Important steps in microbial testing

Sterilization and use of culture media

1. During each configuration, pay attention to whether the production date is within the shelf life, check the opening date and sealing of the bottle mouth to ensure that it does not deteriorate and does not absorb moisture.

When preparing the culture medium, the weighing should be accurate, including the accurate packaging of saltwater.

3. It is necessary to ensure that the freshly prepared culture medium is sterilized, and unsterilized culture media cannot be left for a long time, let alone overnight.

4. During sterilization, it is necessary to ensure constant temperature and pressure, while also ensuring effective sterilization time.

5. Sterilized culture media should be stored in the refrigerator for up to a week, usually not exceeding 3 days. And it is necessary to follow the principle of "first in, first out", and use the ones prepared first.

6. When using, it is necessary to first dissolve the culture medium into a liquid state using a water bath according to the usage of the current shift, and then adjust the water temperature in a timely manner (the pre melted can be taken out of the water and placed on the cover of the water bath) for use. Do not keep the culture medium in a high temperature state for a long time.

7. When conducting product microbiological testing, pour the culture medium at a temperature of around 45 ℃ and do not overheat to avoid scalding the bacteria to death; It should not be too cold, as the melted culture medium will clump and solidify, making it difficult to observe the results.

8. Each bottle of culture medium should be blank.

9. Try to concentrate on sampling and avoid frequent opening of the same bottle of culture medium stoppers to increase the likelihood of contamination and result in errors.

When there is too little remaining culture medium, it can be poured into a blank plate first.

Maintaining a sampling environment

1、 Overall environment (room)

1. When making samples, the windows and air conditioners should be closed, or the room should be spray with alcohol to prevent the air circulation in the room from affecting the internal environment of the ultra clean table (it is better to operate in a constant temperature and humidity sterile room with ventilation and exhaust system).

If the sample is taken in the original raw material microbiological testing room, the ultraviolet light should be regularly turned on to sterilize the room.

2、 Small environment (ultra clean table)

1. Regularly clean the primary filter and replace it in a timely manner.

Before sampling, clean the inside of the ultra clean table, wipe and disinfect it with 75% alcohol, and turn on the UV light of the ultra clean table half an hour in advance to sterilize the internal environment of the ultra clean table.

3. Turn off the UV light, turn on the fan, adjust the appropriate intake air volume, and the air volume should not be too low.

4. After each sample preparation, the interior of the ultra clean table should be cleaned and wiped with 75% alcohol for disinfection.

5. UV lamps should be replaced in a timely manner according to their service life.

6. At the same time as sampling, the corresponding colony detection environment should be blank.