Study on the Suitability of the Microbial Limit Test Method for Linglianhua Granules

doi:10.2095-3593.2026.050016

Abstract

Abstract: Objective： To establish and validate a microbial limit test method for Linglianhua granules， providing a basis for accurately assessing microbial contamination in this preparation. Methods：In accordance with General Chapters of the Chinese Pharmacopoeia (2025 edition)， suitability tests for microbial enumeration and tests for specified microorganisms were conducted. For microbial enumeration， the plate count method (dilution 1∶10 to 1∶200) and the plate method containing neutralizers (1% lecithin， 3% polysorbate 80， 0.5% PVP) at dilutions of 1∶10 and 1∶50 were used to determine the recovery rates of Staphylococcus aureus， Pseudomonas aeruginosa， Bacillus subtilis， Candida albicans， and Aspergillus niger. For the tests for specified microorganisms， the conventional method， the medium dilution method， and the neutralizer method were employed to detect bile-tolerant Gram-negative bacteria， Escherichia coli， and Salmonella. Results： Using the plate method， the recovery ratio for the total aerobic bacterial count at a 1∶100 dilution ranged from 0.82 to 1.05， while that for total molds and yeasts at a 1∶50 dilution ranged from 0.82 to 1.05. After applying the neutralizer (at 1∶50 dilution)， the recovery ratios increased to a range of 0.84 to 1.07. In tests for specified microorganisms， bile-tolerant Gram-negative bacteria and Escherichia coli， were detected by both the conventional and neutralizer methods. Salmonella was detectable only with the medium dilution method (10 g+190 mL TSB) or the neutralizer method (10 g+90 mL TSB containing neutralizers)， as inhibition could not be eliminated by the conventional method. Conclusion： The established method was validated and is suitable for the microbiological limit testing of Linglianhua granules. The neutralizer system effectively eliminated antimicrobial effects without introducing toxicity. It is recommended to use the dilution plate method (1∶100) or the neutralizer method (1∶50) for the total aerobic microbial count， and the neutralizer method (1∶50) for the total combined yeasts and molds count. The conventional method was found to be suitable for testing bile-tolerant Gram-negative bacteria and Escherichia coli， whereas Salmonella requires the medium dilution method or the neutralizer method. This method is accurate， reliable， and applicable for product quality control.

Key words: font-size:medium, ">Linglianhua granules； Microbial limit； Method suitability； Antimicrobial activity； Recovery ratio

CLC Number:

LIAO Hui, HE Chanjuan, YANG Hongxi, ZHANG Lu. Study on the Suitability of the Microbial Limit Test Method for Linglianhua Granules[J]. CHINESE JOURNAL OF DRUG EVALUATION, 2026, 43(3): 189-189-195.

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