Schrader, KK; De Regt, MQ; Tidwell, PR; Tucker, CS; Duke, SO

Bulletin of Environmental Contamination and Toxicology [Bull. Environ. Contam. Toxicol.], vol. 60, no. 4, pp. 651-658, Apr 1998

The most common off-flavor problem in drinking water and fresh water-raised fish is earthy-musty odor. Actinomycetes and cyanobacteria are the microorganisms most frequently associated with producing geosmin and 2-methylisoborneol (MIB) which are responsible for causing earthy-musty odors. The cyanobacterium Oscillatoria cf. chalybea produces MIB, and is the major cause of musty off-flavor in channel catfish in west-central Mississippi. Channel catfish exposed to MIB will absorb the compound within hours while removal of MIB from the fish flesh may take days or weeks. Channel catfish determined to be off-flavor must be held in ponds by the producer for days or weeks until they are deemed to be on-flavor and marketable. Such management dilemmas can increase production costs by an amount equivalent to 12% of the annual revenues received by catfish producers.