應用聚合酶鏈反應於數種不同食品中腸毒素型金黃色葡萄球菌之檢測   全文下載

Application of Polymerase Chain Reaction (PCR) for the Specific Detection of Enterotoxigenic Staphylococcus aureus in Various Food Samples

本研究係利用金黃色葡萄球菌各型腸毒素基因檢測用PCR引子，於不同食品中腸毒素型金黃色葡莓球菌之檢測，結果發現，食品中污染之其他細菌，以及食品之組成分，並不干援PCR檢測之特異性。PCR檢測靈敏度之探討，則發現在PCR循環數為35時，每毫升菌液含10 CFU以內之目標菌，或每克食品含100 CFU以內之目標菌可被檢測出：但PCR循環數降為25時，到每毫升所需菌數增加為104CFU以內。目此，若在適當的PCR循環數下，配合將目標菌短時間增殖，再予以稀釋之觀念，由於活菌可以增殖，死菌則否，PCR方法將有區別死菌及活菌之可能。

In this study, PCR primers specific for Staphylococcus aureus enterotoxin genes were used for the detection of enterotoxigenic S. aureus in foods. Neither the naturally occuring microflora in the food samples nor the food components would interfere with the detection. Study on the detection sensitivity showed that when PCR cycles were 35, DNA from < 10 CFU per ml of target bacterium in culture broth or < 100 CFU per gram of food sample could be detected. However, when the PCR cycles were reduced to 25, the cell numbers required for positive reaction were > 1000 CFU per ml of culture broth. Therefore, a short enrichment of target cells followed by suitable dilution and PCR using a suitable number of cycles could detect viable bacteria. Non-viable cells which could not grow would be diluted out and not be detected by PCR.