1. Pressure Cooker Sterilization:
– Preparation: Fill heat-resistant bags or jars 2/3 full with substrate.
– Setup: Add 2-3 cm of water to the pressure cooker, place bags/jars on a rack.
– Process: Seal cooker, heat to 15 PSI (121°C).
– Sterilization time: 90 minutes for bags up to 1 kg, 2 hours for 1-2.5 kg, 2.5 hours for over 2.5 kg.
– Cooling: Allow to cool naturally, don’t open until pressure drops.
– Advantages: Highly effective, kills most contaminants including spores.
– Disadvantages: Limited capacity, requires specific equipment.
2. Steam Sterilization:
– Preparation: Use a large pot or steam sterilizer with a rack at the bottom.
– Setup: Add water below rack level, place substrate in permeable bags.
– Process: Bring water to boil, then reduce to a gentle boil.
– Sterilization time: 2-3 hours for smaller amounts, 4-6 hours for larger or denser substrate.
– Maintenance: Check and replenish water as needed.
– Advantages: Simpler than pressure cooker, suitable for larger volumes.
– Disadvantages: Less effective than pressure cooker, longer sterilization time.
3. Lime Treatment:
– Preparation: Mix substrate with 5-10% by weight of hydrated lime.
– Process: Thoroughly mix and moisten the mixture.
– Curing: Leave for 3-7 days in a cool place, pH will rise to 12-13.
– pH Adjustment: Wait until pH drops to 5.5-6.5 (may take several days).
– Monitoring: Regularly check pH with a meter or indicator strips.
– Advantages: Simple, doesn’t require special equipment.
– Disadvantages: Time-consuming, requires careful pH monitoring.
4. Fermentation:
– Preparation: Soak substrate in water at a 1:1 ratio.
– Process: Allow to ferment for 3-5 days at room temperature.
– Maintenance: Stir daily for even fermentation.
– Check: Monitor color and smell changes – should be sweet, not rotting.
– Finishing: Drain excess water, adjust moisture.
– Advantages: Natural process, promotes beneficial microorganism growth.
– Disadvantages: Less controllable, risk of unwanted fermentation.
5. Hot Water Pasteurization:
– Preparation: Heat water to 65-80°C in a sufficiently large container.
– Process: Submerge substrate in a permeable bag into hot water.
– Time: Maintain temperature at 65-80°C for 1-2 hours.
– Finishing: Remove substrate, drain and cool.
– Advantages: Simpler than sterilization, sufficient for some substrates.
– Disadvantages: Less effective against resistant spores.
6. Chemical Disinfection:
– Preparation: Prepare a solution of hydrogen peroxide (3%) or other disinfectant.
– Process: Soak substrate in solution for 30-60 minutes.
– Mixing: Thoroughly mix for even disinfection.
– Rinsing: After disinfection, rinse thoroughly with clean water.
– Finishing: Drain and adjust moisture.
– Advantages: Quick, effective against many pathogens.
– Disadvantages: Potential residual chemicals, need for rinsing.
7. UV Radiation:
– Preparation: Spread a thin layer of substrate on a clean surface.
– Process: Place UV lamp 30-50 cm above the substrate.
– Time: Irradiate for 30-60 minutes, then turn and repeat.
– Safety: Use protective eyewear, prevent direct contact with UV.
– Advantages: No chemicals, suitable for small quantities.
– Disadvantages: Effective only on the surface, limited penetration.
8. Microwave Sterilization:
– Preparation: Place a small amount of substrate in a microwave-safe container with some water.
– Process: Heat on high power until boiling point.
– Time: Continue heating for 5-10 minutes after reaching boiling point.
– Finishing: Allow to cool before opening the container.
– Advantages: Quick, suitable for very small quantities.
– Disadvantages: Limited capacity, uneven heating.
When choosing a method, consider:
– Type of substrate and its properties
– Available equipment and resources
– Required level of sterility
– Time and energy you can devote to the process