大肠菌群检测中应注意的关键问题探讨

Discussion on Key Question Issues in Coliform Detection

目的探讨大肠菌群检测中应注意的三个关键问题。方法糕点和卤肉大肠菌群检测均根据GB/T4789.3-2008《食品卫生微生物检验方法大肠菌群计数》规定的方法。结果糕点和卤肉类固体样品选择稀释度10-1、10-2、10-3检验会出现不合格的结果。双料LST培养基发酵的测定方法和初发酵阳性管的判断会出现假阴性结果。结论固体样品稀释度的选择方法为:100、10-1、10-2。双料LST培养基较为合适的检验方法是:采用150 m l锥形瓶双料培养基发酵法。对于肉与肉制品观察产气不明显的样品,可以用手轻轻打动试管,或者将倒管改进成开口不规则的倒管。

Objective To discuss the three key issues that should be focused on in the process of the detection of coliform bacteria.Methods The coliform test of cakes and braised pork was based on the method provided from GB/T4789.3-2008 Methods of microbiological examination of food hygiene coliform count.Results Failure of the test results would appear when the dilution ratio was specifically chosen to be 10-1,10-2,10-3.Fake negative results will appear with the judgment of fermentation and double LST determination of fermentation medium.Conclusions The choice for the dilution ratio should be 100,10-1,10-2.The proper test method for double LST medium was to apply 150mL Erlenmeyer flask to double LST determination of fermentation medium.As for a solution to the unclear observational result of the samples,the tube can be gently removed or improved the opening of the tube to an irregular inverted one.