品管培養基的調菌技術

中華人民共和國食品安全國家標準食品微生物檢驗有關培養基和試劑的品質要求(GB 4789.28-2013)建議操作培養基（如平板計數培養基）的品管試驗時，接種的工作菌懸液菌數為20-200 CFU，而各國藥典也建議藥品微生物限度檢查時需接種不大於100 CFU的菌液進行滋養性培養基(如trypticase soy agar，TSA)生長效能及方法適用性試驗。雖然市場上有不大於100 CFU的菌液販售，但是費用很高，況且菌落計數結果受到品管人員的訓練程度、儀器設備、操作技巧等影響。為了能夠快速並準確地得到正確接種菌量，本研究進行吾等設計的調菌技術評估。測試時挑菌以0.85% NaCl調菌至約相當於麥氏濁度標準No. 0.5，然後用可見光光度計分別測定金黃色葡萄球菌(Staphylococcus aureus)、銅綠假單胞菌(Pseudomonas aeruginosa)、枯草芽孢桿菌(Bacillus subtilis)、白色念珠菌(Candida albicans)與黑麯黴(Aspergillus brasiliensis)五種試驗菌的數種O.D. (optical density)值，菌液經稀釋後每個稀釋菌液分別取不同量塗抹於TSA，結果指出接種濃度之一皆能使測試細菌與酵母菌能準確獲得50-99 CFU，而黴菌40-80 CFU 的接種菌量。本研究所應用的調菌技術可作為工業廠家品管作業時快速調菌至適當濃度的參考。

關鍵字

培養基品管；調菌技術；分光光度計； OD值；麥氏濁度標準No. 0.5

並列摘要

The＂Performance testing of culture media and reagents＂(GB 4789.28-2013) regulations in the National Standards (GB) of Food Microbiological Examination promulgated by the People's Republic of China state that the concentration of a working microbial suspension should be 20-200 CFU when performing quality control testing of culture media (e.g. plate count agar, PCA), whereas inoculating microbial counts of not more than 100 CFU for enriched media (e. g. trypticase soy agar, TSA) are recommended by the pharmacopoeia published by other countries. Although microbial suspensions of ＂not more than 100 CFU＂ have been sold by various companies on the market, these products are expensive and the results obtained by them are affected by the training provided to QC personnel, as well as the equipment, facilities and operation techniques used. This study engaged in the evaluation of microbial concentration-adjustment techniques established by our laboratory. We first picked up a little quantities of microbial c olonies of each species and separately adjusted them to concentrations equivalent to McFarland 0.5 standard, after which the optical density (O.D.) of each was individually determined using a visible light spectrophotometer (600 nm wavelength). The microorganisms used in this evaluation included Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans and Aspergillus brasiliensis. The adjusted microbial suspensions were then individually diluted to a suitable concentration, different volumes of diluted suspensions were then taken for each microorganism type and applied to TSA, after which the spreading method was performed. The results indicated that at least one of the inoculating plates could obtain 50-99 CFU accurately for bacteria and yeast, whereas 40-89 CFU could be accurately obtained for mold. The microbial concentration-adjustment techniques established by our laboratory may thus be used to rapidly adjust microbial concentrations used in the quality control of culture media in industries.

並列關鍵字

Quality control testing of culture media ； microbial concentration-adjustment techniques ； spectrometry ； optical density ； McFarland No. 0.5

國際替代計量

品管培養基的調菌技術

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