A worker checks vinegar fermentation at a vinegar plant in Chishui, southwest China's Guizhou Province, Nov. 11, 2019. Chishui maintained a traditional method to make vinegar which has a long history dating back to Ming Dynasty (1368-1644). The raw materials of rice, glutinous rice and Chinese medicinal herb are processed with over 30 steps including steaming, brewing, airing and fermenting. (Xinhua/Yang Ying)