In candy-making, almost all recipes that require citrus flavoring (lemon, lime, orange, grapefruit, etc.) can benefit from a little pinch of citric acid, a natural, tart tasting fruit acid in powder form.   It can be used in place of fresh lemon juice and act as a preservative. Substitute a ½ teaspoon of citric acid for 2 tablespoons of lemon juice in every quart of canned goods, such as tomatoes and other vegetables. The citric acid helps to keep the food firm and regulate the pH level to prevent bacteria proliferation. This product is Kosher.