But when you want to make your own, we offer this guide to home canning basics, from Ohio State University. Canning Basics From Ohio State University Methods for canning foods at home have changed greatly since the procedure was first introduced almost two centuries ago. Since then, research has enabled home canners to simplify and safely preserve higher quality foods. Knowing why canning works and what causes food to spoil underscores the importance of following directions carefully. How Canning Preserves Foods Invisible microorganisms are all around us.
All foods contain microorganisms, the major cause of food spoilage.
Using heat to destroy microorganisms, proper canning techniques stop this spoilage. During the canning process, air is driven from the jar and a vacuum is formed as the jar cools and seals, preventing microorganisms from entering and recontaminating the food. It does, however, take a specific amount of heat for a specific amount of time to kill certain bacteria. Low-acid foods, such as vegetables, meat, poultry, and fish, must be pressure canned at the recommended time and temperature to destroy Clostridium botulinum, the bacterium that causes botulism food poisoning. Canning low-acid foods in boiling water canners is absolutely unsafe because 212 degrees F is not high enough to destroy botulinum bacteria.