Metanil Yellow
Metanil Yellow is a dye of the azo class. In analytical chemistry, it is used as a pH indicator and it has a color change from red to yellow between pH 1.2 and 3.2.
Although illegal for food use, Metanil Yellow has been used as an adulterant in turmeric and pigeon pea based food products, particularly in India.
Animal studies have suggested that Metanil Yellow is neurotoxic and hepatotoxic.