Tartrazine is an organic sodium salt which is the trisodium salt of tartrazine acid. A synthetic lemon yellow azo dye used as a food colouring. It has a role as a histological dye and a food colouring.

Uses

Tartrazine is a commonly used color all over the world, mainly for yellow, and can also be used with brilliant blue FCF (FD&C Blue 1, E133) or green S (E142) to produce various green shades.

Chemistry

Tartrazine is water-soluble and has a maximum absorbance in an aqueous solution at 425 nm.It is one of the oldest known member of the pyrazolone family of dyes.

Potential health effects on humans

Sensitivity

Tartrazine appears to cause the most allergic and intolerance reactions of all the azo dyes, particularly among asthmatics and those with an aspirin intolerance.Symptoms from tartrazine sensitivity can occur by either ingestion or cutaneous exposure to a substance containing tartrazine. Symptoms appear after periods of time ranging from minutes up to 14 hours.

The prevalence of tartrazine intolerance is estimated at roughly 360,000 U.S. Citizens affected, less than 0.12% of the general population.According to the FDA, tartrazine causes hives in fewer than 1 in 10,000 people, or 0.01%.

It is not clear how many individuals are sensitive or intolerant to tartrazine, but the University of Guelph estimates that it is 1 to 10 out of every ten thousand people (0.01% to 0.1% of the population).There is much controversy about whether tartrazine has ill effects on individuals who are not clearly intolerant.

Total avoidance is the most common way to deal with tartrazine sensitivity,but progress has been made in reducing people’s tartrazine sensitivity in a study of people who are simultaneously sensitive to both aspirin and tartrazine.

Asthma

A systematic review of the medical literature concluded that among patients with asthma, research has shown that exposure to tartrazine does not worsen symptoms and avoidance of tartrazine does not improve symptoms; however, "due to the paucity of evidence, it is not possible to provide firm conclusions as to the effects of tartrazine on asthma control".