Sudan IV Dyes

Sudan IV is a dye used in Sudan dyeing. Similar dyes include Oil Red O, Sudan III and Sudan Black B. Staining is an important biochemical technique that can intuitively identify the presence of the target fatty compound without isolating it. For dyeing, Sudan IV can be made with propylene glycol. Alternatively, the authors report using dyes saturated in isopropanol, 95% ethanol, or 0.05% by weight of acetone: ethanol: water (50:35:15) [citation required]. The idea is to use a moderately non-polar solvent to solubilize the dye, so that the dye is distributed to the highly non-polar fat, and the solvent does not solubilize the fat to be dyed. The International Agency for Research on Cancer has classified Sudan I, Sudan III and Sudan IV as Class 3 carcinogens. The purified form is called Biebrich Scarlet R and should not be confused with water-soluble Biebrich Scarlet. Industrially, it is used to color non-polar substances such as oils, fats, waxes, greases, various hydrocarbon products and acrylic emulsions. Sudan IV was also used as a fuel dye in the UK to dye low-tax heating oil. Therefore, it is also known as the oil tax red. As a food dye, Sudan IV is considered an illegal dye, mainly because it is a carcinogen and therefore has a harmful effect for a long time. It was ruled unsafe in the 1995 Food Safety Regulation Report.

Sudan IV Dyes Figure 1. Chemical structure of Sudan IV.

Safety

IARC has classified Sudan Red IV as a third class of carcinogens, but its primary metabolites, ortho-toluidine and ortho-aminoazotoluole, have been classified as second-class carcinogens, which are known to humans. May be carcinogen. Animal tests show that 150 mg / kg BW o-toluidine is administered to rats for 100-104 weeks, and the incidence of multiple organ sarcoma, fibrosarcoma, and osteosarcoma increases. Dogs given 5 mg / kg BW o-aminoazotoluene for 30 months, then of bladder cancer. In summary, based on the risk assessment of Sudan red in the EU paprika and the possible intake of paprika, if the Sudan red content in the food is very low (only a few milligrams), even if the worst hypothesis is the maximum possible food intake is to be evaluated. The dose of Sudan Red to induce animal tumors is 100,000 to 1 million times the maximum possible human intake, so the carcinogenicity to humans is extremely small. However, if the content of Sudan Red in food is high, reaching thousands of milligrams, the dose of Sudan Red to induce tumors in animals is 100-10,000 times the maximum human intake. As the actual detection of Sudan Red in paprika is usually low, especially because some of Sudan Metabolites are human carcinogens, there is no tolerable intake of these substances, so intake of these substances should be avoided as much as possible. Since Sudan Red is an artificial coloring, it is non-naturally occurring in food and carcinogenic, so it should be banned in food. In view of the fact that some foods in China may also contain Sudan Red Pigment, the monitoring of Sudan Red I in food should be strengthened, but at the same time, the monitoring of Sudan Red II, III, IV cannot be relaxed, and the possible intake of our population to evaluate.