Sterilization of oyster mushroom crop residue substrate by using cold plasma technology

Abstract

Traditional steaming method applied by mushroom entrepreneurs took long time (48 h) to complete the sterilization process. Moreover, improper steaming process causes contamination by soil-borne pathogens. This study will develop a new design by using cold plasma technology for crop residue substrate sterilization process. The cold plasma discharge works as sterilization able to kill the soil-borne pathogens without effect the substrate properties. Hence, focus was intention to examine the efficiency of the dielectric barrier discharges cold plasma (DBD-CP) pen mixer system on the crop residue substrate sterilization process for oyster mushroom cultivation. This renewal process develops by using electric field from voltage breakdown to discharge the plasma. The plasma with variable sterilization duration of 0 min, 5 min, 10 min, 15 min, 20 min and 25 min will discharge on the crop residue substrate. The soil-borne pathogens inactivation occupies on agro-waste substrate will examine using bacteria colony forming unit (CFU) method. Data gathered shows the bacteria colonies reduce from 1.0 9 CFU/mL (0 min) to 1.5 8 CFU/mL (25 min) due to increment of sterilization time. The mushrooms cultivation duration also characterized. The mushroom fruiting body was successfully growth two days earlier on crop residue substrate sterilized using cold plasma technology. Results show 25 min of sterilization duration by cold plasma technology shows the best optimum time. As conclusion, cold plasma technology is an efficient technology and can be applied in oyster mushroom industry for crop residue substrate sterilization process. The mushroom productivity was increase, the mushroom fruiting body growth faster, the sterilization time was shorter and the soil-borne pathogens were reduced.