Medium detection performance test

1. Appearance control

The prepared medium should have a corresponding color for detection. Generally, the detection medium should be clear, without turbidity, and without precipitation. Media assays should be checked for color changes and evaporation/dehydration prior to use.

2. Pollution Control

Select a part of the prepared medium from each batch to test for contamination (sterility test) to confirm that there is no microbial growth before use.

3. Performance test

(1) Selection of test strains The test strains are a group of strains that have the stable characteristics of their representative species and can effectively prove the best performance of specific medium detection in the laboratory. They should be from the ATCC standard strains of the International/National Standard Culture Collection. Refer to the health industry standard WS/T232-2002 "Quality Inspection Regulations for Commercial Microbial Culture Media".

(2) Quantitative test method (improved Miles-Misra method) overnight culture of the test strain and 10-fold incremental dilution; the test plate and the reference plate were divided into 4 areas and marked; starting from the highest dilution, drop a drop of dilution Marked areas on the test plate and control plate; apply the dilution to the entire 1/4 area, and incubate at 37°C for 18 hours; count the easily countable areas, and calculate the growth rate according to the formula (growth rate = total number of colonies / reference medium detection total number of colonies obtained on the plate). The growth rate of the target bacteria on the non-selective medium test should not be lower than 0.7, which should facilitate the growth of the target bacteria; the growth rate of the target bacteria on the selective medium test should not be lower than 0.1.

(3) Semi-quantitative test method (improved streak inoculation method)   Divide the plate into four regions ABCD, and draw 16 lines in total. The parallel lines are about 0.5 cm apart. Each stripe with colony growth was recorded as 1 point. Only half of the strains with colony growth were scored as 0.5 points, and no colony growth or less than half of the strains were scored as 0 points, and the growth index G was obtained by adding the scores. The target bacteria should show typical growth on the medium test, and the growth of non-target bacteria should be partially or completely inhibited. When the growth index G of the target bacteria is greater than 6, the culture medium is qualified.

(4) Qualitative test method (plate inoculation observation method) Use an inoculation loop to take the culture of the test bacteria, and draw a parallel line on the plate to test the surface of the medium. Incubate the inoculated plate according to the incubation time and temperature specified in the standard. Target bacteria should exhibit good growth with typical colony appearance, size and shape, while non-target bacteria should have weak or no growth.

The key testing personnel engaged in microbiological testing in the laboratory should have at least a college degree or above in microbiology or related majors, or have more than 10 years of working experience in microbiological testing. These are objective and rigid requirements for laboratory testing personnel. In addition, laboratory testing personnel should also have a high degree of subjective judgment. According to the individual's bacteriological skills, experience and professional level, the experimental operation and experimental results can be judged and analyzed. At the same time, the laboratory should also be equipped with personnel with corresponding technical capabilities to be responsible for the technical work of the laboratory, and set up quality supervisors.

The laboratory operation manual refers to a set of systematic document requirements that the laboratory should have, covering all aspects of laboratory operation, including but not limited to the responsibilities and authority of personnel at all levels, laboratory safety measures, sample collection and processing guidelines , training  basis and preparation of reagents, etc.  Laboratory manuals are procedural documents, not static. When changes or major changes occur in the laboratory, the operation manual should be revised accordingly to adapt to the operation of the laboratory.

The test environment requirements should meet the national standards. The examination room is required to be sufficiently spacious, ventilated, and well-lit. The walls and floors of the examination room should be of easy-to-clean materials. The examination room can be divided according to the work content, and special rooms can be set up. The backbone testing personnel engaged in microbial testing in the laboratory should have at least a college degree or above in microbiology or related majors, or have more than 10 years of working experience in microbial testing. These are objective and rigid requirements for laboratory testing personnel. In addition, laboratory testing personnel should also have a high degree of subjective judgment. According to the individual's bacteriological skills, experience and professional level, the experimental operation and experimental results can be judged and analyzed. At the same time, the laboratory should also be equipped with personnel with corresponding technical capabilities to be responsible for the technical work of the laboratory, and set up quality supervisors.

The laboratory operation manual refers to a set of systematic document requirements that the laboratory should have, covering all aspects of laboratory operation, including but not limited to the responsibilities and authority of personnel at all levels, laboratory safety measures, sample collection and processing guidelines , training  basis and preparation of reagents, etc.  Laboratory manuals are procedural documents, not static. When changes or major changes occur in the laboratory, the operation manual should be revised accordingly to adapt to the operation of the laboratory.

The test environment requirements should meet the national standards. The examination room is required to be sufficiently spacious, ventilated, and well-lit. The walls and floors of the examination room should be of easy-to-clean materials. The examination room can be divided according to the work content, and special rooms can be set up.