15 43 0 0 15 15
– 6 6 6 6 6
Notes: Solvent A ¼ 0.02 M ammonium acetate (pH 7.8). Solvent B ¼ 90% acetonitrile/10% 0.02 M ammonium acetate (v/v) (final pH 7.8). Curve 6 gave a linear change in solvent composition.
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Table 3. Detection of colours using PDA detector. E Number Wavelength (nm)
(a)
E102
E104
E110
E122
E123
E124
E127
E129
E132
E133
E142
426
414
483
515
523
505
530
509
613
628
635
0.20 E132
0.18
E124
0.16 0.14
E129
E102
0.12 AU
E133 E110
0.10 E122
0.08
E127
0.04 0.02 0.00 0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
11.00
12.00
13.00
14.00
Minutes
(b) 0.20 0.18 E142
0.16 0.14
E123
AU
0.12
E104
0.10 0.08 0.06 0.04 0.02 0.00 0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00 Minutes
8.00
9.00
10.00
11.00
12.00
13.00
14.00
12.00
13.00
14.00
(c) 0.35 0.30
E133
0.25 AU
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0.06
E123
0.20 0.15 0.10
E124 E102
0.05
E110
0.00 0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
11.00
Minutes
Figure 1. Overlay chromatograms of calibrators and a typical sample. The highest peak of each dye recorded at the corresponding wavelength of maximum absorption was used for calculation. (a) Eight mixed calibrators, namely E102 (2.4 min), E110 (6.2 min), E122 (10.6 min), E 124 (5.4 min), E127 (13.4 min), E129 (7.5 min), E132 (2.9 min) and E 133 (11.5 min). (b) Three mixed calibrators, namely E104 (13.0 min), E123 (2.7 min) and E 142 (11.8 min). (c) Overlay chromatogram of a sample containing E102 (2.4 min), E110 (6.2 min), E123 (2.7 min), E124 (5.3 min) and E133 (11.5 min).
samples in one low-fat (drink) and one high-fat (crisps) food. Chromatograms in Figure 1a–c showed wellresolved peaks of colours with negligible interference. All calibration curves were within linear range (Figure 2). The within CVs (%, n ¼ 6) of slope and
calibrated range were both 0.2–0.6, whereas the between-day CVs (n ¼ 6) were, respectively, 0.6–3.0 and 0.7–5.3. Percentage recoveries (n ¼ 3) in crisps (high fat) and in drink (low fat) for these five selected common dyes (0.1–0.5 mg spiked) were 79.1–94.2 and
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K. Yuet-Wan Lok et al.
98.5–106.7, respectively. In addition, the synthetic dyes in each sample were checked and confirmed with their UV spectra. All instrumental controls, data acquisition and integration used Millennium32 Version 4.00 software (Waters Corp.). Results of the samples were then calculated, using Excel, from the peak area over slope of calibration curve adjusted with appropriate dilution and/or weighing factors, wherever necessary. Finally, all the results reported were only corrected for purity percentage but not corrected for recovery percentage.
that commonly existed in the samples in one low-fat (drink) and one high-fat (crisps) food. Absolute detection limit of the detector for each dye was determined by direct injection of each aqueous standard. Detection limit of the assay for each dye was obtained from the corresponding calibration curve (y ¼ mx þ b) of the dye by multiplying the SD of the intercept (b) by 2, divided by the slope (m). Similarly, the lower limit of quantification (LOQ) of the assay was assessed by calculating 10 SD of b/m. The study was approved by the University research ethics committee (CRE-2008.020-T) and written informed consent was obtained from parents.
Precision and stability of the columns and HPLC conditions were monitored and checked from withinday and between-day CVs of slope and calibrated range obtained by repeated injections of standards for day-to-day calibration. Two sets of routine calibration were done externally by analyzing solutions serially diluted from the two mixed stock solutions. Studies of recovery were also attempted to assess recoveries from sampled food by spiking a solution of five synthetic colours (E102, E110, E124, E129, E133)
Calibration curves of dyes
1200000 1000000 Peak area (uV.s)
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Quality control
E102 E104 E110 E122 E129 E127 E133 E142 E123 E124 E132
800000 600000 400000 200000 0
0
100 200 300 400 500 Amount of dye injected (ng)
600
Figure 2. Calibration of the dyes.
Results and discussion Of 164 children (mean age 8.79 [SD 0.55] years and weight 31.79 kg [SD 8.29]) enlisted, 84 were boys and 80 were girls. Table 3 presents the concentrations of the 11 synthetic colours identified in a variety of the food items that are most commonly consumed by these children. Eighty-seven food items out of the 280 shown at interview were analyzed, i.e. about 30% of the total items, as these were found to be commonly consumed by the children. The food groups with synthetic colours frequently consumed by the children were fizzy drinks, followed by ice cream and sweets (Table 4). A total of 91% of the children frequently exposed to drinks with synthetic colours ranging 0–3685. The mean daily intake of drinks with synthetic colours was 160 ml day1. The mean intakes for ice cream were 35.1 and 30.2 ml day1 in boys and girls, respectively. Sweets were also commonly consumed by the children in this sample, with a mean intake of 15.2 g day1. However, despite the frequent intake of certain foods with synthetic colours, the mean intakes of the children were below the recommended ADI. The ADI is an estimate of the amount of a food additive, expressed on a body weight basis, which can be ingested daily over a lifetime without appreciable risk. Derivation of the ADI is
Table 4. Range of of synthetic colour concentrations (mg kg1) in various food items consumed by children in Hong Kong. Food items
E102
E104
E110
E122
E123
E124
E127
E129
E132
E133
E142
Crisps 2.7–161 – 7.1–470 – 0–1.1 – – 24.4–40 – 0.3–6 – Biscuits 7.5–9 – 0–4.5 – – 0–1.6 – 43–57 – 0–12.3 0–1.3 Drinks 3.5–14.5 – 15.9–47.6 – – 0–3.9 – – – 0–0.1 – Desserts 8.7–66.8 – 9.5–3440 – 0–77.4 – – 2.2–104 – 3–4.5 0–3.4 Sweets 8.6–69.4 3.3–12 10.1–42.3 12.3–28.8 6.7–8.3 3–56 0–1.2 11–120.4 5.1–13 0.1–5.8 – Ice cream 1.4–49.4 – 0.5–22.1 – 29.8–37.2 38.5–52.7 0–25.1 0–52.4 – 0.1–66.6 – Jam 0–6 – 0–4.4 – – – – 0–307.6 – – – Cakes 21–42.3 – 0–1.5 – – 8.6–9.8 0–1.9 – – 0–0.7 – Miscellaneous 25.2–111.2 – 3.6–35.3 – 0–5.9 – – – – 0.6–18.8 – Snacks
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100 90 Percentage distribution
80 70 60 50 40 30
27.5
24
20
16.17
13.17
10
1.8
1.2
4.19
6.59
E123
E124
2.4
1.8
1.2
0
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E102
E104
E110
E122
E127
E129
E132
E133
E142
Food colourings
Figure 3. Percentage distribution of colour food additives in the categories studied.
based upon toxicity of a food additive based on data from studies in animals and humans with the incorporation of a safety factor of 100-fold is commonly applied (Benford 2000). Results showed that several synthetic colours, which were stated as being present in the food on the label of the food sample, were not detected (contained) upon analysis and vice versa. Two of the 13 crisp products, one of the 10 dessert products, two of the nine ice cream products, seven of the 19 sweet products and four of the 12 miscellaneous snack tested did not contain a synthetic colorant but an E number was on the label. Two products detected synthetic colours (as confirmed by their ultra-violet spectra) but the label showed no E number. This could have been due to levels below detection or mislabelling of the food items by food manufacturers, which is a violation of the labelling standard of the Hong Kong authorities and warrants further investigation by the Food and Safety Centre in Hong Kong. The use of synthetic colours in foods is strictly controlled by legislation and harmonised across the European Union by formulating Directive 94/35/EU (Minioti et al. 2000). In Hong Kong, the use of synthetic colours follows the Codex Alimentarius Commission of FAO/WHO, which is currently under update. When the percentage distribution of the foods tested for synthetic colours in the various food categories was analyzed (Figure 3), it was found that tartrazine (E102) (27.5%) and sunset yellow FCF (E110) (24.0%) were the most commonly used synthetic colorants, followed by erioglaucine disodium (E133) (16.2%) and allura red AC (E129) (13.2%). Similar observations have been reported from India and Kuwait by Roa et al. (2004) and Sawaya et al. (2008), respectively.
To assess exposure to synthetic food colours, the average daily intakes of synthetic food colours among 8–9-year-old children in Hong Kong were calculated based on the average daily amounts of synthetic colored foods consumed (self-reported FFQ during interview) and the average levels of the synthetic colours in those types of foods, and dividing the result by the average body weights for each age group, males and females (Sawaya et al. 2008). Exposure estimates were compared with the corresponding acceptable daily intakes (ADIs) as set by the FAO/WHO (1999) and ESFA (2009); the average intakes of the 11 synthetic food colorants were all considerably lower than their corresponding ADIs (Table 5). This could be due to underestimation of the actual consumption level as this was only based on 87 products that were analyzed and consumed by a selected age group and district in Shatin, Hong Kong. Study of other three districts of Hong Kong is currently being conducted and results will be available in 2011.
Conclusions Dietary exposure to the 11 synthetic colours for primary school children aged 8–10 in the local area of Shatin was considerably lower than the acceptable daily intakes established by the FAO/WHO and ESFA. It is concluded that primary school children in Hong Kong were unlikely to experience major toxicological effects from synthetic colours. Foods that are responsible for most synthetic food-colour intake were mainly drinks, ice cream and sweets. Therefore, these should be set as the priority focus for food control. From the data obtained, it has been shown that several synthetic food colours, mainly tartrazine (E102) and sunset yellow FCF (E110), are widely used in the food groups commonly consumed by children in
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K. Yuet-Wan Lok et al. Table 5. Average daily intake (ADI) of permitted artificial colours among children in Shatin. Age (years) 8
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Permitted artificial colour additive Tartrazine (E102) Quinoline Yellow (E104) Sunset Yellow FCF (E110) Chromotrope FB (E122) Amaranth (E123) New Coccine (E124) Erythrosine B (E127) Acid Red 1 (E128) Allura Red AC (E129) Indigo Carmine (E132) Erioglaucine Disodium (E133) Lissamine Green B (E142)
9
ADI (mg kg1 body weight)
M
F
M
F
0–7.5 0–0.5* 0–1* 0–4 0–0.5 0–0.7* 0–0.1 0–0.1 0–7 0–5 0–12.5 0–5
0.14 0.00 0.05 0.00 0.04 0.01 0.01 0.00 0.00 0.00 0.00 0.00
0.02 0.00 0.14 0.00 0.01 0.00 0.00 0.00 0.01 0.00 0.00 0.00
0.03 0.00 0.10 0.00 0.01 0.00 0.00 0.00 0.02 0.00 0.00 0.00
0.02 0.00 0.09 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00
Notes: F, Female; M, male. ADI ¼ acceptable daily intake (FAO/WHO, 1999). *EFSA update 2009.
Shatin, Hong Kong. Several products were found with incorrect labelling. Although estimated intake of synthetic colours was considerably lower than the ADI, detailed food consumption data from populationbased studies are needed for further risk assessment.
References Bailey R. 2002. Additives and food safety. Food Sci Technol. 16:37–43. Benford D. 2000. The Acceptable Daily Intake A Tool for ensuring food safety. Washington (DC): International Life Sciences Institute (ILSI) Press. Boley NP, Bunton NG, Crosby NT, Johnson AE, Roper P, Somers L. 1980. Determination of synthetic colours in food using high-performance liquid Chromatography. Analyst. 105:589–99. Coulson N, Eiser J, Eiser C. 1996. Children’s awareness of additives in food. Health Educ J. 55:375–381. Downham A, Collins P. 2000. Colouring our foods in the next millennium. Int J Food Sci Technol. 35:5–22. EFSA 2009. European Food Safety Authority. Updates safety advice on six food colours. Press release 12 Nov 2009. Available at: http://www.esfa.europa.eu/en/press/ news/ans091112.htm. Accessed: 28 June 2010. FAO/WHO 1999. Food and Agriculture Organization/ World Health Organization. Summary of evaluation performed by the joint FAO/WHO Expert Committee on Food Additives (JECFA). Rome: FAO/WHO. E102 1964; E122 - Series 6, 1975; E123 - Series 8, 1975; E127 Series 6, 1974; E132 - Series 6, 1975; E133 - Series 46a, 1969; E142 - Series 6, 1974. Goldman RL, Koduru S. 2000. Chemicals in the environment and developmental toxicity to children: A public
health and policy perspective. Environ Health Perspect. 108:443–448. Limson AS. 1986. Separation and identification of colour additives in food in reverse phase high performance liquid chromatography. Laboratory Information Bulletin No. 3036. Los Angeles District (CA): United States Food and Drug Administration. Metcalfe DD, Sampson HA, Simon RA. 2003. Food allergy: adverse reactions to food and food additives. London: Blackwell. McCann D, Barrett A, Cooper A, Crumpler D, Dalen L, et al. 2007. Food Additives and hyperactive behavior in 3 year old and 8/9 year old children in the community: a randomised double blinded controlled, placebo controlled trial. Lancet. 370:1560–1567. Minioti KS, Sakellariou CF, Thomaidis NS. 2007. Determination of 13 synthetic food colourants in watersoluble foods by reversed-phase high-performance liquid chromatography coupled with diode-array detector. Anal Chim Acta. 538:103–110. Pascual OS. 1985. Technological aspects of the use of tartrazine. Food Technol Aust. 37:511–513. Roa P, Bhat RV, Sudershan RV, Krishna TP, Naidu N. 2004. Exposure assessment to artificial food colours of a selected population in Hyderabad, India. Food Addit Contam. 21:415–421. Rowe KS, Rowe KJ. 1994. Synthetic food colouring and behavior: a dose response effect in a double-blind, placebo controlled, repeated measures study. J Pediatr. 125:691–698. Technical Guidance Notes on Nutrition Labelling and Nutrition Claims. 2008. Centre for Food Safety, Food and Environmental Hygiene Department. Hong Kong: Government Logistics Department. Sawaya WHA, Al-Otaibi J, Al-Foudari M, Hajji A. 2008. Color additive levels in foodstuffs commonly consumed by children in Kuwait. Food Control. 19:98–105.
Food Additives and Contaminants: Part B
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Spears K, Marshall J. 1987. Qualitative analysis of artificial colourings in food. Assoc Publ Anal. 25:47–54. Walford J. 1980. Development Series: Developments in food colours. II. London: Applied Science Publishers. p. 34.
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Vachirapatama N, Mahajaroensiri J, Visessanguan W. 2008. Identification and determination of seven synthetic dyes in foodstuffs and soft drinks on monolithic C18 column by high performance liquid chromatography. J Food Drug Anal. 16:77–82.
Food Additives & Contaminants: Part B: Surveillance Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tfab20
Colour additives in snack foods consumed by primary school children in Hong Kong a
b
b
Kris Yuet-Wan Lok , Wai-Yuen Chung , Iris F.F. Benzie & Jean Woo
a
a
Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, China b
Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hong Kong, China Published online: 17 Aug 2010.
To cite this article: Kris Yuet-Wan Lok , Wai-Yuen Chung , Iris F.F. Benzie & Jean Woo (2010) Colour additives in snack foods consumed by primary school children in Hong Kong, Food Additives & Contaminants: Part B: Surveillance, 3:3, 148-155, DOI: 10.1080/19393210.2010.509815 To link to this article: http://dx.doi.org/10.1080/19393210.2010.509815
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Food Additives and Contaminants: Part B Vol. 3, No. 3, September 2010, 148–155
Colour additives in snack foods consumed by primary school children in Hong Kong Kris Yuet-Wan Loka*, Wai-Yuen Chungb, Iris F.F. Benzieb and Jean Wooa a
Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, China; bDepartment of Health Technology and Informatics, Hong Kong Polytechnic University, Hong Kong, China
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(Received 11 February 2010; final version received 17 July 2010) The objective of the present study was to assess synthetic colours in common snack foods consumed by children and the accuracy of labelling. Dietary exposure to synthetic colours was estimated using food frequency questionnaire data obtained from primary school children in Hong Kong. The concentration of synthetic colours in food items consumed was determined by HPLC with photodiode array detection. Dietary exposure to synthetic colours for an average primary school student was considerably lower than the acceptable daily intake for their age. Estimates fell below the maximum acceptable daily intake established by the Food and Agriculture Organization/World Health Organization (FAO/WHO) and European Food Safety Authority (ESFA). However, data from HPLC analyses showed that several synthetic colours, which were labelled as being present in the food, were not detected and vice versa. Keywords: snack products; additives, general
Introduction Consumer-awareness about the contents of food is largely dependent on labelling information. However, many consumers find this information to be confusing and misleading. Therefore, there is demand for clarification of what the common terms used really mean (Bailey 2002). Additives are ingredients which are not usually regarded or used as foods themselves but which are used in or on food to affect its keeping qualities, appearance, taste, texture or to assist in processing. Providing better information about the ingredients and additives in processed food is an important public health tool. Food labelling is an important communication channel whereby consumers can obtain specific information on individual food products. However, the public is unaware of the realities of the food industry and the techniques and process that operate within it. Consumers express high levels of concern about the use of additives in food, fearing unknown long-term health problems. In particular, consumers tend to have a negative opinion of ‘‘E numbers’’ (colour additives) as these have been anecdotally linked to behavioural changes in children. The most common food colour additive discussed is tartrazine (E102), a synthetic food colorant which has been identified to provoke certain conditions such as asthma, eczema, urticaria and migraine (Rowe et al. 1994). Behavioural changes, such as hyperactivity, restlessness and sleep disturbance, are associated with the ingestion of tartrazine in
*Corresponding author. Email: [email protected] ISSN 1939–3210 print/ISSN 1939–3229 online ß 2010 Taylor & Francis DOI: 10.1080/19393210.2010.509815 http://www.informaworld.com
some children. (Metcalfe et al. 2003). A recent randomised, double blind, placebo-controlled crossover trial from the UK tested whether combinations of artificial food colours affect children’s behaviour. It was found that ingestion of seven food additives could lower a child’s IQ by up to five points (McCann et al. 2007). Evidence has shown also that children may be more susceptible than adults to certain synthetic colours, and their exposure and consumption are often greater than those of adults (Goldman 2000). Lacking local data on the levels of synthetic colours in children’s food items, dietary estimates could not be determined and the associated health risks to the local population were not clear. A study of synthetic colours in children’s snack foods was, therefore, needed to examine the situation locally. In addition, we also examined whether foods are labelled clearly, so that consumers may know precisely what they and their children are consuming. We undertook HPLC analysis of various commercial snack foods containing synthetic colours (E numbers), correlated the results with information on labels and compared typical estimated intakes in local children to the acceptable daily intake (ADI). These are based on toxicological studies on experimental animals and human clinical studies on experimental animals and human clinical studies, repeatedly determined and evaluated by Food and Agricultural Organization (FAO) and World Health Organization (WHO) (Downham et al. 2000).
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Materials and methods
Chemicals
Experimental
Tartrazine, quinoline yellow WS, sunset yellow FCF, amaranth, allura red AC, indigo carmine, lissamine green B, chromotrope FB, new coccine, hydrochloric acid, ammonium acetate and ammonium hydroxide were purchased from Sigma (Sigma-Aldrich Co, St. Louis, MO, USA); erythrosine B, acid red 1 and erioglaucine disodium from IL USA (International Laboratory Limited, San Bruno, CA, USA); acetonitrile and methanol (both HiPerSolv Chromanorm) from BDH (VWR International Ltd, Poole, UK). Water was of Milli-Q quality (18.2 M cm).
Food diary (7 day) and food frequency questionnaire (FFQ) A total of 164 children aged 8–9 years from eight primary schools in Shatin, Hong Kong, were interviewed individually. These schools were selected based on convenience. Before conducting the field survey, food items containing synthetic colours (about 300 food items) were obtained from different supermarkets in Hong Kong. These food items were grouped into nine categories: biscuits, crisps, drinks, desserts, sweets, ice cream, jam, cakes and miscellaneous snacks. Photographs of collected food items were prepared for use during the interview. The food frequency questionnaire was designed to obtain information needed for the assessment of the intake of synthetic colours in these foods by the 8–9year-old children over the course of 1 year. The questionnaire consisted of the following sections: identification, school information, parental education and income information. Child’s height and weight were measured to the nearest 0.1 cm and kg, respectively (Seca, Model 220, Germany), and an un-weighed food diary of foods consumed during 7 days (including one weekend) was kept. From the results of the FFQ, a total of 87 food items were identified as being commonly consumed by the children, and these were analyzed for their content of 11 synthetic colours (Table 1). All foods were purchased in Hong Kong, testing the same type of food items from different origins, including China, Hong Kong, Japan, Malaysia, Europe and USA. Dry food items (e.g. biscuits) were stored at room temperature until tested; perishable goods (e.g. sausage) were stored at 4 C until tested (which was within 1 week), and ice cream was stored at 20 C until tested. Each food was extracted and tested once only. Careful note was taken of synthetic colours and E labelling on the food packaging.
Table 1. Common name and E number of synthetic food colours tested. Synthetic colorants Tartrazine Quinoline Yellow WS Sunset Yellow FCF Chromotrope FB Amaranth New Coccine Erythrosine B Allura Red AC Indigo Carmine Erioglaucine Disodium Lissamine Green B
E number
Colourant classes
E102 E104 E110 E122 E123 E124 E127 E129 E132 E133 E142
Azo compound Chinophthalon derivative Azo compound Azo compound Azo compound Azo compound Xanthenes Azo compound Indigo colorants Triarylmethane group Triarylmethane group
Testing methods Purity of standards Since the synthetic dyes purchased for use as reference materials for identification and measurement were not in pure form, the dye content of each was determined as described by Walford (1980). A 0.010 g (10 mg) portion of a synthetic dye (colour standard) was accurately weighed and dissolved in 10.0 ml of water. Then, 200 ml (or a lesser but known amount for those with stronger absorption) of the solution was diluted to 10.0 ml with 0.02% w/v ammonium acetate. Each solution was then scanned and measured on a DU 730 Life Science UV–Vis spectrophotometer (Beckman Coulter Inc., Fullerton, CA, USA).
Calibration of the HPLC assay All dyes assayed were water-soluble. Standard stock solutions of concentrations from 0.5 to 2 mg ml1, depending on their absorptivity, were prepared in water. Although the HPLC conditions used were found to be able to resolve all the dyes (E142 and E133 eluted closely and could not be distinguished well) in one run, it was preferable to perform two sets of calibrations in case the sample peaks were very large and broad. E133 (maximum absorption at 628 nm) has another minor absorption near 409 nm, which is absent for E142. Therefore, when both E133 and E142 (seldom used together for efficient colour blending) are present, the simplest way is to quantify the total (E133 and E142) amount first at 635 nm (for E142) as usual, followed by re-quantifying the same sample extract again at 409 nm with E133 calibrated alone. The difference between the amounts of the sample measured at 635 and 409 nm will then be the result for E142 in the sample. This design achieved wellseparated peaks of synthetic dyes. Two sets of synthetic dyes for routine calibration were made from the standard stock solutions, with one solution containing nine synthetic dyes (E102, E110, E122, E124, E127, E129, E132 and E133) and the other containing the remaining three synthetic dyes
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(E104, E123 and E142), all in water. In this way, the calibration of the two synthetic dyes with overlapping chromatograms (E142 and E133) were separated. These two composite dye solutions, as stock solutions of mixed standards, were stored at 4 C for a maximum of 1 month. For daily calibration, another two sets of working standards were then prepared by first diluting each stock solution of mixed stock standard 1 in 10 in 0.02 M ammonium acetate, followed by further dilution with 0.02 M ammonium acetate to give two sets of calibrated solutions, each set containing five concentrations (working standard) of each synthetic dye. Finally, to each working standard, an equal volume of methanol was added so that all the standards were dissolved in a 0.02 M ammonium acetate/methanol solution (1 : 1, v/v). All these working standards were kept at 4 C and made fresh weekly. A 10 ml sample of each working standard was injected into the HPLC system.
Food sample analysis A total of 87 foodstuffs were analyzed for 11 synthetic colours (Table 1). Foods were grouped into the following categories: crisps (potato chips), biscuits, drinks, desserts, sweets, ice cream, jam, cakes and miscellaneous snacks.
Extraction of colour additives Synthetic colours from foods were extracted with a solution prepared from methanol diluted with an equal volume of 0.02 M ammonium acetate (i.e. 1 : 1, v/v) containing a few drops of 10% aqueous ammonium hydroxide. This solution, as mentioned in Limson (1986), was used to re-dissolve dried extract for HPLC injection. All measured dyes were checked and found to dissolve in the extracting solution. Solid, hard samples were ground and blended with a mini-blender (Philips, Domestic Appliances and Personal Care B.V., Drachten, The Netherlands), whereas solid, soft (jellylike) or sticky samples were just cut into small pieces. In general, 5.0 g of a sample was weighed and thoroughly vortexed for 1 min with about 10 ml of the extracting solution in a 50 ml centrifuge tube. The mixture was sonicated for 5 min, followed by 1 min vigorously manual shaking and then centrifuged for 5 min at 2500 rpm and room temperature (20 C). The top liquid layer was pipette out to a 50 ml volumetric flask. The extraction procedures were repeated three more times, unless all solids (such as sweets) had solubilised, each with 10 ml of the extracting solution. The combined extract was finally made up to 50.0 ml, mixed thoroughly and 1 ml of the final extract was taken and centrifuged for 10 min at 13,000 rpm and room temperature. Then, 50 ml of the top clear
centrifugate was identified by HPLC using photodiode array (PDA) detection. Similarly, for drinks or liquid samples, 5.0 g of sample was weighed directly into a 50 ml volumetric flask and made up to mark with the extracting solution. Then, 1 ml of the solution was centrifuged for 10 min at 13,000 rpm and room temperature; 50 ml from the top clear supernatant was injected.
Determination of extracted colour additives The HPLC system comprised a Waters Alliance 2695 Separation Module (Waters Corp., Milford, MA, USA) and a Waters 996 photo-diode Array detector (Waters Corp.). The analytical column was a Phenomenex Luna after 5 m C18(2), 250 4.6 mm column (Phenomenex, Torrance, CA, USA) guarded by a Waters Symmetry after 5 m C18, 20 3.9 mm Sentry guard column (Waters Corp.). The instruments and columns were at room temperature and a flow-rate of 1.0 ml min1, but the autosampler was set at 4 C, except for jelly-like extract where room temperature was used. Two mobile phases were used, 0.02 M ammonium acetate at pH 7.8 (solvent A) and 90% acetonitrile/10% 0.02 M ammonium acetate (v/v) at final pH 7.8 (solvent B). Table 2 showed the program for the gradient elution. The detection (Table 3) chosen for each synthetic colorant was the maximum absorption of the corresponding standard scanned by the PDA detector. Each testing sample was gradient-eluted with solvent A decreasing linearly from 85 to 57% and solvent B increasing linearly from 15 to 43% in 13 min, washed with solvent A (100%) for 2 min and finally equilibrated in the initial condition (A 85%, B 15%) for 4 min. Therefore, each run only lasted for 19 min. The detected wavelengths (nm) for E numbers were 426 (E102), 414 (E104), 482 (E110), 515 (E122), 523 (E123), 505 (E124), 530 (E127), 509 (E129), 613 (E132), 628 (E133) and 635 (E142). Studies of recovery were also attempted to assess recoveries from sampled food by spiking a solution of five typical synthetic dyes (E102, E110, E124, E129, E133) that commonly existed in the Table 2. Gradient program – 19 min per run at 1.0 ml min1. Time (min) 0 13 13.1 15.0 15.1 19.0
Solvent A (%)
Solvent B (%)
Curve
85 57 100 100 85 85
15 43 0 0 15 15
– 6 6 6 6 6
Notes: Solvent A ¼ 0.02 M ammonium acetate (pH 7.8). Solvent B ¼ 90% acetonitrile/10% 0.02 M ammonium acetate (v/v) (final pH 7.8). Curve 6 gave a linear change in solvent composition.
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Table 3. Detection of colours using PDA detector. E Number Wavelength (nm)
(a)
E102
E104
E110
E122
E123
E124
E127
E129
E132
E133
E142
426
414
483
515
523
505
530
509
613
628
635
0.20 E132
0.18
E124
0.16 0.14
E129
E102
0.12 AU
E133 E110
0.10 E122
0.08
E127
0.04 0.02 0.00 0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
11.00
12.00
13.00
14.00
Minutes
(b) 0.20 0.18 E142
0.16 0.14
E123
AU
0.12
E104
0.10 0.08 0.06 0.04 0.02 0.00 0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00 Minutes
8.00
9.00
10.00
11.00
12.00
13.00
14.00
12.00
13.00
14.00
(c) 0.35 0.30
E133
0.25 AU
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0.06
E123
0.20 0.15 0.10
E124 E102
0.05
E110
0.00 0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
11.00
Minutes
Figure 1. Overlay chromatograms of calibrators and a typical sample. The highest peak of each dye recorded at the corresponding wavelength of maximum absorption was used for calculation. (a) Eight mixed calibrators, namely E102 (2.4 min), E110 (6.2 min), E122 (10.6 min), E 124 (5.4 min), E127 (13.4 min), E129 (7.5 min), E132 (2.9 min) and E 133 (11.5 min). (b) Three mixed calibrators, namely E104 (13.0 min), E123 (2.7 min) and E 142 (11.8 min). (c) Overlay chromatogram of a sample containing E102 (2.4 min), E110 (6.2 min), E123 (2.7 min), E124 (5.3 min) and E133 (11.5 min).
samples in one low-fat (drink) and one high-fat (crisps) food. Chromatograms in Figure 1a–c showed wellresolved peaks of colours with negligible interference. All calibration curves were within linear range (Figure 2). The within CVs (%, n ¼ 6) of slope and
calibrated range were both 0.2–0.6, whereas the between-day CVs (n ¼ 6) were, respectively, 0.6–3.0 and 0.7–5.3. Percentage recoveries (n ¼ 3) in crisps (high fat) and in drink (low fat) for these five selected common dyes (0.1–0.5 mg spiked) were 79.1–94.2 and
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98.5–106.7, respectively. In addition, the synthetic dyes in each sample were checked and confirmed with their UV spectra. All instrumental controls, data acquisition and integration used Millennium32 Version 4.00 software (Waters Corp.). Results of the samples were then calculated, using Excel, from the peak area over slope of calibration curve adjusted with appropriate dilution and/or weighing factors, wherever necessary. Finally, all the results reported were only corrected for purity percentage but not corrected for recovery percentage.
that commonly existed in the samples in one low-fat (drink) and one high-fat (crisps) food. Absolute detection limit of the detector for each dye was determined by direct injection of each aqueous standard. Detection limit of the assay for each dye was obtained from the corresponding calibration curve (y ¼ mx þ b) of the dye by multiplying the SD of the intercept (b) by 2, divided by the slope (m). Similarly, the lower limit of quantification (LOQ) of the assay was assessed by calculating 10 SD of b/m. The study was approved by the University research ethics committee (CRE-2008.020-T) and written informed consent was obtained from parents.
Precision and stability of the columns and HPLC conditions were monitored and checked from withinday and between-day CVs of slope and calibrated range obtained by repeated injections of standards for day-to-day calibration. Two sets of routine calibration were done externally by analyzing solutions serially diluted from the two mixed stock solutions. Studies of recovery were also attempted to assess recoveries from sampled food by spiking a solution of five synthetic colours (E102, E110, E124, E129, E133)
Calibration curves of dyes
1200000 1000000 Peak area (uV.s)
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Quality control
E102 E104 E110 E122 E129 E127 E133 E142 E123 E124 E132
800000 600000 400000 200000 0
0
100 200 300 400 500 Amount of dye injected (ng)
600
Figure 2. Calibration of the dyes.
Results and discussion Of 164 children (mean age 8.79 [SD 0.55] years and weight 31.79 kg [SD 8.29]) enlisted, 84 were boys and 80 were girls. Table 3 presents the concentrations of the 11 synthetic colours identified in a variety of the food items that are most commonly consumed by these children. Eighty-seven food items out of the 280 shown at interview were analyzed, i.e. about 30% of the total items, as these were found to be commonly consumed by the children. The food groups with synthetic colours frequently consumed by the children were fizzy drinks, followed by ice cream and sweets (Table 4). A total of 91% of the children frequently exposed to drinks with synthetic colours ranging 0–3685. The mean daily intake of drinks with synthetic colours was 160 ml day1. The mean intakes for ice cream were 35.1 and 30.2 ml day1 in boys and girls, respectively. Sweets were also commonly consumed by the children in this sample, with a mean intake of 15.2 g day1. However, despite the frequent intake of certain foods with synthetic colours, the mean intakes of the children were below the recommended ADI. The ADI is an estimate of the amount of a food additive, expressed on a body weight basis, which can be ingested daily over a lifetime without appreciable risk. Derivation of the ADI is
Table 4. Range of of synthetic colour concentrations (mg kg1) in various food items consumed by children in Hong Kong. Food items
E102
E104
E110
E122
E123
E124
E127
E129
E132
E133
E142
Crisps 2.7–161 – 7.1–470 – 0–1.1 – – 24.4–40 – 0.3–6 – Biscuits 7.5–9 – 0–4.5 – – 0–1.6 – 43–57 – 0–12.3 0–1.3 Drinks 3.5–14.5 – 15.9–47.6 – – 0–3.9 – – – 0–0.1 – Desserts 8.7–66.8 – 9.5–3440 – 0–77.4 – – 2.2–104 – 3–4.5 0–3.4 Sweets 8.6–69.4 3.3–12 10.1–42.3 12.3–28.8 6.7–8.3 3–56 0–1.2 11–120.4 5.1–13 0.1–5.8 – Ice cream 1.4–49.4 – 0.5–22.1 – 29.8–37.2 38.5–52.7 0–25.1 0–52.4 – 0.1–66.6 – Jam 0–6 – 0–4.4 – – – – 0–307.6 – – – Cakes 21–42.3 – 0–1.5 – – 8.6–9.8 0–1.9 – – 0–0.7 – Miscellaneous 25.2–111.2 – 3.6–35.3 – 0–5.9 – – – – 0.6–18.8 – Snacks
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100 90 Percentage distribution
80 70 60 50 40 30
27.5
24
20
16.17
13.17
10
1.8
1.2
4.19
6.59
E123
E124
2.4
1.8
1.2
0
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E102
E104
E110
E122
E127
E129
E132
E133
E142
Food colourings
Figure 3. Percentage distribution of colour food additives in the categories studied.
based upon toxicity of a food additive based on data from studies in animals and humans with the incorporation of a safety factor of 100-fold is commonly applied (Benford 2000). Results showed that several synthetic colours, which were stated as being present in the food on the label of the food sample, were not detected (contained) upon analysis and vice versa. Two of the 13 crisp products, one of the 10 dessert products, two of the nine ice cream products, seven of the 19 sweet products and four of the 12 miscellaneous snack tested did not contain a synthetic colorant but an E number was on the label. Two products detected synthetic colours (as confirmed by their ultra-violet spectra) but the label showed no E number. This could have been due to levels below detection or mislabelling of the food items by food manufacturers, which is a violation of the labelling standard of the Hong Kong authorities and warrants further investigation by the Food and Safety Centre in Hong Kong. The use of synthetic colours in foods is strictly controlled by legislation and harmonised across the European Union by formulating Directive 94/35/EU (Minioti et al. 2000). In Hong Kong, the use of synthetic colours follows the Codex Alimentarius Commission of FAO/WHO, which is currently under update. When the percentage distribution of the foods tested for synthetic colours in the various food categories was analyzed (Figure 3), it was found that tartrazine (E102) (27.5%) and sunset yellow FCF (E110) (24.0%) were the most commonly used synthetic colorants, followed by erioglaucine disodium (E133) (16.2%) and allura red AC (E129) (13.2%). Similar observations have been reported from India and Kuwait by Roa et al. (2004) and Sawaya et al. (2008), respectively.
To assess exposure to synthetic food colours, the average daily intakes of synthetic food colours among 8–9-year-old children in Hong Kong were calculated based on the average daily amounts of synthetic colored foods consumed (self-reported FFQ during interview) and the average levels of the synthetic colours in those types of foods, and dividing the result by the average body weights for each age group, males and females (Sawaya et al. 2008). Exposure estimates were compared with the corresponding acceptable daily intakes (ADIs) as set by the FAO/WHO (1999) and ESFA (2009); the average intakes of the 11 synthetic food colorants were all considerably lower than their corresponding ADIs (Table 5). This could be due to underestimation of the actual consumption level as this was only based on 87 products that were analyzed and consumed by a selected age group and district in Shatin, Hong Kong. Study of other three districts of Hong Kong is currently being conducted and results will be available in 2011.
Conclusions Dietary exposure to the 11 synthetic colours for primary school children aged 8–10 in the local area of Shatin was considerably lower than the acceptable daily intakes established by the FAO/WHO and ESFA. It is concluded that primary school children in Hong Kong were unlikely to experience major toxicological effects from synthetic colours. Foods that are responsible for most synthetic food-colour intake were mainly drinks, ice cream and sweets. Therefore, these should be set as the priority focus for food control. From the data obtained, it has been shown that several synthetic food colours, mainly tartrazine (E102) and sunset yellow FCF (E110), are widely used in the food groups commonly consumed by children in
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K. Yuet-Wan Lok et al. Table 5. Average daily intake (ADI) of permitted artificial colours among children in Shatin. Age (years) 8
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Permitted artificial colour additive Tartrazine (E102) Quinoline Yellow (E104) Sunset Yellow FCF (E110) Chromotrope FB (E122) Amaranth (E123) New Coccine (E124) Erythrosine B (E127) Acid Red 1 (E128) Allura Red AC (E129) Indigo Carmine (E132) Erioglaucine Disodium (E133) Lissamine Green B (E142)
9
ADI (mg kg1 body weight)
M
F
M
F
0–7.5 0–0.5* 0–1* 0–4 0–0.5 0–0.7* 0–0.1 0–0.1 0–7 0–5 0–12.5 0–5
0.14 0.00 0.05 0.00 0.04 0.01 0.01 0.00 0.00 0.00 0.00 0.00
0.02 0.00 0.14 0.00 0.01 0.00 0.00 0.00 0.01 0.00 0.00 0.00
0.03 0.00 0.10 0.00 0.01 0.00 0.00 0.00 0.02 0.00 0.00 0.00
0.02 0.00 0.09 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00
Notes: F, Female; M, male. ADI ¼ acceptable daily intake (FAO/WHO, 1999). *EFSA update 2009.
Shatin, Hong Kong. Several products were found with incorrect labelling. Although estimated intake of synthetic colours was considerably lower than the ADI, detailed food consumption data from populationbased studies are needed for further risk assessment.
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