What to Do About Contaminated Shiitake Mushroom Bags? A Detailed Guide to Practical Countermeasures

During indoor incubation, the mushroom bags should be turned 4 to 5 times: the first time 6 to 7 days after inoculation, and thereafter once every 7 to 10 days. When turning the bags, carefully check for contaminating microorganisms and deal with them promptly. In cases of mild contamination, where only scattered dot-like or filamentous small colonies of contaminants appear at the tied opening or in the folds of the bag and have not spread, use a syringe to draw up a mixture of 50 ml of 75% alcohol plus 30 ml of 36% formaldehyde, inject it into the affected area, and gently massage the surface with your fingers so the solution penetrates into the contaminant cells, then seal the injection hole with adhesive tape. Contamination at the inoculation holes: for bags where contaminants have invaded the inoculation holes but the mycelium is still in its growth phase and the impact on shiitake mycelial growth is not too great, first apply the clear supernatant of 5% to 10% limewater, then coat the affected area with 50% carbendazim solution, but avoid applying it to the shiitake mycelium. If dead mycelium is found, re-inoculate under sterile conditions. Severe contamination: when the mushroom bag is basically covered with speckled patches of contaminants, break open the bag and take out the substrate, mix it with a 3% lime solution and let it sit in a pile overnight, then spread it out to dry in the sun, re-mix the ingredients, bag and sterilize them, and then inoculate and incubate again.