The hyaluronic acid factory currently has a D-level clean area and a D+C (partial A-level) clean area. A rich and professional training content is developed for employees every year, including personnel hygiene, standard operation, and daily maintenance of environmental equipment. Online QA and plant facility maintenance personnel monitor the operating status of the clean area on a daily basis. Full-time personnel regularly assess the clean area environment (settling bacteria, surface microorganisms, suspended particles) every month, and specially hire a third-party organization to monitor and confirm each year.