For many families, it's common to use a pair of chopsticks for several years. Experts have observed under a microscope that the longer chopsticks are used, the higher the number of bacteria. Some restaurants' chopsticks, used for over three years, can harbor as many as 100,000 bacteria, making them a Class 1 carcinogen in our midst.
Theoretically, bamboo and wooden chopsticks should be replaced every 3 to 6 months. Chopsticks used for longer than six months may become breeding grounds for aflatoxin. Aflatoxin is classified as a Group 1 carcinogen by the World Health Organization. Once in the human body, it accumulates most in the liver (5 to 15 times more than in other organs) and therefore poses the greatest risk to liver health. While aflatoxin is indeed a contributing factor to some cases of liver cancer, it requires a certain dose to have an effect, so there is no need to be overly alarmed. Of course, to mitigate this risk, chopsticks should still be regularly replaced or disinfected to maintain hygiene and prevent illness from entering through the mouth.