A pressure canner is a specialized kitchen appliance used for preserving low-acid foods, such as vegetables, meats, and poultry. It operates by sealing food in jars and using high pressure and temperature to kill harmful bacteria, ensuring safe long-term storage. This method is essential for preventing foodborne illnesses. Unlike a regular water bath canner, a pressure canner reaches higher temperatures, making it suitable for low-acid foods that require more stringent processing. Proper use of a pressure canner is crucial for maintaining food safety and quality, and it is recommended to follow guidelines from sources like the USDA or National Center for Home Food Preservation.