Alum is an inorganic substance containing aluminum, which will cause damage to brain nerve cells after being absorbed by the human body, and it is difficult to be excreted by the human body and gradually accumulate. Long-term damage to the body is memory loss, depression and irritability, which can lead to terrible diseases such as "Alzheimer's disease". Eating too much is easy to have diarrhea, and what I bought outside is not clean.
It is suggested that you can try to do it yourself, which is healthy and hygienic. Also, don't eat too much when cooking by yourself, because it may affect the holiday if it gets cold. The sauce mixed with cold noodles is sesame sauce, which is harmless. Don't worry. Therefore, it is recommended to eat less cold rice noodles sold outside.
Cold rice noodles are made of pure natural flour and do not contain any chemical components. Therefore, cold rice noodles themselves are harmless, because it is a simple food. However, the hot sale of cold rice noodles now makes some black-hearted vendors add chemicals to the cold rice noodles to improve the taste, which causes the harm of cold rice noodles. Therefore, resisting dirty cold rice noodles is what we should do.