Preservative: Benzoic acid, benzoic acid and benzoic acid have the effect of accompanying growth, and have no toxic smell, and they are almost non-extensive around them. In weak environmental media, benzoic acid at a concentration of 0.1% can inhibit growth. Growth pH has a great influence on the foaming value and antibacterial effect of benzoate alone, and its effect is obvious in the degrading performance. The best effect is reduced when the pH value is between 2.5 and 4.5.