Objective To analyze the important influencing factors of total bacterial count in GB 4789.2-2016 systematically. Methods The influence of the difference of pouring temperature (45 ℃ and 50 ℃), processed sample placement time(0-90 min), culture media infusion volume(12-20 mL) and medium brand (7 types, No.A-N) of PCA medium on the count results of total plate count were evaluated using the fresh strains and freeze-dried samples of Escherichia coli ATCC25922, Staphylococcus aureus ATCC6538 and Bacillus subtilis ATCC6633. Results After the treated samples were placed for 90 min, the count results of total colony count were significantly lower than those of 0 min (P=0.023) and 15 min(P=0.021). The results of colony count obtained by using brand B medium were significantly lower than those obtained by using brand F medium (P=0.024). The influence of PCA medium pouring temperature (45 ℃ and 50 ℃) and pour into volume (12-20 mL) for the result of the total number of bacterial colony count was not significant (P>0.05). Conclusion It is necessary to refine the inspection process of the national standard test method for total population of bacterial colonies, develop and introduce reliable reference medium, and highly standardize the inspection process to ensure the stability and reliability of test data.
标题：食品安全国家标准中菌落总数测定方法影响因素分析
英文标题：Influencing factors analysis of the aerobic plate count method in the national standard of food safety
