Effect of peracetic acid–ultraviolet combination treatment on microbial and endotoxin levels in a pharmaceutical water system

In the pharmaceutical industry, the microbiological quality of water is vital. This research investigated how combining peracetic acid (0.1% V/V) and UV light (>150 mJ/cm2) as wide-spectrum disinfectants affect microbial and endotoxin levels in a pharmaceutical water system. Water samples were taken aseptically from 12 points across the system. The pour plate technique and membrane filtration were used for microbial counts. The presence of endotoxin in distilled water samples was investigated by the Limulus amebocyte lysate (LAL) test gel-clot method. After peracetic acid–UV combination treatment, microbial counts of samples significantly decreased (P < 0.05) compared with UV treatment alone, and they were lower than the action limits specified by the European Pharmacopeia (100 CFU/ml for purified water and 10 CFU/100 ml for water for injection). In addition, water samples were mainly LAL-negative (10 negative weekly reports out of 12 total reports). It is concluded that disinfection of all stages of the water system with peracetic acid–UV combination remarkably improved the microbial quality of the water system. Therefore, rotation between more than one disinfectant policy and periodic disinfection of the water system by peracetic acid–UV combination is recommended to minimize contamination of the water system and pharmaceutical products as well as bacterial infections in product consumers.