- 期刊
不同檢驗方法對食品衛生指標菌能力試驗檢測結果的差異
Discrepancy in the Efficacy of Different Methods for Food Microbiology Proficiency Testing
摘要
檢驗室對日常檢測品質可藉由參加能力試驗（proficiency testing）計畫進行評估。本研究將分析使用不同的檢驗方法對含有Escherichia coli O157:H7、Enterobacter cloacae和Staphylococcus aureus之兩個不同能力試驗檢體的衛生指標菌檢測結果的影響，參加檢測衛生指標菌的項目為生菌數、大腸桿菌群與大腸桿菌計數。參加者使用的檢驗方法包括台灣衛生福利部食品藥物管理署公告方法（以下簡稱TFDA法）或商業化簡便方法（以下簡稱簡便法），結果顯示兩種方法對生菌數檢測的滿意度均達90%以上。在大腸桿菌群的定量檢測方面，參加者使用45.5℃培養溫度的舊有TFDA法，檢體一及二的滿意度分別為66.7%（14/21）及76.2%（16/21），而使用簡便法者分別為92.3%（36/39）及83.8%（31/37）。在大腸桿菌定量檢測方面，使用TFDA法的單位檢體一及二之未檢出率分別佔66.7%（12/18）及58.8%（10/17），其餘檢出者的菌數範圍可從少量至2.4×10^4 MPN/mL，相反地，利用簡便法檢測的所有參加單位（檢體一者為42家，而檢體二者為39家）對兩個檢體中的大腸桿菌均無法檢出（即所有參加者對兩檢體的不滿意度均為100%）。由於TFDA即將施行之「食品中微生物衛生標準」規定某些食品若為大腸桿菌陽性，需另外操作大腸桿菌O157:H7之檢驗，因此，食品檢驗室從業人員有必要選擇適當的方法進行檢驗。
並列摘要
The quality of food microbiology laboratories is monitored by proficiency testing. In this study, the effect of methods used for detection and quantification of bacteria in two separate samples containing a mixture of Escherichia coli O157: H7, Enterobacter cloacae, and Staphylococcus aureus was evaluated. Participating laboratories were requested to perform 3 tests, including (1) aerobic plate counts, (2) quantification of coliform bacteria, and (3) quantification of Escherichia coli O157:H7. Two different methods were used by various participants, including the one published by the Taiwan Food and Drug Administration (TFDA) (referred to as the TFDA method hereafter) and a simplified commercial method (referred to as the simplified method hereafter). Results showed that both methods were satisfactory for aerobic plate counts as more than 90% of the participants passed the test. For quantification of coliform bacteria, 14 of 21 (66.7%) participants correctly tested sample 1, and 16 of 21 (76.2%) participants correctly tested sample 2 using the old TFDA method with higher incubation temperature. With the simplified method, 36 of 39 (92.3%) and 31 of 37 (83.8%) participants correctly tested sample 1 and sample 2, respectively. For quantification of Escherichia coli O157:H7, 12 (66.7%) of the 18 participants that tested sample 1 failed, and 10 (58.8%) of the 17 participants that tested sample 2 failed using the TFDA method. In contrast, all participants (42 tested sample 1 and 39 tested sample 2) that used the simplified method failed on both samples (i.e. 100% unsatisfactory rates). For those who successfully completed the test, the most probable number (MPN) of Escherichia coli O157:H7 determined was approximately 2.4×10^4 MPN/mL. As detection and quantification of Escherichia coli O157:H7 will be required according to the upcoming ＂Hygiene Standards for Microorganisms in Foods＂ of TFDA, it is critical for food microbiology laboratories to use appropriate methods for testing.