PDA 即食用菌母种培养基,易遭受细菌污染,导致母种培养失败。在食用菌生产中,必需注意 PDA 细菌污染症状,及时采取有关防治措施。将方法介绍如下:(一)污染症状:1、接种后24～36小时,接种块附近出现粘糊物质,分泌出其它杂色汁液。2、接种块本身或旁边有零星白色或杂包小点。3、污染严重时,有酸臭味散出。4、将试管培养基背面正对太阳光,发现白包菌丝下有黄褐色大小不规则的圆斑。(二)防治措施:1、做好接种箱(室)的灭菌 PDA is the edible fungus mother medium, susceptible to bacterial contamination, resulting in failure of breeding mother. In the edible fungus production, must pay attention to PDA bacterial contamination symptoms, take timely control measures. The method is described as follows: (a) pollution symptoms: 1, 24 to 36 hours after inoculation, sticky substance appeared near the inoculation block, the secretion of other variegated juice. 2, the vaccination block itself or next to a sporadic white or sundial dot. 3, serious pollution, there sour smell spilled. 4, the back of the tube culture medium is facing the sun and found that there are round brown octagonal irregular size of the circular spot. (B) prevention and control measures: 1, do vaccination box (room) sterilization