Salsas are usually mixtures of high acid foods, such as tomatoes and/or fruit, with low acid foods, such as onions and peppers. With the addition of lemon juice, citric acid, or vinegar in the right proportion, salsa becomes a high acid food and can be safely processed in a boiling water canner. However, only research-based recipes should be used. The recipes included in this publication are research-based for safe home canning.