I am looking for some help from some people who know something about home preservation of sauces. I am not a chef and have never sold anything, but I make some really good mustard and japanese sauces that I'm interested in bottling and selling at a food market. The problem is that my sauces do not last for longer than a week without preservatives, and there is no market for that... even at a farmers market. I looked into some preservatives such as potassium sorbate and sodium benzoate, which I don't know if A.) that's what I should be using or B.) if it is, what quantities to use. My Japanese sauce has soy sauce as an ingredient which already has potassium sorbate in it... should I just add more? I've heard that using whey preserves mustard up to 3 months, is that true? The help would be greatly appreciated, thank you very much.