Depuration rates and the sensory threshold concentration of geosmin responsible for earthy-musty taint in rainbow trout, Onchorhynchus mykiss

After exposure to GSM for 24 h, initial GSM levels in the trout at the start of the depuration study were 1.68±0.12 μg kg−1, 2.98±0.39 μg kg−1 and 6.25±0.75 μg kg−1, in the three experimental groups described as mildly tainted, tainted and grossly tainted, respectively. Purge times were found to be directly related to initial taint concentration in fish of similar mass and fat content, held at the same temperature (14.5 °C). Depuration times in all experimental groups were significantly increased when the time for a population of fish (95% upper confidence limit, UCL) to purge clear was considered rather than the period required for the arithmetic mean concentration to reach sensory threshold limit. Exponential regression analysis equations describing the trend lines fitted through 95% UCL data sets for each group were Y=1.5269e−0.01XR2=0.7229, Y=2.9212e−0.0168XR2=0.9588 and Y=4.5478e−0.0133XR2=0.8493 for the groups described as mildly tainted, tainted and grossly tainted, respectively.