Mycelial growth of Oyster mushroom is very important. Because the management of careless mycelial growth can be caused contamination and low yield of fruit body. To reduce contamination, it is necessary to maintain clean cooling room, inoculation room and cultivation room. First of all, we investigate death rate of microorganism according to ultraviolet(uv) irradiation in cooling room, inoculation room and contamination rate according to sterilization condition of substrate. Though contamination rates according to sterilization conditions were not showed big differences, the amount of electricity-used was the lowest at 121°C for 90 minute. As results of UV irradiation time effect on death rate of microorganism, density of bacteria was not detected after UV irradiation for 6 hours by using UV lamp(40watt) in the room of 56m3. However the death rate of fungi is not big in the same UV irradiation conditions.

• Il-Sun Baek(Mushroom Research Institute, Gyeonggi-Do Agricultural Research and Extension Services(GARES))
• Yun-Kyeoung Jeoung(Mushroom Research Institute, Gyeonggi-Do Agricultural Research and Extension Services(GARES))
• Jeong-Han Kim(Mushroom Research Institute, Gyeonggi-Do Agricultural Research and Extension Services(GARES))
• Han-Bum Lee(Mushroom Research Institute, Gyeonggi-Do Agricultural Research and Extension Services(GARES))
• Jeong-Hyun Chi(Mushroom Research Institute, Gyeonggi-Do Agricultural Research and Extension Services(GARES))