When bean curd is fermented by fermented bean curd, it is easy to be contaminated by microorganisms. protein in bean curd is oxidized and decomposed to produce sulfur-containing compounds, which is harmful to human health if eaten excessively. The content of salt and purine in bean curd is generally high. Patients with hypertension, cardiovascular disease, gout, kidney disease and digestive tract ulcer should eat less or not, so as not to aggravate the condition.