Handling health certificates is mainly aimed at the staff in catering industry, pharmaceutical industry, water-making industry and beauty industry, aiming at ensuring that they do not carry germs and have an impact on the surrounding people. Stool examination is one of the routine projects, and stool samples are cultured and analyzed to detect whether there are infectious pathogens such as typhoid Bacillus, Vibrio cholerae and Bacillus paratyphi. Infectious diseases, if carried by patients and not treated or controlled in time, will cause infection after contact with food or water and further spread to others.