The experiment of wiping the table with a rag shows that the number of bacteria growing on the brand-new rag will be surprising after a week of use at home. In restaurants, food stalls and stalls, the sanitary condition of rags will be worse. Therefore, wipe the table with a rag and clean it before use. The rag should be boiled and disinfected with water every three or four days. Of course, if disposable tablecloths can be used, the harm caused by rags can be avoided.