Red 40 that makes it poisoning

Upon its introduction into the market, there were fears that Allura Red AC (Red Dye 40) was carcinogenic; however, studies have since shown that this is not the case. The initial reports of its consumption causing tumors have since been shown to have been caused by the presence of para-cresidine. Although para-cresidine is an important reactant in the manufacture of Allura Red AC and is a known carcinogen, further studies conducted since have found no trace of para-cresidine to be present in food-grade Allura Red AC.