Sudan Red I is one of a group of 7 Sudan colourants. It is an industrial, red dye, used legally to colour a number of non-food products such as shoe and floor polishes, oil, waxes and solvents. Sudan Red I – IV is prohibited for use as a food colourant in South Africa and many other countries around the world.
What levels of Sudan Red colourant are likely to be found in food and are they unsafe?
Fortunately, very small quantities of this illegal dye appear to be required to achieve the desired colouring effect in chillies and chilli-based products, which were the products implicated in the Sudan Red incidents in 2005 and 2007 in South Africa. The amount of dye in a contaminated chilli powder will naturally be much greater in the powder than in a sauce and ultimately would be much diluted, possibly to parts per billion in a final meal. At the levels found in food, the immediate risk of illness is considered to be very small. However, expert opinion is to keep exposure to these Sudan Red colours as low as possible. It is not possible to identify a safe level of intake and hence quantify the real risk.
Can Sudan Red cause cancer in humans at the levels consumed in food?
According to evaluations carried out by World Health Organisation’s International Agency for Research on Cancer (WHO/IARC), Sudan I is carcinogenic to mice following subcutaneous (beneath the skin) administration, producing liver tumours. Tests by oral (ingestion through the mouth) administration were negative. The results of studies carried out on Sudan II and III by subcutaneous and oral administration cannot be evaluated because of either the inadequacy of the numbers of animals used, the duration of the experiment, the dose used or the degree of reporting. Additionally, no cases of cancer from Sudan Red have been reported to the WHO/IARC. For this reason Sudan Red I, II and III are regarded as “Not classifiable as to carcinogenicity to humans” (Group 3 classification) by the WHO/IARC.
Available experimental data indicates that Sudan Red dyes may only be potentially genotoxic and it is for this reason that it is not possible to establish a tolerable daily intake limit. It may also exert sensitising effects by dermal route or inhalation. The risk for human health is very small and only when exposed frequently over a very long period could harm be done. However, there are many causes of cancer and it would be unjustified to blame these chemicals in isolation. South Africa has excluded the use of Sudan Red in foodstuffs from the Regulations related to Food Colourants, R. 1008 of 1996, which therefore makes it illegal to be used for this purpose.
If the risk of illness is so small, why did retailers remove product from sale in March 2007?
The first and most important reason was as a precautionary measure to protect the public. Although no immediate health concerns existed at the doses found, food safety cannot be compromised. The second reason is because the National Department of Health requested that local authorities in all provinces, as a matter of urgency, take steps to ensure that all products alleged to contain Sudan Red be removed from shelves and subjected to further testing. Thirdly, Sudan Red is prohibited for use in foods and if found, is illegal.
What is the background to the “crisis” that existed at the time?
Despite it not being allowed, the dye had found its way into food products such as chilli powder, since the price of chilli powder is largely linked to the intensity of the colour and its maintenance. Consequently, traces of the dye had also been found in other products where the chilli was used as an ingredient such as spice blends, sauces, spicy foods and some prepared meals. This kind of deliberate adulteration of a food for financial purposes is known as “economic adulteration”.
Because of a combination of factors such as the global nature of business, ignorance, lack of vigilance, the high cost of extensive testing of food products plus the ineffectiveness of food control authorities around the globe that are often under-resourced – especially in the third world, Sudan Red I – IV had found its way into some food products in South Africa.
A number of products were removed from retail shelves in 2005 and then again in 2007.
What was done to solve the problem?
The Department of Health worked with the food industry and local authorities to make sure that all products that had been identified as allegedly containing Sudan Red were removed from sale in retail outlets. Once independent testing by the state Forensic Laboratory or a SANAS accredited laboratory had been completed, action was taken based on the results. Those products that confirmed that Sudan Red was NOT detected were permitted to be restocked on retail shelves. For those products that were found to contain Sudan Red colourants I – IV, the appropriate action was taken as provided for under the Regulations Related to Inspections and Investigations, R 1128 of 24 May 1991. Random sampling for compliance was also undertaken at ports by local authorities and by the larger, more reputable retailers. Many manufacturers still require evidence, such as Certificates of Analysis, from their suppliers that products supplied to them are free of Sudan Red.
How is Sudan Red tested in foods and when is a product free of Sudan Red?
There are a number of test methods using different equipment, each with a different degree of accuracy. The most commonly used methods are by High Performance Liquid Chromatography (HPLC) or by Liquid Chromatography Mass Spectrometry (LC-MS/MS). Being a red colour, the presence of the dye can produce false positives if the laboratory staff is not sufficiently trained and the laboratory itself, not sufficiently equipped to detect such discrepancies. In addition, it is advisable to use a laboratory which has SANAS (South African National Accreditation System) accreditation for the method it uses for testing for Sudan Red.
It is important to note that there is no such thing as “Sudan Free” as the testing methods are not able to detect the colourant to a level of zero. However, certain testing methods measure the detection of Sudan Red to parts per billion, which can be regarded as “free” for all practical purposes. The detection of a level of up to 10 parts per billion is regarded as accurate by most international standards.
Prepared for FACS by LAn (2019)
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