Effect of different cotton seed hull substrate pre-treatments on the gossypol content of Pleurotus ostreatus.

Gossypol levels were determined in Pleurotus ostreatus fruit bodies grown on a substrate containing 87% cotton seed hulls that had been fermented for 18 d,or fermented for 3 d and then sterilized by autoclaving at 100 ℃ for either 240 or 600 min or at 126 ℃ for either 20 or 40 min. All samples contained gossypol levels that were below the National Security Standard (≦0.02%;200 mg/kg),with the lowest value (24.0 mg/kg) recorded in fruit bodies grown on the substrate that had been fermented for 18 days.