Metanil Yellow Explained

Metanil Yellow (Acid Yellow 36) 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.^{[1] [2] [3] [4]}

Animal studies have suggested that Metanil Yellow is neurotoxic^[2] and hepatotoxic.^[5]

Notes and References

1. 5302347. 2016. Dhakal. S. Evaluation of Turmeric Powder Adulterated with Metanil Yellow Using FT-Raman and FT-IR Spectroscopy. Foods. 5. 2. 36. Chao. K. Schmidt. W. Qin. J. Kim. M. Chan. D. 10.3390/foods5020036. 28231130. free.
2. 8095244. 1993. Nagaraja. T. N. Effects of chronic consumption of metanil yellow by developing and adult rats on brain regional levels of noradrenaline, dopamine and serotonin, on acetylcholine esterase activity and on operant conditioning. Food and Chemical Toxicology . 31. 1. 41–4. Desiraju. T. 10.1016/0278-6915(93)90177-z.
3. Practice of using metanil yellow as food colour to process food in unorganized sector of West Bengal . International Food Research Journal . 22 . 4 . 1424–1428 . 2015 . Nath, P. P., Sarkar, K., Tarafder, P., Mondal, M., Das, K. and Paul, G .
4. https://www.indiatoday.in/education-today/gk-current-affairs/story/common-food-adulterants-in-india-1370601-2018-10-19 "Common food adulterants in India"
5. 4721164 . 2015 . Saxena . B . Food Color Induced Hepatotoxicity in Swiss Albino Rats, Rattus norvegicus . Toxicology International. 22 . 1 . 152–157 . Sharma . S . 10.4103/0971-6580.172286 . 26862277 . free .