Tartrazine, also known as CI 19140, is a synthetic yellow azo dye used primarily in the food and beverage industry. It is a water-soluble, bright yellow pigment that is commonly employed to add vibrant color to various products, including soft drinks, candies, snacks, desserts, and processed foods. 

Tartrazine is also used in non-food products like cosmetics and medications, serving as a coloring agent to enhance their visual appeal. However, it's important to note that some individuals may be sensitive or allergic to tartrazine, and its use is subject to regulatory guidelines and labeling requirements in many countries to ensure safety and transparency for consumers.