High pressure steam sterilizer sterilization effect verification:
Only small number of culture only need heat and dissolve, and no need to for autoclaving, large number of the culture need 121℃ high temperature sterilization for 15-30 minutes, especially for the sterile culture, the sterilization of the culture would effect the test result. As a result, it is necessary to carefully verify the sterilization effect.
A. Bacillus thermophilus paper. Bacillus stearothermophilus (5-l05CFU/) ATCC7053 is a commonly used biological indicator of this method. Spores containing: 5-105CFU/tablet.
B. 121℃ pressure steam sterilization chemical indicator.
C. Bromine violet water medium 116 minutes high pressure sterilization by 20 minutes.
D. 0-150℃ drop thermometer.
method and result:
The Bacillus cereus strip (hereinafter referred to as bacteria) is sterilized in a sealed test tube with sterile tweezers. The chemical indicator and the drop point thermometer are placed in the open test tube. Prepare 5-10 copies of each of the two test tubes. Place the tubes in the autoclave steam mouth, bottom of the exhaust port and the bottom of the water outlet, or up, down, left, right, middle of the autoclave five places separately. If the sterilizer has two layers, you need to put in 10 places.
After drop thermometer can be used for verification and test only after it is qualified. Before test, the column of the thermometer shall be swung below 40 degrees before testing. After each monitoring, the temperature difference is less than 1℃， then it indicates the temperature distribution inside the autoclave is even.
Bacterium after sterilization should be placed in the sterilized bromocresol purple peptone water under the conditions of medium 56-60 ℃ for 24-48 hours of culturing, to observe the color change. If the culture medium turns yellow, it shows that the Bacillus thermophilus in the bacterial tablet has not been completely inactivated, the bacteria can still grow in the medium, decompose the glucose, produce the acid and turn yellow. If the medium does not change in color, it is still purple, it indicating that the spores are inactivated. Non sterilized paper need to be put into culture medium as a positive compare, blank without paper medium as negative compare at the same time.
The indicator color on the chemical indicator card is changed from light yellow to black after sterilization. Compared with the contrast color during the color change to judge whether the sterilization effect meets the requirement. The chemical indicator card should be kept in a dry place.Or it would effect the observation of sterilization effect after it tides.
The steam run smoothly into the sterilizer fro high pressure sterilization to contact with the items for sterilization, and discharge the original cold air to achieve the sterilization effect. The no-load heat distribution and full load thermal penetration verification should be conducted (2/3 of the total volume is less than the full load). The two verification should be repeated for three times separately, that is six times in total.
If , the chemical indicator card is black, and the color is the same as the color for contrast, then it shows that the temperature is 121 is evenly displays in 5 points for 6 time. If the medium has not changed color, it shows that the sterilization effect of high-pressure steam is qualified.
High pressure sterilizer belongs to strong inspection instrument, but strong inspection is only the examination of physical parameters of instrument. Therefore, the sterilization effect test still need to be verified after the strong examination is passed. Some institute often overlook this important issue. Domestic market portable sterilizer, often instrument pointer to achieve the required temperature, but the actual temperature of sterilization items did not meet the requirements., which lead to incomplete sterilization, and affect the result of experiment. The sterilization of culture medium is not complete, which affects the use of culture medium and result judgment. Therefore, the validation of the aseptic effect of autoclave is a problem that must be paid attention to.