In environmental monitoring, in order to detect microorganisms in the air, in addition to selecting a suitable sampler, it is also necessary to understand the performance, classification, sampling method and sample inspection of the sampling medium.
1. Air microbiological sampling medium
(1) Performance of sampling medium
1. Stability: The sampling medium should not interfere with the collected microorganisms to maintain the original properties of the microorganisms.
2. Adhesion: Especially when sampling with a sampler, if the vessel has no medium or the medium adhesion is very low, the capture rate of bacterial particles can be reduced, so the medium must have a certain viscosity, so that the collected bacterial particles can be firmly attached While being captured.
3. Non-toxic: The sampling medium should be non-toxic and irritating, so that the collected microorganisms can survive and count after cultivation.
4. Protection: The sampling medium should not be easy to dry, and has the properties of water solubility and anti-inactivation to protect air microorganisms.
(2) Classification
At present, there are many types of sampling media, such as sugars, proteins, alcohols, silicones, tissue culture, mixed, etc., can be selected according to the type of microorganisms collected.
There are also many mediums for cultivating air bacteria. For example, the general nutrient agar medium can be used for the cultivation of the total number of bacteria. .
Second, the sampling method
The sampling method of air microorganisms should be determined according to the requirements of the sampler used. Since there are many types of samplers, they should be flexibly applied according to the characteristics of various samplers.
When sampling in a static airflow with a sampler, the sampling head is generally upward, while in the state of airflow, the sampling head should face the direction of airflow. Since most of the indoors are in a turbulent state without a certain direction, the airflow can be ignored The question of direction. The sampling volume and the number of measurement points can be determined according to the indoor cleaning conditions.
3. Sample inspection
The detection of air microorganisms can be identified according to the requirements of the Ministry of Health. During the sampling and sample delivery process, the occurrence of pollution should be prevented, and the sample should be tested for the corresponding indicators as soon as possible after sampling. Under the condition of 0 ～ 4 ℃, the inspection time can be extended properly but not more than 24 hours.
Air microbial sampling should ensure that the sample can reflect the original state as much as possible. However, although various sampling methods have their own advantages, they generally cannot fully meet this requirement. In short, some progress has been made in the monitoring of air microbes. , The rapid and automatic identification of air microorganism sampling methods will be more perfect.
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