食品中大肠菌群平板计数结果不确定度的评定

Uncertainty evaluation for plate counts of coliforms in foods

依据国家标准和测量不确定度的评定方法以及国际通行的普松理论(poissontheory),评定食品中大肠菌群检测结果的不确定度。通过分析影响食品中大肠菌群平板计数结果的不确定度来源,建立一种简单适用的大肠菌群平板计数不确定度评定方法。结果表明,影响食品中大肠菌群平板计数结果不确定度的主要因素为取样量的不确定度、稀释倍数的不确定度、加样体积的不确定度、平板上大肠菌群数量的不确定度和煌绿乳糖胆盐(BGLB)肉汤管产气比例产生的不确定度,其中后两者产生的不确定度所占分量最大。

Basing on national standards and evaluation of uncertainty in measure,as well as Poisson theory we evaluated uncertainty in plate counts of coliform group in foods.According to analyzing the resources of uncertainty for plate counts of coliform group in foods,we set up a simple and feasible method for uncertainty evaluation for plate counts of coliform group in foods.The results showed that the major factors of Uncertainty evaluation for plate counts of coliform group in foods were from sample quantity,dilution times,testing volumes of food samples,plate counts of coliform group and the proportion of producing gas in brilliant green lactose bile（BGLB）vessel,in which the last two factors played a dominant role.