Sudanfarging

Sudanfarging, or Sudan dyeing, refers to the use of Sudan dyes—specifically Sudan I, II, III, and IV—as colorants, usually in fats and oils, and in some cases illicitly in foods to intensify color. The term highlights a practice associated with food adulteration rather than legitimate food coloring.

These dyes are synthetic azo compounds and are lipophilic, which makes them more soluble in fat than in water. They have historically been used as textile dyes and laboratory stains, but their presence in edible products is widely considered illegal or unsafe. In food contexts, Sudan dyes have been linked to adulteration of spices, sesame seeds, chili powders, curry blends, and other oil-rich products.

Regulatory and safety concerns are central to the topic. Sudan I–IV are not approved as food additives in most jurisdictions. Sudan I is commonly classified as possibly carcinogenic to humans (IARC Group 2B), and many countries prohibit their use in foods altogether. Their appearance is often the result of illicit practices aimed at producing a more intense color profile, particularly in spice and oil products.

Detection and enforcement rely on chemical analysis rather than consumer-level testing. Food-safety authorities employ chromatographic methods such as high-performance liquid chromatography (HPLC) and liquid chromatography–mass spectrometry (LC-MS) to screen for Sudan I–IV. When detected, affected lots are typically recalled or barred from sale.

See also: Sudan dye, Food adulteration, Food safety, Colorants.