You know, preserved eggs rich in protein and fat are made from a variety of chemical raw materials. Protein and egg yolk contain a lot of soda ash. If you eat preserved eggs alone, the soda ash inside will directly damage the gastrointestinal tract. Therefore, vinegar should be added to neutralize its alkalinity when eating preserved eggs, so as not to harm the gastrointestinal tract. Just don't put too much vinegar, don't stop for a long time, mix it and eat it right away. Otherwise, acetic acid and protein will become hard and white if they stay together for a long time. It tastes bad, too.