Used cutting boards, first scraping the residues on the cutting board horizontally with a kitchen knife, and then washing with hot water at 95 degrees Celsius or above, can kill more than 80% of the bacteria. However, if it is a cutting board that has just finished cutting meat, hot water is not recommended. Because meat is rich in protein, washing it with hot water will promote bacterial growth. As a result, minced meat will be cooked. Therefore, it is recommended to use cold water first. Supplies can be cleaned. In addition, hot water, such as boiled vegetables, is rich in nutritious soups like meat. It cannot be used to clean the cutting boards, but it will promote the growth of bacteria.