18 Year analysis of RASFF notifications on Sudan dye adulterated cases in palm oil (2004 to 2022) and the principles of the technique for its detection

Abstract

Palm oil is one of the most widely consumed food products globally. Despite the restriction of Sudan dyes as a food colouring agent, these dyes still feature prominently in palm oil adulteration, which occurs in most developing countries. The current study aims to provide insight into the recent palm oil adulteration over 18 years and the methods for detecting this adulterant. By using the European Union's (EU) rapid alert system for food and feed (RASFF), data on palm oil adulterated with Sudan dye was extracted between the years 2004 to 2022 and analysed to determine their overall pattern. Adulteration of palm oil was categorised by the origin and concentration of various Sudan dyes. The results from RASFF could confirm a total of 204 cases of Sudan dye adulteration in palm oil. African countries recorded the highest number of alerts for exporting palm oil adulterated with Sudan dye to European countries. Additionally, 70 reported cases of palm oil adulteration were recorded in 2004 and this was a result of increased regular testing of Sudan dyes in foods within the EU community. Also, the concentration of Sudan IV dye was the highest in all the palm oil tested by the notifying countries, since it is highly soluble in crude palm oil compared to Sudan I, Sudan II and Sudan III. Finally, the results presented in this manuscript highlight the importance of the detection of Sudan dye adulteration in palm oil from 2004 to 2022 from the RASFF database. The techniques frequently used for analysing palm oil included gas chromatography mass spectrometry (GC-MS), gas–liquid chromatography (GLC), reversed-phase high-performance liquid chromatography (RP-HPLC), high performance liquid chromatography (HPLC), differential scanning calorimetry (DSC), NIR spectroscopy, MIR spectroscopy, FTIR spectroscopy, Raman spectroscopy, surface enhanced Raman spectroscopy (SERS), and electronic tongue. Among the methods reviewed, HPLC and GC-MS were frequently used; however, rapid non-destructive methods such as spectroscopic techniques for the onsite Sudan dye detection in palm oil would be very beneficial for many palm oil-producing countries in Africa.