食品微生物能力验证样品菌落总数检验方法

Detection methods of aerobic plate count on food microbiological proficiency testing

目的探讨菌落总数能力验证的检验方法及注意事项。方法采用PCA直接倾注法、增加覆盖一层琼脂培养基的方法、添加TTC方法、陶瓦盖代替平皿盖的方法同时进行试验,并采用提前观察、增加观察的频率和培养时间,加强计数准确性。结果在前期培养过程中加强观察能够有助于计数,而延迟培养时间则可避免迟缓生长的细菌漏检;采用含有0.5%TTC培养基进行培养或陶瓦盖平板法能有效抑制蔓延菌生长,且不影响总体计数结果。结论采用多种检验方法有助于菌落总数能力验证试验结果的准确报告。

ObjectiveTodiscuss the methods and precaution of aerobic plate count proficiency testing. MethodsFour methods were tested including pouring plate count agar directly, covering a layer of agar me-dium, adding TTC and using terracotta cover instead of petri dish. Meanwhile, using the early observation, in-creasing the frequency of observation and the time of cultivation to strengthen count accuracy.Results The results showed that the accuracy of results during the pre-cultivation counting was improved, and the missing of slow growing bacteria extending the time of cultivation was also avoided. In addition, it was effective to inhibit the spread of bacteria by culturing with the medium containing 0.5%TTC or using terracotta cover, and these methods did not affect the overall count results.Conclusion It is conductive to get accurate results by variety of methods for aerobic plate count proficiency testing.