Yu Xiaolian wanted to build a Red Sausage Factory. The recipe for the red sausage was in her culinary compendium, consisting of simple ingredients. Although there were no preservatives at that time, Yu Xiaolian had learned a method for meat preservation from Ding Wulang's wife, Zhang, while in Luocheng.
Niter could also be used for meat preservation. Its main component is sodium nitrate, which can keep the meat fresh, red, and prevent deterioration. Zhang's father was a hunter; when he had surplus game that couldn't be consumed immediately, he would turn it into hams for storage. Ham made with niter was red and resistant to maggots, allowing long-term storage.
Aside from niter, ancient people also used salt, lime, plant ash, strong white wine, and various "niter" and "alum" as preservatives. The simplest method was using "glauber salt," sodium sulfate, for tanning leather, making preservation no concern.
