Even disposable tableware may not be clean, because in fact, many tableware may be packed without cleaning. Otherwise, disposable tableware may have bacteria if it is left for a long time. For example, disposable chopsticks should be used within six months after production, because the shelf life of disposable chopsticks is only four months at the longest. Once the shelf life has passed, it is likely to contain pathogenic bacteria such as Staphylococcus aureus and Escherichia coli.