How to preserve fishball sauce?

Good day! I recently opened my own foodcart. I am selling fishball, siomai and shopao. I am planning to make my own fishball sauce, since i have the recipe that is in my mind. I plan to produce around 5 liters of sauce, that i would be using later on. Probably, i will be using it for almost 3 weeks.

My problem is, how can i preserve it, since it is highly perishable. Without putting it in the ref. thanks!

Salt or vinegar act as preservatives.