Welcome To Huida

Standard operating procedure (SOP) for monitoring bacterial sedimentation in clean areas

Principle: The sedimentation method is used, that is, the biological particles in the air are collected in a petri dish by using the principle of natural sedimentation, and after culturing for no less than 48 hours, they are allowed to multiply to a visible colony at 30-35 ° C for counting. The number of colonies is used to determine the number of living microorganisms in the clean environment, and this is used to evaluate the cleanliness of the clean room (area).
Main content:
1. Equipment:
Autoclave: Strictly follow the instructions when using it.
Constant temperature incubator: The thermometer of the incubator must be checked regularly.
Petri dish: Φ90mm glass petri dish
Medium: Nutrient agar

Petri Dish Glass Culture,Petri Dish Glass,Glass Petri Dish 90mm

2. Operating procedures
2.1 Sampling
Place the prepared petri dish as required, open the lid of the petri dish, expose the surface of the medium for 0.5 hours, then cover the petri dish and turn it upside down.
2.2 Cultivation:
2.2.1 After all sampling, place the petri dish upside down in a constant temperature incubator for cultivation.
2.2.2 Culture in a 30~35℃ incubator for no less than 48 hours.
2.2.3 Each batch of culture medium should have a control experiment to check whether the culture medium itself is contaminated. Three petri dishes can be selected in each batch for control experiments.
2.3 Colony counting
2.3.1 Count directly with the naked eye, mark or count on the colony counter, and then check with a 5-10 times magnifying glass to see if there is any omission.
2.3.2 If there are 2 or more colonies on the petri dish overlapping, still count 2 or more colonies when they can be distinguished.
2.4 Notes
2.4.1 The test utensils should be sterilized to ensure the reliability and correctness of the test.
2.4.2 Take all measures to prevent artificial contamination of the samples.
2.4.3 Make detailed records of the culture medium, culture conditions and other parameters.
2.4.4 Due to the wide variety of bacteria, the difference is very large. When counting, generally use transmitted light to observe carefully on the back or front of the petri dish. Do not miss the count of colonies growing on the edge of the petri dish. Pay attention to the difference between bacterial colonies and culture medium sediments. Identify with a microscope.
2.4.5 The quality of each petri dish should be carefully checked before sampling, and those found to be deteriorated, damaged or contaminated should be rejected.
3. Test Rules
3.1 Test Status
3.1.1 Before the sedimentation bacteria test, the temperature and humidity of the tested clean room (area) must meet the specified requirements, and the static pressure difference, the number of ventilation times, and the air flow rate must be controlled within the specified values.
3.1.2 Before the sedimentation bacteria test, the tested clean room (area) has been sterilized.
4.1.3 There are two types of test states: static and dynamic. The choice of test state must meet the production requirements, and the test state shall be indicated in the report.
3.2 Testers
3.2.1 Testers must wear work clothes that meet the environmental cleanliness level.
3.2.2 During the static test, there shall be no more than two indoor testers.
3.3 Test time
3.3.1 For unidirectional flow, such as 100-level clean room and laminar flow workbench, the test should start no less than 10 minutes after the normal operation of the clean air-conditioning system.
3.3.2 For non-unidirectional flow, such as clean rooms with class 10,000 and class 100,000 or above, the test should start no less than 30 minutes after the clean air-conditioning system operates normally.
3.4 Counting of sedimentation bacteria
3.4.1 Number of sampling points and their arrangement
The minimum number of sampling points for sedimentation bacteria test can be determined by referring to Table 1. While meeting the minimum number of measuring points, it should also meet the minimum number of petri dishes