A look: If you find bamboo chopsticks or wooden chopsticks have non-natural spots, and some even black spots, indicating that the chopsticks are likely to have become mildew, can not continue to use. If it is too white it may be chemically treated. Disposable chopsticks are fumigated with sulphur dioxide and become very white. However, the combination of sulfur dioxide and other substances will become sulfites, and sulfites have been found in the medical community to cause asthma and threaten human health.
Second touch: Chopsticks appear damp, or appear bent, deformed, it means that it has been damp or shelved for too long, it may have passed the shelf life.
Three smells, if the pungent smell of disposable chopsticks must not be used. If there is obvious acidity, it is a sign of contamination or expiration and cannot be used.