Abstract: The test method of aerobic bacterial count which is presented in the 2015 edition of the Pharmacopoeia of the People's Republic of China,may be greatly influenced by the color of the test sample.One consequence of that is obtaining false-negative results.A novel method called membrane filtration method was studied.The results of aerobic bacterial count test of colorant given by the novel method were compared with those given by the traditional method.The novel method was found to be accurate and reliable,which met the demands of 2015 edition of the Pharmacopoeia of the People's Republic of China.The membrane filtration method can be used in the determination of the total count pathogenic bacteria.

Key words: toothpaste, colorant, microb analysis, traditional method, membrane filtration method