Quinoline Yellow WS is a greenish-yellow dye that is also known as Quinoline Yellow, E104, C.I. 47005, and Food Yellow 13. It is a mixture of related chemicals derived from 2-(2-quinolyl) indan-1,3-dione. The “WS” in the name refers to water solubility. There is also an “SS” form of the chemical mixture that is not soluble in water.
Food manufacturers use quinoline yellow WS when they want to impart a greenish-yellow Gatorade-like lemon-lime color to a liquid. It's found in some juices and in some brands of sorbets, scotch eggs, and smoked haddock. Quinoline yellow is made from coal tar.
Quinoline yellow has a side effect that most food additives do not. It increases the absorption of aluminum through the digestive tract. The accumulation of aluminum in the brain is thought to contribute to the degenerative process in Alzheimer's disease.
Like may other food additives, quinoline yellow causes allergy symptoms in people who are allergic to aspirin and aspirin-like compounds. Consuming quinoline yellow after taking aspirin, or after consuming foods that contain aspirin-like chemicals (raisins, prunes, dill, curry powder, paprika, oregano, or peppermint), can cause hives, wheezing, sneezing, or itching. This reaction occurs in about 1 in 300 people. About 1 in 1000 people may also have autoimmune reactions that may include migraines, attention deficit, dizziness, or stomach upset. About 1 in 100 people develops a skin reaction (redness, itching, flaking, peeling) after exposure of quinoline yellow to the skin.
Are you likely to have a reaction to quinoline yellow WS? Most people don't, but the few who do tend to have especially severe problems. The governments of Australia, Japan, and the USA ban the use of the dye, but it's still in many food products sold in the UK.
The surest way to avoid exposure to quinoline yellow WS in juices is to make your own—especially your own lemon and lime juices for lemonade and limeade, margaritas, and other mixed drinks. It just takes a few moments to get fresher, more flavorful juice with a citrus extractor to avoid any problems from quinoline yellow in your citrus juice drinks.