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I. Purpose: These procedures are intended to provide a standardized set of guidelines for operations in microbiology laboratories； II. Scope of application: Microbiology laboratory ； III. Responsible party: Laboratory, Microbiology tester ； IV. Safety precautions: Strictly follow aseptic procedures to prevent microbial contamination; operators entering the microbiology laboratory should turn off the ultraviolet light first. V. Standard Operating Procedures for Microbiology Laboratories: 1. Microbiology laboratories should be equipped with a sterile operation room and a buffer room. The cleanliness level of the sterile operation room should reach Class 10,000, with the indoor temperature maintained at 20–24°C and the humidity at 45–60%. The cleanliness level of the laminar flow hood should reach Class 100. 2. Microbiology laboratories should be kept clean; the storage of miscellaneous items is strictly prohibited to prevent contamination. 3. Strictly prevent contamination of all sterilization equipment and culture media; those that have become contaminated should be discontinued from use. Microbiology laboratories should be equipped with disinfectant at a working concentration (75% alcohol). 4. Microbiology laboratories should be regularly disinfected and cleaned using appropriate disinfectants to ensure that their cleanliness meets the required standards. 5. All items to be taken into the microbiology laboratory, such as instruments, equipment, petri dishes, etc., must be properly wrapped and sterilized using appropriate methods. 6. Before entering the microbiology laboratory, staff must wash their hands with soap or disinfectant, then change into special work clothes, shoes, hats, masks, and gloves in the buffer room; they must also wipe their hands again with a 75% alcohol solution before they can enter the laboratory to carry out their tasks. 7. Before use, the microbiology laboratory must be irradiated with ultraviolet light for more than 30 minutes to achieve sterilization, and at the same time, the fume hood should be turned on to allow air circulation. After the operation is completed, the microbiology laboratory should be cleaned promptly, followed by sterilization using ultraviolet light for 30 minutes. 8. Before inspection, the sample’s outer packaging must remain intact and not opened to prevent contamination. Before inspection, disinfect the outer surface with a cotton ball soaked in 75% alcohol. 9. A blank control should be used in each procedure to verify the reliability of aseptic techniques. 10. When drawing up the bacterial solution, it must be done using a suction bulb; never touch the pipette directly with your mouth. 11. Before and after each use, the inoculation needle must be sterilized by flame treatment; it can be used to inoculate the culture only after it has cooled down. 12. The pipettes, test tubes, and petri dishes containing the bacterial solution were placed in an autoclave at 121°C for 20 minutes, after which they were taken out and cleaned. 13. If bacterial solution spills on the table or floor, it should be immediately covered with 75% alcohol solution on the contaminated area for at least 30 minutes before further action is taken. If work clothing, hats, etc. are contaminated with bacterial solutions, they should be removed immediately and washed after high-pressure steam sterilization. 14. Any items containing live bacteria must be disinfected before being rinsed under a tap; it is strictly prohibited to contaminate the sewer system. 15. Microbiology laboratories should check the colony count monthly. With the laminar flow cabinet turned on, several sterile petri dishes with an inner diameter of 90 mm were taken. Using aseptic techniques, approximately 15 mL of nutrient agar medium that had been melted and cooled to around 45°C was poured into each dish. After the medium solidified, the dishes were placed upside down in an incubator at 30–35°C for 48 hours. Once it was confirmed that the dishes were sterile, 3–5 of them were taken and placed in positions such as the left, center, and right parts of the working area. After exposing them to the air for 30 minutes with the lids removed, they were again placed upside down in an incubator at 36°C for 48 hours before being taken out for inspection. In a Class 100 clean area, the average number of total colonies on surfaces should not exceed 1, while in a Class 10,000 clean room it should not exceed 3 colonies. If the limit is exceeded, the microbiology laboratory must be thoroughly disinfected until repeated testing shows it meets the requirements.