ABSTRACT: This study employed an engineering design, planning and analysis to achieve the objectives of the study. The established operating time for the chemical pasteurization, cooling, and substrate discharging processes were 30 minutes, 90 minutes and 30 minutes, respectively. The temperature range for the chemical pasteurization process was 55°C – 60°C. The draining time after the cooling process was 30 minutes. The established acceptable proportion of rice straw to volume of water was 5 kg of rice straw to 200 liters of water. The pasteurization rate of 0.5 kg/min, cooling rate of 0.167 kg/min and discharging rate of 0.5 kg/min were recorded during the performance testing. The over-all production rate was 0.1 kg/min. The time needed for spawn to colonize the substrate depends on the spawning rate and its distribution, the substrate moisture and temperature, and the nature and quality of the substrate.

Keywords: chemical pasteurization, rice straw-based mushroom substrate, incubation time, inoculation time