Methodology Validation Study of Microbial Limit Examination of Qingyi Oral Liquid

OBJECTIVE To establish a method of microbial limit examination of Qingyi oral liquid, ensuring the validity and creditability of results. METHODS According to the method of the 2010 Chinese Paharmacopoeia, microbial limit examination of three batches of Qingyi oral liquid were studied. RESULTS The recoveries of Staphylococcus aureus and Asperqillus niger using plate method were less than 70%, and they were more than 70% while using culture medium dilution method. Escherichia coli were not determined using the method of the Chinese Paharmacopoeia. CONCLUSION The plate method can be used in microbial limit examination of Escherichia coli, Bacillus subtilis and Candida albicans in Qingyi oral liquid, while the culture medium dilution method can be used in microbial limit examination of Staphylococcus aureus and Asperqillus niger.