How to verify the sterilization effect of pressure steam sterilizer

1. Test materials

① Bacillus thermophilus paper; Bacillus thermophagus atcc7053, spore content 5-105 CFU / tablet

② 121 ℃ pressure steam sterilization chemical indicator card; Bromocresol purple peptone water medium, 116 ℃ for 20 minutes, high pressure and standby.

③ 0-150 ℃ retention thermometer

2. Methods and results

Put the paper piece of Bacillus thermophilus into a sealed test tube with sterile tweezers. Put the chemical indicator card and the thermometer in an open test tube. Prepare 5-10 copies of each of the above two test tubes. They are respectively placed at the steam port, bottom exhaust port, bottom water inlet or 5 places in the middle of the upper, lower, left and right. If the pressure steamer is on the second floor, it needs to be placed 10 places. The retention point thermometer can be used for verification test after it is standardized and qualified. Before testing, the mercury column of the thermometer shall be thrown below 40 ℃. After each monitoring, the temperature difference of the reserved point thermometer shall be between 1 ℃, which indicates that the temperature distribution in the pressure steamer is uniform. The bacteria tablet shall be placed in bromocresol purple peptone water medium under strict aseptic operation conditions. Culture at 56-60 ℃ for 24-48 hours and observe the color change. If the culture medium turns yellow, it indicates that the thermophilic Bacillus in the bacteria tablet has not been completely inactivated, the bacteria can still grow in the culture medium, decompose glucose and produce acid and turn yellow. If the color of the medium remains purple, it indicates that the spore has been inactivated. At the same time, put the untreated paper into the culture medium as the positive control, and the blank culture medium without paper as the negative control. The indicator color block on the chemical indicator card changes from light yellow to black when the pressure steamer. With the change of color depth, and compared with the control color, it can judge whether the effect meets the requirements. The chemical indicator card shall be kept in a dry place. It will change color in case of tide, which will affect the observation effect. The effect of the pressure steamer can be achieved only when the steam enters the steamer smoothly, contacts with articles, and discharges the original cold air. No load heat distribution and full load heat penetration shall be verified (no more than 2 / 3 of the total volume at full load). The two kinds of verification are repeated three times, and a total of six tables are made. Six tests at five points show that the temperature is 121 ℃, and the chemical indicator card turns black; The degree is consistent with the control color; The color of the culture medium has not changed, indicating that the effect of the pressure steamer is qualified