Blodgett Robert J
U.S. Food and Drug Administration, HFS-705, Rm 2D-011, 5100 Paint Branch Pkwy, College Park, MD 20740, USA.
J AOAC Int. 2006 Jan-Feb;89(1):166-71.
A serial dilution experiment estimates the microbial concentration in a broth by inoculating several sets of tubes with various amounts of the broth. The estimation uses the Poisson distribution and the number of tubes in each of these sets that show growth. Several factors, such as interfering microbes, toxins, or disaggregation of adhering microbes, may distort the results of a serial dilution experiment. A mild enough distortion may not raise suspicion with a single outcome. The test introduced here judges whether the entire set of serial dilution outcomes appears unusual. This test forms lists of the possible outcomes. The set of outcomes is declared unusual if any occurrence of an observed outcome is on the first list, or more than one is on the first or second list, etc. A similar test can apply when there are only a finite number of possible outcomes, and each outcome has a calculable probability, and few outcomes have tied probabilities.
连续稀释实验通过用不同量的肉汤接种几组试管来估计肉汤中的微生物浓度。该估计使用泊松分布以及每组中显示生长的试管数量。几个因素，如干扰微生物、毒素或附着微生物的解聚，可能会扭曲连续稀释实验的结果。足够轻微的扭曲可能不会因单一结果而引起怀疑。这里介绍的测试判断整个连续稀释结果集是否显得异常。该测试形成可能结果的列表。如果观察到的结果的任何出现位于第一个列表上，或者不止一个位于第一个或第二个列表上等，则结果集被宣布为异常。当只有有限数量的可能结果，并且每个结果都有可计算的概率，并且很少有结果具有相同的概率时，可以应用类似的测试。
