A mushroom spore syringe is a sterile syringe containing microscopic spores suspended in an aqueous solution, typically distilled water. This specialized tool is used to introduce the spores to a prepared, sterile growth medium, such as grain spawn or agar. Spores are the reproductive units of the fungus, which germinate and develop into mycelium, the vegetative body of the fungus. Maintaining absolute sterility throughout the entire process is the most important factor for success, as the nutrient-rich environment is also ideal for unwanted microorganisms like mold and bacteria.
Preparation and Sterility
Establishing a clean, controlled environment is the crucial first step to successful inoculation. Airborne spores and bacteria are the primary threat, as they thrive in the same conditions that support mushroom growth. Select a low-traffic area with minimal air movement, actively avoiding drafts from open windows, vents, or fans.
Thoroughly clean all surfaces, equipment, and the exterior of the spore syringe using a 70% isopropyl alcohol solution. Allow the disinfectant to air dry completely to effectively eliminate contaminants. Personal hygiene is equally important; wash hands thoroughly and wear a face mask and sterile gloves, sanitizing the gloves with alcohol before handling any tools.
Many cultivators utilize a Still Air Box (SAB) or a laminar flow hood, specialized enclosures designed to keep the inoculation area free of circulating air and dust. A Still Air Box allows gravity to pull contaminants out of the workspace, creating a pocket of clean air. Gather all necessary supplies, including the spore syringe, alcohol wipes, a flame source, and the sterilized substrate containers, to ensure everything is within reach before the syringe is opened.
The Inoculation Procedure
Before attaching the needle, the spore solution inside the syringe must be evenly dispersed because the microscopic spores settle at the bottom over time. Gently shake the syringe for about 30 to 60 seconds, or roll it between your palms, to break up any visible clumps. This action ensures that each drop of liquid expelled contains an adequate concentration of reproductive material for germination.
Next, attach the sterile needle, removing the protective cap only when ready to sterilize the tip. Sterilizing the needle is done using a flame source, heating the metal until the tip glows visibly red-hot, which typically takes 5 to 10 seconds. This process of heat sterilization is necessary to kill any microorganisms present on the needle’s surface.
Allow the needle to cool for a few seconds before proceeding, as a needle that is too hot can destroy the spores upon contact. Once cooled, the needle is ready to pierce the injection port or the self-healing lid of the sterilized substrate container. Insert the tip deep enough to reach the center of the grain or substrate, which facilitates an even distribution of the spores.
Expel the spore solution slowly and steadily by pushing the plunger, injecting a small amount of liquid into the substrate. The volume used is typically 1 to 2 milliliters for jars, or 2 to 5 milliliters for larger grain bags; using too much solution increases the risk of bacterial contamination due to excess moisture. After the required amount is expelled, quickly remove the needle and immediately seal the injection site. If inoculating multiple containers, re-sterilize the needle with the flame and allow it to cool completely between each injection.
Post-Inoculation Storage and Disposal
Once inoculation is complete, handling remaining spore solution and disposing of the needle require careful attention to safety protocols. If there is excess solution, remove the needle and securely replace the sterile cap onto the syringe. Store the remaining spore solution in a cool, dark location, such as a refrigerator, at temperatures between 35 and 46 degrees Fahrenheit.
Proper storage helps maintain spore viability, allowing them to remain dormant and usable for 12 to 18 months under refrigeration. The used needle must be handled as a sharp and cannot be thrown directly into the regular trash, as used sharps pose a significant biohazard risk.
Sharps must be placed immediately into a dedicated puncture-proof container. An FDA-cleared sharps container is the preferred disposal vessel, but a heavy-duty plastic bottle with a secure, tight-fitting lid can be used as a substitute. Once sealed and labeled clearly as “Sharps” or “Biohazard,” dispose of the container according to local guidelines.