Analysis of Carcinogenic Sudan Azo Dyes in Food Products
Abstract
T. Gottapu1 and D. Cunningham1, 1Department of Chemistry and Physics, 2Department of Kinesiology Nutrition Recreation, Southeast Missouri State University. ANALYSIS OF CARCINOGENIC AZO DYES IN FOOD PRODUCTS. Previous studies have found carcinogenic Sudan azo dyes in food products including red palm oil. Our initial work showed the addition of red Sudan IV to light yellow inexpensive oils at levels of 1-5 ppm produced a red colour similar to the natural red palm oil. To quantitate the Sudan IV level in adulterated oils and palm soup cream, samples were extracted with hexane and pre-treated using solid phase extraction (SPE). Sample addition, washing and elution from the SPE cartridges were characterized by HPLC analysis of fractions from the cartridges. Due to the hydrophobic nature of Sudan IV, a very high organic HPLC mobile phase (95% methanol; 5% pH 5 buffer) was used with a C-18 column. Linear calibration curves were obtained in the 50-5000 ppb range at 340 nm with an analysis time of 15 minutes.
Introduction
Sudan I–IV are azo dyes used for colouring Food products, triglycerides and lipoproteins (Hunger et al. 2000). They are labelled category 3 carcinogens by the IARC (IARC Monographs on the Evaluation of the Carcinogenic Risks to Humans 1987) and are not permitted to be used in foods in most countries. Because these dyes are looks bright in colour and not expensive, they have been used intentionally to adulterate palm oil and spices to enhance the adulterated quality of the product. Following Dyes are widely using in Food.
Sudan I (limit of limit of 0.5 ug per g of Sunset Yellow FCF)
Sudan I
Sudan II
Sudan III
Sudan III
Sudan IV
Adulteration with dyes has been used to cover up products in which the natural colour has been lost due to improper drying, storage or fungal infestations where pigment is degraded (Arora & Bharti 2005; Mishra et al. 2007). The first adulteration of chilli powder with Sudan I was found in 2003, and the source of contamination was identified that chilli powder imported from India named with the brand name genus with a concentration of 4000 mg kg−1 (RASFF 2003; ASTA 2005). Government was imposed rule to quality analytical test for all the products imported with the brand name genus to ensure adulteration with sudan I. (European Commission 2003). In 2004, this requirement was expanded to test Sudans II–IV also. Testing was expanded to include palm oil and the genus Curcuma in 2004 (turmeric) (European Commission 2005). In the UK in 2005, Sudan I was found in a sauce (3 μg ml−1) that was found to contain adulterated chilli powder (80 mg kg−1) (RASFF 2005). This sauce had been used to prepare a lot of foods including soups, salad dressings, sausage ready meals, pate, seafood, mince. (Sudan I Consolidated Product List from February 2005). As a result, almost 500 food products were recalled, and it is the largest recall in the UK history. Unauthorised colours continue to be reported in the RASFF portal, with a total of 16 notifications in 2014 and 2015 (RASFF 2015).
Method
Chemicals and Reagents: Some of the chemicals and reagents utilized in the experiment included fresh palm fruit extract from Neat Food Company from Ghana, Praise Palm Cream from Praise Export Services Limited from Ghana, HPLC methanol, hexane, ethyl ether, and ethyl acetate.
Solid-phase extraction (SPE) clean-up and preparation of extracts: SPE was performed using LC-Alumina-B SPE tubes (1 g/3 ml) from Supelco (Tran et al. 2005). The cartridge was conditioned with 6 ml of methanol, 6 ml of ethyl acetate and 6 ml of hexane. Then, 1 ml of the sample solution was added to the SPE column. The sample was washed with 6 ml of hexane and 6 ml wash of ethyl ether (palm oil only), followed by 2 ml of ethyl acetate The Sudan dyes were then eluted from the column using 8 ml of 90:10 ethyl acetate: methanol solution. The extract was filtered through a 0.2 μm PTFE filter and internal standard was added (10 μl of 1 ng/μl d6-Sudan III solution) prior to LC-MS/MS analysis.
Procedure: Shimadzu conducted the separation and quantification of Sudan IV levels in the spiked oil and palm soup cream in Japan. A high-performance liquid chromatography (HPLC) was employed for the process. Before the HPLC technique, the samples were pre-treated using solid-phase extraction (SPE). The SPE procedure is mostly employed for extraction, concentration, and fractioning of organic compounds (Andrade-Eiroa et al. 641; Rocha et al. 803). The equipment compresses a degasser, a gradient pump, a liquid sampler, a column oven, and a diode array detector (Esen et al. 73; Moldoveanu and Victor 9; Hu et al. 2126; Weisz et al. 1835). The chromatographic conditions involved the use of high organic HPLC mobile phase (95% methanol, 5% pH 5 buffer) and C-18 column. After the chromatographic specifications, the calibration curves were plotted in the 50-5000 ppb range at 340 nm with an analysis time of 15 minutes. Finally, the presence of Sudan IV in different quantities of the prepared palm oil and cream were determined from the generated chromatograms.
Figure 1: The Prepared Samples
Results
The study started with the calibration of the equipment using different samples of Praise and Neat. The data obtained from the first experiment was recorded, as presented in Table 1. Besides, the data obtained for red palm oil is recorded in Table 1, whereas the results for the palm cream are illustrated in Figure 2.
Table 1: The Calibration Data
SAMPLES
OBSERVATIONS
2500 S4 1/2 S1 1/2Carotene
Sudan IV peak at 11.54 min
5000 S4 S1 Carotene
Sudan IV peak at 11.57 min
500 S4 S1 Carotene
Sudan IV peak at 11.59 min
1000 S4 S1 Carotene
Sudan IV peak at 11.65 min
250 S4 S1 Carotene
Sudan IV peak at 11.72 min
Table 2: The results from the analysis of red palm oil samples
SAMPLES
OBSERVATIONS
250 ng/mL SIV 450 S1
Sudan IV peak at 11.07 min
100 ng/mL SIV 180 S1
Sudan IV peak at 11.51 min
50 ng/mL SIV 180 S1
Sudan IV peak at 11.70 min
25 ng/mL SIV 180 S1
No Sudan IV peak
10 ng/mL SIV 180 S1
No Sudan IV peak
Unspiked1 red palm oil
No Sudan IV peak
Figure 2: The Chromatogram for the Palm Cream
Conclusion
It was observed that there was no presence of Sudan IV dye in the neat oil palm oil. However, it could not be confirmed whether the oil had zero quantities of Sudan IV because the technique used for quantification began detecting the dye when 50 ng/mL and above volumes were added. It was also observed the time taken to separate the dye from the mobile phase decreases with the increasing quantities of the compound. Similarly, the results for palm cream indicate that there was no presence of Sudan IV for the unspiked sample. It was concluded that both the red palm oil and the palm cream considered in the study might not have Sudan IV dye. However, the accuracy of the process used was in doubt. Therefore, for future analysis, more accurate methods, such as liquid chromatography-mass spectrometry (LC-MS)/mass spectrometry (MS), Fourier transform infrared spectroscopy (FTIR), and mid-infrared spectroscopy (MIR), should be utilized. Overall, the experiment was successfully conducted.
Works Cited
Ahmed, F., et al. "Non-destructive FT-IR Analysis of Mono Azo Dyes." Bulg. Chem. Commun, Vol. 48, No.1, 2016: pp. 71-77.
Al Tamim, Abdullah, et al. "Fast and Simple Method for the Detection and Quantification of 15 Synthetic Dyes in Sauce, Cotton Candy, and Pickle by Liquid Chromatography/Tandem Mass Spectrometry." Arabian Journal of Chemistry Vol. 13, No.2 (2020: pp, 3882-3888.
Andoh, Sampson Saj, et al. "Qualitative Analysis of Sudan IV in Edible Palm Oil." Journal of the European Optical Society-Rapid Publications, vol. 15, No.1, 2019: pp. 1-5.
Andrade-Eiroa, Auréa, et al. "Solid-Phase Extraction of Organic Compounds: A Critical Review (Part I)." TrAC Trends in Analytical Chemistry, Vol. 80, No. 1, 2016: pp. 641-654.
Aresta, Antonella, Nicoletta De Vietro, and Carlo Zambonin. "Ultra-Trace Determination of Sudan I, II, III, and IV in Wastewater by Solid-Phase Microextraction (SPME) and on-Line Solid-Phase Extraction (SPE) with High-Performance Liquid Chromatography (HPLC)." Analytical Letters, Vol. 3, No. 1, 2020: pp. 1-12.
Arora S, Bharti S. Effect of mechanical drying on quality of chilli varieties. J Food Sci Technol. 2005; 42:179–182.
ASTA. Sudan Red and related dyes - white paper [Internet]. 2005. [cited 2015 Mar 5].
Dhakal, Sagar, et al. "Detection of Additives and Chemical Contaminants in Turmeric Powder Using FT-IR Spectroscopy." Foods, Vol. 8, No.5, 2019: pp.143-158.
Esen, Betül, Tülay Oymak, and Emrah Dural. "Determination of Food Colorings in Pharmaceutical Preparations and Food Additives by a Validated HPLC Method." International Journal of Scientific & Engineering Research, Vol. 9, No. 8, 2018: pp. 72-76.
European Commission. Commission decision of 20 June 2003 on emergency measures regarding hot chilli and hot chilli products. Off J Eur Commun L. 2003:114–115.
European Commission. Commission decision of 23 May 2005 on emergency measures regarding chilli, chilli products, curcuma and palm oil. 2005/402/EC. Off J Eur Commun L. 2005:34–35.
Hu, Mingzhu, et al. "Determination of Sudan Dyes in Juice Samples via Solidification of Ionic Liquid in Microwave-Assisted Liquid-Liquid Microextraction Followed by High-Performance Liquid Chromatography." Food analytical methods, Vol. 9, No.7, 2016: pp. 2124-2132.
Hunger, K.; Mischke, P.; Rieper, W. Ullmann’s encyclopedia of industrial chemistry. Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA; 2000. Azo dyes, 1. General.
Iarc Monographs on the Evaluation of the Carcinogenic Risks to Humans. International Agency for Research on Cancer. Lyon: World Health Organization; 1987.
Lohumi, Santosh, et al. "Quantitative Analysis of Sudan Dye Adulteration in Paprika Powder Using FTIR Spectroscopy." Food Additives & Contaminants: Part A, Vol. 34, No.5. 2017: pp. 678-686.
Moldoveanu, Serban C., and Victor David. Selection of the HPLC method in chemical analysis. Elsevier, 2016.
Ntrallou, Konstantina, Helen Gika, and Emmanouil Tsochatzis. "Analytical and Sample Preparation Techniques for the Determination of Food Colorants in Food Matrices." Foods, Vol. 9, No.1, 2020: pp. 58-82.
Oliveira, Marciano M., J. P. Cruz‐Tirado, and Douglas F. Barbin. "Nontargeted Analytical Methods as a Powerful Tool for the Authentication of Spices and Herbs: A Review." Comprehensive Reviews in Food Science and Food Safety 18.3 (2019): 670-689.
Otero, Paz, et al. "Simultaneous Determination of 23 Azo Dyes in Paprika by Gas Chromatography-Mass Spectrometry." Food Analytical Methods, Vol. 10, No. 4, 2017: pp. 876-884.
RASFF. Contamination of Worcester sauce by the unauthorised colour Sudan I [Internet]. 2005. [cited 2015 Mar 5].
RASFF. Rapid Alert System for Food and Feed (RASFF), 2003 [Internet]. Luxembourg: Publications Office of the European Union; 2003. Annual report 2003 ed. [cited 2015 Mar 5]
RASFF. Rapid alert system for food and feed (RASFF) – RASFF portal, 2015 [Internet]. Online Searchable Database. 2015. [cited 2016 Jan 4].
Rocha, Fabio RP, et al. "Solid-Phase Extractions in Flow Analysis." Anais da Academia Brasileira de Ciências, Vol. 90, No.1, 2018, pp. 803-824.
Sudan I consolidated product list from February 2005 recall [Internet]. 2015. [cited 2014 Mar 4].
Susie Genualdi, Shaun MacMahon, Katherine Robbins, Samantha Farris, Nicole Shyong, and Lowri DeJager Method development and survey of Sudan I–IV in palm oil and chilli spices in the Washington, DC, area.
Tran, K.; Young, M.; Neue, U. Effective SPE strategies for LC-MS determination of Sudan dyes in chili products [Internet]. 2005. [cited 2015 Mar 5].
Weisz, Adrian, et al. "Determination of Sudan I and a Newly Synthesized Sudan III Positional Isomer in the Color Additive D&C Red No. 17 Using High-Performance Liquid Chromatography." Food Additives & Contaminants, Vol. 34, No.11, 2017: pp. 1831-1841.