liver carcinogenicity may not be due to the genotoxic effects of Sudan 1. No carcinogenic effects were visible in livers of mice after the application of Sudan 1. But when Sudan 1 is applied subcutaneously to mice, liver tumors were found. Furthermore, DNA damage was depicted in the stomach and liver cells of mice. In rats there was found to be no significant increase in the amount of micro-nucleated epithelial cells of the gastrointestinal tract. This indicates the absence of genotoxic compounds in the gastrointestinal epithelial cells in rats. Contradictive to the findings in the gastrointestinal tract and liver, there was an increase in micro-nucleated cells found in the bone marrow. The frequency of micro-nucleated bone marrow cells increased in a dose-dependent manner. Significantly higher incidences of micro-nucleated immature erythrocytes (MNIME)were found at a dose of 150/mg/day or more. This supports the explanation that Sudan 1 is oxidized or activated by peroxidase in the blood cells and thereby forming micro-nucleated cells. Guanosine DNA adducts derived from peroxidase metabolites of Sudan 1 were also found in vivo in the bladder of rats. The bladder also contains high levels of tissue peroxidase. Toxicology Sudan I is genotoxic. It is also carcinogenic in rats. Comparisons between experimental animals and human Cytochrome P450 (CYP) strongly suggest animal carcinogenicity data can be extrapolated to humans. Sudan I is also present as an impurity in Sunset Yellow FCF, which is its disulfonated water-soluble version. Food scare In February 2005, Sudan I gained attention, particularly in the United Kingdom. A worcestershire sauce produced by Premier Foods was found to be contaminated with Sudan I. The origin was traced to adulterated chili powder. The contamination was discovered by the Food Standards Agency. See also Para Red References External links BBC NEWS | Health | Food alert on cancer-causing dye Food Standards Agency - Sudan dyes 2-Naphthols Azo dyes Food colorings IARC Group 3 carcinogens Sudan dyes