Thus, any home canned products that shows signs of mold growth should be discarded. The exception to this is jellied products. Jellied products with extensive mold should be discarded. Soak jars for several hours in a solution containing 1 cup of vinegar and 1 gallon of water. Salt is used for flavor only and is not necessary to prevent spoilage.
Sugar is added to improve flavor, help stabilize color, and retain the shape of the fruit.
It is not added as a preservative. Recommended processing methods must be used to assure safety. For best quality, yes. However, some vegetables can be packed raw or cold into jars before processed in the pressure canner. Corn, peas and lima beans are starchy and expand during processing.