Sensory properties of thio‐ and alkyl‐ phenols causing flavor tainting in fish from the upper Wisconsin River

A mixture of 10 ppb thiophenol, 1 ppb 3‐isopropylphenol, 1 ppb 2,4‐diisopropylphenol and 1 ppb carvacrol had nearly the same flavor quality as environmentally tainted northern pike when added to the flesh of untainted northern pike. Trout exposed to a mixture of alkylphenols and thiophenol (1–2 ppb each) in water did not become flavor tainted, but trout fed a formulated feed (2% body weight/day) containing 100 ppb added alkylphenols and thiophenol became strongly flavor tainted. Results suggest tainting via the food chain is important with these compounds. Tainting caused by thiophenol and isopropylphenols in tank‐held trout was removed by holding the fish in clean water for 5 days.