Quality control operation procedures for microbiological testing

There are many complex factors in the actual work of microbiological testing, may bring deviation or even error to the test results, so many factors affecting the test results must be controlled to ensure the correctness of the test results, and constantly improve the quality control of microbiological testing1The(1) Microbiological testing of the inspectors cannot be completely dependent on fully automatic identification instruments, and each step of the inspection requires a high degree of subjective analysis and judgment, which is closely related to the individual's experience, skills and the basic level of microbiological testing(2) In addition to requiring microbiological testers to have a serious work attitude, sophisticated observation and operating habits, pay attention to personal hygiene, but also must be trained to master microbial testing technology(3) inspectors should implement the pre-induction training system, pre-induction training qualified to be able to operate, but also take the initiative to participate in learning, training, lectures, learning new technologies, master microbiology testing methods, standards and related laws and regulations(4) participate in the preparation of test procedures and instrument operating procedures, learning the quality assurance system knowledge and the basic knowledge of metrology(5) participate in various level and blind tests to improve the level of detection and analysis of problems, problem-solving ability(6) The person in charge of the microbiology laboratory shall regularly assess the professional knowledge and operational proficiency of the inspectors and improve the quality of the inspectors21 in order to ensure the quality index of dry powder medium, in practice should pay attention to,(1) strengthen the sealing performance of packaging,(2) use to minimize the opening time,(3) general dry medium in low temperature dry environment preservation, for moisture-prone varieties, after activation should be put into the dryerto save;2 medium sisphers should be formulated in strict accordance with the standard method, and do a good job of the original record3 in order to ensure that the medium must be carried out in a glass container, enamel or aluminum pot, such as copper, iron utensils, will have a toxic effect on microbial growth;5 to take drugs with a special angle spoon to avoid cross-contamination and affect the test results,medium preparation is best using distilled water or deionized water, avoid the use of tap water, because it contains chlorine and other antibacterial substances;7 effect test refers to the corresponding strains of different mediums, to observe the bacterial hair, colony shape, pigment, hemolytic blood and other characteristics, and to determine whether the medium meets the requirements3Inspection qualityin addition to the national standard method of testing the required items, in the actual work should also pay attention to the following aspects, otherwise it will affect the accuracy of the test results:(1) in quantitative inspection with weight or volume method, test results will have errors, because this weight is not equal to 1 sample, 1ml and 1g of laboratory results will never be equalgeneral solid-state samples should be used weight method, liquid samples should be used volume methodbut for viscous liquids (e.gyogurt), such as the volume method, will adhere a certain amount of samples to the straw, so such samples are best used by weight(2) If the sample needs to be diluted with sterile water or sterile physiological saline, it is best to use a homogenizer or tissue shredder, at a speed of 8000'10000 rpm treatment 1min, to make a uniform bacteria suspension(3) sample dilution, often will be stranded a small number of samples inside and outside the straw, should pay more attentioninhaling liquid, should be slowly injected along the pipe wall into the incremental dilution, pay special attention to the tip of the straw at this time must not touch the dilution(4) in the medium injection sample, bacteria suspension, note that the temperature of the medium should be between 45 degrees C-50 degrees C, and make the medium and the sample, the bacteria suspension is fully mixed (5) microbial culture, the correct culture temperature and time should be selected according to the requirements (6) apply sterile water or sterile physiological saline for blank control, if bacteria are detected in a blank control, it can be considered that there is a problem with the quality of the medium or there is contamination during operation , the quality of the medium was observed by using the standard strains as a positive control (7) strictly observe sterile operation throughout the inspection process (8) check the results in a timely manner and record the original data 4 Reference strains and their preservation laboratories should prepare sufficient types and numbers of reference strains to meet the needs of medium, kit and reagent quality testing Save strains to be passed down regularly, pay attention to sterile operation, so that the strains do not pollute, do not die, do not discard 1 should be set up a person to keep safe, strain storage box should be locked to place suitable environment, take out the use should be registered ; 2 preservation strains should be registered, the basic project should include the name of the strains, separation sources, separation dates, transmission dates, preservation methods, main characteristics, custodians, occupiers, etc. ; 5 Common reference strain preservation methods bacteria (1) oxygen-demanding bacteria with low nutritional requirements can survive for 1 year on the slope of pancreatic soybean agar (2) long-term storage of aerobic or anaerobic bacteria needs to be frozen and dried or stored at -70 degrees C (3) the low nutritional requirements of the freeze-dried bacteria species every 5 years to thaw separation and refreeze (4) bacteria can be suspended in sterilized defat milk, containing 15% glycerin, pancreatic soybean broth or sterile horse blood fungal (1) yeast treated in the same way as bacteria with low nutritional requirements (2) mold is stored at 4 degrees C on the potato glucose agar slope for 6 months-1 year, and the oblique surface covered with sterilized paraffin oil can be stored at room temperature for a long time the method of concitering 6 The method of preserving the bacteria 1 regular transplant preservation method: inoculate the species in the appropriate oblique or liquid culture medium, can also be perforated culture, such as growing into a robust bacteria (interstitial cells, sexual spores or asexual spores), the bacteria species will be placed at a time 4 degrees C refrigerator preservation, each interval needs to be re-cultivated Bacillus spores are transplanted once for 3-6 months, and other bacteria are transplanted once a month 2 liquid paraffin preservation method: this method is a supplement to the regular value-shifting preservation method, covering a layer of sterile paraffin on the well-growing slope surface, liquid surface 1cm higher than the medium, its test tube rack in an upright state of low temperature preservation, liquid paraffin can prevent water evaporation, isolation of oxygen, so can extend the preservation time 3 sand pipe preservation method, soil preservation method 4 bran preservation method 5 distilled water preservation method 6 liquid nitrogen ultra-low temperature preservation method 7 glycerin preservation method 8 frozen drying preservation method freezing drying preservation method general process (1) ampoule pipe --- acid, washing --- drying---- (2) The preparation of protective agent ---- sub-assembled ---- sterilization (3)--- culture--- preparation of bacterial suspension (added 2) ---- the pre-frozen---- ---- vacuum drying ---- installed on the manifold vacuum ----- the flame melting the ampoule port ---- detection vacuum ---- preservation 7 internal quality control (1) internal quality control In order to ensure the reliability and precision of the continuous evaluation results of the laboratory, the repeatability and reproducibility of the methods used must be measured regularly For different control systems, the laboratory must establish limits, and correction measures should be taken to exceed them internal quality control in practice may include: (1) systematic use of one-sided colony count determination, (2) parallel samples by the same inspector and several inspectors, and (3) regular or irregular blind sample testing (ii) External quality control laboratory shall participate in external quality control activities and each test carried out shall participate in the corresponding inter-room quality control test samples issued by the relevant laboratory or regulatory body should be treated strictly as normal samples, a method that contributes to the accuracy and repeatability of the laboratory's daily tests and is a test of the methods, reagents, equipment, and personnel capabilities used in the laboratory errors in interroom sample testing can find deficiencies in the laboratory, and improvements in staff education can improve the quality of laboratory testing problems in the return of interroom measurement ratings should be convened to the body's employees for discussion, and improvements (including changes in methods, changes in employees, retraining of employees, replacement of the source of the medium and reagent purchase, etc.) should be documented some projects lack inter-room quality control, the laboratory can set up indoor quality control, semi-annualself self-assessment often participate in microbiological laboratory quality control activities, help to strengthen the basic skills of testing personnel training, enhance the sample test ingons in the process of "quantity" concept laboratory quality control can be carried out at home and abroad, capable laboratory should strive to participate in inter-country quality control activities, establish a good reputation for testing the quality control of microbiological testing is more complex, there is no unified norms, the domestic laboratory conditions are uneven, in order to make the quality control of microbial testing day by day perfect, still need the majority of microbial testing personnel to work together