Aseptic operations are relative; there is no absolute aseptic operation. Asepsis and contamination are matters of probability. By minimizing the likelihood of contamination, we can achieve aseptic culture.

All Possible Contamination Scenarios and Corresponding Solutions:

1. Damaged Intake Filter, Open the filter jacket and inspect the filter for visible cracks, accumulation of fermentation materials, other impurities, or stagnant water that cannot be drained.

2. Leaks in the Fermenter, Maintain positive pressure and use soap bubble tests to detect leaks. If positive pressure is maintained throughout the fermentation process, minor leaks are usually not a significant issue. However, leaks in the inlet pipeline are strictly unacceptable.

3. Dead Angles in the Fermenter, Dead zones are critical. Inspect all openings, unscrew them, and clean them thoroughly with alcohol.

4. Mechanical Seal Leakage (Oil Leak), This is generally unlikely to occur.

5. Fermentation SterilizationOperations

For small fermenters, energy conservation is not a concern, especially since many small fermenters do not require direct steam contact. However, certain issues can still arise:

（1）Excessive Steam Flow: This can cause false pressure, particularly in fermenters where steam enters the tank. Rapid heating and low outlet flow can lead to a sudden rise in tank pressure while cold air remains trapped in the pipes.

（2）Insufficient Agitation During Sterilization: Poor heat transfer can create false pressure. Maintain the temperature at 90°C for a while before proceeding. To protect the motor, agitation may stop once the temperature exceeds 100°C.

（3）Unbalanced Steam Distribution: False pressure can occur if steam enters areas where it shouldn’t, such as steam inlets above the liquid level (though this is rare in small fermenters).

（4）Incomplete Sterilization: Beginners often overlook certain areas. A good rule of thumb: All inlet and outlet pipeline valves should be hot to the touch during sterilization.

（5）Over-Adjustment of Steam Inlet and Exhaust Valves: Rapid adjustments during sterilization can cause pressure fluctuations and foaming.

（6）Excessive Foaming: Too much foam can lead to incomplete sterilization.

（7）Material Handling: For materials prone to clumping, ensure they do not form clumps inside the tank. Pre-dissolve such materials externally before adding them to the fermenter.

（8）Incomplete Air Filter Sterilization: Depending on the fermenter, ensure the steam filter is sterilized with the fermenter. Check for leaks in the pipeline and ensure the filter is properly dried.